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Describe and explain the events that occur in full contraction of the heart

-To start the sinoatrial node (SAN) on the wall of the right atrium sends an electrical signal across the right and left atria to contract and the blood moves into the ventricles. A layer of non-conductive t...
RP
Answered by Rosie P. • Biology tutor
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Describe the sequence of events in DNA transcription

An enzyme called DNA helicase breaks the hydrogen bonds holding the complimentary base pairs together in a double stranded DNA molecule. This causes the DNA helix to unwind, exposing the unpaired bases. Anot...
EM
Answered by Ellie M. • Biology tutor
3812 Views

When is Chi-squared the most appropriate statistical test to use?

Chi-squared is about establishing whether the difference in results between groups is likely to be due to chance, or due to some genuine difference in the groups' properties. It aims to answer the question, ...
AP
Answered by Anastasia P. • Biology tutor
3001 Views

Describe the events that occur leading to an action potential, and briefly explain why it is described as "all or nothing"?

Across the membrane of a neuron, the membrane potential at rest is approximately -70mV. When a stimulus of some kind is detected by sensory receptors (for example the nociceptors on the skin surface which de...
BA
Answered by Bilaal A. • Biology tutor
4509 Views

Describe the series of events leading to atherosclerosis.

Atherosclerosis is a cardiovascular disease where fatty, cholesterol filled plaque builds up in the arteries, it is the main contributor to coronary artery disease. These plaques narrow the vessel and obstru...
CM
Answered by Charlotte M. • Biology tutor
7576 Views