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List and briefly explain the two main mechanisms by which mammalian genes can be exchanged or 'translocated' between chromosomes. What are the importance of these types of recombination? (8 marks)

i. Homologous Recombination. A conservative, error-free DNA replication pathway that mainly allows for the repair of DNA under duress and also for the resetting of replication forks. The pathway is regulated...
BA
Answered by Benjamin A. • Biology tutor
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Describe how allopatric speciation occurs.

In a population of a species a barrier forms (for example the formation of a new river, or the division between two islands). This leads to two isolated groups of the original species. In the two isolated gr...
AP
Answered by Amelia P. • Biology tutor
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Describe the structure of glycogen and explain why it is a suitable molecule to store energy.

Glycogen is a polysaccharide. Polysaccharides are carbohydrates made up from a large number of monosaccharides joined together by glycosidic bonds formed in condensation reactions. Glycogen, sometimes referr...
Answered by • Biology tutor
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When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the presynaptic knob. Describe how.

A nerve impulse is an electrical current that is transmitted down the axon of a neurone and to the synaptic knob. The impulse depolarises the membrane and causes a change in voltage across the membrane. This...
Answered by • Biology tutor
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How do vaccinations work? Relating to humoral immunity and the secondary immune response.

The body has both humoral and cell mediated immunity. A vaccination involves injecting a patient with inert (Inactivated) or dead material from a pathogen, be that a bacterium or a virus. Once injected into ...
SJ
Answered by Sophie J. • Biology tutor
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