Wednesday 11th January 2012 Flashcards
Some seeds contain lipids. Describe how you could use the emulsion test to show that a seed contains lipids. 3 marks
- Crush
- Add ethanol
- Add water
- Forms emulsion - cloudy
A triglyceride molecule is formed by condensation. From how many molecules is this triglyceride formed? 1 mark
4
The structure of a phospholipid molecule is different from that of a triglyceride. Describe how a phospholipid is different. 2 marks
- 2 fatty acid tails
- Phosphate group
Use the diagram to explain what is meant by an unsaturated fatty acid. 1 mark
- Double bonds
- Between carbon atoms
The diaphragm helps to bring about the changes shown by the curve A. Explain how. 3 marks
- Diaphragm relaxes
- Domed shape
- Increased pressure
- Decrease volume
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
- Extend graph
- Read of the graph where it flattens
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
- Without inhaler the bronchioles are narrower
- Muscles surrounding the bronchioles contract
- Less air able to pass through
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
- Mitochondria respire
- Release ATP
- Transport against gradient
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
- Ribosomes make proteins/enzymes
- Enzymes are proteins
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
- Microvilli - increase surface area.
Scientists who investigate disease may look at risk factors. What is a risk factor? 1 mark
- Something that increases chance
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
- Correlation does not mean causation
- Other factors
- Negative correlation
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
- Left ventricle
Explain how the structure of this chamber causes this high pressure. 1 mark
Thick walls
What is the evidence from the diagram that this antibody has a quaternary structure? 1 mark
4 polypeptide chains
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
- Antibody region has a specific amino acid sequence
- Shape of the binding site
- Complementary with antigens
- Forms complex between antigen and antibody.
Name the monomers that make up the active site of the enzyme. 1 mark
- Amino acid
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
- Affects one amino acid
- Not found in all active sites
Aspirin is an enzyme inhibitor. Explain how aspirin prevents substrate molecules being converted to product molecules. 2 marks
- Occupies active site
- E-S no longer form
Aspirin may reduce the risk of myocardial infarction (lines 8 – 12). Explain how. 3 marks
- Prevents formation of thromboxane
- Blood clots less likely to form
- Don’t block coronary arteries
- Heart muscle gets oxygen
Vaccines protect people against disease. Explain how. 5 marks
- 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;
Oral rehydration solutions (ORS) are used to treat diarrhoeal disease. What does an ORS consist of and how does it work? 5 marks
- Contains glucose
- Sodium
- Co-Transport
- Sodium and glucose taken up from the lumen.
- Increases water potential gradient
- Water taken up by osmosis
