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Why do different blood vessels have different lumen sizes (relative to their overall size)?

Lumen sizes in blood vessels differ due to the differing functions of the vessels themselves. Arteries have to carry oxygenated blood away from the heart to the tissues at high pressure. Small lumen (relativ...
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Answered by Jessica S. • Biology tutor
83739 Views

How is a nerve impulse transmitted along a synapse?

The nerve impulse arrives at the synapse. This triggers vesicles to release chemical messengers (neurotransmitters) into the synapse. These chemicals diffuse across the synapse and bind with membrane recepto...
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Answered by Alex H. • Biology tutor
3633 Views

Can you explain the food chain?

You always start with the sun which gives its every to grass which is a producer of energy. The arrow in the food chain, therefore, travels in the direction the energy travels in (in this case from the sun t...
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Answered by Amelia H. • Biology tutor
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Amy has cystic fibrosis which is caused by a recessive allele. Her partner is heterozygous for cystic fibrosis. What is the chance that her future child has cystic fibrosis?

Alleles are different forms of a gene which can become mutated to cause different characteristics or diseases. They can be dominant (usually denonimated by a captial letter H) or recessive (usually denominat...
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Answered by Rebecca M. • Biology tutor
4500 Views

How may cells be specialised to their function?

Despite animal cells all having a nucleus (for genetic information storage and reproduction), a cytoplasm (for structure), mitochondria (for aerobic respiration), ribosomes (for protein synthesis) and a cell...
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Answered by Alec M. • Biology tutor
17698 Views