I km = 1000m
1m = 100 cm
1 cm = 10 mm
1 mm = 1000 micrometres
1 micrometre = 1000 nanometres
Magnification = size of image/size of real object
esolution is the ability to distinguish between two separate points
R
Magnification is the amount you can make something bigger
Animal cells - structure and function
- Nucleus : controls all the activities of the cell and is surrounded by the nuclear
membrane. Contains the genes on the chromosomes that carry instructions for making
proteins needed to build new cells / organisms
- Cytoplasm - a liquid gel in which organelles are suspended and where most of the
chemical reactions take place
- Cell membrane - controls the passage of substances such as glucose and mineral ions
into the cell. Movement of urea/hormones out of cell
- Mitochondria - where aerobic respiration occurs - releasing energy for the cell
- Ribosomes - where protein synthesis occurs
Plant cells
all plant and algal cells have a cell wall of cellulose that strengthens the cell and gives it
→
support
- Chloroplasts : green substance called chlorophyll which absorbs light so can plant can
make food by photosynthesis (apart from root hair cells - underground)
- Permanent vacuole - space in cytoplasm filled with cell sap. Keeps cell rigid to support
the plant
ukaryotic cells
E
Have cell membrane, cytoplasm and genetic material that is enclosed in a nucleus called DNA
→ linear DNA
- Animals, plants, fungi, protists are eukaryotes
rokaryotes
P
Bacteriaare single celled. Have cytoplasm and andcell membrane surrounded by cell wall, but
cell wall does not contain cellulose
Free floating circular and circular DNA
ALso contain small rings of DNA called plasmids
, rder of magnitude
O
X = 10y
Y is 1 order of magnitude over x
ifferentiation and specialisation
D
In animals
Most animal cells differentiate at an early stage of development, but plants can differentiate
throughout life.
s the cell differentiates, it gets different subcellular structures that enable it to carry out a
A
particular function.
→nerve cell
- S pecialised to carry electrical impulses around the body of an animal
- Rapid communication
- Lots of dendrites to make connections
- Axon carries nerve impulse from one place to another
- Very long
- Nerve endings (synapses) are adapted to pass the impulses to another
cell or between a nerve cell and a muscle in the body using special
transmitter chemicals. COntain lots of mitochondria needed to make the
transmitter chemicals
muscle cells
→
Contract and relax
Striped muscle cells work together in tissues called muscles
Muscles contract and relax in pairs to move bones -- allows for movement
⇒smooth muscle cells form layer of tissue in digestive system and contract for peristalsis
- Special proteins slide over each other to make fibres contract
- Mitochondria for energy for contractions
- Can store glycogen - broken down and used in cellular respiration by mitochondria
sperm cells
→
Usually released far from the egg.
Contain genetic information from male parent
Need to move through water/female reproductive system to reach egg
Then have to break into egg
- Long tail whips to help move
- Middle section full of mitochondria for tail
- Acrosome stores digestive enzymes for breaking down the outer layer of egg
- Large nucleus with genetic information
1m = 100 cm
1 cm = 10 mm
1 mm = 1000 micrometres
1 micrometre = 1000 nanometres
Magnification = size of image/size of real object
esolution is the ability to distinguish between two separate points
R
Magnification is the amount you can make something bigger
Animal cells - structure and function
- Nucleus : controls all the activities of the cell and is surrounded by the nuclear
membrane. Contains the genes on the chromosomes that carry instructions for making
proteins needed to build new cells / organisms
- Cytoplasm - a liquid gel in which organelles are suspended and where most of the
chemical reactions take place
- Cell membrane - controls the passage of substances such as glucose and mineral ions
into the cell. Movement of urea/hormones out of cell
- Mitochondria - where aerobic respiration occurs - releasing energy for the cell
- Ribosomes - where protein synthesis occurs
Plant cells
all plant and algal cells have a cell wall of cellulose that strengthens the cell and gives it
→
support
- Chloroplasts : green substance called chlorophyll which absorbs light so can plant can
make food by photosynthesis (apart from root hair cells - underground)
- Permanent vacuole - space in cytoplasm filled with cell sap. Keeps cell rigid to support
the plant
ukaryotic cells
E
Have cell membrane, cytoplasm and genetic material that is enclosed in a nucleus called DNA
→ linear DNA
- Animals, plants, fungi, protists are eukaryotes
rokaryotes
P
Bacteriaare single celled. Have cytoplasm and andcell membrane surrounded by cell wall, but
cell wall does not contain cellulose
Free floating circular and circular DNA
ALso contain small rings of DNA called plasmids
, rder of magnitude
O
X = 10y
Y is 1 order of magnitude over x
ifferentiation and specialisation
D
In animals
Most animal cells differentiate at an early stage of development, but plants can differentiate
throughout life.
s the cell differentiates, it gets different subcellular structures that enable it to carry out a
A
particular function.
→nerve cell
- S pecialised to carry electrical impulses around the body of an animal
- Rapid communication
- Lots of dendrites to make connections
- Axon carries nerve impulse from one place to another
- Very long
- Nerve endings (synapses) are adapted to pass the impulses to another
cell or between a nerve cell and a muscle in the body using special
transmitter chemicals. COntain lots of mitochondria needed to make the
transmitter chemicals
muscle cells
→
Contract and relax
Striped muscle cells work together in tissues called muscles
Muscles contract and relax in pairs to move bones -- allows for movement
⇒smooth muscle cells form layer of tissue in digestive system and contract for peristalsis
- Special proteins slide over each other to make fibres contract
- Mitochondria for energy for contractions
- Can store glycogen - broken down and used in cellular respiration by mitochondria
sperm cells
→
Usually released far from the egg.
Contain genetic information from male parent
Need to move through water/female reproductive system to reach egg
Then have to break into egg
- Long tail whips to help move
- Middle section full of mitochondria for tail
- Acrosome stores digestive enzymes for breaking down the outer layer of egg
- Large nucleus with genetic information
