2016 Unit 2

Question 1

Explain what is meant by the term phylogenetic group

Answer 1

• (Grouped according to)
evolutionary
links/history/relationships /
common ancestry

Question 2

Explain what is meant by the term species

Answer 2

• Able to reproduce

* To produce fertile offspring;

Question 3

What term is used to describe the structure of a protein made of two or more
polypeptides?

Answer 3

• Quaternary (structure);

Question 4

Each alpha polypeptide has 141 amino acids.

Calculate the minimum number of DNA bases needed to code for the number of amino
acids in one alpha polypeptide.

Answer 4

• 423

Question 5

Describe the role of haemoglobin in supplying oxygen to the tissues of the body.

Answer 5

• Oxyhaemoglobin formed in area of higher ppO2
• (Oxygen) unloaded/dissociates
(in area of lower ppO2 / in capillaries/to cells/tissues)

Question 6

Explain the advantage to a person with anaemia of the change shown in the oxygen dissociation curve

Answer 6

• (Anaemia curve shifted to right)
haemoglobin has lower affinity for
oxygen 
• Releases more oxygen/oxygen
dissociates/ unloads more readily
to muscles/tissues/cells
• (For) respiration

Question 7

What is meant by species diversity?

Answer 7

• Number of species in a community;

Question 8

Give two pieces of information needed to calculate an index of diversity for a community.

Answer 8

• Number of (organisms of) each
species
• Total number of organisms (of all
species) / Total number of species

Question 9

Name the structure through which gases enter and leave the body of an insect

Answer 9

• Spiracle;

Question 10

Name the small tubes that carry gases directly to and from the cells of an insect.

Answer 10

• Tracheole/trachea

Question 11

Explain the movement of oxygen into the gas exchange system of an insect when it is at
rest

Answer 11

• Oxygen used in (aerobic) respiration;
• (So) oxygen (concentration) gradient
(established)
• (So) oxygen diffuses in;

Question 12

Describe how temporary mounts are made

Answer 12

• Thin slice/section
• Put on slide in water / solution / stain
• Add cover slip

Question 13

Describe how the scientist could have used the temporary mounts of leaves to determine the mean number of chloroplasts in mesophyll cells of a leaf.

Answer 13

• Select large number of cells / select
cells at random;
• Count number of chloroplasts
• Divide number of chloroplasts by
number of cells

Question 14

There are many different types of cell in a leaf, each with its own function.
What term is used to describe a structure such as a leaf?

Answer 14

• Organ

Question 15

What is the name of a position of a gene on a chromosome?

Answer 15

• Locus;

Question 16

What is meant by genetic diversity?

Answer 16

• Differences in DNA / differences in base

sequence of DNA

Question 17

Suggest the advantage of the change in blood flow in the mesenteric artery during
exercise.

Answer 17

• More blood flows to (skeletal) muscles
(during exercise)
• (Supplying) more oxygen / glucose /
removing more carbon dioxide/ lactic
acid/ heat
• For high (rate of) respiration / to meet
increased demand for energy/ATP

Question 18

Blood leaving the kidney eventually returns to the kidney.
Describe the pattern of blood circulation in a mammal that causes blood to return to the
kidney.

Answer 18

• (Blood flows from kidney along) renal
vein to vena cava;
•  (Along) vena cava to right atrium/side
of heart;
• (Along) pulmonary artery to lungs; 
• (Along) capillaries to pulmonary vein;
• (Along) pulmonary vein to left
atrium/side of heart
• (Along) aorta to renal artery (to
kidney); 
• Blood may pass through several
complete circuits before returning to
kidney;