WJEC Biology (BY2) Revision sheets: Assorted past paper question and answers

Assorted from the past few years past-papers and I used mark-schemes for the answers. Good to learn the sequence of some longer questions as they might come up. As you go through questions they get older and older.

Hope this helps someone :-)

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  • Created by: Rebecca
  • Created on: 29-05-13 11:59
Preview of WJEC Biology (BY2) Revision sheets: Assorted past paper question and answers

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BIOLOGY PAST-PAPER QUESTIONS
Explain how inspiration is bought about (2)
External intercostal muscles contract, ribcage moves upwards and diaphragm lowers so volume
increases
This means the pressure is less than atmospheric so air flows in
Explain why the bicuspid valve often has to be replaced because it ceases to work effectively and
why the tricuspid valve rarely needs replacing (1)
Valve is exposed to higher pressure in left ventricle. Right ventricle valve is exposed to lower pressure
What would happen to the flow of blood if the bicuspid valve is damaged? (1)
Blood leaks back from the ventricle to the atrium
Suggest on symptom a person with a failing bicuspid valve may have (1)
Either of;
Breathlessness
Fluid retention
Fatigue
Rapid or irregular heartbeat
Blue lips
Water is a dense medium with low oxygen content. Explain how bony fish have overcome the
problems of oxygen uptake in water (4)
1. Water is forced over the gills by ventilation mechanism/continuous swimming
2. One way flow
3. Counter-current flow of blood and water
4. So concentration gradient is maintained
5. Over the entire gill surface
6. High affinity of haemoglobin
Describe two features associated with epithelium and explain why each is important for the cell to
function effectively (4)
1. Microvilli ­ increases surface area for diffusion
2. Mitochondria ­ synthesis of ATP for active transport
What is the function of a Goblet cell? (1)
Lubrication (produces mucus)

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Explain the phloem's role in the plant (1)
Carries sugars and other nutrients around the plant
Explain how the endodermis cells carry out their function in the uptake of water and minerals in
the plant (4)
Water proof casparian strip
Blocks apoplast pathway
Transport of minerals
Into symplast pathway
Active transport of minerals into pericycle
Water follows by osmosis
Water and minerals move into xylem vessels
Name the three stages in the life cycle of a grasshopper? (3)
1. Egg
2. Nymphs
3.…read more

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Explain how the flow of water into guard cells leads to opening of stromatal pores (4)
Active transportation of potassium ions into guard cells which lowers water potential
Water flows into guard cells by osmosis/down water potential gradient
Guard cells become turgid
Inner wall of guard cell is thicker/inelastic
So guard cells bend away from each other
What is the role of the intercostal muscles in the thorax of a mammal? (1)
Move ribs and enlarge thorax
Give two advantages to a mammal of having…read more

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Explain what is meant by the terms source and sink (2)
Source ­ region where sugar is produced and exported e.g. leaves
Sink ­ region where photosynthesis is used e.g. roots
What name is given to the transport in plants from source to sink? (1)
Translocation
Name the tissue and the type of cell where you would expect the greatest amount of radioactivity
(sucrose) to be detected (2)
1. Phloem
2.…read more

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What is the significance of the Bohr effect (shift to right)? (1)
More oxygen available/dissociates more easily/ lower affinity for oxygen
Suggest one change which could be observed in the blood of an athlete who had been training at
high altitude (1)
More red blood cells/ more haemoglobin
How are homologous structures used as evidence for evolution? (1)
Suggests existence of common ancestors
Suggest why organisms with a which combine asexual reproduction with period when they
produce sexually, are stimulated by certain environmental conditions (e.g.…read more

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