exam stuff

Question 1

placenta structure

Answer 1

The villi providing a large surface area for diffusion
capillaries bring nutrients and remove waste products
blood supply maintains a diffusion gradient
cloe distance between mothers ans fetal blood for short diffusion pathway

Question 2

how can baby do active transport because of moms cells transferred

Answer 2

oxygen (1)
glucose (1)
respiration (1)
energy / ATP (1)
to use for active transport

Question 3

type of molecule mom gives to fetus to battle infection

Answer 3

antibodies (from mother) (1)
(bind to) antigens (1)
to kill bacteria / pathogen /
virus eq (1)

Question 4

Describe the changes that take place in the eye when it focuses on a near object.

Answer 4

1. the ciliary muscle(s) contract / structure I
   contract(s) / eq (1)
2. the tension in the suspensory ligament(s) is
   reduced / loosened / slackens / eq (1)
3. the lens becomes thick(er) / wide(r) /
   fat(ter) / round(er) / more convex / eq (1)
4. the light is refracted more / bent more / eq
   (1)
5. accommodation (1)

Question 5

withdrawal from hot object (5)

Answer 5

receptor / nerve ending; sensory neurone / sensory nerve;
impulse / message / signal;
CNS / spinal cord / grey matter;
synapse;
relay neurone / relay nerve;
motor neurone ;
muscle / effector;
contract;

Question 6

measure SA to V of cylinder

Answer 6

Ruler

Question 7

semi lunar valves

Answer 7

from arteries to ventricles

Question 8

A doctor claims that if he stops giving antibiotics to any patients who are ill, he can reduce the number of predicted deaths caused by resistant bacteria in 2050.

Comment on this claim (4)

Answer 8

stopping antibiotics allows non-resistant
bacteria to increase / grow / no more
increase in resistance or antibiotics allow
resistant bacteria to increase / grow (1)
* less selection pressure (for antibiotic
resistance) / competition (for resources)
(1)
* most infections (would now be) caused
by non-resistant bacteria (1)
* antibiotics will be effective in most cases
/ against more bacteria (1)
* use new / different antibiotics (instead of
not using any) (1)
* some patients may die / suffer / eq if not
given antibiotics / from other things (1)

Question 9

enzymes at 55 degrees in respiration

Answer 9

enzymes denatured (1)
* changes shape of active site (1)
* substrate can no longer fit / E/S complexes do not form

Question 10

Forty per cent of the energy in the producers transfers to decomposers.
Only twenty per cent of the energy in the primary consumers transfers to decomposers.
Explain this difference in energy transfer

Answer 10

producers / plants contain cellulose (1)
* less energy in producers absorbed / transferred to
(primary) consumers / eq (1)
* (more) producers / plants are undigested / not digested
/ not eaten / eq (1)
* decomposers can digest cellulose / eq (1)
* (primary) consumers lose more energy in respiration /
respire more / more heat loss (1)
* (primary) consumers lose more energy in movement /
eq (1)

Question 11

test without chlorophyll

Answer 11

keep all leaves in normal atmosphere / no NaOH (1)
* use variegated leaf / eq / use a leaf with chlorophyll and
one without (1)
* compare blue black / starch areas with green areas /
areas with chlorophyll / eq (1)

Question 12

Explain the differences in the pattern of inheritance between a condition caused
by a dominant allele and a condition caused by a recessive allele

Answer 12

dominant allele is always expressed (in
phenotype) / only requires one allele /
recessive allele requires two copies to be
expressed / recessive alleles are only
expressed when homozygous / eq (1)
* dominant condition more common / frequent
/ high probability of passing on / eq (1)
* recessive condition has carriers (1)
* recessive version can appear when both
parents unaffected / skips generations / eq
(1)

Question 13

Describe how the structure of the leaf is adapted for photosynthesis. (5)

Answer 13

leaf flat / wide / large SA for diffusion / gas exchange / light absorption (1)

 leaf thin so no cells far from surface to absorb light / short diffusion distance (1)

 upper epidermis transparent to allow light through (1)

 palisade (mesophyll) cells contain many chloroplasts / much chlorophyll (near surface) to absorb light (1)

 spongy (mesophyll) / cells have air spaces / not tightly packed / for gas exchange / diffusion (1)

(lower surface) has stomata to absorb carbon dioxide (1)

 xylem / vascular bundle bring water for photosynthesis

Question 14

There are tear glands that release liquid into the eye.
This liquid contains an enzyme called lysozyme that breaks down cell walls.

(i) Suggest why the liquid contains lysozyme.

Answer 14

 (breaks down / digests cell walls of / kill / prevent growth of / remove / protect from ) bacteria / fungi / pathogens / microorganisms / eq (1)
 prevent infection / disease (1)

Question 15

reflex arc

Answer 15

The pin (the stimulus) is detected by a (pain/pressure/touch) receptor in the skin on the person’s foot

A sensory neurone sends electrical impulses to the spinal cord (the coordinator)

An electrical impulse is passed to a relay neurone in the spinal cord (part of the CNS)

A relay neurone synapses with a motor neurone

A motor neurone carries an impulse to a muscle in the leg (the effector)

When stimulated by the motor neurone, the muscle will contract and pull the foot up and away from the sharp object (the response)

Question 16

Explain why the actual response time is different from the time taken for a
nerve impulse to travel 180cm.

Answer 16

response time slower / longer
/delay / (more) time taken / eq
(1)
2. (delay / transmission ) between
neurones / in between neurones /
not just speed along neurones /
eq (1)
3. (includes time) to generate
impulse (in receptor) / (time) for
muscle to contract / eq (1)
4. chemical coordination / diffusion /
eq (1)
5. synapse (1)
6. neurotransmitter / named
neurotransmitter (1)

Question 17

yeast in bread production (5)

Answer 17

yeast respires (aerobically) / eq (1)

yeast (then) respires anaerobically / eq
(1)

converts starch to maltose / maltose to
glucose / starch to glucose / eq (1)

using amylase / maltase /eq (1)

releases carbon dioxide /eq(1)

causes (dough / bread) to rise / bubbles
trapped / volume increases /eq (1)

Question 18

Explain why selective breeding with crop plants is easier and quicker than
selective breeding with farm animals.

Answer 18

plants produce many more
(seeds) / offspring /more yield /
eq (1)
 quicker to reach maturity /
quicker to develop / shorter life
cycle / eq (1)
 plants can be self-pollinated / eq
(1)
 easier to control plants
environment / eq (1)

Question 19

Describe the production of adrenaline and its effects on the body

Answer 19

1. produced by adrenal glands (1)
2. causes heart rate to increase /eq (1)
3. prepares body for fight / flight / fright / eq (1)
4. increases blood flow to muscles / blood diverted from
   intestines/eq (1)
5. increases breathing rate / depth / eq (1)
6. converts glycogen into glucose / increase blood glucose
   /increase blood sugar / eq (1)
7. pupils dilate / eq (1)
8. reactions are faster / eq (1)

Question 20

which one is inhaled and which one is exhaled

Answer 20

left inhaled right exhaled
right will have more co2 so will turn cloudy

Question 21

State what is meant by the term allele.

Answer 21

(alternative) form / version of a gene /

Question 22

State what is meant by the term gene.

Answer 22

section of dna that codes for a specific protein

Question 23

recombinant

Answer 23

contains foreign DNA

Question 24

vitamin D sources

Answer 24

supliments and sunlight

Question 25

pain withdrawal answer not mark scheme

Answer 25

Receptors in skin detect stimulus receptors send impulses to sensory neuron sensory neuron send impulses to relay neuron impulses travel between neurons via diffusion of neurotransmitters in synapses to motor neuron sends impulses to effector

Question 26

what does soda lime do

Answer 26

absorb carbon dioxide