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If fetal haemoglobin is so good at binding oxygen, why aren't we adapted to keep it until adulthood?

Firstly, although fetal haemoglobin is better at binding oxygen, it is also worse at giving up oxygen to the tissues which need it. Secondly, if adults had haemoglobin with the same affinity for oxygen as fe...
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Answered by Amber B. • Biology tutor
5198 Views

Describe the stages in viral replication

The first stage in viral replication occurs when a virus attaches to the surface of a host cell. The viral nucleic acid (VNA) then enters the cell. The VNA then takes over the cell, altering the metabolism o...
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Answered by Tara F. • Biology tutor
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I often understand the question and think I have answered it correctly, but I don't get all the marks for my answer. What am I doing wrong?

One of the things that you need to remember about Biology A Level is that you have to memorise the key points of the mark scheme. Something that I consistently struggled with when I was doing past papers is ...
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Answered by Shannon M. • Biology tutor
7079 Views

Describe the pathway of electrical activity in the heart during contraction.

The sino-atrial node (SAN) is located within the wall of the right atrium, and acts like a pacemaker (it instigates the rhythms of the heart). The SAN sends out regular waves of electrical activity along the...
JR
Answered by Jack R. • Biology tutor
7133 Views

what is the structure of a plant cell?

cell wall- this is strong, due to the cellulose nucleus- what is the person of a nucleus- contains genetic information vacuole- sap filled membrane that gains water and loses water, giving the plant cell sta...
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Answered by Nikita V. • Biology tutor
3203 Views