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Biology
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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...

Answered by Amber B. Biology tutor
4085 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 metabolis...

Answered by Tara F. Biology tutor
13526 Views

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 ...

Answered by Shannon M. Biology tutor
5406 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 ...

Answered by Jack R. Biology tutor
5473 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 ...

Answered by Nikita V. Biology tutor
2292 Views

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