Sciences for 2016 Third Edition - Kerboodle · PDF fileTeacher Guide GCSE AQA Biology Third edition Series Editor: ... AQA Physics Third edition Jim ... including automarked tests

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Sciences Third EditionAQA

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Biology Third edition

2Ann FullickSeries Editor: Lawrie Ryan

AQA

2

2

Lawrie RyanSeries Editor: Lawrie Ryan

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AQA Chemistry Third edition

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Physics Third edition

2Jim BreithauptSeries Editor: Lawrie Ryan

AQA

Jim Breithaupt

Ann FullickLawrie RyanSeries Editor: Lawrie Ryan

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AQA for Combined Science: Trilogy

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GCSE

Biology for GCSE Combined Science: Trilogy Third edition

2

Ann FullickSeries Editor: Lawrie Ryan

AQA

2Lawrie RyanSeries Editor: Lawrie Ryan

GCSE

AQA Chemistry for GCSE Combined Science: Trilogy Third edition

GCSE

Physics for GCSE Combined Science: Trilogy Third edition

2

Jim BreithauptSeries Editor: Lawrie Ryan

AQA

Jim BreithauptAnn FullickLawrie RyanSeries Editor: Lawrie Ryan

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AQA for Combined Science: Synergy

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New and updated editions of the most trusted resources for AQA GCSE Science

Course Structure

2

Student Book Teacher Handbook Revision Guide Workbook

Biology Separate Sciences

Biology for Combined Science: Trilogy

Chemistry Separate Sciences

Chemistry for Combined Science: Trilogy

Physics Separate Sciences

Physics for Combined Science: Trilogy

Combined Science: Trilogy

Combined Science: Synergy

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AQA

GCSE



AQA

Foundation WorkbookG

CSE



AQA

Revision Guide

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AQA

Higher Workbook

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AQA

GCSE



AQA

Teacher Guide

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AQA

Revision Guide

978 019 835937 1 978 019 835943 2 978 019 835940 1

978 019 835926 5 978 019 835930 2978 019 835934 0978 019 837483 1


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Teacher Guide


GCSE



GCSE


Foundation Workbook


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Revision Guide


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Revision Guide2


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Higher Workbook

978 019 835938 8 978 019 835944 9 978 019 835941 8

978 019 835927 2 978 019 835931 9978 019 835935 7978 019 837484 8

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AQA

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AQA

Teacher Guide

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Physics for GCSE Combined Science: Trilogy

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AQA

Foundation Workbook

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AQA

Revision Guide

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Third edition


AQA

Revision GuideGCSE


Third edition


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Higher Workbook

978 019 835939 5 978 019 835945 6 978 019 835942 5

978 019 835928 9 978 019 835932 6978 019 835936 4978 019 837485 5


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2



GCSE

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Teacher Guide



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Revision Guide

978 019 835925 8 978 019 837486 2 978 019 835929 6


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Workbook

978 019 835933 3


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Covers all speci� cations• A bank of resources including animations, revision podcasts, webquest research tasks, and

interactive activities• Assessment materials, including automarked tests and end-of-chapter tests with formative feedback• Practical resources build the knowledge and skills needed for the new practical exam questions,

with full teacher and technician support• A range of support for maths skills including calculation worksheets, interactives,

and worked examples• Includes access to the Kerboodle Books – online interactive versions of the Student Books

These new editions of AQA GCSE Sciences have been tailored for the new 2016 AQA GCSE (9-1) specifi cations. They support your students with the new more demanding content and increased maths requirements, as well as all required practicals. All Student Books have entered the AQA approval process.

AQA GCSE Sciences Third Edition

3

• Matched to the new specifi cations

Combining the most popular features of both current Oxford courses, these new editions have been tailored specifi cally for the new 2016 specifi cations. Student Books are available to cover the new Biology, Chemistry and Physics specifi cations, Combined Science: Trilogy and Combined Science: Synergy.

• Making assessment and progress tracking easy

AQA GCSE Sciences Third Edition has built-in assessment and progress tracking based on the widely-adopted structure used in Activate for KS3, to support eff ective assessment throughout the new linear courses.

• Supporting students of all abilities Supporting students of all abilities through

the new, more demanding GCSE, with ramped questions for every topic in the Student Books, Foundation and Higher Workbooks, and further support and extension material on Kerboodle.

• Building maths skills Worked examples and practice questions are

incorporated throughout the Student Books and on Kerboodle to support your students with the new increased maths requirement. Kerboodle also has direct links to MyMaths.co.uk, the most popular Maths learning platform in the UK.

• Prepare for the new practicals Practical skills are developed throughout the

Student Books, with specifi c practice for the new practical exam-style questions and a bank of practical activities on Kerboodle.

• Plenty of practice questions Multiple-choice, maths, practical and synoptic

practice questions are included throughout.

• Accompanied by AQA GCSE Sciences Third Edition is accompanied

by Kerboodle, the most popular digital solution for science teaching in the UK, with a bank of online resources to support assessment, diff erentiation, maths skills and the new required practicals.

See page 10 to fi nd out more.

How to evaluateOrder your AQA GCSE Sciences Third Edition Evaluation Pack (978 019 837527 2) online at www.oxfordsecondary.co.uk/aqagcsescience or by emailing [email protected].

Available January 2016.

Worked examples and practice questions are

What’s changing in the specifi cations?

How does AQA GCSE Sciences deliver?

New grades 9 – 1● New GCSEs will be graded 1 – 9, with 9 being

the top grade, to allow greater diff erentiation between students

● Broadly the same proportion of students will achieve grade 4 and above as currently achieve a grade C and above

✓ Student Books and Kerboodle based on a new assessment model matched to the new grades 1–9

✓ Follows on from the widely adopted assessment model used in Activate for KS3

✓ Diff erentiated content throughout

● New topics include human genome in biology, nanoparticles in chemistry and energy and space in physics

✓ Lots of new content written specifi cally for the new topic requirements and submitted to the AQA approval process

✓ Full support for teacher and technicians on Kerboodle and in the easy-to-use Teacher Handbooks

● The new GCSEs will have increased and more challenging mathematical content

● The maths required will be up to the level required for GCSE maths in the corresponding tier

✓ Maths links and worked examples throughout

✓ Maths skills interactives and support sheets on Kerboodle

✓ Kerboodle is the only digital resource for AQA GCSE with direct links to MyMaths.co.uk

● Practical skills will now be assessed by exam only, and the exams will contain questions to draw on students’ understanding and experience of practical experiments

● Each single science GCSE requires a minimum of eight practical activities, and combined science a minimum of sixteen

● At least 15% of the total marks available for each GCSE will be dedicated to scientifi c experimentation questions

✓ Full support for teachers and technicians for all core required practicals

✓ Practical skills developed throughout the Student Books

✓ Bank of practicals on Kerboodle to support the specifi cation and link theory and practice

4

What’s changing?

More demanding content

Increased maths requirement

Practicals

● The new GCSEs will be assessed by exam only, with no controlled assessment components

✓ Plenty of practice questions and auto-marked quizzes to monitor progress

✓ Checkpoint assessment system to help monitor progress and provide specially-targeted follow-up by ability

✓ Revision guides, quizzes and podcasts

Exam-only assessment

Kerboodle is the only digital resource for AQA GCSE

5

Reliable assessment across five years

AQA GCSE Science Third Edition is structured to provide a five-year progress tracking and assessment solution, by building on the assessment principles and pedagogy behind Oxford’s Key Stage 3 course Activate.

The assessment framework that underpins AQA GCSE Science Third Edition is based upon the Programme of Study and new grading structure for Key Stage 4, so it can be used to dovetail any Key Stage 3 course. Schools using Activate will recognise underpinning principles such as the popular progression and assessment model and the Checkpoint assessments and follow-up lessons.

Activate Band

Developing Secure Extending

Level equivalent

3 4 5 6 7 8

Bloom’s Taxonomy

Remembering & Understanding

Application & Analysing

Evaluation & Creating

Activate KS3 Assessment Model

The Checkpoint assessment system assesses students at the end of each chapter, helping to ensure that all students achieve their full potential. Follow-up lessons are provided, with support and extension tasks designed to allow everyone to perform at their best. Use the Checkpoint system for GCSE or all 5 years from Year 7 to Year 11 to ensure all your students make progress and are ready for the challenges of GCSE assessment.

Assessment for learning with our Checkpoint system

New AQA GCSE Assessment Model

The AQA GCSE Assessment Model highlights the most important aspects of new GCSE assessment to inform effective targets, progress, assessment and tracking.

5 Year Progress Tracking and Assessm

ent Framew

ork

Ramped objectives, questions and outcomes throughout

Ramped objectives, questions and outcomes throughout

OUP GCSE Target Target 2 Target 5 Target 8

New GCSE Grades

Old GCSE Grades G F E D C B A A*

1 3 4 6 7 9Grade2

Grade5

Grade8

1918

■ B1 Cell structure and transport

People with cystic fibrosis (see Topic 14.7, Inherited disorders) have thick, sticky mucus in their lungs, gut and reproductive systems. This causes many different health problems and it happens because an active transport system in their mucus-producing cells does not work properly. Sometimes diffusion and osmosis are not enough.

All cells need to move substances in and out. Water often moves across the cell boundaries by osmosis. Dissolved substances also need to move in and out of cells. There are two main ways in which this happens:

●● Substances move by diffusion, down a concentration gradient. This must be in the right direction to be useful to the cells.

●● Sometimes the substances needed by a cell have to be moved against a concentration gradient, across a partially permeable membrane. This needs a special process called active transport.

Moving substances by active transportActive transport allows cells to move substances from an area of low concentration to an area of high concentration. This movement is against the concentration gradient. As a result, cells can absorb ions from very dilute solutions. It also enables them to move substances, such as sugars and ions, from one place to another through the cell membranes.

It takes the breakdown of ATP to provide the energy for the active transport system to carry a molecule across the membrane and then return to its original position (see Figure 1). The ATP needed for active transport is produced during cell respiration. Scientists have shown in a number of different cells that the rate of respiration and the rate of active transport are closely linked (see Figure 2).

In other words, if a cell is making plenty of ATP, it can carry out lots of active transport. Examples include root hair cells in plants and the cells lining your gut. Cells involved in a lot of active transport usually have many mitochondria to provide the ATP they need.

The importance of active transportActive transport is widely used in cells. There are some situations where it is particularly important. For example, mineral ions in the soil, such as nitrate ions, are usually found in very dilute solutions. These solutions are more dilute than the solution within the plant cells. By using active transport, plants can absorb these mineral ions, even though it is against a concentration gradient (see Figure 3).

Sugar, such as glucose, is always actively absorbed out of your gut and kidney tubules into your blood. This is often done against a large concentration gradient.

Learning objectivesAfter this topic, you should know:

●● how active transport works●● the importance of active transport

in cells.

B1.9 Active transport

transport proteinrotates and releasesmolecule inside cell(using ATP fromrespiration to supplythe energy needed)

transport proteinrotates back again(often using ATP fromrespiration)

useful molecule

transport protein

outside cell inside cell

Figure 1 Active transport uses the energy released when ATP changes to ADP (by releasing phosphate) to move substances against a concentration gradient

Figure 3 Plants use ATP from respiration in active transport to move mineral ions from the soil into the roots against a concentration gradient

0 rate of respiration

rate

of a

ctiv

e tr

ansp

ort

Figure 2 The rate of active transport depends on the rate of respiration

mineral ions in soil –low concentration

mineral ions in plant –higher concentration

mineral ions movedinto plant against aconcentrationgradient

●● Active transport moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient)

●● Active transport uses ATP from respiration to provide the energy required.

●● Active transport allows plant root hairs to absorb mineral ions required for healthy growth from very dilute solutions in the soil against a concentration gradient.

●● Active transport enables sugar molecules used for cell respiration to be absorbed from lower concentrations in the gut into the blood where the concentration of sugar is higher.

Key points

Synoptic linkTo help you to understand how the root hair cells in plants are adapted to their functions see Topic B1.5.

Study tipDo not refer to movement along a concentration gradient. Always refer to movement as down a concentration gradient (from higher to lower) for diffusion or osmosis and against a concentration gradient (from lower to higher) for active transport.

1 Describe how active transport works in a cell.

2 a Describe how active transport differs from diffusion and osmosis.b Explain why cells that carry out a lot of active transport also

usually have many mitochondria.

3 Explain fully why active transport is so important to:

a marine birds such as albatrosses, which have special salt glands producing very salty liquid

b plants.

Synoptic linksYou can find out more about the absorption of glucose in the gut in Topic B4.6 and about the absorption of solutes in the kidney in Topic B12.3.

For example, glucose is needed for cell respiration so it is important to get as much as possible out of the gut. The concentration of glucose in your blood is kept steady, so sometimes it is higher than the concentration of glucose in your gut. When this happens, active transport is used to move the glucose from your gut into your blood against the concentration gradient.

Figure 4 Some crocodiles have special salt glands in their tongues. These remove excess salt from the body against the concentration gradient by active transport. That’s why members of the crocodile species Crocodylus porosus can live in estuaries and even the sea

835937_AQA_GCSE_Biology SB_Ch01.indd 18-19 8/13/15 6:15 PM

Learning objectives are laid out at the start of each topic

Study tips reinforce students’ learning

6

Student Books

New accessible Student Books that help build students’ maths, literacy and working scientifi cally skills, with diff erentiated practice questions matched to the innovative assessment model designed for the new GCSE 9-1 grading. Available for Biology, Chemistry, Physics, Combined Science: Trilogy and Combined Science: Synergy.

All Student Books have entered the AQA approval process.

Synoptic links are highlighted throughout to give a rounded understanding and help students make links between topics

transport is produced during cell respiration. Scientists have shown in a number of different cells that the rate of respiration and the rate of active

In other words, if a cell is making plenty of ATP, it can carry out lots of active transport. Examples include root hair cells in plants and the cells lining your gut. Cells involved in a lot of active transport usually have

The importance of active transportActive transport is widely used in cells. There are some situations where it is particularly important. For example, mineral ions in the soil, such as nitrate ions, are usually found in very dilute solutions. These solutions are more dilute than the solution within the plant cells. By using active transport, plants can absorb these mineral ions, even though it is against

Sugar, such as glucose, is always actively absorbed out of your gut into your blood. This is often done against a large

against a concentration gradient

1918













in cells.




useful molecule

transport protein





rate

of a

ctiv

e tr

ansp

ort









Key points








b plants.





Key points are summarised at the end of each double-page spread

Ramped summary questions on every spread to embed students’ understanding

76

Maths for Science GCSEHow big is a bacterium? How far away is the Moon? And what is the size of a nanoparticle?

Scientists use maths all the time – when collecting data, looking for patterns, and making conclusions. This section will help support the mathematical skills you will need for your GCSE science courses. There are also many opportunities to practise using maths in science throughout the student books.

Quantities and unitsSI Units (BCP)When you make a measurement, or calculate a physical quantity, you need both a number and a unit.

You will use the SI system of units. There are seven base units. All other units are derived from these base units.Figure 1 How big is bacterium

Table 1 The six base units you will encounter in your GCSE science courses

Quantity Base Unitdistance metre, mmass kilogram, kgtime second, s,current ampere, Atemperature kelvin, Kamount of substance

mole, mol

Quantity Derived Unitfrequency hertz, Hzforce newton, Nenergy joule, Jpower watt, Wpressure pascal, Pacharge coulomb, Celectric resistance ohm, Ω

Table 2 Some examples of other quantities and their units

Figure 2 Time is measures in seconds

For example, 32 seconds is an example of a measurement. The number 32 is not a measurement because it does not have a unit.

Some quantities that you calculate do not have a unit because they are a ratio, for example, magnification or refractive index.

Using units in equations (BCP)When you put quantities into an equation it is best to write the number and the unit. This helps you to work out the unit of the quantity that you are calculating.

Step 2: Write down the equation you need.

speed = distance

Step 3: Do the calculation and include the units.

speed = 100 m = 10 m/s

time

Worked example: Speed = distance ÷ timeA sprinter can run 100 m in 10 s. Calculate the speed of the sprinter.

Step 1: Write down what you know.

distance = 100 m time = 10 s

10 s

Study tipThe / in a unit means ‘per’. So the unit m/s means ‘metres per second’.

Standard form (BCP)In science numbers can be very large, like the distance from the Earth to the Sun, or very small, like the size of an atom or a virus. In standard form you can write numbers with one non-zero digit in front of the decimal place, multiplied by the appropriate power of ten. The power of ten can be positive or negative.

For example, you can write:

● 1000 metres as 1.0 ×103 m

● 0.1 s as 1.0 ×10−1 s

● 20 000 Hz as 2 × 10 Hz

● 0.0005 kg as 5 × 10−4 kg

This means that:

● the distance from the Earth to the Sun = 150 000 000 000 m = 1.5 ×1011 m

● the diameter of an atom is 0.000 000 000 1 m = 1.0 × 10−10 m.

● the diameter of a red blood cell is around 0.000 007 m = 7 × 10 −6 m

Many of the physical constants you will use are written in standard form. For example:

● the speed of light = 3 × 108 m s−1.

● Avagadro’s constant = 6.022 × 1023

Scientific calculators have a button to use when you are calculating with numbers in standard form. Work out which button you need to use (it could be EE, EXP, 10x, ×10x).

Multiplying numbers in standard formWhen you multiply two numbers in standard form together you add the powers of ten. When you divide two numbers you subtract the power of ten of the second number from the power of ten of the first. For example

● 102 × 103 = 10(2 + 3 = 5) = 105 or 100 000

● 102 ÷ 104 = 10(2 – 4 = −2) = 10−2 or 0.01

Figure 3 The Sun is 1.5 × 1011m from the Earth

Study tipNote that 1.0 ×103 m is the same as 103 m.

Figure 4 These red blood cells have a diameter of around 7.0 × 10-6 m

Figure 5 You need a scientific calculator to do calculations involving standard form

8382

■ P1 Forces in balance

Cyclists know that it is more difficult to travel uphill than it is to travel on a flat road (Figure 1). The reason is that the weight of the cyclist and the bicycle has a downhill effect. To understand this effect, consider a small box on a slope as shown in Figure 2. The weight of the box as a force vector is shown by the line labelled OB. You can think of the force vector as two parts or components – one force component acting down the slope, and the other force component acting perpendicular or normal to the slope. The process of looking at force in this way is called resolving a force into two components and is carried out as follows:

●● A rectangle OABC is drawn on Figure 2 with the weight as the vertical diagonal OB and the sides parallel and perpendicular to the slope.

●● Side OA of the rectangle on the slope gives the component of the weight acting down the slope. The box stays at rest on the slope and does not slide down, because friction acts on it. The component of weight acting down the slope is too small to overcome this frictional force. For the cyclist on an uphill road, the component of weight acting down the slope is the amount of force that has to be overcome to keep moving up the hill.

●● Side OC of the rectangle OC gives the component of the weight acting normal to the slope. This is the force pressing on the slope due to the box.


●● what is meant by resolution of a force●● how to resolve a force●● about the forces on an object in

equilibrium●● how to use a force diagram to work

out whether or not an object is in equilibrium.

P1.9 Resolution of forces

●● Resolving a force means finding perpendicular components that have a resultant equal to the force.

●● To resolve a force in two perpendicular directions, draw a rectangle with adjacent sides along the two directions so that the diagonal represents the force vector.

●● For an object in equilibrium, the resultant force is zero.

●● An object is in equilibrium if the resultant force on it is zero and the object is not moving.

Key points

Figure 1 Cyclists on an uphill road

Figure 2 Resolving a force

weight

box

90°

O

A

B

C

parallelcomponent

perpendicularcomponent

slope

Test an inclineUse the arrangement in Figure 3 to measure the force F needed to keep a trolley in the same position on the inclined board.

Figure 3 Testing an incline

inclined board

trolley

newtonmeter

1 Use a newtonmeter to measure the weight W of the trolley and the force F.

Add weights to the trolley to find out how F changes as the weight of the trolley is increased.

2 Repeat the test with the board at a different angle to the laboratory bench.

Record all your measurements in a table, and plot a graph of your results.

●● Write your conclusions from your measurements.

EquilibriumAn object at rest is said to be in equilibrium. The key conditions for an object to be in equilibrium are:

●● The resultant force on the object is zero

●● The forces acting on the object have no overall turning effect.

To work out whether or not an object is in equilibrium:

●● If the lines of action of the forces are parallel, the sum of the forces in one direction must be equal to the sum of the forces in the opposite direction. This means that the resultant force on the object is zero.

●● If the lines of action of the forces are not all parallel, the forces can be resolved into two components along the same perpendicular lines. The components along each line must balance out if the resultant force is zero.

Higher

12kN

10˚

Figure 4 Car parked on an uphill road

Figure 5

12kN

10˚

1 An aircraft in level flight is travelling due east at a constant speed when it is acted on by a horizontal wind force of 800 N as shown in Figure 6. By resolving the wind force into two perpendicular components, determine the component of the wind force along the line in which the aircraft is moving.

2 A student pushed a trolley of weight 510 N up a slope that is inclined at 15° to the horizontal.a Determine the component of the trolley’s weight down the slope.b The force exerted by the student was greater than the answer to

part a. Give one possible reason for this difference.3 Explain why a ladder placed against a wall would slide down the

wall if the floor was too slippery.

4 A box of weight 50 N is at rest on a slope. The slope is at an angle of 30° to the horizontal as shown in Figure 7,a Copy the diagram and find the components of the weight parallel

and perpendicular to the slope.b Describe the friction between the box and the slope.

wind force = 800N

30˚

Figure 6 Aircraft in level flight

30˚

W = 50N

Figure 7 Box resting on a slope

Worked exampleA car of weight 12 kN is parked on an uphill road. The road is inclined at an angle of 10° to the horizontal as shown in Figure 4.

a Use a geometrical method to find the component of the car’s weight acting down the slope.

b Describe the force of friction of the road on the car tyres.

Solutiona See Figure 5. The ratio of the rectangle’s small side to the

diagonal = 1 : 6.0. Therefore, the parallel component of the weight = 12/6 kN = 2.0 N.

b The frictional force = 2.0 N acting up the slope.

835939_AQA_GCSE_Physics SB_Ch01.indd 82-83 8/13/15 12:21 PM

Practical skills boxes provide further context to develop understanding

7All Student Books have entered the AQA approval process.

Worked examples are incorporated throughout to support your students with the required maths

Teacher Handbooks

18 19


AQA spec Link: 1.3.3 Active transport moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient). This requires energy from respiration.

Active transport allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soil. Plants require ions for healthy growth.

It also allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration. Sugar molecules are used for cell respiration.

Target Outcome (Level) Checkpoint

Question Activity

Securing GRADE 2

Define active transport as the movement of a substance against a concentration gradient using energy.

1 Starter, Plenary 1

Identify where active transport takes place. Starter 1, Main 1,

Use a representational model to show active transport. Main 2

Securing GRADE 5

Explain why active transport is important for living organisms. 3, end of chapter question 5

Starter, Main 1

Explain the differences between diffusion, osmosis, and active transport.

2, end of chapter question 5

Starter 1, Plenary 1

Suggest some improvements/limitations to a representational model that shows active transport.

Main 2

Securing GRADE 8

Describe how active transport takes place. 2 Main 1

Suggest how a cell that carries out active transport is adapted to this function.

Plenary 2

Design and evaluate a representational model to show active transport.

Main 2

MathsStudents can consider the difference in concentration between mineral ions in the soil and inside the root cells. They can use this to calculate the difference in orders of magnitude.

Students can consider the difference in LiteracyStudents extract information from the Student Book to find out where active transport is used in humans and explain why it is important. They work in groups and follow instructions to model active transport.

Key Wordsactive transport, kidney tubulesStudents extract information from the

Starter Support/Extend Resources

Absorption of mineral ions (5 min) Show the class an unlabelled diagram showing active transport in plant roots and ask them why mineral ions cannot move from the soil into the roots via diffusion. Reveal the labels and explain that mineral ions have to move from a low to high concentration (against the concentration gradient). A process called active transport is used which requires energy.

Plant roots (10 min) Ask students to write down what substances move into roots from the soil. Then ask them what process moves water into the plant roots. Explain that osmosis is used because water is travelling from a high to low concentration. Explain that mineral ions cannot move into roots via diffusion because they are very dilute in the soil. Because they have to move from a low to high concentration of mineral ions (against the concentration gradient) a process called active transport is used which requires energy.

Support: Display the labels on the diagram from the start.

Extend: Share with students the difference in concentration of mineral ions: 10 µmol/dm3 in the soil and 100 m mol/dm3 in the cell. Ask them to work out the difference in order of magnitude.

Main Support/Extend Resources

Active transport (20 min) Show the class a video or animation of active transport and ask them to write down an outline of what they learnt.

Ask them to use the information in the corresponding Student Book spread to find one example of where active transport is used in humans and why it is important.

Modelling active transport (20 min) Students work in small groups to carry out a model of active transport. Ask for a couple of groups to demonstrate their model, while the rest evaluate its effectiveness and comment on possible improvements.

Extend: Ask students to explain why respiration is needed for active transport.

Extend: Students devise their own model.

Activity: Modelling active transport

Plenary Support/Extend Resources

Exchange of materials (10 min) Give students a series on osmosis, diffusion, and active transport. Students identify which statements relate to which process.

Active transport (10 min) Students label a diagram of active transport then match some key words relating to active transport to their definitions.

Extend: Include some statements that are incorrect and have students correct them as well as assigning them to a process.

Interactive: Active transport

Homework

Ask students to find out why increasing the amount of oxygen available to plant roots increases growth. This can be linked to using aeration in hydroponics.


1918













in cells.




useful molecule

transport protein





rate

of a

ctiv

e tr

ansp

ort









Key points








b plants.




AQA GCSE Early Start Pack TG_Biology Ch01.indd 18-19 8/13/15 7:33 PM

The Teacher Handbooks provide a page-by-page match to the Student Books, with support for your teaching including lesson plans, diff erentiation suggestions and assessment guidance. Use the Teacher Handbooks alongside the Student Books for Biology, Chemistry, Physics, Combined Science Trilogy and Combined Science: Synergy.

Curriculum links match each Student Book spread to the speci� cation

Differentiated lesson outcomes, maths and literacy links and ideas for support and extension Full lesson plans with

starters, plenaries and homework suggestions are provided

8

9

Revision Guides and Student Workbooks will be available from Summer 2016. Find out more at www.oxfordsecondary.co.uk/aqagcsescience.

Also available

92 93

■ P2 Motion

AQA spec Link: 1.6.1 The speed of an object can be calculated from the gradient of its distance–time graph.

If an object is accelerating, its speed at any particular time can be determined by drawing a tangent and measuring the gradient of the distance–time graph at that time.

The acceleration of an object can be calculated from the gradient of a velocity–time graph. The distance travelled by an object can be calculated from the area under a velocity–time graph.

The following equation applies to uniform motion:

(final velocity)2 − (initial velocity)2 = 2 × acceleration × distance [v2 − u2 = 2 a s]

final velocity v in metres per second, m/s; initial velocity u in metres per second, m/s; acceleration a in metres per second squared, m/s2; distance s in metres, m

P2.4 Using graphs

Starter Support/Extend Resources

Graph matching (10 min) The students have to match the description of the movement of objects with distance–time and velocity–time graphs. Provide three different descriptions of journeys and three graphs that represent the movement for the students to match them with.

Extend: Use similar graphs and ensure the descriptions contain similar numerical values.

Plot (10 min) Give the students a set of velocity–time data for a moving object, and ask them to plot a graph of displacement against time. Check the graphs for accuracy of plotting and clear labelling of the axes.

Support: Provide partially completed graphs to add points to.

Main Support/Extend Resources

Using distance–time graphs (15 min) Lead the students through the process of determining the gradient of a line using tangents. Ensure the students can identify when the object is speeding up and when it is slowing down clearly. Students should find some velocities from example graphs to ensure they have mastered the technique.

Velocity–time graphs (15 min) Discuss finding acceleration from velocity–time graphs, making sure that students are aware of the difference between this type of graph and the earlier distance–time graph.

Ask the students to analyse a few graphs and find acceleration using the gradient.

Extend: The tangent techniques can be used to find the acceleration when objects are not accelerating uniformly.

Activity: Velocity–time graphs

Velocity-time graphs and distance travelled (10 min) Recap the idea that the area beneath the line on the graph represents the distance travelled. This can now be linked to the mathematical equations which find the area of the shapes, noting that these are a product of the velocity and the time. Students then discuss the origin of this equation of motion (v 2 = u2 + 2as). Adding the area of the triangle and the rectangle together will lead to the expression.

Extend: The students can be led through the derivation, and this can reinforce their understanding of it.

An equation of motion (10 min) Students should discuss the origin of this equation of motion (v 2 = u2 + 2as), which derived from the last part of the previous activity.

Extend: The students can be led through the derivation, and this can reinforce their understanding of it.

Plenary Support/Extend Resources

Dynamic definitions (10 min) The students should provide detailed definitions of speed, velocity, distance, displacement, and acceleration, including how they are represented on graphs.

Support: Students should be provided with definitions to match up with the key terms.

Motion graphs and velocity (10 min) Students answer true or false statements on velocity, then identify velocity–time graphs.

Extend: Students correct the false statements..

Interactive: Motion graphs and velocity

Homework

The students have completed their look at graphs of motion and so should attempt a series of more formal questions to check their progress and identify areas to develop.

Support: Select appropriate levels of questions for the students.

Target Outcome (Level) Checkpoint

Question Activity

Securing GRADE 2

Identify speed on a distance–time graph using change in gradient. 2 Starter 1, Main 1

Identify acceleration on a velocity–time graph using change in gradient. 2 Main 2

Calculate the distance travelled by an object at constant velocity using data extracted from a graph.

Main 3

Securing GRADE 5

Calculate the speed of an object by extracting data from a distance–time graph.

1 Main 3

Use a tangent to determine the speed of an object from a distance–time graph.

Main 2

Use the equation v2 − u2 = 2as in calculations where the initial or final velocity is zero.

4 Main 4

Securing GRADE 8

Calculate the acceleration of an object by extracting data from a velocity–time graph.

3 Main 2

Use the gradient of a velocity–time graph to determine the acceleration of an object.

3 Main 2

Apply transformations of the equation v2 − u2 = 2as in calculations involving change in velocity and acceleration where both velocities are non-zero.

4 Main 4

MathsThe students will be using tangents of lines to determine gradients leading to speed or acceleration. They will find the area of shapes to determine the distance travelled. Students will also use equations describing the motion of objects under constant acceleration.

The students will be using tangents of LiteracyConversion between graphs and descriptions of graphs is crucial in this lesson, and scientific language development should be focussed in this area.

Key WordsTangent, acceleration, gradient, speed, velocity, distance

Title Cardboard graphs

Equipment Cardboard pieces in rectangles, triangles, and squares. The pieces could be cut from card with a grid pattern printed on it to make the activity easier.

Overview of method Students can construct graphs from the cut-out shapes, placing them together in different combinations onto a grid background. This will allow them to analyse the area of the graph, leading to distance travelled for velocity–time graphs.

Safety considerations None applicable.

Practical

9392

■ P2 Motion

Using distance–time graphsFor an object moving at constant speed, you saw at the start of this chapter that the distance–time graph is a straight line sloping upwards.

The speed of the object is represented by the gradient of the line. To find the gradient, you need to draw a triangle under the line, as shown in Figure 1. The height of the triangle represents the distance travelled, and the base of the triangle represents the time taken. So:

the gradient of the line = the height of the triangle

the base of the triangle

and this represents the object’s speed.

For a moving object with changing speed, the distance–time graph is not a straight line. The red line in Figure 2 shows an example.


●● how to calculate speed from a distance–time graph:– where the speed is constant– where the speed is changing.

●● how to calculate acceleration from a velocity–time graph

●● how to calculate distance from a velocity–time graph.

P2.4 Using graphs

Study tipMake sure that you know whether you are dealing with a distance–time graph or a velocity–time graph. The gradients of these two types of graph represent different quantities.

●● The speed of an object moving with constant speed is given by the gradient of the line on its distance–time graph.

●● The acceleration of an object is given by the gradient of the line on its velocity–time graph.

●● The distance travelled by an object is given by the area under the line of its velocity–time graph.

●● The speed of an object moving at changing speed is given by the gradient of the tangent to the line on its distance–time graph.

Key points

0 2 4time in seconds, s

dist

ance

in m

etre

s, m

6 8 10

160

120

80

40

0

Figure 1 A distance–time graph for constant speed

Figure 2 A distance–time graph for changing speed

0 5 10time in seconds, s

15 20

200

160

120

80

40

0

dist

ance

in m

etre

s, m

12

tangent

11s

130m

at time = 12 s,

gradient of triangle = heightbase

speed = gradient of triangle = = 11.8 m/s130m11s

Using velocity–time graphsFigure 3 shows the velocity–time graph of an object moving with a constant acceleration. Its velocity increases at a steady rate. So the graph shows a straight line that has a constant gradient.

To find the acceleration from the graph, remember that the gradient of the line on a velocity–time graph represents the acceleration.

In Figure 3, the gradient is given by the height divided by the base of the triangle under the line. The height of the triangle represents the change of velocity, and the base of the triangle represents the time taken.

So the gradient represents the acceleration, because:

acceleration = change of velocity

time taken

0

18

16

14

12

8

10

6

4

2

02 4 6

time in seconds, s

velo

city

in m

etre

s pe

r se

cond

, m/s

8 10

Figure 3 A velocity–time graph for constant acceleration

To find the distance travelled from the graph, remember that the area under a line on a velocity–time graph represents the distance travelled. The shape under the line in Figure 3 is a triangle on top of a rectangle. So the distance travelled is represented by the area of the triangle plus the area of the rectangle under it. Prove for yourself that the triangle represents a distance travelled of 40 m and that the rectangle also represents a distance of 40 m.

1 a Work out the speed of the object in the graph in Figure 1. b Describe how the speed changes in the graph of Figure 2.

2 The graph in Figure 4 shows how the velocity of a cyclist on a straight road changes with time.a Describe the motion of the cyclist.

b Use the graph in Figure 4 to work out the acceleration of the cyclist and the distance travelled in:i the first 40 s ii the next 20 s.

c Calculate the average speed of the cyclist over the journey.

3 In a motorcycle test, the speed from rest was recorded at intervals in a table (Table 1).

Time (seconds, s) 0 5 10 15 20 25 30

Velocity (metres per second, m/s) 0 10 20 30 40 40 40

Table 1 Motorcycle test results

a Plot a velocity–time graph of these results. b Calculate the initial acceleration. c Calculate how far the motorcycle moved in:

i the first 20 s ii the next 10 s.4 Use the data in Question 3 and the equation v2 = u2 + 2as to

calculate the velocity of the motorcycle after 1.0 km from the start if it had kept the same acceleration as it had during the first 20 s.

time in seconds, s

velo

city

in m

etre

spe

r se

cond

, m/s

0 10 20 30 40 50 60

9876543210

Figure 4

AccelerationUse the graph in Figure 3 to find the acceleration of the object.

SolutionThe height of the triangle represents an increase of velocity of 8 m/s (= 12 m/s − 4 m/s).

The base of the triangle represents a time of 10 s.

So the acceleration = change of velocitytime taken

= 8 m/s10s

= 0.8 m/s2

Distance, velocity, and accelerationIn Figure 3, the total distance travelled is 80 m, and the time taken t is 10 s. So the average velocity is 8 m/s, which is equal

to 12

(u + v), where the initial velocity u = 4 m/s, and the final

velocity = 12 m/s. So the distance travelled s = 12

(u + v) × t.

Because the acceleration a = v − ut

, then

a × s = v − ut

× 12

(u + v) × t = 12

(v2 − u2)

Rearranging this equation gives v2 − u2 = 2asThis equation is useful for calculations where the time taken is not given. You do not need to know how to prove this equation.

Higher Tier

In Figure 2, the gradient of the line increases, so the object’s speed must have increased. You can find the speed at any point on the line by drawing a tangent to the line at that point, as shown in Figure 2. The tangent to the curve is a straight line that touches the curve without cutting through it (in this case at 12s). The gradient of the tangent is equal to the speed at that point.

AQA GCSE Early Start Pack TG_Physics Ch02.indd 92-93 8/13/15 8:22 PM

Higher Tier learning outcomes and curriculum links are highlighted in bold

Building practical skillsKerboodle practicals build the knowledge and skills needed for the new practical exam questions. Kerboodle covers all of the new required practicals and more, with full teacher and technician support.

P1, Topic 1.2 P1, Topic 1.2

AQA Physics GCSE Teacher practical Name ............................................................................... Class ..................... Date ........................

© Oxford University Press 2015 This resource sheet may have been changed from the original.

1

Resultant forces and their effects Aims In this worksheet students will apply their knowledge and understanding of zero and non-zero resultant (balanced and unbalanced) forces. They will gain confidence in interpreting force diagrams and in describing the effects of force on

different objects. They will reinforce and familiarize themselves with more complex calculations of resultant forces from two or more forces applied on different objects.

Learning outcomes ¥ be able to label forces acting on an object ¥ be able to draw a free body diagram ¥ calculate the resultant force acting on an object ¥ explain how the resultant force affects the motion of the object. Teacher notes

Question 1 serves as a good opportunity to support the teaching of resultant forces and

their effect on stationary and moving objects. It can also help to address some common

misconceptions, such as the effect of a resultant backward force on an object moving

forward. Some students believe the force will immediately cause an object to reverse,

whereas the effect is to decelerate, stop and then start reversing the object. The questions are increasingly difficult and offer a natural differentiation of work for pupils of

different abilities. For a less able class you may wish to use questions 1 and 2 only. Answers 1 a i Left arrow: Braking force (friction between brake and wheel)

(1)

Right arrow: Driving force

(1)

ii Forces are equal in size and opposite in direction. (1)

iii The motorbike will not move/will stay stationary. (1)

b i The motorbike will start moving forward

(1)

ii Drag/air resistance/friction between tyre and road (1)

iii At constant speed/velocity

(1)

iv Maximum 3 marks There is no longer a driving force.

(1)

The drag force is still large, and the braking force increases. (1)

Overall there is a resultant backward force, which will cause the motorbike to slow down until it stops.

(1)

The drag force gradually reduces as the motorbike slows. (1)

Maths skills support

B1, Topic 1.1 B1, Topic 1.1AQA Biology GCSE Student calculation sheet

Name ...............................................................................

Class ..................... Date ........................

© Oxford University Press 2015

This resource sheet may have been changed from the original.

1

Magnification calculations

Specification references: 3.1.1.5

Aims The aim of this activity is to carry out calculations involving magnification, real

size, and image size. You should be able to:

¥ recognise and use expressions in decimal form

¥ recognise expressions in standard form

¥ make order of magnitude calculations

¥ change the subject of an equation.

Learning outcomes

After completing this activity, you should be able to:

¥ use a light microscope

¥ calculate total magnification

¥ use the formula: magnification =image size

specimen size

¥ measure the size of cells.

Introduction Most cells are very small and can only be seen through a microscope. The cell

image that you see through the microscope will be much larger than the object is

in real-life and so it can be hard to imagine exactly how small it actually is.

However, if we know the magnification of the microscope then we can use the

image size to calculate the actual size of the cell using the following formula:

Specimen size =image size

magnification

We can also rearrange this equation so that, if we need to, we can work out what

the image size will be or what the magnification of the microscope is. These two

equations are: Image size = magnification× specimen size

Magnification =image sizespecimen

Maths calculation worksheets provide worked solutions and ramped practice questions.

P1, Topic 1.2 P1, Topic 1.2AQA Physics GCSE Student practical

Name ...............................................................................

Class ..................... Date ........................



2

(1)

b These questions are about the effects of resultant forces.

i The biker now releases the front brake. Describe how the motion of the

bike changes in this situation. (1)

ii A different backward force will now act on the bike. Name this force.

(1)

iii Eventually, the backward force becomes equal to the forward force.

How does the motorbike move now? (1)

iv The biker approaches a red traffic light. Explain how the forces acting

on the motorbike will change as the biker releases the throttle and

applies the brakes, and what effect these forces will have on the

motion of the bike.

(3)

Answers1

P1, Topic 1.2 P1, Topic 1.2

AQA Physics GCSE Student practical Name ............................................................................... Class ..................... Date ........................


3

2 Look carefully at the forces applied on the plane below and answer the following questions.

These questions are about the effects of resultant forces on an object. a Label all the forces acting on the plane with a suitable name.

(4) b The plane is flying along a horizontal line. Describe the motion of the plane

in this situation.

(1) c How should the vertical forces change, if the plane were to change direction to a diagonal downward line? Explain your reasoning.

(1) d Calculate the horizontal resultant force on the plane.

(1)


These questions are about the effects of resultant forces on an object. Label all the forces acting on the plane with a suitable name.The plane is flying along a horizontal line. Describe the motion of the plane

How should the vertical forces change, if the plane were to change direction to a diagonal downward line? Explain your reasoning.

Calculate the horizontal resultant force on the plane.

These questions are about the effects of resultant forces.

The biker now releases the front brake. Describe how the motion of the

A different backward force will now act on the bike. Name this force.

Eventually, the backward force becomes equal to the forward force.

The biker approaches a red traffic light. Explain how the forces acting

on the motorbike will change as the biker releases the throttle and

applies the brakes, and what effect these forces will have on the

P1, Topic 1.2 P1, Topic 1.2AQA Physics GCSE Student practical Name ............................................................................... Class ..................... Date ........................

© Oxford University Press 2015 This resource sheet may have been changed from the original. 1

Resultant forces and their effects

Specification references: 1.1 b)

Learning outcomes ¥ be able to label forces acting on an object ¥ be able to draw a free body diagram ¥ calculate the resultant force acting on an object ¥ explain how the resultant force affects the motion of the object.

Setting the scene In this exercise you will look at the forces acting on objects and describe how they affect their motion. By drawing free body diagrams you can work out the resultant force acting on the object.

Remember that forces in equilibrium do not change the motion of the object, but that resultant forces can cause the object to accelerate, decelerate or change direction.

Since forces have a direction, to sum two forces pointing in opposite directions you will need to take away the smaller force from the bigger force.

Questions 1 Look at the diagram below. The biker has put the bike in gear and he is turning

the throttle slowly, but he is also applying the front brake so the bike is not yet moving.

a These questions are about the effects of forces in equilibrium.

i Label the two forces acting on the motorbike in the above diagram.

(2)

ii The two forces on the motorbike are in equilibrium. Explain what this means.

(1)

iii Describe what will happen to the motorbike if these two forces remain in equilibrium.

1

Maths skills interactives include step-by-step worked solutions and practice questions with feedback, as well as exclusive links to MyMaths.co.uk

Practical worksheets with differentiated questions for all core practicals and more

A Level Physics for OCR A Kerboodle

The UK’s most popular digital solution for AQA ScienceAQA GCSE Sciences Third Edition Kerboodle provides unrivalled digital support for the new 2016 AQA GCSE Science (9-1) specifi cations, with a bank of resources, activities and an online assessment package.

10

Student method sheets guide students through each activity step-by-step

Teacher and technician notes provide detailed guidance and example data for each practical

To request a free in-school Kerboodle demo, email [email protected] or contact your local Educational Consultant using www.oxfordsecondary.co.uk/repfi nder.

11

Prepare for the linear exam

P1, Topic 1.2 P1, Topic 1.2AQA Physics GCSE Student worksheet

Name ...............................................................................

Class ..................... Date ........................



1

What is the resultant force? Summing forces acting

on objects

Task In this exercise you will look at free body diagrams and use them to work out the

resultant force on a runner.

Remember that forces have a direction, so to find the resultant force of two forces

pointing in opposite directions you will need to take away the smaller force from

the bigger force.

Questions 1 The runner in the photo is ready to sprint. Look carefully at the horizontal

forces applied on her body and answer the questions below.

a Label the two forces acting on the runner in the diagram with a suitable

name.

(2)

b Describe the forces acting on the runner. (2)

c Calculate the resultant force on the runner in this situation.

(1)

d Explain the effect of this resultant force on the runnerÕ s motion

(2)

40 N

40 N

Checkpoint quizzes with differentiated follow-up activities track students’ progress and provide formative feedback

Practice questions and full practice papers for both Higher and Foundation levels provide checkpoints of students’ progress

Revision podcasts with Higher and Foundation content highlighted

Support and extension

B1, Topic 1.4 B1, Topic 1.4AQA Biology GCSE Student extension

Name ...............................................................................

Class ..................... Date ........................



2

2 How are cone cells adapted to carry out their function?

3 The other types of photoreceptor cells in the retina are rod cells. There are

approximately 120 million of these. Explain how rod cells help us to see.

4 People who are colour blind cannot distinguish one colour from another.

Approximately 8% of men are red/ green colour blind. Explain, in terms of rod

and cone cells, why colour blindness occurs.

Extension worksheets stretch higher-ability students and increase depth of knowledge

2

B1, Topic 1.4 B1, Topic 1.4AQA Biology GCSE Student extension Name ............................................................................... Class ..................... Date ........................

© Oxford University Press 2015 This resource sheet may have been changed from the original. 1

The human eye

Specification references: ¥ 3.1.1.3 Cell specialisation

Aims We are able to see things because light reflects off them and enters our eye. The eye contains cells that respond to the light that hits them and sends signals to our brain. The brain deciphers the information that it receives to tell us the colour, size, shape or movement of the object we are looking at. The part of the eye that contains the cells that respond to light is the retina. These specialized cells are called photoreceptors. There are two types of photoreceptors in the retina: rods and cones. In this activity you are going to look at the functions of these two specialised cells and how each of them is adapted to carry out their functions.

Learning objectives After completing this worksheet, you should be able to:

¥ understand how cells may be specialised to carry out a particular function ¥ understand how the structure of different types of cells relates to their function

in a tissue, an organ or organ system, or the whole organism.

Task Use the Internet to research rod and cone cells and then answer the questions that follow.

Questions 1 There are approximately 6 million cone cells, of three different types, in the

retina. Explain what the three different types of cone cells are and how they help us to see.

Webquest research tasks encourage independent learning and study

B1, Topic 1.3 B1, Topic 1.3

AQA Biology GCSE Student Go further Name ............................................................................... Class ..................... Date ........................


1

Plasmids and genetic engineering Specification references: ¥ 3.1.1.1 Eukaryotes and prokaryotes Aims Prokaryotic cells consist of a cell membrane surrounded by a cell wall. The genetic material is not enclosed in a nucleus. It is a single DNA loop and may have one or more small rings of DNA called plasmids. Plasmids can be used in genetic engineering and in this activity you will find out how they can be used in this way.

Learning outcome After completing this activity, you should be able to: ¥ understand how prokaryotic cells and plasmids are used in genetic

engineering.

Task Do some research on how plasmids are used in genetic engineering and then answer the questions below. You may need to do some further research to answer some of the questions. Genetically engineered bacteria can make proteins that we need. For example, people with diabetes need supplies of the hormone insulin. In the past they used animal insulin extracted from pigs. Now they can use pure human insulin produced by genetically engineered bacteria. In this process, the gene for insulin production is cut out of a human chromosome

and inserted into the plasmid of a bacterium cell. The bacteria are allowed to reproduce many times and then the insulin is harvested from those cells. If this is

done on a large scale then enough insulin can be produced to treat diabetes. We can use engineered genes to improve the growth rates of plants and animals

which increases yields and therefore profit for farmers. Crops can also be engineered to be resistant to pests. However, there is also concern about the use

of genetic engineering as no one knows what the long-term effects might be.

Kerboodle BooksKerboodle Books are digital versions of the AQA GCSE Sciences Third Edition Student Books which can be accessed online. Student and teacher access to the Kerboodle Books is automatically included with the relevant Kerboodle package, so you and your students have easy access to the textbooks at home.

Engage your studentsExplore key concepts with animations and interactive activities

Interactive activities for use as starters or plenaries

Animations clearly linked to learning objectives to help consolidate learning

Go Further worksheets for high-ability students bridge the gap between GCSE and A Level

54


The cells that make up our bodies are typical animal cells. All cells have some features in common. You can see these features clearly in animal cells.

Animal cells – structure and functionThe structure and functions of the parts that make up a cell have been made clear by the electron microscope (see Figure 1). You will learn more about how their structure relates to their functions as you study more about specific organ systems during your GCSE biology course. An average animal cell is around 10–30 µm long (so it would take 100 000–33 333 cells to line up along the length of a metre ruler). Human beings are animals so human cells are just like most other animal cells, and you will see exactly the same structures inside them.

●● The nucleus – controls all the activities of the cell. It contains the genes on the chromosomes that carry the instructions for making the proteins needed to build new cells or new organisms. The average diameter of a nucleus is around 10 µm.

●● The cytoplasm – a liquid gel in which most of the chemical reactions needed for life take place.

●● The cell membrane – controls the passage of substances such as glucose and mineral ions into the cell. It also controls the movement of substances such as urea or hormones out of the cell.

●● The mitochondria – structures in the cytoplasm where aerobic respiration takes place. They are very small: 1–2 µm in length and only 0.2–0.7 µm in diameter.

●● Ribosomes – where protein synthesis takes place, making all the proteins needed in the cell.

Plant cells have all the features of a typical animal cell, but they also contain features that are needed for their very different way of life (see Figures 2 and 3). Algae are simple aquatic organisms. They also make their own food by photosynthesis and have many similar features to plant cells. For centuries they were classified as plants, but now they are classified as part of a different kingdom – the protista.

All plant and algal cells have a cell wall made of cellulose that strengthens the cell and gives it support.

Many (but not all) plant cells also have these other features:

●● Chloroplasts are found in all the green parts of a plant. They are green because they contain the green substance chlorophyll. Chlorophyll absorbs light so the plant can make food by photosynthesis. Each chloroplast is around 3–5 µm long. Root cells do not have chloroplasts because they are underground and do not photosynthesise.

●● A permanent vacuole is a space in the cytoplasm filled with cell sap. This is important for keeping the cells rigid to support the plant.


●● the main parts of animal cells●● the similarities and differences

between plant and animal cells.

B1.2 Animal and plant cells

Figure 1 Diagrams of cells are much easier to understand than the real thing seen under a microscope. This picture shows a simple animal cheek cell magnified ×1350 times under a light microscope. This is the way a model animal cell is drawn to show the main features common to most living cells

nucleus

cytoplasm

cellmembrane

mitochondria

ribosomes

Synoptic linkYou will find out more about classifying the living world in Chapter B16.

Synoptic linkFor more information on photosynthesis, look at Topic B5.1.

Figure 2 Algal cells contain a nucleus and chloroplasts so that they can photosynthesise

Figure 3 A plant cell has many features in common with an animal cell, as well as other features that are unique to plantsnucleus

cytoplasm

cellulosecell wall

cell membrane

chloroplasts

permanentvacuole

mitochondria

ribosomes

Go furtherThe ultrastructure of a cell – the details you can see under an electron microscope – includes structures such as the cytoskeleton, the Golgi apparatus, and the rough and smooth endoplasmic reticulum. They support and move the cell, modify and package proteins and lipids, and produce the chemicals that control the way your body works. If you study A level biology you will meet these organelles and more, and unravel the mysteries of their structure and function in the cell.

Study tipRemember that not all plant cells have chloroplasts.

Do not confuse chloroplasts and chlorophyll.

Looking at cellsSet up a microscope to look at plant cells (for example, from onions or Elodea) and/or algal cells. You should see the cell wall, the cytoplasm, and sometimes a vacuole. You will see chloroplasts in the Elodea and the algae, but not in the onion cells because they do not photosynthesise.

Figure 4 Some of the common features of plant cells show up well under the light microscope. Here, the features are magnified ×40

Study tipLearn all the parts of cells and their functions.

●● Animal cell features common to all cells: a nucleus, cytoplasm, cell membrane, mitochondria, and ribosomes.

●● Plant and algal cells contain all the structures seen in animal cells as well as a cellulose cell wall.

●● Many plant cells also contain chloroplasts and a permanent vacuole filled with sap.

Key points1 a List the main structures you would expect to find in a human cell.

b You can find all the things in animal cells in a plant or an algal cell. State the three extra features that may be found in plant cells but not animal cells.

c Describe the main functions of these three extra structures.

2 Suggest why the nucleus and the mitochondria are so important in all cells.

3 Chloroplasts are found in many plant cells but not all of them. Suggest two types of plant cells that are unlikely to have chloroplasts and in each case explain why they have none.

Plant cells – structure and functionPlants are very different organisms from animals. They make their own food by photosynthesis. They do not move their whole bodies about from one place to another. Plant cells are often rather bigger than animal cells – they range from 10 to 100 µm in length.


Freepost RTJL-STAC-RRCZH

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tel +44 1536 452620 email [email protected] +44 1865 313472 web www.oxfordsecondary.co.uk/aqagcsescience K4

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Biology Ann FullickAnn Fullick was a biology teacher for many years before becoming a Head of Science. She is a successful published author of more than 80 titles, including many UK A Level and GCSE biology textbooks, as well as a producer of online resources and apps. She also has examining experience, has been closely involved in UK curriculum development, and is a Fellow of the Society of Biology.

Physics Jim BreithauptJim Breithaupt has extensive experience of teaching Physics in schools and colleges, and was the Physics author for the previous editions of Nelson Thornes’s popular AQA GCSE Science series. He has also written a number of highly regarded A Level textbooks including AQA Physics A, Understanding Physics for A Level and Physics in Context for Cambridge International A Level.

Chemistry Lawrie RyanLawrie Ryan is the author and series editor of best-selling titles including Advanced Chemistry for You, Spotlight Science, and the previous edition of AQA GCSE Sciences, originally published by Nelson Thornes.

About the authors

GCSE



AQA

2


GCSE


GCSE


2Jim Breithaupt

Series Editor: Lawrie Ryan

AQA

GCSE


2

Ann FullickSeries Editor: Lawrie Ryan

AQA


GCSE

AQA Chemistry for

GCSE Combined

Science: Trilogy

Third edition

GCSE

Physics for GCSE Combined Science: Trilogy Third edition

2

Jim BreithauptSeries Editor: Lawrie Ryan

AQA

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