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AREA OF STUDY 1Cells in action

Pete Hamilton Sandringham College

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Biology:

is a natural science concerned with the study of life living organisms their structure, function, growth, origin,

evolution, distribution, taxonomy and interrelationships.

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Biology:

Utilises Observation and

the Scientific Method

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Flying Blind – Lazzaro Spallanzani and Bats

In 1790 an Italian scientist, Lazzaro Spallanzani observed that owls were not able to fly in complete darkness whilst bats had no difficulty.

He experimented by isolating the bats ability to see, smell, vocalise and hear.

Spallanzani discovered that bats without the use of vision or smell could still navigate and avoid objects, however those with plugged ears, particularly just one plugged ear, could not.

He concluded bats see by hearing. Not many people believed him.

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It was not until the 1930’s that an American scientist Donald Griffin would finally determine the mechanism for bats navigation.

Griffin, using experiments with Little Brown Bats, determined that the bats were emitting a series of very high-pitched clicks that increased as they approached prey.

These clicks were echoed back to the bat from the objects and the bats were using these echoes to determine the precise location of the object.

Echo Location

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The Scientific Method Based on Observation Hypotheses are generated

Possible explanations for an observed phenomena Hypotheses can be either supported or rejected by

experiments Experiments are designed and conducted Results are analysed Conclusions are deduced Results are reported and published Method is replicated and tested by others

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Organisms are living things How do we know that something is living

or non-living?

Animals: -

Plants: -

Mould: -

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Seven Characteristics of Living Organisms:

• Movement• Respiration • Sensitivity • Growth • Reproduction • Excretion • Nutrition

MRS GREN

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Living, dead or non living?

Non- LivingIn order to consider something non-living, it must not have any of the 7 characteristics of living things.

orIt was living or dead and has been processed (chemically altered)

DeadIn order to consider something dead, it must have been alive at one time and it no longer has any of the 7 characteristics of living things.

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Living, dead or non living?Item Living , dead or

non living?Explanation

Fruit in a bowl

Leaves attached to a tree

Bark on a tree

Paper

Egg

Water

Fish in the ocean

Potato

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Cell Intro video

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The Cell Theory All living things are made up of

one or more cells – cells are very small

There can be different kinds of cells within living organisms. (skin cells, brain cells, muscle

cells)

Cells are the functional unit of all living things This means that they are where

all the action happens, they process food, give structure and many other things.

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The Cell Theory

All cells come from pre-existing cells.

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Cells and organisms vary greatly in size

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Units of measurement:1 micrometer = 1 micron 1 μm = 1 μm

1 micrometer = 0.001 millimeter 1 μm = 0.001 mm

1 micrometer = 0.0001 centimeter 1 μm = 0.0001 cm

1 micrometer = 1.0 × 10-6 meter 1 μm = 1.0 × 10-6 m

Single or multicelled?

Unicellular organisms: composed of only 1 cell- Microscopic Euglena 10 microns

Multicellular organisms: composed of many cells, cells specialised - Microscopic to Macroscopic Hydra 10,000 microns

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Cells and Microscopes There are several types of microscopes, each can allow us

to view cells differently and to a different degree.

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Cell Structure

There are many types of cells and each has its own structure and purpose. each cell has

features that help it carry out its purpose.

(e.g Nerve cells)

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Properties of cells Despite cells having different functions, all cells

have some things in common.

• Plasma or Cell membrane - separates the cell from it’s external environment.

• Cytoplasm – Jelly like holds all the organelles, ions, salt, enzymes, nucleus and is 90% water. Cytosol is the fluid part of the cytoplasm.

• DNA- genetic material that directs the cell’s activities.

•Organelles – Components inside the cells cytoplasm that perform different functions.

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Prokaryotes Vs Eukaryotes PRO More primitive cells Lack membrane bound

organelles Smaller than

Eukaryotic cells

EU Complex cells Have membrane bound

specialised organelles Larger than prokaryotic

cells

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Prokaryote cells simple cells (example: E. coli)

capsule: slimy outer coating

cell wall: tougher middle layer

cell membrane: delicate inner skin

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cytoplasm: inner liquid filling DNA in one big loop pilli: for sticking to things flagella: for swimming ribosomes: for building

proteins

Prokaryote cells (example: E. coli)

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Prokaryote lifestyle

unicellular: all alone

colony: forms a film

filamentous: forms a chain of cells

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Prokaryote Feeding Photosynthetic: energy from sunlight Chemosynthetic: energy from chemicals

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Prokaryote Feeding Disease-causing: feed on living things Decomposers: feed on dead things

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Prokaryote E. coli bacteria on the head of a steel pin.

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Eukaryotes DNA is located inside the nucleus as thread like

chromosomes Specialised organelles each performing a specific function

Eukaryotes

Protists

* Mostly single

celled but occasionall

y multicellul

ar (seaweed)

* Very diverse- include moulds, algae,

protozoan

Fungi

* Some are

unicellular but mostly they are

multicellular

* Made of thread like filaments

call hyphae* Are

heterotrophs

* Do not have

flagella or cilia

Animals*

Multicellular

organisms* Highly Mobile

* Heterotrop

hic

Plants*

Multicellular*

Autotrophic

* Have a cell wall made of cellulose*Large

fluid filled vacuoles

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Eukaryotes are larger and more complex

Have organelles Have chromosomes can be multicellular include animal and plant cells

Animal cells Intro

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Organelles are membrane-bound cell parts

Mini “organs” that have unique structures and functions

Located in cytoplasm

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Cell membrane delicate lipid and

protein skin/membrane around cytoplasm

found in all cells

Cell Structures

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Nucleus a membrane-bound sac

evolved to store the cell’s chromosomes (DNA)

has pores: holes

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Nucleolus inside nucleus location of ribosome

factory RNA

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mitochondrion Releases the cell’s

energy the more energy the

cell needs, the more mitochondria it has

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Mitochondria

Mitochondria

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Ribosomes build proteins from

amino acids in cytoplasm

may be free-floating, or may be attached to ER made of RNA

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Endoplasmic reticulum may be smooth:

builds lipids and carbohydrates

may be rough: stores & transports proteins made by attached ribosomes

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Golgi Complex takes in sacs of

raw material from ER

sends out sacs containing finished cell products

Golgi Apparatus

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Lysosomes sacs filled with digestive

enzymes digest worn out cell parts digest food absorbed by cell

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Centrioles pair of bundled tubes organize cell division

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Cytoskeleton

made of microtubules

found throughout cytoplasm

gives shape to cell & moves organelles around inside.

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Cytoskeleton

cytoplasmic streaming

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Structures found in plant cells

Cell wall very strong made of cellulose protects cell from

rupturing glued to other cells

next door

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Vacuole huge water-filled

sac keeps cell

pressurized stores starch

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Chloroplasts filled with

chlorophyll turn solar energy

into food energy

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Chloroplasts

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How are plant and animal cells different?

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Structure Animal cells Plant cells

cell membrane Yes yes

nucleus Yes yes

nucleolus yes yes

ribosomes yes yes

ER yes yes

Golgi yes yes

centrioles yes no

cell wall no yes

mitochondria yes yes

cholorplasts no yes

One big vacuole no yes

cytoskeleton yes Yes

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Advantages of each kind of cell architecture

Prokaryotes Eukaryotes

simple and easy to grow

can specialize

fast reproduction multicellularity

all the same can build large bodies

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Examples of specialized euk. cells liver cell:

specialized to detoxify blood and store glucose as glycogen.

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sperm cell: specialized to deliver DNA to egg cell

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Mesophyll cell specialized to

capture as much light as possible

inside a leaf

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How do animal cells move?

Some can crawl with pseudopods

Some can swim with a flagellum

Some can swim very fast with cilia

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Pseudopods

means “fake feet” extensions of cell

membrane example: amoeba

Amoboid movement

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Flagellum/flagella large whiplike tail pushes or pulls cell

through water can be single, or a

pair

Cilia & Flagella

Cilia fine, hairlike

extensions attached to cell

membrane beat in unison

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Organelles

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Organelles

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Organic and Inorganic compounds

Compounds are organized into 2 types: Organic compounds –

These are complex chemical compounds which contain Carbon and Hydrogen.

Inorganic compounds- These are all non-organic compounds. e.g. water, oxygen, nitrogen.

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Inorganic components

Water- most organisms are 70-90% water Surface tension Heat capacity Cohesiveness

Oxygen and carbon dioxide Oxygen is needed for cells to release energy from food

molecules Carbon is the key molecule in organic molecules.

Nitrogen Nitrogen is needed to make proteins.

Minerals Are needed for the structural part of cells, the body and in

enzymes and vitamins

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Organic molecules

Carbohydrates Important source of energy Made of carbon, hydrogen and oxygen

Lipids fats and oils important for energy stores and some

structures.

Proteins Vital for all sorts of functions!

Nucleic Acid Genetic material for all organisms

Vitamins Required for normal functioning.

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Eukaryotic Cells

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Eukaryotic Cells

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Eukaryotic Cells

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Overview of cell structure TEA

Tour of the cell Bozemanscience