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Biology
A Level

What is a protein?

A protein is a sequence of many amino acids. All proteins are made of amino acids. Humans have 20 distinguished amino acids that can arrange in thousands of different combinations and this means that they...

MM
Answered by Matilde M. Biology tutor
3771 Views

Describe what each point of an ECG represents.

P wave: atrial depolarisation and subsequent contraction. QRS complex: Ventricular depolarisation and subsequent contraction. Q wave is negative due to left to right depolarisation of ventricular septum. ...

HC
Answered by Humza C. Biology tutor
7350 Views

Explain how the alveoli create a surface for efficient gaseous exchange

Firstly, the alveoli walls consist of a one-cell thick layer of squamous epithelium. This means there is a thin barrier to diffusion, and a small distance for oxygen molecules to diffuse across to get to ...

HC
Answered by Humza C. Biology tutor
20866 Views

How are some plants able to fix gaseous nitrogen from the atmosphere?

Leguminous plants have nodules on their roots that contain, symbiotic bacteria. These bacteria are capable of turning gaseous nitrogen ultimately to nitrate, which the plant can then use in order to synth...

SC
Answered by Sam C. Biology tutor
3609 Views

What is the difference between osmolarity and osmolality?

First of all, it is important to define osmosis. If you have two solutions separated only by a semi-permeable membrane, and one solution is more concentrated than the other, then water will move from the ...

KW
Answered by Kelly W. Biology tutor
16506 Views

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