June 2016 Wjec unit 1

Question 1

Organic molecule example?

Answer 1

starch
amino acid

Question 2

Tissue example?

Answer 2

blood

Question 3

Ion example?

Answer 3

phosphate

Question 4

Polymer example?

Answer 4

starch

Question 5

Element example?

Answer 5

Phosphorous

Question 6

Why is phospholipid both hydrophobic and hydrophillic?

Answer 6

Head - hydrophillic
tail - hydrophobic

Question 7

One function of triglyceride?

Answer 7

buoyancy
thermal insulation
protection of delicate internal organs
source of metabolic water

Question 8

Phospholipid?

Answer 8

component of cell membrane

Question 9

Why is DNA described as a polymer?

Answer 9

chain of repeating monomers

Question 10

What connects the cytoplasm of adjacent plant cells?

Answer 10

plasmodesmata

Question 11

Describe how this substance was secreted from the cell?

Answer 11

membrane of secretory vesicles with cell membrane
contents released from cell
exocytosis

Question 12

Explain the formation of Hydrogen bonds between water molecules?

Answer 12

Polar moleule
H is slightly positive
O is slightly negative
forms bonds between Hydrogen and oxygen on adjacent molecule

Question 13

What is the significance of ice being less dense than water?

Answer 13

so floats on surface, provides a habitat to live on

Question 14

Latent heat of vaporisation?

Answer 14

has a role in cooling the body through sweating

Question 15

cohesion between water molecules?

Answer 15

allows movement through the xylem
surface tension - allows insects to walk

Question 16

High specific heat capacity?

Answer 16

minimises temp fluctuation in aquatic habitats

Question 17

Dissolves ionic substances?

Answer 17

used for transport of molecules

Question 18

State the relationship between the variables?

Answer 18

between 0 and 2%, the polyphenol oxidase concentration doubles the time taken for the standard brown colour to develop halves
above 1% time taken plateaus

Question 19

What factor would be limiting the reaction?

Answer 19

substrate concentration

Question 20

What would addition of lemon juice do?

Answer 20

enzyme is not at optimum pH
enzymes dentured
less enzyme - substrate complexes formed

Question 21

Freezing immediately after prepration?

Answer 21

Lowers kinetic energy
fewer successful collisions

Question 22

Vacuum packing?

Answer 22

no 02
oxygen needed for enzyme activity

Question 23

Straight line uptake?

Answer 23

diffusion
as concentration difference increases, the rate of uptake also increases
not affected by respiratory inhibitors

Question 24

Straight line then plateau?

Answer 24

facilitated diffusion
at high concentration differences, rate of uptake plateaus
carrier proteins are saturated
not affected by respiratory inhibitors because the process needs ATP

Question 25

The straight line then plateaus and goes down?

Answer 25

Active transport
at high concentration differences, rate of uptake levels
are affected by respiratory inhibitors because the process needs ATP

Question 26

Why is the percentage of transmission the lowest between sodium chloride concentrations of 0 and 3?

Answer 26

water moves by osmosis
higher water potential outside the red blood cell
there is no cell wall to prevent bursting
most haemoglobin is released, therefore lowest transmission of light

Question 27

Why is there a range of concentrations at which hemolysis occurs?

Answer 27

different cells have different solute concentrations
each cell would require a different external water potential

Question 28

What would happen to the cell that was placed in a concentrated salt solution?

Answer 28

plasmolysis of cell
therefore cytoplasm decreases in volume
cell membrane pulls away from cell wall
vacuole decreases in volume

Question 29

Pressure potential of the cell after it had been in the concentrated salt solution?

Answer 29

0 kPa?