Mistakes from Module 2 Practice Questions

Question 1

how to prepare a blood smear that can be used on a slide

Answer 1

1. use pipette to place blood on the slide
2. please blood near one end of the slide
3. use cover slip to spread it by placing it at an angle

Question 2

Explain how the students would use the different objective lenses of a light microscope to focus and observe the pond water sample at high power magnification.

Answer 2

1. select low power lens
   then higher power ✓
   use coarse focus to
2. find, correct field of
   view / object ✓
3. use fine focus for
   clear(er) image ✓
   ref to x4 / x10 / x40
4. (lens power /
   magnification) ✓

Question 3

estimate diameter of e.coli cell

Answer 3

0.1 - 10 𝝁m

Question 4

Roles of the cell surface membrane

Answer 4

cell signalling/communication
regulates what substances can enter and leave the cell
site of some chemical reactions

Question 5

effect of cholesterol on membrane fluidity

Answer 5

low temp → cholesterol increases fluidity
high temp → cholesterol decreases fluidity
the conc of saturated and unsaturated fatty acids / presence of a solvent can also affect the fluidity

Question 6

what is a purine

Answer 6

has hexagon and pentagon
adenine and guanine

Question 7

what is a pyrimidine

Answer 7

has only hexagon
thymine, cytosine, uracil

Question 8

correct description of the structure of adp

Answer 8

it is a nucleotide

Question 9

use of dna polymerase in cells

Answer 9

catalyse formation of phosphodiester bonds between nucleotides in template strand

Question 10

use of dna helices in cells

Answer 10

unwind/unzip DNA’s double helix