Biology June 2009 Unit 1

Question 1

State the function of the smooth muscle fibres

Answer 1

To constrict bronchous

Question 2

Explain why blood capillaries and alveoli are very close together

Answer 2

Shorter diffusion pathway

So that concentration gradient is steeper

Question 3

State the function of cholesterol

Answer 3

Stabilise membrane, controls fluidity of membrane

Question 4

State the function of glycoproteins

Answer 4

To allow for communication

Question 5

State the role of the phospholipid bilayer

Answer 5

Act as a barrier

Selects what enters or leaves the cells

Question 6

Explain what is meant by cell signalling

Answer 6

Communication between cells

2. Cell recognition, identification
   Cells work together/co ordination between action

Question 7

State and explain two adaptions of leaves that reduce evaporation

Answer 7

Additional Guidance
Allow the first point once as further explanation for A1 – A4 in addition to the linked explanation:
reduce water (vapour) potential gradient / diffusion gradient ;
[A 1] hairy leaves ;
trap water vapour / moisture ;
[A 2] stomata, in pits / sunken ; pits trap, water vapour / moisture ;
DO NOT ACCEPT ‘water’ for ‘water vapour’ throughout
DO NOT ACCEPT ‘transpiration’ for diffusion of water
[A 3] rolled leaves / presence of hinge cells ;
reduce surface area OR (rolled leaves) trap water vapour / moisture ;
vapour throughout DO NOT ACCEPT surface area to volume ratio
[A 4] high solute concentration in cells ; reduces water potential inside leaf cells ;
[A 5] thick(er) cuticle ;
(which is) waterproof / (relatively) impermeable ;
[A 6] small leaves / needles ; smaller surface area ;
ACCEPT ‘spines’
DO NOT ACCEPT surface area to volume ratio
[A 7] fewer stomata ;
reduces diffusion (of water vapour) ;
[A 8] stomata close, during the day ; reduces diffusion (of water vapour) ;
[A 9] most stomata on lower surface ;
less exposure to sun OR cooler OR reduces diffusion (of water vapour)

Question 8

Suggest two processes inside cells that rely on the cytoskeleton for movement

Answer 8

Movement of organelles or named organelles

Movements of chromomes/ chromatids

Question 9

Suggest what might happen if the genetic information is not checked

Answer 9

1. Mutation/ faulty DNA produced
2. Daughter cells will not receive identical genetic info
3. proteins made won’t function

Question 10

Name the profess that creates pressure inside the heart chambers (1 mark)

Answer 10

Systole/contraction