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Explain how mRNA is formed. (6 marks)

DNA helicase breaks the hydrogen bonds between the base pairs in the double-stranded DNA. RNA nucleotides then line up beside their corresponding nitrogenous base (A-T, C-G) along the template strand of the ...
LN
Answered by Laura N. • Biology tutor
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How are B cells activated?

A phagocyte will engulf the pathogen by endocytosis. The vesicle containing the pathogen will fuse with the lysosome where it is degraded by hydrolytic enzymes. Short peptides of the pathogen will be display...
EB
Answered by Eleanor B. • Biology tutor
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Discuss the possible effects that mutation can have on the structure and function of a protein (3 marks)

Mutation can result in changes to a proteins primary, secondary and tertiary structure . Deletion mutations and mutations resulting in a new stop codon can result in the shortening of a protein. Proteins can...
EM
Answered by Emma M. • Biology tutor
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Explain a reflex arc

A reflex arc is the nerve pathway which follows a reflex action. First a stimulus, like a pin prick, is detected by receptors in the skin. A sensory neurone then sends electrical impulses to a relay neurone,...
CS
Answered by Clara S. • Biology tutor
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What does ADH do in the Kidney?

ADH or Anti Diuretic Hormone is a hormone that regulates the amount of water absorbed in the kidney. It acts on the collecting duct of the kidney, which is the last part of the nephron (a single functional u...
JH
Answered by Julia H. • Biology tutor
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