As Biology

Front 1

People with mitochondrial disease have mitochondria that do not function properly.
Some people with mitochondrial disease can only exercise for a short time. Explain
why a person with mitochondrial disease can only exercise for a short time. (2)

Back 1

(Mitochondria) use aerobic respiration;

Mitochondria produce ATP/release energy;

Energy/ATP required for muscles
(to contract);

Front 2

The sinoatrial node (SAN) is in the right atrium of the heart. Describe the role of the sinoatrial node. (2)

Back 2

Sends out electrical activity/ impulses;

Initiates the heartbeat / acts as a pacemaker / (stimulates)
contraction of atria;

Front 3

A glucose biosensor is an instrument used to measure glucose concentration. It contains an
enzyme called glucose oxidase.
A glucose biosensor detects only glucose. Use your knowledge of the way in which enzymes work to explain why.

Back 3

Enzyme/active site has a (specific) tertiary
structure;

Only glucose has correct shape / is complementary / will
bind/fit;

To active site;

(Forming) enzyme-substrate complex;

Front 4

A drug company produced a new type of insulin. Scientists from the company carried out a trial in which they gave this new type of insulin to rats. They reported that the results of this trial on rats were positive. A newspaper stated that diabetics would benefit from this new drug. Suggest two reasons why this statement should be viewed with caution.

Back 4

Study not carried out on humans / only carried out on rats;

Long-term/side effects not known;

Scientists have vested interest;

Study should be repeated / further studies / sample size not
known;

Front 5

Describe the role of the enzymes of the digestive system in the complete breakdown of starch.

Back 5

Amylase;

(Starch) to maltose:

Maltase;

Maltose to glucose;

Hydrolysis;

(Of) glycosidic bond;

Front 6

Describe the processes involved in the absorption of the products of starch digestion.

Back 6

Glucose moves in with sodium (into epithelial cell);

Via (carrier/channel) protein/symport;

Sodium removed (from epithelial cell) by active
transport/sodium-potassium pump;

Into blood;

Maintaining low concentration of sodium (in epithelial cell) /
maintaining sodium concentration gradient (between lumen
and epithelial cell);

Glucose moves into blood;

By (facilitated) diffusion;

Front 7

A sample of microorganisms in a petri dish were being kept alive fed on a solution of glucose and mineral salts.
The glucose supply became exhausted and so the food source was changed from glucose to maltose. Within 24 hours the microbes had stopped reproducing and within 48 hours they were all dead.
Suggest with explanations why the microbes lived when fed on glucose but died when fed on maltose.

Back 7

The microbes had the correct enzyme to digest the glucose but did not have the correct enzyme to hydrolise the maltose into glucose and so could not release the energy from the maltose for respiration.