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6. Describe the role of ATP in the sliding filament theory.

  • ATP binds to myosin head, releasing it from actin, then it is hydrolysed to ADP, 'recocking' the head.
  • ATP binds to the myosin head, altering the myosin tail's angle, pulling the actin along
  • ATP binds to troponin molecules on the actin, releasing the myosin head

7. Summarise the differences between DNA and RNA.

  • The backbone of DNA is based upon deoxyribose whereas RNA's backbone is based upon ribose, RNA uses uracil in place of thymine.
  • The backbone of DNA is based upon ribose whereas RNA's backbone is based upon deoxyribose, RNA uses uracil in place of thymine.
  • The backbone of DNA is based upon ribose whereas RNA's backbone is based upon deoxyribose, RNA uses uracil in place of adenine.

8. Progesterone...

  • ...is secreted from maturing follicles and inhibits LH and FSH secretion up until a critical threshold, upon which they are in fact stimulated.
  • ...is secreted from the corpus luteum and maintains the uteral lining (if a fertilised egg has attached).
  • ...is secreted from the pituitary gland and inhibits LH and FSH secretion up until a critical threshold, upon which they are in fact stimulated.
  • ...is secreted from the pituitary gland and maintains the uteral lining (if a fertilised egg has attached).

9. A complete gene, comprised of 37.5% introns, in a particular DNA section undergoes transcription, splicing then translation. The original DNA section was 1.728kBp long. What is the number of amino acids in the resulting polypeptide?

  • 361
  • 359
  • 360
  • 575
  • 576
  • 577

10. A hormone from question 24 is secreted from the alpha cells of the pancreas. What are its effects?

  • It decreases blood glucose concentration by stimulating glycogenolysis and increased respiration rate, in addition to promoting cellular uptake of glucose.
  • It increases blood glucose concentration by stimulating glycogenolysis and gluconeogenesis.
  • It decreases blood glucose concentration by stimulating the uptake of glucose by cells, formation of new glycogen, formation of lipid stores and by increasing respiration rate.

11. Stem cells can only be obtained from embryos. True or false?

  • 11.5
  • False
  • True

12. During transcription, [1] 'unzips' the DNA strand and [2] moves in to create complementary [3]. The DNA strand has only ~[4] bases separated during this process.

  • 1: DNA helicase, 2: RNA polymerase, 3: pre-mRNA, 4: 10
  • 1: RNA polymerase, 2: DNA helicase, 3: mRNA, 4: 20
  • 1: DNA helicase, 2: RNA polymerase, 3: pre-mRNA, 4: 150

13. If a [1] mutates it may become a [2] which stimulates [3], leading to uncontrolled cell division, or a [4]

  • 1: oncogene, 2: excitatory oncogene, 3: autolysis, 4: tumour
  • 1: proto-oncogene, 2: oncogene, 3: cell division, 4: tumour
  • 1: tumor suppressor gene, 2: oncogene, 3: cell division, 4: tumour

14. Calcium ions bind to [1] on [2] molecules, freeing binding sites for [3] on [4] filaments

  • 1: Actin, 2: Tropomyosin, 3: Myosin heads, 4: Troponin
  • 1: Troponin, 2: Tropomyosin, 3: Myosin heads, 4: Actin
  • 1: Tropomyosin, 2: Myosin heads, 3: Actin, 4: Troponin

15. Acetylcholine causes the opening of which channel in the post-synaptic membrane?

  • Calcium ion channel
  • Sodium ion channel
  • Potassium ion channel

16. The chemo- and pressure receptors responsible for keeping the heart rate in check are found where?

  • In the aortic arch
  • In the carotid arteries
  • In the brain stem

17. What does it mean to suffer from 'Type I' diabetes mellitus?

  • Type I diabetics do not produce sufficient insulin, suspected to be due to an autoimmune response to pancreatic cells and must inject insulin to maintain their BGC.
  • Type I diabetics have cells which are unresponsive to insulin (often due to obesity), and so must manage their carbohydrate intake to maintain their BGC

18. Which of the factors affecting nervous impulse velocity has the most significant effect?

  • Myelination
  • Axon diameter
  • Temperature

19. The channels responsible for inducing a generator potential in the pacinian corpuscle are known as what?

  • Stretch-mediated sodium ion channels
  • Voltage-gated sodium ion channels
  • Sodium-potassium pumps

20. Heart rate is controlled by what region of the brain?

  • Medulla oblongata
  • Frontal lobe
  • Hippocampus