AQA AS Biology Paper 1 Exam Questions | | | | | | |
with verified detailed solutions
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Describe a biochemical test to show that raffinose solution contains a non-
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reducing sugar. - Correct answer ✔First heat the sample with an acid in a water
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bath and neutralise, then heat with Benedict solution in a water bath for five
| | | | | | | | | | | | | |
minutes. A positive test should produce a red precipitate.
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Explain the arrangement of phospholipids in a cell-surface membrane. -
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Correct answer ✔Phospholipids are arranged in a phospholipid bilayer. The
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hydrophobic fatty acid tails point away from the water and the hydrophilic
| | | | | | | | | | | |
heads attract the water.
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Describe how an ester bond is formed in a phospholipid molecule. - Correct
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answer ✔An ester bond is formed between a glycerol and a fatty acid,
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producing a water molecule in a condensation reaction.
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State and explain the property of water that helps to prevent temperature
| | | | | | | | | | | |
increase in a cell. - Correct answer ✔Water has a high specific heat capacity.
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This buffers changes in temperature, so lots of energy is required to change the
| | | | | | | | | | | | | |
temperature.
Describe how a phagocyte destroys a pathogen present in the blood. - Correct
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answer ✔The phagocyte is attracted to the pathogen by chemoattractants. The
| | | | | | | | | | |
phagocyte binds to the pathogen. The pathogen is engulfed and lysosomes
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migrate to the phagosome. The lysosomes then release lytic enzymes which
| | | | | | | | | | |
, break down the pathogen. The breakdown products are then absorbed by the
| | | | | | | | | | | |
phagocyte.
Give two types of cell, other than pathogens, that can stimulate an immune
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response. - Correct answer ✔Cancer cells and virus infected cells.
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What is the role of a disulphide bridge in forming the quaternary structure of an
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antibody. - Correct answer ✔It joins two polypeptide chains
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Outline the role of organelles in the production, transport and release of
| | | | | | | | | | | |
proteins from Eukaryotic cells. | | |
Do not include details of transcription or translation in your answer. - Correct
| | | | | | | | | | | | |
answer ✔DNA in the nucleus codes for the amino acids which make up
| | | | | | | | | | | | |
proteins. Ribosomes on the RER then synthesise these proteins. Mitochondria
| | | | | | | | | |
produce ATP for use in protein synthesis. The Golgi apparatus then packages
| | | | | | | | | | | |
and modifies proteins which are transported to the cell surface membrane in
| | | | | | | | | | | |
vesicles where they fuse. | | |
Give one advantage of viewing a biological specimen using a transmission
| | | | | | | | | | |
electron microscope compared with using a scanning electron microscope. -
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Correct answer ✔There is a higher resolution / view internal structures
| | | | | | | | | |
Describe and explain the mechanism that causes lungs to fill with air. - Correct
| | | | | | | | | | | | | |
answer ✔The diaphragm muscle contracts and external intercostal muscles
| | | | | | | | |
contract. This causes an increase in volume and decrease in pressure. This
| | | | | | | | | | | |
causes air to move down the pressure gradient and into the lungs.
| | | | | | | | | | |
with verified detailed solutions
| | |
Describe a biochemical test to show that raffinose solution contains a non-
| | | | | | | | | | |
reducing sugar. - Correct answer ✔First heat the sample with an acid in a water
| | | | | | | | | | | | | | |
bath and neutralise, then heat with Benedict solution in a water bath for five
| | | | | | | | | | | | | |
minutes. A positive test should produce a red precipitate.
| | | | | | | |
Explain the arrangement of phospholipids in a cell-surface membrane. -
| | | | | | | | | |
Correct answer ✔Phospholipids are arranged in a phospholipid bilayer. The
| | | | | | | | | |
hydrophobic fatty acid tails point away from the water and the hydrophilic
| | | | | | | | | | | |
heads attract the water.
| | |
Describe how an ester bond is formed in a phospholipid molecule. - Correct
| | | | | | | | | | | | |
answer ✔An ester bond is formed between a glycerol and a fatty acid,
| | | | | | | | | | | | |
producing a water molecule in a condensation reaction.
| | | | | | |
State and explain the property of water that helps to prevent temperature
| | | | | | | | | | | |
increase in a cell. - Correct answer ✔Water has a high specific heat capacity.
| | | | | | | | | | | | | |
This buffers changes in temperature, so lots of energy is required to change the
| | | | | | | | | | | | | |
temperature.
Describe how a phagocyte destroys a pathogen present in the blood. - Correct
| | | | | | | | | | | | |
answer ✔The phagocyte is attracted to the pathogen by chemoattractants. The
| | | | | | | | | | |
phagocyte binds to the pathogen. The pathogen is engulfed and lysosomes
| | | | | | | | | | |
migrate to the phagosome. The lysosomes then release lytic enzymes which
| | | | | | | | | | |
, break down the pathogen. The breakdown products are then absorbed by the
| | | | | | | | | | | |
phagocyte.
Give two types of cell, other than pathogens, that can stimulate an immune
| | | | | | | | | | | | |
response. - Correct answer ✔Cancer cells and virus infected cells.
| | | | | | | | |
What is the role of a disulphide bridge in forming the quaternary structure of an
| | | | | | | | | | | | | |
antibody. - Correct answer ✔It joins two polypeptide chains
| | | | | | | | |
Outline the role of organelles in the production, transport and release of
| | | | | | | | | | | |
proteins from Eukaryotic cells. | | |
Do not include details of transcription or translation in your answer. - Correct
| | | | | | | | | | | | |
answer ✔DNA in the nucleus codes for the amino acids which make up
| | | | | | | | | | | | |
proteins. Ribosomes on the RER then synthesise these proteins. Mitochondria
| | | | | | | | | |
produce ATP for use in protein synthesis. The Golgi apparatus then packages
| | | | | | | | | | | |
and modifies proteins which are transported to the cell surface membrane in
| | | | | | | | | | | |
vesicles where they fuse. | | |
Give one advantage of viewing a biological specimen using a transmission
| | | | | | | | | | |
electron microscope compared with using a scanning electron microscope. -
| | | | | | | | | |
Correct answer ✔There is a higher resolution / view internal structures
| | | | | | | | | |
Describe and explain the mechanism that causes lungs to fill with air. - Correct
| | | | | | | | | | | | | |
answer ✔The diaphragm muscle contracts and external intercostal muscles
| | | | | | | | |
contract. This causes an increase in volume and decrease in pressure. This
| | | | | | | | | | | |
causes air to move down the pressure gradient and into the lungs.
| | | | | | | | | | |
