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Emphysema is a disease affecting the lungs. People with emphysema are often short of breath and find exercise difficult. Explain what happens to the lungs in this disease to cause the symptoms mentioned.

Emphysema affects the structure of the lungs called the alveoli. Each healthy alveolus has a large surface area in order for maximum diffusion of oxygen in the lungs.

If someone is affected by emph...

Answered by Elodie L. • Biology tutor

17205 Views

How does mark-recapture work?

Mark-recapture is a method of estimating a population size. A sample from the population is captured using an appropriate method, marked, and released. A second sample is then captured after an interval a...

Answered by Ciaran S. • Biology tutor

20605 Views

Explain the process of DNA replication in prokaryotes.

Replication involves the synthesis of the leading and lagging strand which occur in a 5' to 3' direction. First helicase unwinds the DNA strand, while topoisomerase relieves the strain created by the unwi...

Answered by Kristen K. • Biology tutor

3455 Views

Why does cholesterol need to be reduced and how do statins do this?

-High levels of cholesterol (especially LDL's, the 'bad' type) clog the arteries with a thick fatty substance

-This causes narrowing of the coronary arteries (which carry blood to the heart)

Answered by Isobel P. • Biology tutor

2705 Views

Can you explain the process of synaptic transmission?

A synapse is the junction between a neurone and the next cell. At the synapse there is both a presynaptic neurone, with vesicles containing neurotransmitters (chemical messengers) and a post synaptic neuo...

Answered by Jack D. • Biology tutor

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