Top answers

Describe Gaseous exchange in the alveoli of the lungs

Lungs contain millions of alveoli which act as the gas exchange surface for the body, O2 is absorbed and Co2 is excreted by the body via the lungs which contain a large number of small 'air sacs' known as al...
OW
Answered by Oliver W. • Biology tutor
3732 Views

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 emphysema, the...
EL
Answered by Elodie L. • Biology tutor
19090 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 and ...
CS
Answered by Ciaran S. • Biology tutor
25397 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 unwindi...
KK
Answered by Kristen K. • Biology tutor
4115 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) -The narrowing a...
IP
Answered by Isobel P. • Biology tutor
3257 Views