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AQA A Level Biology 4_5_6 mark Questions And Answers
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AQA A Level Biology 4_5_6 mark Questions And Answers
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10/23/24, 10:01 AMAQA A Level Biology 4/5/6 mark questions And Answers
Terms in this set (53)
1 (Simple / facilitated) diffusion from high to low
concentration / down concentration gradient;
2 Small / non-polar / lipid-soluble molecules pass via phospholipids / bilayer;
OR
Many different substances enter and leave Large / polar / water-soluble molecules go through proteins;
a cell by crossing its cell surface 3 Water moves by osmosis / from high water potential to low water potential / from
membrane. Describe how substances can less to more negative water potential;
cross a cell surface membrane. (5) 4 Active transport is movement from low to high
concentration / against concentration gradient;
5 Active transport / facilitated diffusion involves proteins/carriers;
6 Active transport requires energy / ATP;
7 Ref. to Na+ / glucose co-transport;
1 Many alveoli / alveoli walls folded provide a large surface area;
2 Many capillaries provide a large surface area;
3 (So) fast diffusion;
________________________________________________
4 Alveoli or capillary walls / epithelium / lining are thin / short distance between
Describe and explain how the lungs are
alveoli and blood;
adapted to allow rapid exchange of
5 Flattened / squamous epithelium;
oxygen between air in the alveoli and
6 (So) short diffusion distance / pathway;
blood in the capillaries around them. (5)
7 (So) fast diffusion;
________________________________________________
8 Ventilation / circulation;
9 Maintains a diffusion / concentration gradient;
10 (So) fast diffusion;
1. Vaccine contains antigen/ dead pathogen
Scientists believe that it may be possible to 2. Microfold cells take up/bind and present/transport antigen (to immune system)
develop vaccines that make use of 3.T-cells activate B-cells
microfold cells. Explain how this sort of 4.B cells divide / undergo mitosis
vaccine would lead to a person developing 5. B cells produce antibodies
immunity to the pathogen (5) 6. Memory cells produced
7. More antibodies produced faster in secondary response
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1.B lymphocytes produce antibodies/involved in humoral response;
2.T lymphocytes involved in cell mediated immunity;
3.Macrophages present antigens;
4.(specific) B lymphocytes recognise/bind to antigen;
5. increase in numbers by mitosis;
Explain the role of B-lymphocytes and T-
6. produce plasma cells (which make antibodies);
lymphocytes in the defence of the body
7.antibodies bind to and clump/ agglutinate virus;
against a virus infection. (6)
8. memory cells produced by 1st exposure/cloned on 2nd exposure;
9. T lymphocytes(helpers) produce 10.lymphokines/chemicals;
11. which aid B lymphocyte cloning;
12. encourages phagocytes to engulf clumped virus;
13. killer T cells kill virus infected cells;
1. Water enters root hair cells;
2. By osmosis;
Explain how water enters a plant root from 3. Because active uptake of mineral ions has crated a water potential gradient;
the soil and travels through to the 4. Water moves through cortex;
endodermis. (5) 5. Down water potential gradient;
6. Through cell vacuoles and cytoplasms (symplastic pathway);
7. And through apoplastic pathway (cell walls);
Root pressure is a force that is partly 1. Entry of ions leads to a reduced water potential;
responsible for the movement of water 2. Water potential established between xylem and surrounding cells;
through xylem in stems. Explain how the 3. Plasma membranes of surroudning cells are partially permeable;
active transport of mineral ions into the 4. Water enters xylem by osmosis;
xylem vessels in the roots results in water 5. Volume of water in xylem increases;
entering these vessels and then being 6. Cannot move back due to gradient;
moved up the xylem tissue. (5) 7. Pressure in xylem increases and forces water upwards.
1. Evaporation from leaves (transpiration);
The presence of an air bubble in a xylem
2. Water in xylem under tension (pulled up);
vessel in the stem blocks the movement
3. Because water molecules cohere (stick together) (because of hydrogen bonds);
through that vessel. Use the cohesion-
4. So water travels in a single column;
tension theory to explain why. (4)
5. A water bubble would break the column;
1. (water is used in) the light-dependent reactions of photosynthesis;
2. electrons from water enable ATP production / H+ are used to reduce NADP /
In daylight, most of the water evaporates produces O2;
from the leaves but some is used by the 3. (water can be used in) hydrolysis reactions within the plant;
plant. Describe the ways in which this water 4. to create turgor;
could be used by the plant. (6) 5. as a solvent for transport;
6. as a medium for chemical reactions;
7. component of cells / cytoplasm;
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