Top answers

Why is the genetic code described as being universal?

The genetic code refers to DNA, which is like a blueprint that can be found in all living organisms. DNA is made up of 4 nucletotides: Adenine (A), Thymine (T), Guanine (G) Cytosine (C), whether in a bacteri...
LJ
Answered by Laureen J. • Biology tutor
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How do internal stimuli affect a positive and a negative feedback loop?

Deviation from homeostasis causes the activation of feedback loops in order to restore equilibrium to the organism. An example of a negative feedback loop is the homeostasis of blood glucose; the increase in...
AK
Answered by Alexia K. • Biology tutor
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What is another model for enzyme activity?

Another proposed model is induced fit. This suggests that the substrate and active site are not a perfect match to each other. So inorder to fit together both the substrate and active site must change shape ...
EM
Answered by Emily M. • 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.
AP
Answered by Alastair P. • Biology tutor
7957 Views

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.
AP
Answered by Alastair P. • Biology tutor
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