Wrong questions bio

Question 1

The geneticist could obtain the HGH gene using any one of three methods.
1.      Use restriction enzymes to cut out a fragment of DNA containing the HGH gene from a human genome.
2.      Convert mRNA for HGH into cDNA using reverse transcriptase.
3.      Create the HGH gene using a ‘gene machine’.
(a)     The geneticist decided not to use restriction enzymes to cut out a fragment of DNA containing the HGH gene from a human genome. She made this decision because only methods 2 and 3 would produce DNA that E. coli could use to make HGH.
Explain why only methods 2 and 3 would produce DNA that E. coli could use to make HGH.

Answer 1

 1.      Human DNA / human gene / HGH gene contains introns
OR
Methods 2 and 3 produce DNA / HGH without introns;
2.      E. coli cannot remove introns / cannot splice mRNA / cannot splice pre-mRNA;

Question 2

     The desired gene in the diagram was from an insect. In stage 6, the plant containing this gene was able to use it to synthesise an insect protein.
The plant is able to synthesise the insect protein. Explain why this is possible

Answer 2

  1.      Genetic code is universal/triplets in DNA always code for same amino acid;
2.      It/insect DNA can be transcribed;
3.      Can be translated (process/mechanism same in all organisms/cells);
2. Accept (basic) transcription (process/mechanism) same in all organisms/cells;

Question 3

Any DNA in the sample is hydrolysed by enzymes before the sample is added to the reaction mixture.

Answer 3

  1.      To remove any DNA present;
2.      As this DNA would be amplified / replicated;

Question 4

Explain the advantage of lipid droplet and Michelle formation

3 marks

Answer 4

1. Droplets increase surface areas (for lipase /
   enzyme action);
2. (So) faster hydrolysis / digestion (of
   triglycerides / lipids);
3. Micelles carry fatty acids and glycerol /
   monoglycerides to / through membrane / to (intestinal epithelial) cell;

Question 5

Describe the role of micelles in the abrosbtpion of fats into the cells lining the ileum

(3 marks but 5 points)

Answer 5

1. Micelles include bile salts and fatty acids;
2. Make the fatty acids (more) soluble in water;
   For ‘fatty acids’ accept fats / lipids.
3. Bring/release/carry fatty acids to cell/lining (of the ileum);
   For ‘fatty acids’ accept fats/lipids.
   4.Maintain high(er) concentration of fatty acids to cell/lining (of the ileum);
4. Fatty acids absorbed by diffusion

Question 6

Give one similarity and one difference between a taxis and a tropism.

Answer 6

. Similarity − directional response (to a stimulus) / movement
towards / away from a stimulus;
2. Difference − taxis (whole) organism moves and tropism a growth (response).

Question 7

The use of IPS cells advantages over gene therapy

Answer 7

1. iPS cells) divide;
2. (iPS cells) develop/differentiate into (green sensitive) cones;
   2
   (f) 1. (Use of iPS cells) long-term;
   Accept ‘gene therapy short-term’ or ‘only two years’
   Accept ‘permanent’
3. (Use of iPS cells) less chance of rejection/immune response;
4. (Use of iPS cells) single treatment;
   Accept ‘gene therapy ‘regular/frequent treatment’’
5. Harm/side effects from using viruses (in gene therapy);

Question 8

Something sex linked affects men more than women,
Why

Answer 8

Gene/allele) is on the X chromosome;
2. Females require two alleles/females can be heterozygous/carriers and males require one allele;

Question 10

If the glomerular filtrate of a diabetic person contains a high concentration of glucose, he produces a larger volume of urine. Explain why.

Answer 10

Glucose in filtrate lowers water potential;
Ignore ‘urine’. Accept increase solute potential
Lower Ψ gradient / less difference in Ψ filtrate − Ψ plasma;
Ignore ‘concentration’
Less water reabsorbed by osmosis;

Question 11

Damage to the myelin sheath of neurones can cause muscular paralysis (lines 2-4).
Explain how.

Answer 11

(Refers to) saltatory conduction
OR
(Nerve) impulses/depolarisation/ions pass to other neurones
OR
Depolarisation occurs along whole length (of axon);
Accept suitable description that refers to (transmission) from node to node (of Ranvier).
Accept action potential for depolarisation.
1 and 2. Accept action potentials for impulses.

(Nerve) impulses slowed/stopped;
(Refers to) neuromuscular junction
OR
(Refers to) sarcolemma;

Question 12

synapses ensure that nerve impulses only travel towards the muscle fibre.
Explain how.

Answer 12

NT made in pre synap

Receptors only on the post synapse

Question 13

A woman takes moderate exercise. Explain what causes her heart rate to increase while she exercises.

Answer 13

Rate of resp increases

carbon dioxide concentration increases / pH falls / H+ increases / acidity
increases;
3. chemoreceptors in aortic / carotid bodies / medulla (accept reference to aorta /
carotid arteries not sinus);
4. (impulses to) medulla / cardioaccelerator centre;
5. increased frequency of impulses (award only once);
6. along sympathetic pathway to sinoatrial node / SAN

Question 14

suggest how these two species of palm tree arose by
sympatric speciation.

Answer 14

1. Occurs in the same habitat/environment/population;
2. Mutation/s cause different flowering times;
3. Reproductive separation/isolation
   OR
   No gene flow
   OR
   Gene pools remain separate;
4. Different allele/s passed on/selected OR
   Change in frequency of allele/s;
5. Disruptive (natural) selection;
6. Eventually different species cannot (inter)breed to produce fertile offspring;

Question 15

For inhibiting the enzyme that breaks down acetylcholine why is it good (3m)

Answer 15

Less/no acetylcholine broken down;
2. Acetylcholine attaches to receptors;
3. (More) Na+ enter to reach threshold/for depolarisation/action potential/impulse;