1
Q
Eukaryotic cells
A
Complex - includes all animal and plant cells
2
Q
Prokaryotic cells
A
- Simpler and smaller
- Single celled organisms
3
Q
Nucleus
A
Contains genetic material that controls the cell
4
Q
Cytoplasm
A
Where most reactions happen. Enzymes control the reaction
5
Q
Cell membrane
A
Controls what comes in and out
6
Q
Mitochondria
A
Where most reactions for aerobic respiration occur
7
Q
Ribosomes
A
Where proteins are made
8
Q
Rigid cell wall
A
- only in plant
- made of cellulose
- supports and strengthens the cell
9
Q
Permanent vacuole
A
- only in plants
- contains cell sap (weak solution of sugar and salts)
10
Q
Chloroplasts
A
- only in plants
- where photosynthesis occurs (makes food for the plants)
- contains a green substance called Chlorophyll
11
Q
Plasmids
A
- (Not in plant or animal but in bacterial cells)
- small rings of DNA
12
Q
Bacterial cell contains… (5)
A
- cytoplasm
- cell wall
- cell membrane
- (optional) plasmids
- single circular strand that floats freely in the cytoplasm
13
Q
Bacterial cells are…
A
Prokaryotes
14
Q
Light microscopes use…
A
Light
15
Q
Electron microscopes use…
A
Electrons - better than light microscopes
16
Q
Magnification formula
A
Magnification = image size / real size
17
Q
How many μm in 1mm?
A
1000
18
Q
Differentiation
A
When a cell changes to become specialised for its job
19
Q
Stem cells
A
Undifferentiated cells
20
Q
Sperm cell. (4)
A
- reproduction
- long tail and streamline
- lots of mitochondria
- carries enzymes
21
Q
Nerve cell. (4)
A
- rapid signalling
- carries electrical signals around the body
- long to cover more distance
- branched connections to form a network across the body
22
Q
Muscles cells. (3)
A
- contracts quickly (function)
- long to have space to contract
- lots of mitochondria to generate the energy needed
23
Q
Root hair cells. (3)
A
- absorbing water and minerals
- on the surface of plant roots
- big Surface Area to absorb water and minerals
24
Q
Phloem cells (4)
A
- transportation
- forms Phloem tubes which transport food and water
- long and join end to end
- few sub-cellular structure so stuff can go through
25
Xylem cells (4)
- transportation
- forms xylem cells
- long and joined end to end
- hollow
26
What contains your chromosomes?
Nucleus
27
Chromosomes are coiled up lengths of...
DNA Molecules
28
Amount of chromosomes in a human cell
23 pairs (total 46)
29
Stage 1 of the cell cycle?
Growth and DNA replication
30
Stage 2 of the cell cycle?
Mitosis
31
Stage 3 of the cell cycle?
Cytokenisis
32
What happens during stage 1 of the cell cycle? (3)
- DNA is spread into long strings
- cells increases amount of sub-cellular structure
- duplicates its DNA forming X-shaped chromosomes
33
What happens during stage 2 of the cell cycle? (2)
- the chromosomes line up at the centre of the cell
| - cell fibres pull them apart
34
What happens during stage 3 of the cell cycle? (3)
- inner membrane forms around the new set of chromosomes
- the cytoplasm and cell membrane divides
- forms two new daughter cells
35
Stem cells that cannot turn into any cell type
Adult stem cells
36
Positives of stem cell research (3)
- cure diseases by transferring healthy cells to a patient
- replace faulty cells
- therapeutic cloning makes the embryo have the same genetic info as the patient meaning it wouldn't get rejected
37
Negatives of stem cell research. (2)
- human embryos are a potential life threat
| - cells grown in labs could get contaminated
38
Where are stem cells found in the plant?
The meristems
39
Meristems
Part of the plant where growth occurs
40
Cells in meristem tissues can differentiate. True of false?
True
41
Advantages of using stem cells in plants. (2)
- produce clones of whole plants quickly (for endangered plants)
- grow more plants
- make crops with desirable features (eg. Disease resistant)
42
Osmosis definition
Osmosis is the moment of water molecules through a partially permeable membrane from a region of higher water concentration to an area of lower water concentration
43
Active transport
Substance that need to be absorbed against a concentration gradient
44
Example of active transport
- plants need minerals for health growth
- the concentration of minerals is usually higher in the root hair cell than in the soil around it
- so they need to absorb minerals against the concentration gradient
45
Active transport doesn't need energy. True of False?
False - needs energy from respiration to make it work
46
Larger Surface Area means you can absorb more substances at once. True of False?
True
47
How do you find out how easy it is for an organism to exchange substance?
Surface Area : Volume Ratio
48
Ways in which exchanging surfaces are adapted to maximise effectiveness. (4)
(Both) - thin membrane = short distance to diffuse
(Both) - big Surface Area = lots of substances can diffuse at once
(Animal) - lots of blood vessels = gets things in and out of blood quickly
(Animal) - gas exchange surfaces are ventilated = air moves in and out
Biology
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