Key Questions

Question 1

Explain how the monoclonal antibody works to treat pancreatic cancer.

Answer 1

monoclonal antibody is attached
to radioactive substance / toxin /
drug / chemical
monoclonal antibody will (only)
attach to / target (antigen on)
cancer cells / tumour
(so) radioactive substance /
toxin / drug / chemical will (bind
to cancer cells and) stop them
growing / dividing

Question 2

Explain how pancreatic cancer may cause a person to lose weight.

Answer 2

reduced / no enzyme production
/ release (from pancreas)
food is not broken down fully or
food is not digested fully
less glucose / sugar absorbed
or less glucose / sugar passes
into the blood(stream)
(so) less glucose available for
respiration so more (body /
stored) fat used up in
metabolism / respiration

Question 3

what is an enzyme?

Answer 3

protein which catalyses biological reactions

Question 4

why might axolotl die in low concs of oxygen?

Answer 4

concentration gradient (of
oxygen) is shallow(er) / less
steep
(therefore) less oxygen diffuses
into blood / cells / gills
(so) less (aerobic) respiration
occurs so less energy is
released / available
or
(so more) anaerobic respiration
occurs so less energy is
released / available
(so) less metabolism

Question 5

what is a double circulatory system?

Answer 5

blood is pumped to the lungs by
one / right side of the heart
and
blood is pumped to the body by
the other / left side of the heart

Question 6

how is small intestine adapted?

Answer 6

projections / folds / villi provide a
large surface area
walls of projections / folds / villi /
capillaries are thin / one cell
thick for shorter absorption /
diffusion distance
(small intestine is) very long,
increasing time (for absorption)
good / efficient blood supply to
maintain concentration gradient
cells have many mitochondria
for (aerobic) respiration for
active transport

Question 7

Explain how diabetes can cause the body cells to lose more water

Answer 7

the blood is more concentrated
or less dilute (than the solution
in the cells)
(so) water moves out of cells by
osmosis
water moves through a partially
permeable membrane

Question 8

Explain why a person with a leaking heart valve has difficulty exercising.

Answer 8

less oxygen supplied to muscles / cells
* (so) less aerobic respiration
* (so) less energy released
* (so) less (efficient) muscle contraction
* anaerobic respiration takes place
* less (efficient) removal of lactic acid

Question 9

Suggest one box reason for the difference in the rate of water loss from the two plants

Answer 9

one plant has more stomata

Question 10

What are the 3 stages of the cell cycle?

Answer 10

1. Interphase:
   The cell grows and prepares for division, replicating its DNA and making copies of its organelles.
2. Mitosis:
   The replicated DNA is separated and pulled to opposite ends of the cell, forming two new nuclei.
3. Cytokinesis:
   The cytoplasm and cell membranes divide, resulting in two genetically identical daughter cells

Question 11

what are the risks of stem cells in medicine?

Answer 11

Stem cells could cause viral infection and tumour development

Question 12

monoclonal antibody steps i always forget

Answer 12

Monoclonal antibodies are collected and purified and you have to allow them to divide before injection

Question 13

advantage of bile

Answer 13

Alkaline conditions increase the rate at which fat is broken down by lipase