Top answers

Biology
A Level

What is ultrafiltration?

Ultrafiltration is a process in the kidney by which urea, salt, water and glucose etc. is extracted from the blood. When blood passes through the top of the nephron, it enters a structure called the glome...

CD
Answered by Charlotte D. Biology tutor
55560 Views

What is negative feedback in terms of homeostasis?

To regulate a number of processes in the body, there needs to first be recognition of current levels in order to respond in the appropriate way. For example there is a temperature "norm" (~36.9°...

CD
Answered by Charlotte D. Biology tutor
4187 Views

What is homeostasis?

This is the way that the body maintains a stable internal environment, which is vital for correct functioning of the cells in the body. For a stable environment there are several things which need to be r...

CD
Answered by Charlotte D. Biology tutor
3913 Views

Describe how restriction enzymes are used to cut out DNA fragments

Restriction enzymes cut at specific sequences named palindromic sequences. These are unique as they read the same in opposite directions. A specific palindromic sequence is complementary to a specific res...

AC
Answered by Abigail C. Biology tutor
9011 Views

How is selective reabsorption acheived in the kidneys?

In the cells lining the proximal convoluted tubule, sodium-potassium pumps present in the membrane in contact with tissue fluid pump sodium ions out of the cells. This lowers the concentration of sodium i...

NS
Answered by Nianqi S. Biology tutor
14209 Views

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