BIOLOGY UNIT 1

HOW ARE PHOSPHOLIPIDS ARRANGED IN A MEMBRANE?

HOW IS THE GOLGI BODY INVOLVED IN SECRETION OF PROTEINS?

WHY DO AREAS OF THE HEART DIE DURING A MYOCARDIAL INFARCTION?

WHY IS PRESSURE IN THE VENTRICLE RELATED TO THE THICKNESS OF THE VENTRICLE WALL

HOW IS PRESSURE IN THE VENTRICLE RELATED TO BLOOD FLOW IN THE AORTA?

Describe how bacteria are destroyed by phagocytes.

Explain how fibrosis caused by tuberculosis could have produced the changes in FEV.

People given whole-cell vaccines were more likely to develop harmful side effects than
the people given the vaccines containing parts of the bacterial cells

) People given whole-cell vaccines produced a greater range of antibodies against the
bacterium than the people given the vaccines containing parts of the bacterial cells

Infection by the cholera bacterium can cause acute diarrhoea. Explain how.

In areas where there are repeated outbreaks of cholera, most people who become
infected by cholera bacteria do not become ill. Suggest and explain one reason why.

Describe how you would test a sample of food for the presence of starch.

Microfold cells take up the antigens and transport them to cells of the immune system. Antigens are not able to pass through the cell-surface membranes of
other epithelial cells. Suggest two reasons why.

Scientists believe that it may be possible to develop vaccines that make use of
microfold cells. Explain how this sort of vaccine would lead to a person
developing immunity to a pathogen.

Describe how a heartbeat is initiated and coordinated.

Explain how the heart muscle and the heart valves maintain a one-way flow of blood
from the left atrium to the aorta.

Describe how the gut wall is adapted to push food down the oesophagus

Describe how gut wall is adapted to neutralise the stomach acid in the duodenum

Describe how the gut is adapted to absorb the products of digestion in the iluem.

Describe how solubility in lipid affects the rate of diffusion through a membrane.
Explain your answer.

Describe how molecular size affects the rate of diffusion. Suggest an explanation
for your answer

Name two factors which affect the rate of facilitated diffusion of a substance through a membrane

Describe how you would use a biochemical test to show that a solution contained a
non-reducing sugar, such as sucrose.

Order in which pellets were produced by ultracentrifugation
1
2
3 Chloroplasts
4
5

Suggest why the rate of oxygen uptake was measured when the mammals were
at rest.

Explain the role of phospholipids in the structure and functioning of cell membranes.

Describe the processes involved in the digestion of triglycerides and the absorption of
the products of this digestion in the small intestine.

Describe how a sample consisting only of chloroplasts could be obtained from
homogenised plant tissue.

What's the function of the fatty acid tail in the phospholipid membrane?

Explain how the cells of the cortex and the epidermis support the stem.

Explain how the structures of the stomach wall and the ileum wall are related to the
functions of these organs.

Bile is made in the liver. Explain one function of bile.

Explain how three features of a plasma membrane adapt it for its functions.