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Biology

A Level

How is an action potential transmitted across a synapse?

Looking at a cholinergic synapse:The action potential arrives at the presynaptic knob. This causes voltage-gated calcium ion channels to open, and calcium ions to diffuse into the presynaptic knob.The inf...

Answered by Megan M. • Biology tutor

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Rat poison is not always an effective rodenticide and will reduce in effectiveness with age. Explain why

Any type of poison is not guaranteed to eradicate rats entirely. This is due to genetic mutations allowing an individual to be immune to certain types of toxins. Whilst the population may be eradicated, i...

Answered by Charles D. • Biology tutor

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Explain how an action potential is transmitted across a cholinergic synapse.

The action potential arrives at the synaptic knob of the presynaptic neurone. The action potential stimulates the opening of voltage-gated calcium ion channels in the presynaptic neurone, allowing calcium...

Answered by Kathryn E. • Biology tutor

2209 Views

The pancrease secretes protease enzymes. How do organelles within a cell work together to PRODUCE and RELEASE these protein molecules from the cell?

The nucleus contains the gene that codes for the enzyme and is where transcription happens to produce mRNA . The mRNA leaves the nucleus and attaches to a ribosome on the rough endoplasmic reticulum. The ...

Answered by Jessica E. • Biology tutor

13201 Views

Describe how phagocytosis of a virus leads to presentation of its antigens and how presentation of this antigen leads to the secretion of an antibody against this virus antigen.

The macrophage engulfs the virus and the phagosome fuses with a lysosome, the virus is then broken down by hydrolytic enzymes inside the lysosome, and virus' antigens are displayed on the cell surface mem...

Answered by Oenone R. • Biology tutor

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