Practice question mistakes

Question 1

Give one way that an image produced by a LSC microscope differs from an electron microscope [1]

Answer 1

• lower res
• fluorescent tag
• movement
• diff layers

Question 2

Explain how to measure the diameter of the nucleus of one of the cells when observing thru a LIGHT microscope [4]

Answer 2

• use eyepiece graticule
• calibrate graticule, using stage micrometer (calc length of 1 epu)
• measure the diameter of nucleus in epu
• take repeat measurements & calc a mean diameter in epu
• multiply epu by calibration factor to calc diameter

Question 3

3 improvements to dry mount and explain why they increase validity [6]

Answer 3

• sharp blade (so slide is thin enough & individual cells are visible)
• wet mount (prevents dehydration/distortion of cells)
• squash slide (easier to see individual cells)

Question 4

Describe how the student could use the temporary mounts to determine the mean number of chloroplasts in the leaf cells [3]

Answer 4

• select large number of cells OR select cells at random
• count the total number of chloroplasts in those cells
• divide the number of chloroplasts by the number of cells counted

Question 5

What is the animal cell organelle that contains 70S ribosomes [1]

Answer 5

mitochondria

Question 6

Describe why ATP is the universal energy currency [3]

Answer 6

why it is universal: Used in all organisms
why it is energy: Releases energy in small quantities
why is it currency: coupled w/ energy requiring activities

Question 7

Explain the importance of the cytoskeleton being a dynamic structure and how its presence could aid with the movement of cell material [5]

Answer 7

TBC

Question 8

Describe the roles of the cytoskeleton [3]

Answer 8

• cell support
• movement of cilia/flagella
• changing cell shape eg muscle contraction
• organelle movement/holding in place
• movement of chromosomes