Topic 1 - Cell biology: Cell Structure

Question 1

Name two pieces of laboratory equipment the student could have used to
prepare cells to view using a microscope

Answer 1

cover slip
* dye / stain

Question 2

What is the function of the focus on a microscope

Answer 2

to focus (the image / cells) or improve resolution

Question 3

Compare the structure of a red blood cell with the structure of a plant cell

Answer 3

differences:
* red blood cell has no nucleus or plant cell has a nucleus
* red blood cell has no cell wall or plant cell has a cell wall
* red blood cell is a biconcave disc or there are many different
shapes of plant cell
* red blood cell contains haemoglobin or plant cells do not
contain haemoglobin
* red blood cells do not contain chlorophyll or plant cells (may)
contain chlorophyll

Similarities:
ences:
* red blood cell has no nucleus or plant cell has a nucleus
* red blood cell has no cell wall or plant cell has a cell wall
* red blood cell is a biconcave disc or there are many different
shapes of plant cell
* red blood cell contains haemoglobin or plant cells do not
contain haemoglobin
* red blood cells do not contain chlorophyll or plant cells (may)
contain chlorophyll

Question 4

Explain why the red blood cell bursts but the plant cell does not burst

Answer 4

water enters
plant cell has cell wall

Question 5

How is a root hair cell adapted to increase the absorption of substances from the soil

Answer 5

(d) large surface / area for faster osmosis

Question 6

Describe one feature of the cell that helps it to carry out its function. (nerve cell)

Answer 6

long
* has branches

Question 7

Describe two aseptic techniques the student should have used to prepare antibiotics use on bacteria

Answer 7

sterilise equipment / surfaces (before use)
* (use) sterilised agar
* secure lid of the Petri dish with (adhesive) tape

Question 8

(d) Suggest one way the student could improve the investigation. (anitbiotics on bacteria)

Answer 8

• repeat and calculate a mean
  or use a control disc

Question 9

(c) Name the cells in a leaf that control the rate of water loss.

Answer 9

guard cells

Question 10

(e) Which change would decrease the rate of water loss from a plant’s leaves?

Answer 10

(e) increased humidity

Question 11

(f) Compare the structure and function of xylem tissue and phloem tissue. (6) Structure

Answer 11

xylem is made of dead cells + phloem is made of living cells
* xylem is hollow or xylem does not contain cytoplasm + phloem contains cytoplasm
* xylem contains lignin + phloem does not

Question 12

Compare the structure and function of xylem tissue and phloem tissue. (6) function

Answer 12

xylem transports water / mineral ions
and
phloem transports (dissolved) sugars
* xylem is involved in transpiration
and
phloem is involved in translocation
* xylem transports unidirectionally
and
phloem transports bidirectionally

Question 13

Give two similarities between the prokaryotic cell and the eukaryotic cells
in the diagram above

Answer 13

cytoplasm
* (cell) membrane
* DNA / genetic materia

Question 14

(b) Give three differences between the prokaryotic cell and the eukaryotic cells

Answer 14

prokaryotic cell is smaller
* prokaryotic cell has plasmids
* prokaryotic cell has no nucleus

Question 15

Name the type of cell division that produces genetically identical body cells
for growth and repair.

Answer 15

mitosis

Question 16

Describe what happens during each stage of the cell cycle.
Stage 1

Answer 16

DNA / chromosomes replicate / duplicate
sub-cellular structures increase in number

Question 17

Describe what happens during each stage of the cell cycle.
Stage 2

Answer 17

one set of chromosomes is pulled / moved to each end of the cell

Question 18

Describe what happens during each stage of the cell cycle.
Stage 3

Answer 18

the cytoplasm and cell membrane divides to form two genetically identical cells

Question 19

Give two advantages of using an electron microscope instead of a light
microscope.

Answer 19

(f) high(er) magnification
high(er) resolution or high(er) resolving power

Question 20

(f) Why might scientists want to clone plants?

Answer 20

(f) to protect endangered plants from extinction

Question 21

(g) What is the advantage of cloning plants using tissue culture?

Answer 21

(g) plants can be produced quickly

Question 22

Name one substance in the growth medium.

Answer 22

glucose / sugars / starch
* amino acids / protein
* hormones

Question 23

What is the function of ribosomes?

Answer 23

c) make / synthesise / produce protein

Question 24

Explain why the mean rate of water uptake is higher on a hot day than on a
cold day in a plant (3)

Answer 24

(on hot day) more water lost

more transpiration

so more water taken up (by roots) to replace (water) loss (from leaves)

Question 25

Explain why root hair cells contain mitochondria.

Answer 25

(aerobic) respiration occurs in mitochondria

(mitochondria / respiration) release energy
do not accept energy produced / made / created

(energy used for) active transport

to transport ions, against the concentration gradient

Question 26

What type of microscope is needed to see ribosomes and mitochondria?

Answer 26

electron