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Past papers - biology > Wednesday 11th January 2012 > Flashcards

Wednesday 11th January 2012 Flashcards

1
Q

Some seeds contain lipids. Describe how you could use the emulsion test to show that a seed contains lipids. 3 marks

A
  • Crush
  • Add ethanol
  • Add water
  • Forms emulsion - cloudy
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2
Q

A triglyceride molecule is formed by condensation. From how many molecules is this triglyceride formed? 1 mark

A

4

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3
Q

The structure of a phospholipid molecule is different from that of a triglyceride. Describe how a phospholipid is different. 2 marks

A
  • 2 fatty acid tails

- Phosphate group

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4
Q

Use the diagram to explain what is meant by an unsaturated fatty acid. 1 mark

A
  • Double bonds

- Between carbon atoms

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5
Q

The diaphragm helps to bring about the changes shown by the curve A. Explain how. 3 marks

A
  • Diaphragm relaxes
  • Domed shape
  • Increased pressure
  • Decrease volume
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6
Q

You could use curve A to find the total volume of air that this person could breathe out in one complete breath. Describe how. 2 marks

A
  • Extend graph

- Read of the graph where it flattens

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7
Q

The inhaler which the person used contained a substance that dilates bronchioles. Use this information to explain why curve A is different from curve B. 2 marks

A
  • Without inhaler the bronchioles are narrower
  • Muscles surrounding the bronchioles contract
  • Less air able to pass through
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8
Q

This cell is adapted for the three functions listed below. Use the diagram to explain how this cell is adapted for each of these functions.
Use a different feature in the diagram for each of your answers.
The active transport of substances from the cell into the blood. 2 marks

A
  • Mitochondria respire
  • Release ATP
  • Transport against gradient
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9
Q

This cell is adapted for the three functions listed below. Use the diagram to explain how this cell is adapted for each of these functions.
Use a different feature in the diagram for each of your answers.
The synthesis of enzymes. 2 marks

A
  • Ribosomes make proteins/enzymes

- Enzymes are proteins

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10
Q

This cell is adapted for the three functions listed below. Use the diagram to explain how this cell is adapted for each of these functions.
Use a different feature in the diagram for each of your answers.
Rapid diffusion of substances from the lumen of the gut into the cytoplasm. 1 mark

A
  • Microvilli - increase surface area.
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11
Q

Scientists who investigate disease may look at risk factors. What is a risk factor? 1 mark

A
  • Something that increases chance
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12
Q

The scientists concluded that substances in the air from vehicle exhausts did not cause the increase in asthma between 1976 and 1980. Explain why. 3 marks

A
  • Correlation does not mean causation
  • Other factors
  • Negative correlation
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13
Q

The human heart has four chambers.

In which one of the four chambers of the human heart does pressure reach the highest value? 1 mark

A
  • Left ventricle
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14
Q

Explain how the structure of this chamber causes this high pressure. 1 mark

A

Thick walls

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15
Q

What is the evidence from the diagram that this antibody has a quaternary structure? 1 mark

A

4 polypeptide chains

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16
Q

Scientists use this antibody to detect an antigen on the bacterium that causes stomach ulcers. Explain why the antibody will only detect this antigen. 3 marks

A
  • Antibody region has a specific amino acid sequence
  • Shape of the binding site
  • Complementary with antigens
  • Forms complex between antigen and antibody.
17
Q

Name the monomers that make up the active site of the enzyme. 1 mark

A
  • Amino acid
18
Q

Aspirin only affects one of the enzymes in this pathway. Use information in lines 5 – 7 to explain why aspirin does not affect the other enzymes. 2 marks

A
  • Affects one amino acid

- Not found in all active sites

19
Q

Aspirin is an enzyme inhibitor. Explain how aspirin prevents substrate molecules being converted to product molecules. 2 marks

A
  • Occupies active site

- E-S no longer form

20
Q

Aspirin may reduce the risk of myocardial infarction (lines 8 – 12). Explain how. 3 marks

A
  • Prevents formation of thromboxane
  • Blood clots less likely to form
  • Don’t block coronary arteries
  • Heart muscle gets oxygen
21
Q

Vaccines protect people against disease. Explain how. 5 marks

A
  • Vaccines contain antigens
  • Dead pathogens
  • Memory cells made
  • On second exposure memory cells produce antibodies
  • Rapidly produce antibodies / produces more antibodies
  • Antibodies destroy pathogens;
  • Fewer people to pass on disease;
22
Q

Oral rehydration solutions (ORS) are used to treat diarrhoeal disease. What does an ORS consist of and how does it work? 5 marks

A
  • Contains glucose
  • Sodium
  • Co-Transport
  • Sodium and glucose taken up from the lumen.
  • Increases water potential gradient
  • Water taken up by osmosis

Past papers - biology (17 decks)

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