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Name a non-reducing sugar and outline a test which can identify its presence. (6)

Sucrose (1)Rule out reducing sugars - heat in a water bath. Add Benedict's solution. Should remain blue. (1)Add dilute HCl to a new sample and heat in a water bath (1)Neutralise with NaHCO3 (1)Add Benedict's...
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Answered by Annie R. • Biology tutor
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Explain what causes the Bohr shift to occur, and give one situation in which this is useful.

The Bohr Shift describes the movement of the oxygen dissociation curve to the right of normal. This occurs due to increased levels of carbon dioxide, such as when a person increases their exercise level, whi...
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Answered by Danielle P. • Biology tutor
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Describe the similarities and differences between haemoglobin and collagen.

Similarities:Both have a quaternary structure (consisting of more than one polypeptide).Both are found in animals (haemoglobin is found in blood and collagen is found in the muscles, skin, bones and tendons)...
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Answered by Shannon M. • Biology tutor
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Explain the transmission of a nerve impulse across a cholinergic synapse referring to action potentials. (6)

When an action potential reaches the terminal of a pre-synaptic cleft, voltage-gated calcium channels are stimulated to open, causing an influx of Ca+ ions in the pre-synaptic neuron. This infux of Ca+ ions ...
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Answered by Sarah W. • Biology tutor
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Why does a base substitution in DNA not always result in the formation of non-functional proteins?

Protein structure is determined by amino acid sequence. Each amino acid is coded for by a triplet of RNA bases. These are transcribed from a DNA molecule. If a DNA base is substituted for another base, then ...
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Answered by Abby R. • Biology tutor
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