The KRAS gene codes for a protein called K-Ras - AQA - A-Level Biology - Question 8 - 2023 - Paper 2
Question 8
The KRAS gene codes for a protein called K-Ras. The protein relays signals from outside a cell to a cell's nucleus, stimulating cell division. An alteration in the K... show full transcript
Worked Solution & Example Answer:The KRAS gene codes for a protein called K-Ras - AQA - A-Level Biology - Question 8 - 2023 - Paper 2
Step 1
Mutation (in KRAS gene)
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Answer
An alteration in the KRAS gene usually occurs due to a mutation, which may involve a change in the base sequence of the KRAS gene. This mutation can alter the structure of the K-Ras protein, affecting its ability to relay signals effectively.
Step 2
Change in (signalling) protein
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Answer
The resultant change in the K-Ras protein may lead to increased production of the signalling protein. This often results in persistent activation of pathways that stimulate cell division, leading to uncontrolled cell proliferation.
Step 3
Results in rapid/uncontrollable cell division
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The rapid and uncontrollable cell division caused by the altered signalling can lead to tumour formation as the normal regulatory mechanisms that control cell growth are bypassed.
