Long question answers (AS Biology)

these are possible long answer questions that could come up =)

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  • Created by: flower123
  • Created on: 29-03-12 08:51

Possible long questions and answers

Describe and explain the effects of deforestation/gardening/agriculture on the species diversity index

·         Removal of hedgerows/trees

·         Loss of habitats/niches

·         Weeding/removal of some plants/producers

·         Herbicides/pesticides kill organisms

·         Some selection of species

·         Loss of species that live in those habitats

·         Removing of primary consumers= less food in food chain

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Explain how resistance to an antibiotic could become widespread in a bacterial population following a gene mutation conferring resistance in just one bacterium.

·         Horizontal gene transmission

·         Conjugation tube

·         plasmid

·         Vertical gene transmission

·         Overuse of antibiotics favours the resistant alleles

2 of 9

Describe and explain how an insect is adapted for efficient gas exchange.

·         Spiracles= gases in/out

·         Tracheal tubes-narrow, large SA

·         Ventilation by rhythmic contraction

·         Increases conc gradient

·         All cells close to tracheal tube

·         Shortens diffusion path

3 of 9

Describe and explain how different ‘variants’ of haemoglobin allow organisms to obtain oxygen under different conditions.

-lugworm

-sand burrows/low p oxygen

-Hb has high affinity for oxygen

-altitude low p oxygen eg. Llama

-has high affinity to pick up oxygen

-small animals eg mice high metabolic rate

-low affinity increases unloading to respiring cells

4 of 9

Explain how the structure of starch and glycogen are suited to their functions.

Starch -helical/coiled chains of a –glucose

-Compact storage of energy

-Insoluble does not affect water potential of cells/no osmotic effect

Glycogen-like starch but more highly branched

-more ‘ends’ for enzymes

-Rapidly hydrolysed 

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Describe and explain the effects of deforestation/gardening/agriculture on the species diversity index

·         Lowers diversity

·         Removal of weeds/plants

·         Removal of niches/habitats

·         Less food

·         Use of pesticides/herbicides kills weeds/pests

·         One crop is grown- monoculture

6 of 9

Describe and explain how an insect is adapted for efficient gas exchange.

·         Small size means high sa:vol ratio for gas exchange

·         But waterproof cuticle/exoskeleton

·         Holes-spiracles open to allow gas

·         Tracheal tubes penetrate body allowing oxygen to diffuse to cells

·         Reduces diffusion pathway

·         Movement forces air in/out –maintaining conc gradient

7 of 9

Describe and explain how different ‘variants’ of haemoglobin allow organisms to obtain oxygen under different conditions.

·         High altitude animals have Hb with a high affinity for O

·         O at altitude is at low pp

·         Means Hb will LOAD O at lower pp’s

·         Foetal Hb higher affinity than mother’s

·         So oxygen is released by mother-foetus

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Some questions for you to have a go at :)

What is the importance of mitosis?

What is the importance of meiosis?

How are the structures of arteries and veins related to their functions?

Describe and explain the effect of ENVIRONMENTAL FACTORS on the rate of transpiration

Explain how resistance to an antibiotic could become widespread in a bacterial population following a gene mutation conferring resistance in just one bacterium.

Land-dwelling insects lose water from their gas exchange surface. Use Fick’s law to explain why they lose less water when the air is humid.

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