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Describe the differences between active transport and facilitated diffusion.

Facilitated diffusion is a passive process that occurs down a concentration gradient. Active transport requires energy (from ATP) to allow movement of substances against a concentration gradient.
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Answered by Laura N. Biology tutor
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What is the definition of osmosis?

Osmosis is the process describing the random movement of water molecules through a permeable membrane from an area of high water concentration to an area of low water concentration until equilibrium is reached.
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Answered by Finlay M. Biology tutor
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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 ...
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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...
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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...
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Answered by Emma M. Biology tutor
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