Answer to Q 5 The Chemicals of LIfe

Replication, Transcription and Translation are biochemical processes related to  DNA. 

(i)         Describe the difference between each process and state the location in the cell where each process occurs.

Replication      1 of:      All DNA copied; for cell multiplication;

Location:           Nucleus / cell nucleus

Transcription   1 of:      Section of DNA copied; one gene only copied; segment of DNA for protein synthesis copied

Location:           Nucleus / cell nucleus

Translation      1 of:      Triplet code translated to transfer RNA / base sequence for amino acid;  AVP

Location:           Cytoplasm; ribosomes on RER

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(ii)        What is meant by the term "Complimentary Base Pairing"?

A & T always paired, G & C always paired; A can only join to T , G to C or full base names given                                                                                                              [ 1 ]

(iii)       Genetic diseases occur due to a mutation in gene formation.  Explain how a change in the base sequence of a gene can lead to a genetic disease.  1 mark is available for the written quality of the explanation.

7 of:

transcription; a base change copied to / on mRNA; mRNA translated / translation with base change; to / onto tRNA / at ribosomes /RER;  primary structure change;  sequential change in protein synthesis; final protein structure altered; AVP; grammar, spelling, ordered sequence use if biological terms - award 1 mark.

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[Total: 14]