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Explanation of the lac operon, based on 9700/41/M/J/18 Question 3

It is made up of 3 genes: lacZ, lacY and lacA which encode for B-galactosidase (LacZ), lactose permease (LacY), and another enzyme (not studied at A level) respectively.The functions of LacZ (the enzyme) is ...
JV
Answered by Jose V. • Biology tutor
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What is osmosis and how does it differ from diffusion

osmosis is the movement of water Across a semi permeable membrane. Water molecules more from an area of high water concentration to an are of low water. This would bean water would move from an area where th...
KF
Answered by Kathryn F. • Biology tutor
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Identify the various structures in a reflex arc in the context of a pin prick. What is the end response and why is this beneficial?

Stimulus --> receptor --> coordinator --> effector --> response. Pin prick --> skin receptors --> sensory neurone --> relay neurone --> motor neurone --> effector muscle --> con...
SP
Answered by Sai P. • Biology tutor
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Outline the folding of a protein to form its 3D structure.

Folding of proteins occurs in 4 distinct stages: primary, secondary, tertiary and quaternary. Primary structure is the formation of the amino acid (peptide) sequence, here the amino acids are joined together...
OG
Answered by Olga G. • Biology tutor
4460 Views

Explain the differences between aerobic and anerobic respiration in terms of the roles of co-enzymes

During aerobic respiration, NAD and FAD collect protons and electrons from respiratory substrates. These electrons can be released into the transport chain of the mitochondrial matrix because oxygen is prese...
SB
Answered by Solomon B. • Biology tutor
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