Top answers

Biology
A Level

Why do foetuses have different haemoglobin to adults?

Normal adult haemoglobin is primarily comprised of 2 alpha and 2 beta subunits and foetal haemoglobin has 2 gamma subunits instead of the 2 betas. Now what this does is increase the binding affinity of th...

MB
Answered by Max B. Biology tutor
3569 Views

What is saltatory conduction?

Motor neurones have a myelin sheath made of Shwann cells. It's an electrical insulator meaning action potentials cannot pass through them. Along the axon there are gaps where there's no myelin sheath, cal...

EB
Answered by Emily B. Biology tutor
3151 Views

How come the antibodies in our blood and lymphatic system do not attack our own, but only specific antigens?

Antibodies and antigens are made out of proteins. Proteins have a specific primary structure. The primary structure is the sequence of the amino acids that make up the protein. This sequence is specific t...

CU
Answered by Cassandra U. Biology tutor
2768 Views

How do you get from an a base like adenine to an enzyme/protein?

There are four bases- ATGC adenine, thymine guanine and cytosine.

Each base is attached to a deoxyribose sugar and a phosphate sugar. This makes up a nucleotide. Three nucleotides are called a codo...

JJ
Answered by Joshny J. Biology tutor
2804 Views

How does heart muscle contract rhythmically in unison?

The heart is composed of a specialied muscle type called cardiac muscle. This has unique properties such that each muscle cell is connected together by gap junctions in their cell membranes (electrical sy...

JC
Answered by Jonathan C. Biology tutor
5770 Views

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