exam Q's

Question 1

an optical microscope cannot be used to see plasma membrane. explain why

Answer 1

the resolution is too low as light has a longer wavelenght

Question 2

what are the similarities between diffusion, active transport and osmosis

Answer 2

-all include movement of particles
-all occur in nature

Question 3

what are the similarities between osmosis and active transport

Answer 3

both need a semi permeable membrane

Question 4

what are the similarities of osmosis and diffusion

Answer 4

-both are passive
-high to low concentration movement

Question 5

what are the similarities between diffusion and active transport

Answer 5

both involve transport of solutes

Question 6

how do you calculate precentage change in mass

Answer 6

(final - original) / original mass

Question 7

how do you work out surface area of a sphere

Answer 7

pie r squared times 4

Question 8

what two substances are are required to break the glycosidic bond in lactose?

Answer 8

-water
-lactase/enzyme

Question 9

explain how the hydrophobic region of bilayer contributes to the stability of the plasma membrane

Answer 9

-hydrophobic tails inside so helps form a bilayer
-contains cholesterol which regulates fluidity

Question 10

suggest and explain hy a low pH might cause the red pigment to leak out of the beetroot cells

Answer 10

-low pH causes tertiary structure of the phospholipid bilayer to denature
-lets more pigment through

Question 11

for which macromolecule does a plant need both nitrogen and phosphate

Answer 11

DNA

Question 12

explain how carrying out replicates improves investigation

Answer 12

-identifies anomoloies
-so a mean can be calculated

Question 13

explain the importance of osmosis in plant support

Answer 13

-water enters vacuole
-pressure against cell walls
-makes cell more turgid

Question 14

why is it neccessary to calculate precentage change in mass

Answer 14

-initial starting masses of all samples werent the same
-allows comparison between the different samples