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Biology

A Level

Two species of frogs, each found on one of two neighbouring islands yet with the same genus, are identified. Scientists believe that the two species originated from a common ancestor. Explain how these species could have evolved.

Questions about speciation are at their core based on Darwin's theory of evolution. As a result, we must recall GCSE knowledge of natural selection to combine with the new concepts in speciation introduce...

Answered by Iqra S. • Biology tutor

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Draw a genetic diagram to show how unaffected parents could have a son with Haemophilia but also other children who do not suffer from the disease.

First figure out the phenotype (what is visible/expressed) of parents: Normal male x Normal female Next write down their gametes: X^Hy and X^H X^...

Answered by Lucy F. • Biology tutor

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DNA helicase is important in DNA replication - explain why.

DNA helicase acts to unwind the 2 strands of DNA by breaking the Hydrogen bonds between them. This means that free nucleotide bases can be attracted and bind to the exposed bases.

Answered by Rachel M. • Biology tutor

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Describe how an action potential stimulates synaptic release of neurotransmitters. (5 marks)

action potential depolarises the synaptic terminal this activates the voltage gated calcium channels Calcium ions diffuses into the cell down the electrical gradient Calcium ions stimulate the release of ...

Answered by Sofia P. • Biology tutor

2781 Views

Could you explain the structure of the plasma membrane to me? (A level)

The cell membrane, also known as plasma membrane, you will know from GCSE is a feature of both animal and plant cells that helps contain cellular contents and control entry and exit of substances from the...

Answered by Rita H. • Biology tutor

2876 Views