Top answers

Human Biology
A Level

What are the three main differences between a molecule of DNA and RNA?

Firstly, we can see a difference in the letters, DNA has a D whereas RNA has an R, when we think about the full names we come to deoxyribose and ribose, which correspond to the different sugar molecules f...

LA
3392 Views

How is water reabsorbed in the loop of Henle?

To understand how water is reabsorbed in the loop of Henle, it helps to first consider what happens in the ascending limb. The ascending limb is permeable to ions but impermeable to water. Ions are pumped...

ER
20542 Views

Summarise the role of the transferrin receptor and its importance in health and disease.

The transferrin receptor (TfR) is a transmembrane glycoprotein that is highly expressed on multiple cell types, apart from highly differentiated cells. Two forms of the receptor have been characterised to...

AE
2903 Views

Explain how the HPV vaccine produces long-term immunity in individuals.

A vaccination is where tiny particles are introduced into the body to stimulate the immune system to defend itself against a micro-organism. Human Papilloma Virus (HPV) antigens are included in the HPV va...

TR
4079 Views

Please describe how the kidney concentrates urine?

This is through a mechanism called the countercurrent mechanism at the Loop of Henle that looks like a hair pin. It works by creating a concentration gradient between the nephron and the interstitium whic...

SD
3100 Views

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