Gene Control (OCR A Level Biology)

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Gene Control

  • The nucleus of every cell in the human body contains the same genes
    • However, not every gene is expressed in every cell
    • In addition, not all of these genes are expressed all the time

  • There are several mechanisms that exist within cells to make sure the correct genes are expressed in the correct cell at the correct time
    • These mechanisms are known as regulatory mechanisms
    • They control which genes are expressed at different points in time (e.g. during development)

  • There are three main types of regulatory mechanisms, including:
    • Regulation at the transcriptional level (i.e. regulatory mechanisms that occur during transcription)
    • Regulation at the post-transcriptional level (i.e. regulatory mechanisms that occur after transcription)
    • Regulation at the post-translational level (i.e. regulatory mechanisms that occur after translation)

  • These regulatory mechanisms are controlled by many different regulatory genes

Structural and regulatory genes

  • A structural gene codes for a protein that has a function within a cell (e.g. enzymes, membrane carriers, hormones etc.)
    • For example, the F8 gene codes for the protein Factor VIII involved in blood clotting

  • Regulatory genes code for proteins (or various forms of RNA) that control the expression of structural genes

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Alistair

Author: Alistair

Expertise: Biology & Environmental Systems and Societies

Alistair graduated from Oxford University with a degree in Biological Sciences. He has taught GCSE/IGCSE Biology, as well as Biology and Environmental Systems & Societies for the International Baccalaureate Diploma Programme. While teaching in Oxford, Alistair completed his MA Education as Head of Department for Environmental Systems & Societies. Alistair has continued to pursue his interests in ecology and environmental science, recently gaining an MSc in Wildlife Biology & Conservation with Edinburgh Napier University.