Control of Growth and Development

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Control of Growth and Development
2012-04-09 08:47:46
Control Growth Development Biology

Higher Biology - Unit Three - Control of Growth and Development
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  1. What is a gene?
    A gene is a segment of DNA that codes for a protein. The structure and function of a cell is controlled by its genes
  2. The ability to switch genes on or off prevents resources being wasted. Give one of these resources
    • Amino acids
    • ATP
  3. What is lactose composed of?
    Glucose and galactose
  4. Lactose is digested to glucose and galactose by the enzyme...?
  5. E-coli only produces β-galactosidase when lactose is present / absent ?
  6. Switching on a gene only when the enzyme is needed is called...?
    enzyme induction
  7. What does the regulator gene do?
    It codes for the repressor molecule
  8. What does the operator gene do?
    It controls the structural gene
  9. What does the structural gene do?
    It contains DNA which codes for the enzyme
  10. What does a repressor molecule do?
    It stops the operator gene switching the structural gene on
  11. What does the inducer do?
    The inducer joins with the repressor and stops it inactivating the operator gene
  12. Draw the diagram to show the Jacob - Monod hypothesis of gene action in bacteria
    See jotter or P142 in textbook
  13. What is metabolism?
    The name given to all the chemical reactions which occur in the body.
  14. PKU is an example of inborn...?
    error of metabolism
  15. What is the normal metabolic pathway that phenylalanine undergoes?
  16. A PKU sufferer has a mutation of gene...?
  17. Using a diagram, show what happens as a result of this mutation
    • Enzyme 1 is not produced
    • Phenylalanine is not converted to tyrosine
    • Phenylalanine accumulates in the blood
    • Some phenylalanine passes through a different metabolic pathway which produces toxins
    • Excess phenylalanine and toxins disrupt normal development of organs, including brain
    • Limits mental development if untreated
  18. How are the worst effects of PKU being reduced?
    By screening newborn babies and restricting any sufferers diet
  19. In the same metabolic pathway what enzyme are albinos unable to make and therefore what subtance are they unable to make?
    Enzyme 3 - melanin
  20. What physical differences do albinos have?
    They have light skin, pure white hair, pale blue or pink irises
  21. What must albinos avoid exposure to?
    Ultraviolet radtion
  22. What are expressed genes?
    Genes that are switched on in all cells - needed for essential biochemical processes eg enzymes involved in respiration
  23. What are cell specific genes?
    Genes that are only switched on in particular types of cells where they code for proteins characteristic of that cell type eg haemoglobin in red blood cells. Other genes not needed by the cell are permanently switched off.
  24. The more specialised the cell the _____ genes switched on