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An extract of DNA contains 4000 base pairs. The extract is identified to contain 300 guanine bases. How many adenine bases can be found in the DNA extract?.

3700

Answered by Kirushanth S. • Biology tutor

2071 Views

Explain how the physical properties of water enable organisms to survive over a range of temperatures.

Water has a very high specific heat capacity due to the collective forces of the many hydrogen bonds. A lot of energy goes into breaking these bonds rather than raising the temperature of the water, hence...

Answered by Arunima B. • Biology tutor

20979 Views

How is the the small intestine adapted for absorption?

The Ileum is long (up to 7m!) and has a very high surface area due to the presence of many villi and microvilli. A single villus is made up of many cells, each with lots ...

Answered by James P. • Biology tutor

23067 Views

Tetrodotoxin (TTX) is a chemical found in pufferfish which binds to voltage-gated sodium channels causing inactivation via a conformational change. Poisoning can result in paralysis leading to death. How might this occur? (4 marks)

This question asks about nerve action potential generation. There are a couple of clues - these include 'voltage-gated sodium channels' and 'paralysis' which suggests the idea of failure of impulse transm...

Answered by Rafee A. • Biology tutor

4162 Views

What are the main stages of the cardiac cycle?

Blood enters the atria. It cannot pass into the ventricles because the atrioventricular valves are closed. The heart is in diastole.The atria contract. The pressure in the atria becomes greater than the p...

Answered by Anshul A. • Biology tutor

4618 Views