Exam specific answers

Question 1

describe the role of one organelle in digesting bacteria? (3)

Answer 1

lysosomes
fuse with the vesicle
they release hydrolytic enzymes

Question 2

outline the role of organelles in the production, transport and release of proteins from eukaryotic cells? (5)

Answer 2

DNA in nucleus codes for proteins
ribosomes produce proteins
mitochondria produce ATP for protein synthesis
Golgi apparatus package and modify proteins
RER transports proteins

Question 3

name two structures found in all bacteria that are not found in plant cells? (2)

Answer 3

plasmids, 70S ribosomes, murein cell wall

Question 4

why is it important that a thin section of tissue is cut for light microscopy? (2)

Answer 4

so the light rays can penetrate through the tissue to prevent overlapping of organelles

Question 5

describe two ways in which molecules of cellulose are similar to molecules of starch? (2)

Answer 5

they are both polymers
they are both made of monomers
both molecules can be broken down by a hydrolysis reaction
both contain glycosidic bonds

Question 6

contrast the way optical microscopes and transmission electron microscopes work and contrast their limitations? (6)

Answer 6

TEM uses electrons and optical use light
TEM allows greater resolution
with TEM smaller organelles can be observed
TEM only views dead specimens and optical can view live specimens
TEM doesn’t show colour but optical can
TEM requires thinner specimens
TEM requires more complex preparation
TEM focuses using magnets and optical uses lenses

Question 7

explain how to prepare a specimen for viewing with an optical microscope? (4)

Answer 7

1. add a drop of water to a glass slide
2. obtain a thin section of tissue and place on slide
3. stain with iodine in potassium iodide
4. lower cover slip using mounted needle

Question 8

explain why the solution used in homogenisation must be cold, isotonic and buffered? (3)

Answer 8

cold - slow enzyme activity to prevent digestion of organelles
isotonic - prevent osmosis so organelles don’t shrink
buffer - maintain pH so enzymes aren’t denatured

Question 9

give two ways in which the hydrolysis of ATP is used in cells? (2)

Answer 9

1. to provide energy for other reactions
2. to add phosphate to other substances and change their shape