1. Cell Structure

Question 1

Magnification

Answer 1

The number of times larger an image is than the actual object

Question 2

Resolution

Answer 2

The ability to distinguish between two objects that are very close together; the higher the resolution of an image, the greater the detail that can be seen

Question 3

Describe the role of plasmodesmata in transport in plants. [3m]

Answer 3

• allow substances, eg. amino acids, sucrose, to be transported from 1 cell to another
• without crossing the cell surface membrane & cell wall
• also allows signalling/communication between cells

Question 4

Explain why, at the same magnification, an electron micrograph is able to provide more detail than a light micrograph. [2m]

Answer 4

• electron microscope has a higher resolution
• b/c electrons have shorter wavelength than light
• higher resolution gives a greater ability to distinguish between 2 objects very close together

Question 5

State the advantages of light microscopy, rather than electron microscopy, for studies of the cell cycle. [3m]

Answer 5

• allows living cells to be observed
• can use stains/dyes
• all chromosomes can be seen at once
• can see cell cycle (eg. mitosis) in real time

Question 6

Some features visible in an electron micrograph may not be present in the living cell. Explain why. [1m]

Answer 6

Lengthy preparation process may distort cell contents/introduce artefacts

Question 7

4 functions of large vacuole

Answer 7

1. holds cell sap
2. holds sugars, minerals, pigments
3. gives turgidity
4. holds waste products