B1 Cell biology

Question 1

What is the function of the cell membrane?

Answer 1

controls the movement of substances in and out of the cell

Question 2

What is the function of the mitochondria?

Answer 2

site of respiration
transfers energy for the cell

Question 3

What is the function of chloroplasts?

Answer 3

Contain chlorophyll to absorb light energy for photosynthesis

Question 4

What is the function of ribosomes?

Answer 4

Enable production of proteins (protein synthesis)

Question 5

What is the structure of the main genetic material in a prokaryotic cell?

Answer 5

single loop of DNA

Question 6

How are electron microscope different to light microscopes?

Answer 6

Electron microscopes use beams of electrons whereas light microscopes use beams of light;
Electron microscopes cannot be used to view living samples whereas light microscopes can;
Electron microscopes are more expensive than light microscopes;
Electron microscopes have a higher magnification and resolution than light microscopes;

Question 7

What is the function of a nerve cell?

Answer 7

carries electrical impulses around the body

Question 8

Give two adaptations of a nerve cell.

Answer 8

1. Branched endings;
2. Myelin sheath insulates the axon

Question 9

Give two adaptations of a sperm cell.

Answer 9

1. Tail;
2. Contains lots of mitochondria

Question 10

What is the function of a palisade cell?

Answer 10

Carries out photosynthesis in a leaf

Question 11

Give two adaptations of a palisade cell.

Answer 11

1. Lots of chloroplasts containing chlorophyll
2. located at the top surface of the leaf

Question 12

Give two adaptations of a root hair cell.

Answer 12

1. Long projections (to increase surface area for osmosis of water)
2. Lots of mitochondria to produce energy for active transport of minerals

Question 13

Give the function of a plant vacuole

Answer 13

When filled with cell sap it puts pressure on cell wall keeping the cell rigid and supporting the plant

Question 14

Explain why methylene blue is added to a cell sample on a slide

Answer 14

Makes the nucleus and other sub cellular structures more visible

Question 15

Xylem tissue transports water and mineral ions around the plant. Explain how xylem tubes form

Answer 15

1. lignin builds up in the cell walls
2. The cells die
3. Forms long hollow tubes

Question 16

Explain two ways xylem tissue is adapted for its function

Answer 16

1. long hollow tubes - allows water and mineral ions to move easily around the plant
2. Lignin makes the cells very strong - can withstand the pressure of water moving

Question 17

Describe how to prepare and view a sample of plant cells using a light microscope

Answer 17

1. Cut slice of plant
2. Place on a microscope slide
3. Add a drop of a stain (e.g. iodine)
4. Carefully lower a coverslip onto the slide
5. Soak up excess liquid using filter paper
6. Put the slide on the microscope stage at its highest setting
7. Choose the lowest powered objective lens
8. Lower slide using focusing knob until the cells come into focus
9. Repeat with a higher objective lens to get a more detailed image

Question 18

Describe one difference between the cell walls of plant and bacterial cells

Answer 18

Plant cell walls contain cellulose; bacterial cell walls contain peptidoglycan

Question 19

Describe the differences between the way genetic material is stored in a prokaryotic cell and in a eukaryotic cell

Answer 19

In eukaryotic cells DNA is in the nucleus whereas in a prokaryotes it is in the cytoplasm (not in the nucleus);
In eukaryotic cells DNA is linear in the form of chromosomes whereas in prokaryotes DNA is circular in the form of plasmids