Learning Model Answers - bryncelynnog.org.ukbryncelynnog.org.uk/wp-content/uploads/2016/07/Year-11-Double-Mixed.pdf · radioactive decay? Random When doing experimental work with

1 Learning Model AnswersYear 11 Double Science

What is a classification system based on? It is based on morphological features or DNA analysis.

Name the 5 kingdoms Bacteria, Single celled organsims,plants,fungi and animals.

Give the hierarchical order for classification. Kingdom,phylum,class,order,family,genus and species

What do animals compete for? Food,mates,space and water.

Define biodiversityBiodiversity is the variety of different species and numbers of

individuals within those species in an area.

Describe ionic bonding

Occurs between metals and non-metals. Electrons are

transferred. There is an electrostatic force of attraction

between oppositely charged ions.

Describe covalent bonding Occurs between non-metals. Electrons are shared in pairs

Describe metallic bondingOccurs between metals. Regular arrangement of positive ions

surrounded by a 'sea' of delocalised electrons.

Why do ionic compounds have high melting

and boiling points?Strong forces between ions that need a lot of energy to break.

Why do giant covalent compounds have high

melting and boiling points?

Strong bonds between atoms that need a lot of energy to

break.

What is the unit of speed? m/s

What is the unit of acceleration? m/s2

What is thinking distance? DISTANCE travelled whilst reacting.

What is braking distance? Distance travelled after hitting brakes.

How do you calculate stopping

distance?Thinking didtance + braking distance.


Why is biodiversity important?Biodiversity is important as it provides food, potential foods,

industrial materials and new medicines.

Give some examples of how biodiversity can

be conservedSeed banks, national parks and captive breeding programmes

Describe how quadrats can be used to

investigate the abundance of a species.

Measure the area. Randomise coordinates. Count the number

of the organisms in the quadrat. Calculate a mean and then

multiply by the area of the site.Describe how a line transect can be used to

investigate the change in abundance of a

species .

Place a tape measure on the ground. At regualr intervals put

the quadrat down and count the number of the organism

within it.

Describe how to count the number of a

moving organsim.Use the capture/recapture technique.

Why do simple covalent molcules have low

melting and boiling points?

Weak forces between molecules that don’t need much energy

to break.

Why do ionic compounds only conduct when

molten or in solution?Because the ions are free to move.

Why do metallic substances conduct

electricity?

Because they have free electrons that can move throughout

the structure.

Why don’t covalent compounds conduct

electricty?Because there are no free electrons.

HT Why does MgO have a higher melting

point than NaCl?

Magnesium and oxide ions have greater charges (2+ and 2-) so

has a stronger attraction.

What factors affect thinking

distance?Alcohol; Drugs; Tiredness.

What factors affect braking distance? Worn tyres; Ice/Snow; Condition of brakes.

What factors affect both thinking and

braking distance?Speed

What is meant by the term, isotope?Elements with equal numbers of protons but differing

numbers of neutrons.

Why do radioactive emissions occur? An imbalance between the numbers of protons and neutrons.


What assumptions are made when using the

capture /recapture method ?

There is no death, immigration, emigration and marking does

not affect the chance of survival.

Define an alien species.A species that has been introduced into an area in which they

do not naturally occur.

Define biological controlThe control of a pest by introduction of a natural enemy or

predator

Why must research take place before using

biological control?To assess the effects and to ensure it does not become a pest .

What are chromosomes?They are linear arrangements of genes found in pairs in the

nucleus

Why is diamond hard? Each carbon is strongly bonded to four others (covalent bonds)

Why is graphite soft?

Each carbon is covalently bonded to three others in hexagonal

layers. There are weak forces between layers so they can slide

over each other.

Why can graphite conduct electricity?Each carbon is covalently bonded to three others, the fourth

electron is free to move throughout structure.

What can fullerenes be used for? drug delivery, lubricants, catalysts

Give three properties of carbon nanotubes? high strength, low density, good conductors

Why is waste from nuclear power

stations and nuclear medicine

difficult to store?

They are radioactive substances with long half-lives.

How can you describe the process of

radioactive decay?Random

When doing experimental work with

radiation, how can the random

nature be accounted for?

Repeat reading; measurments made over a long period; small

variations to be expected as it is random.

What is the order of penetrating

power for the types of radiation

(high to low)?

Gamma-Beta-Alpha

What is the order of ionising power

for the types of radiation (high to

low)?

Alpha-Beta-Gamma


What is the function of mitosis? Growth, repair and asexual reproduction.

What is the function of meiosis? Formation of gametes for sexual reproduction.

Explain the process of mitosisThe genetic material is copied and then the cell divides into

two genetically identical cells.

Explain the process of meiosis

Copies of genetic information are made. The cell then divides

twice to make four gametes, each has a single set of

chromosomes.

What is cancer the result of? Uncontrolled mitosis.

What does nanometre mean and how big is a

nanoparticle?nm = 1 billionth of a metre, nano particle = 1-100atoms

Give properties and uses of nano particles of

silver.

Properties: antibacterial, antiviral, antifungal Uses:

plasters, antiseptic sprays, socks, deoderant sprays

Give properties and uses of nano particles of

titanium dioxide.

Properties: absorb and reflect UV light, transparent Uses:

sunscreen, self cleaning windows.

HT What are the possible risks of

nanoscience?

long term affects are unknown, could easily be absorbed into

body or environment

What is a smart material?materials that have properties that change reversibly when a

change occurs in their environment.

Describe a alpha particle. Helium NUCLEUS / Two protons & two neutrons.

Describe a beta particle. High energy electron.

Describe gamma radiation. High energy electromagnetic wave.

Name some natural sources of

radiation. Cosmic rays; Radon gas; Rocks/buildings.

Name some man made sources of

radiation. Medical uses; Nuclear power stations.


What are stem cells?Cells from human embryos and bone marrow that are capable

of changing into specialised cells.

Why are stem cells so important in modern

medicine?They can replace faulty cells to cure conditions like paralysis.

What are the benefits of using your own stem

cells?

No rejection, no need to find a donor, no need for tissue

typing.

What are the ethical issues surrounding use

of stem cells?

The cells come from embryos which are a potential human

life.

Describe the structure of DNA.Two long chains of alternating sugar and phosphate

connected by bases twisted into a doube helix.

What do thermochromic pigments do? Change colour with temperature

What do photochromic pigments do? Change colour with changing light intensity

What do polymer gels do?absorb water and swell or release water and shrink due to

changes in pH or temperature

What do shape memory alloys and polymers

do?Regain original shape when heated

What colour would a strong acid appear with

univeral indicator and what pH does it have?Red, pH 1-2

How does background radiation

change at higher altitudes. There will be more cosmic rays.

Why does the level of Radon gas

change vary?

Radon comes from rocks, especially granite, so it depends on

the amount of granite in the area.

How can householders be protected

from Radon?Good ventilation.

What is the half life of a radioactive

substance?

The time taken for the activity/number of radioactive nuclei to

reduce by half.

What is Newton's first law?Any body will either remain at rest or at a constant velocity

unless a resultant force acts upon it.


Name the four bases. Adenine, thymine, cytosine and guanine.

Why is the order of the bases important?

The order of the bases forms the code which determines the

order in which different amino acids are linked together to

form different proteins.

What is the triplet code?The sequence of three bases which identifies a particular

amino acid.

What is the process of genetic profiling?

It involves cutting the DNA into short pieces which are then

separated into bands. The pattern of bands can then be

compared for criminal, paternity and classification purposes.

What are the ethical issues surrouding

genetic profiling?

The information could be kept on a police database, passed

on to life insurance companies and used in job applications.

What colour would a strong alkali appear with

univeral indicator and what pH does it have?Purple, pH 13-14

What colour would a neutral substance

appear with univeral indicator and what pH

does it have?

Green, pH 7

What ions do acids and alkalis contain?Acids: H+ (Hydrogen ions)

Alkalis: OH- (Hydroxide ions)

What is made when an acid reacts with a

metal?A salt and hydrogen

What would you see when an acid reacts with

a carbonate?Fizzing because carbon dioxide is made

What is Newton's second law? Resultant Force = mass x acceleration

What is Newton's third law?If a body A exerts a force on body B then body B exerts an

equal and opposite force on body A.

What is inertia?The ability of an object to resist a change in motion (things

with larger masses have more inertia).

What is 'g'? Gravitational field strength. It is 10N/kg on Earth.

What is weight? The force on an object due to gravity.


What is a gene? A section of DNA that determines an inherited characteristic.

What is an allele? A different form of an individual gene.

What is a gamete?A sex cell, egg and sperm that contains half the number of

chromosomes of a body cell.

In humans if you have an XY

chromosome pair, what sex are you?Male

What is a dominant allele?If a dominant allele is present that characteristic will be

expressed.

What is made when an acid reacts with a

base?A salt and water

HT What is the ionic equation for

neutralisation?

How would you test to identify sulfate ions? Add barium chloride, a white precipitate should be seen.

What is an ore?A mineral found in the Earth's crust that contains enough metal

to make it worthwhile extracting.

State two metals which are found in the

ground in their native state.Gold and Silver

What is the unit of force? newtons (N)

What is mass? The amount of matter in an object.

Why does an object reach terminal

speed?The air resistance balances out the weight.

What is work done? Energy transferred OR force x distance

What is the unit of work done? joules (J) OR Nm

𝑯+ + 𝑶𝑯− → 𝑯𝟐𝑶


What is a recessive allele?Two recessive alleles need to be present for the characteristic

to be expressed.

Define genotype and phenotype.Genotype is the alleles present eg Bb and phenotype is the

characteristic eg brown hair.

What is F1 and F2?F1 is the first filial set of offpsring born and F2 the second

generation.

What is genetic modification? The artificial transfer of genes from one organism to another.

Give some advantages of genetic

modification.Disease resistance and increased yield.

Describe oxidation and reduction in terms of

oxygen.Oxidation is gaining oxygen, reduction is losing oxygen

What is a displacement reaction? A chemical reaction in which a more reactive element

displaces a less reactive element from its compound

What are the 4 raw materials added to the

blast furnace?Iron ore, coke, limestone, hot air

Why is coke added to the blast furnace? Used as a fuel and produces carbon monoxide for reduction.

Why is limestone added to the blast furnace? To remove impurities as slag

What is the energy a body has due

to its motion?Kinetic energy

What is the energy a body has due

to its position?Gravitational Potential Energy

If an object obeys Hooke's Law,

what happens when a force is

applied?

Force is proportional to extension

How can energy efficiency of a car

be improved?

Streamline it; Have correctly inflated tyres; Stop-start systems;

making them lighter.

What is the job of a air bag/crumple

zone (in terms of energy)?

Increase the distance over which the energy is transferred so

reducing the force.


Give some disadvantages of genetic

modification.

Unknown effects on health. Transfer of the gene to other

species could have effects on the environment.

Which type of variation shows a

large range of differences?Continuous.

Which type of variation produces

clones?Asexual reproduction.

What is a mutation? A random change in DNA.

What can increase mutation rates?Ionising radiation; the greater the dose the greater the chance

of mutation.

Why is hot air blasted in at the bottom of the

furnace?Provides oxygen so that the coke can burn.

What is electrolysis? Splitting up of a compound using electricty.

What is oxidation and reduction in terms of

electrons?Oxidation is loss of electrons, Reduction is gain of electrons.

What happens to positive ions when the move

to the negative electrode?They gain electrons (are reduced)

What happens to negative ions when the

move to the positive electrode?They lose electrons (are oxidised)

What is the job of a air bag/crumple

zone (in terms of momentum)?

The same change in momentum happens over a longer time

so there is decreased deceleration as the force decreases.

What is the order of the planets (in

terms of inreasing distance from the

Sun)?

Mercury-Venus-Earth-Mars-Jupiter-Saturn-Uranus-Neptune

Which planets are rocky? Mercury-Venus-Earth-Mars

Which planets are gaseous? Jupiter-Saturn-Uranus-Neptune

Where is the asteroid belt and what

does it contain?

Between Mars and Jupiter. Many rocky asteroids and dwarf

planets.


What is cystic fibrosis?A recessive inherited disease that causes the production of

thick mucus that blocks the bronchioles.

How is cystic fibrosis treated?It is treated by gene therapy. The introduction of genes via a

inhaler.

Why are scientists researching the

human genome?

They can use the information to develop new ways to treat,

cure or even prevent disease.

What is natural selection?

Individuals with characteristics adapted to their environment

are more likely to survive and breed successfully passing their

genes on to their offspring.

Who proposed the theory of natural

selection?Charles Darwin and Alfred Wallace

Why is aluminium ore dissolved in molten

cryolite for electrolysis?

It dissolves at a temperature much lower than its melting point

so saves energy.

What happens to the oxygen produced during

the electrolysis of aluminium oxide?It reacts with the carbon electrodes producing carbon dioxide.

Give 5 properties of metals.high melting points, malleable, ductile, good conductors of

heat and electricity

Where are the transition metals found on the

periodic table?Betweeen groups 2 and 3.

What properties do transition metals have

that are different to 'normal' metals?Form more than one type of ion, form coloured compounds.

How do comets orbit? Highly elliptical orbits.

True or False: Most planets have

moon orbiting around them. TRUE

What is a planetary system? It comprises a star and all the objects which orbit it.

What is a galaxy? A large collection of stars

What is an A.U.?An astronomical unit. The mean distance from the Sun to the

Earth.


Give two examples of ongoing

evolution.

Antibiotic resistance in bacteria and warfarin resistance in

rats.

Why do species become extinct?The process of natural selection has been too slow for the

organisms to adapt to new environmental conditions.

Which organs control blood glucose

levels?

The pancreas releases insulin and glucagon. The liver and

muscles respond to them.

What is diabetes?

A disease in which a person has high blood sugar levels. Type

1 is due to lack of insulin production. Type 2 is due to body

cells not responding to insulin.

What solution is used to test for

glucose?Benedicts. It turns yellow/red when sugar is present.

HT What colour solutions to Fe2+, Fe3+ and

Cu2+ ions form?Fe2+- pale green Fe3+- brown and Cu2+- blue

What is an alloy? A mixture made by mixing molten metals.

What factors influence the location of metal

extraction plants.transport links, electricty supply, how far away a town or city is.

What is the activation energy? The miniumum amount of energy needed to start a reaction?

Describe an exothermic reactionExothermic reactions release energy to the surroundings

(increasing temperature).

What is a light year? The DISTANCE light travels in a year.

What is the process of generating

heat and light in a star called?Nuclear fusion.

What is the life cycle of a low mass

star?

Protostar-Main sequence-Red Giant-White dwarf-Brown

dwarf

What is the life cycle of a low mass

star?

Protostar-Main sequence- Red Supergiant-Supernova-Neutron

Star OR Black hole

Describe how main sequence stars

stay stable.Radiation pressure = Gravitational force.


Name the stimuli for sense organs light, sound, touch, temperature and chemicals.

What does the CNS consist of? Brain and spinal cord.

What are the properties of reflex

actions?

fast, automatic and some are protective eg blinking and pupil

size.

Higher- Give the components of the

reflex arc.

Stimulus, receptor, sensory neurone, relay neurone, motor

neurone, effector and reponse.

What is a synapse?A gap between neurones over which the message is

transferred by a chemical messenger.

Describe an endothermic reactionEndothermic reactions absorb energy from the surroundings

(decreasing temperature).

What is crude oil? A mixture of hydrocarbons.

What is a hydrocarbon? A compound made of hydrogen and carbon only.

How is crude oil separated ?Fractional distillation: vaporised, then condensed at different

points in column.

How does carbon chain length affect viscosity

and colour?

The longer the chain the more viscous the compound is, also

the darker in colour it becomes.

What happens when a star runs

short of Hydrogen?

It will fuse helium and then other increasingly heavier

elements to maintain fusion.

Why wil the star swell when it runs

out of Hydrogen?

Gas and Radiation pressure increases as heavier elements are

fused.

What happens when fusion stops?Gravitational force exceeds the gas and radiation pressure and

the star shrinks.

What do Supernova create? Elements heavier than Iron.

How did the solar system begin?Gravitational forces caused matter to get closer creating the

Suna nd the planets.


What is homeostasis?Keeping temperature , pH, sugar and water levels within a

narrow range.

What are hormones?Chemical messengers secreted by glands and carried in the

blood.

What happens when blood sugars

are high?

The pancreas releases insulin which causes the liver to convert

glucose to glycogen and store it.

What is involved in temperature

regulation?

Change in diameter of blood vessels, sweating, erection of

hairs and shivering to generate heat.

Give the long term effects of alcohol

on the bodyLiver disease, circulatory and heart disease.

How does carbon chain length affect boiling

point?Why?

The longer the chain the higher the boiling point as there are

stronger forces between molecules.

How does carbon chain length affect ignition? The shorter the chain length, the easier it is to ignite.

Describe combustion of fuels Burning in oxygen to produce carbon dioxide and water.

Give 2 advantages of using hydrogen as a fuel.Water is the only product of combustion so doesn’t contribute

to global warming. Made from water so is renewable.

Give two disadvantages of using hydrogen as a

fuel.

Lots of energy needed to produce it, storage requires bulky and

heavy pressurized containers.

Name the 4 types of microbe. Bacteria, fungi , viruses and protists.

Define a pathogen. A micro-organism that causes disease.

What does a bacterial cell consist of? A cell wall, cell membrane, cytoplasm and no distinct nucleus.

What does a virus consist of? A number of genes surrounded by a protein coat.

How can communicable diseases be

spread?

By contact, aerosol, body fluids, water, insects and

contaminated food.


Which three things make up the fire triangle? Fuel, oxygen, heat

What is cracking?heating hydrocarbons at high temperatures with a catalyst to

make them break down into smaller molecules.

What is the general formula for an alkene?

Describe how you would prepare crystals of

salt from an acid and an insoluble base.

Add excess base to use up all the acid, filter to remove excess

base, evaporate water to form crystals.

Name the first five alkanes methane, ethane, propane, butane, pentane

How does the body defend itself?

Intact skin forming a barrier, blood clots to seal wounds,

phagocytes in the blood ingesting microbes and lymphocytes

producing antibodies and antitoxins.

What is an antigen?A molecule that is recognised by the immune system; foreign

antigens trigger lymphocytes to produce specific antibodies.

What are antibiotics?

Medicines orginally produced by living organisms, such as

fungi. They can kill or prevent growth of bacteria but do not

kill viruses.

What can overuse of antibiotics lead

to?Evolution of resistant bacteria such as MRSA.

What are the control measures for

MRSA?

Hand washing, thorough cleaning of hospital wards, use of

alcohol gels and MRSA screening.

How would you test for alkenes?Add bromine water, will change from orange brown to

colourless.

What is a monomer?A small reactive molecule that can be joined together to make

a polymer.

State the uses of polythene and poly(propene)polythene = bags, plastic bottles, poly(propene) = ropes and

crates

State the uses of poly(vinylchloride) and

poly(tetrafluoroethene)PVC = drain pipes, window frames, PTFE = non - stick pans

What are the environmental issues with using

plastics?

take up space in landfill, don’t bio-degrade, made from crude

oil (a non-renewable resource)

𝐶𝑛𝐻2𝑛


Why do new drugs take a long time

to develop?

They may have side effects so require large scale rigorous

testing

What are the issues surrounding

drug testing?They may be tested on animals.

Higher- What is a vaccine?Usually dead or weakend microorgansims with antigens which

will stimulate an immune response.

Higher- How do we become

immune?

After an antigen is encountered, memory cells remain in the

body and antibodies are produced very quickly if the antigen

is encountered again.

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Learning Model Answers - bryncelynnog.org.ukbryncelynnog.org.uk/wp-content/uploads/2016/07/Year-11-Double-Mixed.pdf · radioactive decay? Random When doing experimental work with