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Describe the primary, secondary and tertiary structure of proteins

The primary structure of a protein involves a sequence of amino acids. This forms a polypeptide chain and there are 20 different amino acids that may contribute to the primary protein structure. The secondar...
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Answered by Annie S. • Biology tutor
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What are the requirements for natural selection?

Evolution by natural selection needs three conditions to be satisfied: variation, heredity, and competition (also called differential fitness). There must be variation in a population of a certain species. W...
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Answered by Michael C. • Biology tutor
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Explain the flow of ions during an action potential of a typical neurone

There are numerous ionic fluxes during an action potential, which involves depolarisation, repolarisation and hyperpolarsation. During depolarisation, voltage-gated sodium ion channels open. In turn, sodium ...
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Answered by Annie S. • Biology tutor
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What is the role of ADH in water regulation

ADH is a hormone made in the hypothalamus and secreted from the pituitary gland. It circulates in the blood to the collecting ducts of the kidneys where it makes aquaporin channels through the collecting duc...
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Answered by Luwaiza M. • Biology tutor
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Explain how the left ventricle of the heart creates higher blood pressure

The left ventricle has a thicker muscular wall and therefore produces stronger contractions.
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Answered by Jess C. • Biology tutor
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