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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


CELL STRUCTURE
CELL THEORY:
Structural and functional unit of all living things
New cells arise from already existing cells
Cells contain information that instructs growth. This information can be passed onto new cells.

MICROSCOPES:
There are two main types of microscopes:…

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]




STAINING:
Used to have better visualisation of cells under a microscope
Used because some cell components are transparent
ACETIC ORCEIN- stains DNA dark red
GENETIAN VIOLET- stains bacterial cell walls
IODINE- stains starch granules
METHYLENE BLUE/EOSIN- used for light microscope
Specimen…

Page 3

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


Cell Surface Membrane Made of lipids and Controls movement of substances in
proteins and out of cells
Has receptor molecules that allows it
to respond to chemicals (hormones)
separate cell contents from outside
the cell
separate cell components from the
cytoplasm…

Page 4

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


Vesicle Small fluid sac in cytoplasm Transports substances in and out cell
with membrane Formed at Golgi apparatus, ER, cell
surface membrane

Lysosome Round organelle Contains digestive enzymes to break
surrounded by membrane down materials
Can be used to digest invading…

Page 5

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


Grana (stack of thylakoids) Grana- carries out light dependent
Lamella (thin, flat pieces of stage of photosynthesis
thylakoids)

Vacuole Filled with cell sap Keeps plant supported, rigid and
turgid
produces enzymes to destroy
bacteria



PROTEIN PRODUCTION:
This is an example of…

Page 6

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


Prokaryotes are useful to humans:
Food production e.g. yoghurt
Vitamin K- digestion in mammalian
intestines
Skin bacteria- help keep out harmful
bacteria
Sewage treatment and recycling- uses
bacteria to break down waste products




EUKARYOTES PROKARYOTES

Larger cells (2- 200 µm diameter)…

Page 7

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]




Membrane consist of arranged phospholipids
Head is hydrophilic- attracts water
Tail is hydrophobic- repels water
Molecules arrange themselves into a bilayer- the heads face outwards on either side of
the membrane
Centre of bilayer is hydrophobic so membrane doesn't allow water-soluble…

Page 8

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


Glycolipids Act as receptors for cell signalling, cell binding and cell recognition
Help maintain stability of membrane



COMMUNICATION AND CELL SIGNALLING:
CELL SIGNALLING:
1) Cells communicate messages to each other
2) Cell releases a messenger molecule (hormone)
3) Then travels to…

Page 9

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


When molecules have evened out, they are evenly distributed
They still move around but there's no net movement
RATE OF DIFFUSION:
TEMPERATURE: Increasing the temperature increases kinetic energy- movement of
diffusion increases
CONCENTRATION GRADIENT: The higher it is the faster the…

Page 10

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Unit One: Cells, Exchange and Transport [BIOLOGY REVISION NOTES]


Specific for certain molecules General: non-specific

Faster than simple diffusion Go at same speed as diffusion

Against concentration gradient Down a concentration gradient




WATER POTENTIAL- The measurement of tendency of water molecules to diffuse from one
place to another
Highest water…

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