BIOLOGY MOCK AS 1 2023 QUESTIONS

• Describe the primary structure of all proteins:

  • sequence of amino acids
  • joined by peptide bonds
• Universal - same codon always codes for same amino acid

  non overlapping - each base is only part of one codon

  degenerate- more than one codon codes for each amino acid
• Describe how the appearance of the area containing DNA in TEM image of eukaryotic will differ:

  • eukaryotic has nucleus
  • mitochondria will be present
• One difference between structure of DNA in prokaryotic and eukaryotic:

  • prokaryotic has circular DNA, not linear
• Describe the mechanism of breathing that causes air to enter the lungs:

  • diaphragm muscles contract and flatten
  • external intercoastal muscles contract and ribcage pulled up
  • causes volume increace in lungs, pressure decreases below atmospheric pressure
• How bacteria with thicker capsule are more likely to survive and cause lung disease:

  • thicker capsule in phagocytes less likely to bind to meurin in cell wall
  • phagocytosis reduces, more binary fission ( replication)
• 2 differences in the structure of triglyceride and phospholipid:

  • no phosphate group
  • 3 fatty acids rather than 2
• Why phospholipid can form billayer and triglycerides can’t:

  • phospholipid both hydrophobic and hydrophilic
  • triglycerides only hydrophobic
  • hydrophilic attracts water to bilayer
• Suggest why the fluidity higher at 4 months:

  • fatty acid A is saturated
  • at 4 months, less A and more B
  • increaced fluidity cause more B from fish oil
• One feature of E microscope vs optical:

  • nuclear membrane visible
  • e microscope has greater resolution
• One role of T helper cell:

  • stimulates B cells
• Role of tRNA in translation:

  • anti codon on TRNA binds to complimentary codon on MRNA
  • TRNA brings specific amino acid to ribosome
• Describe how gas exchange offers in single felled organisms and why can’t this be used by large organisms:

  • diffusion across cell surface membrane
  • large organisms have high SAV
  • diffusion path long means slow rate
• What’s found in HPV:

  • capsid and attachment protein
• Enzymes in replication:

  • DNA helicase
  • DNA polymerase
• Why HPV can cause cancer:

  • uncontrolled cell cycle
• Evaluate if Boys 10-12 should be given HPV vaccine:

  • herd immunity from boys
  • may be side effects
  • needs given before exposure
  • boys less risk than girls
• Why did he put plant root in acid;

  • stop mitosis
• Safety with HCL:

  • gloves
  • eye protection
• Explain how sucrose transport proteins in leaf cells enable production of a pressure gradient in phloem:

  • sucrose Co transport into phloem
  • causes water potential in phloem to decrease
  • water enters into phloem by osmosis
• 2 reasons why glucose uptake by muscle cells Increase in excersize:

  • increaced respiration- to provide ATP for muscle contraction
  • more carrier proteins in membrane- glucose enters by facilitated diffusion