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Biology

A Level

Why is it that an action potential only travels in one direction?

(draw/picture of nerve cell with its ion channels and after learning about the action potential trace and how it's derived) After each action potential, see on the trace there's a refractory period where ...

Answered by Jasmine L. • Biology tutor

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Why do 3 protons need to pass from the intermembrane space into the matrix of the mitochondrion in order to form 1 ATP molecule?

It has to do with the structure of the ATP synthase protein. The part in the centre moves 120 degrees with each prototon that passes through. This makes the 3 ATP/ADP binding sites to change shape. Each o...

Answered by Beatrice B. • Biology tutor

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How does a mutation lead to a non-functional enzyme?

Chanege in base sequence= change in sequence of triplet codes= change in sequence of amino acids= change in primary structure= change in hydrogen/ionic/disulfide bonds= change in tertiary structure= chang...

Answered by Samatar O. • Biology tutor

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How is information contained in the nuclear DNA of a cell converted into proteins? Outline the role of each molecule and enzyme involved in the process.

DNA is a double-stranded nucleic acid that consists of four different bases (A, T, C, G) which make up the 'language' of the genome. Sets of three bases on the coding strand of DNA, known as a triplet cod...

Answered by Timothy L. • Biology tutor

2692 Views

Describe the part played by each of the organelles involved in the production and secretion of the enzymes. (10)

The Nucleus contains the DNA code for the amino acid sequence (2) 3. The Nucleolus makes rRNA (4) 5. The Ribosomes translate mRna in protein synthesis 6. The endoplasmic reticulum allows for the tra...

Answered by Aoife M. • Biology tutor

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