Top answers

What is a proposed model for enzyme activity?

The lock and key model: Only substrates of a specific shape that is complementary to the active site of an enzyme can fit into the active site, in a way that is analagous to a key fitting into a lock.
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Answered by Alastair P. • Biology tutor
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How is the structure of alveoli suitably adapted for efficient gas exchange?

Very thin walls result in a short diffusion distance which makes gas exchange particularly favourable. Lots of branches and sacs result in a large surface area so gas exchange can be maximised.
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Answered by Alastair P. • Biology tutor
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What are the differences between exons and introns found in DNA.

Exons are coding regions of DNA, and are copied into mRNA and transcribed as proteins. Introns are non-coding regions of DNA, and are spliced out of pre-mRNA so are not copied into mRNA.
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Answered by Alastair P. • Biology tutor
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What is homeostasis?

Homeostatis is the regualtion of the internal conditions of the body to ensure that everything remains balanced.
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Answered by Amna R. • Biology tutor
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What is the differences between respiration and breathing?

Breathing is the mechanism that allows oxygen to enter the lungs. Resiration is the process that uses oxygen along with glucose to produce energy.
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Answered by Amna R. • Biology tutor
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