New Paper 1

Question 1

Advantages of asexual reproduction

Answer 1

1. (Fewer stages so) quicker
2. Only one parent involved to can colonise new environment on its own
3. Produces clones so successful genotype maintained

Question 2

Advantage of sexual reproduction

Answer 2

Increases genetic diversity so greater chance of survival of species

Question 3

Explain why the Vmax of competitive inhibitor is higher than the Vmax of non-competitive inhibitor

Answer 3

1. Comp inhib binds to active site but non-comp inhib binds to allosteric site
2. Non-comp inhib changes the shape of enzyme active site but comp inhib
3. So with comp inhib, enzyme active site still available after use, but non-comp inhib no active site of enzyme available
4. Therefore at higher substrate concentration likelihood of enzyme substrate complex formation increases with comp inhib but doesn’t with non-comp inhib

Question 4

What does it mean when PCC (R) is POSITIVE , eg. 0.50,with P<0.0001

Answer 4

1. Positive correlation
2. The probability of getting this čõrrėłãtìõñ is less than 0.0001
3. So čõrrėłãtìõñ is highly significant
   (R CAN BE AN EXAMPLE FOR ANY RESULT SO JUST REPLACE Correlation FOR DATA)

Question 5

Contrast the structure of human (eukaryote) cell no bacteria (prokaryote) cell (7 marks)

Answer 5

1. Bacteria don’t have a nucleus but human cells do
2. Bacteria don’t have membrane-bound organelles but human cells do
3. Bacterial ribosomes are smaller(70s) than human cells(80s)
4. Bacterial DNA is circular but human DNA is linear
5. Bacterial DNA is naked but human DNA is bound to histones
6. Bacterial cell is MUCH smaller than human cell
7. Bacterial cell has cell wall but human cells do not

Question 6

Describe how the bacteria Nm can become resistant to to an antibiotic (2017 version) [3 marks]

Answer 6

1. Random Mutation
2. Results in bacterial cell with resistant allele to the antibiotic
3. This cell survives and passes allele to offspring as it reproduces

Question 7

Describe how a vaccine can result in immunity

Answer 7

1. Vaccine contains pathogen antigens
2. Phagocyte presents antigen on cell surface membrane
3. Antigen binds to surface receptor on B cell
4. Activated Helper T cells stimulate the B cell to divide by mitosis and produce clone of plasma cells
5. Plasma cells release antibodies
6. Some B cells develop into memory cells
7. Memory cells produce more antibodies and faster on encounter to same antigen

Question 8

Role of stop codons on mRNA

Answer 8

1. Stop translation

2. Resulting in the detachment of polypeptide from ribosome

Question 9

Structural differences between virus and bacterial cell

Answer 9

Bacteria:
1. Cell surface membrane 
2. Cytoplasm 
Virus:
 Capsid

Question 10

Adaptations of arteries to its functions

Answer 10

1. Muscle layer contracts and relaxes to control blood flow
2. Elastic tissue to expand and recoil to maintain blood pressure
3. Smooth endothelium to reduce friction
4. No valves

Question 11

2 ways to ensure no oxygen in solution

Answer 11

1. Use boiled and cooled water
   OR
2. Layer of oil in top of solution;

Question 12

Describe and explain how active transport and facilitated diffusion are used in the uptake of ions (calcium/chloride)

Answer 12

Without oxygen:

1. Between 0 and 0.1 (calcium) ions cannot enter because no diffusion gradient
2. Between 0.1 and 0.3 ions can enter by facilitated diffusion;
3. As oxygen is not required for facilitated diffusion;
   With oxygen:
4. Between 0 and 0.1 ions enter by active transport;
5. Movement is against the concentration gradient;
6. As oxygen is required for active transport;