yr12 content

• State the image produced by a scanning electron microscope?

  SEM - 3D image
• State image produced by a transmission electron microscope TEM?


  TEM - 2D image
• state max magnification and resolution of an TEM - transmission electron microscope?

  Magnification - x2000000

  resolution - 0.1nm
• state max magnification and resolution of an SEM- Scanning electron microscope?

  magnification - x200000

  resolution - 20nm
• State magnification equation

  Magnification = image size divided by actual size
• what are fungi cell walls made of?


  chitin
• what are bacterial cell walls made of?


  Peptidoglycan
• Laser scanning confocal microscopes:

  • laser light used to create image
  • creates 3D image
  • high resolution
• describe phospholipids structure?


  Phospholipids have a hydrophilic head and hydrophobic tails, forming a bilayer in cell membranes.
• name functions of triglycerides in living organisms?

  thermal insulation

  energy storage

  respiratory substrate

  buoyancy
• lipids are less dense than proteins
• what are purines?


  Nitrogenous bases with a 2 carbon ring structure

  adenine guanine
• What are pyrimidines?

  nitrogenous bases with a 1 carbon ring structure eg thymine cytosinde
• Introns - non-coding regions of DNA that are removed from the mRNA after transcription
• exons - sequence of bases in a gene that code for a sequence of amino acids
• Start codon - enables ribosome to attach
• stop codon - causes ribosome to detach and end translation
• isotonic solution - when the water potential of a solution is the same in the solution and the cell within the solution
• hypotonic solution - when the water potential of a solution is more positive than the cell, cause cell to swell
• hypertonic - the water potential of solution is more negative than the cell, water moves out of cell, crenation/plasmolysis
• benedicts test for non-reducing sugars:

  negative result - reagent remains blue

  hydrolyze non-reducing sugars by adding hydrochloride acid and heat in boiling water bath

  neutralise solution using sodium carbonate

  normal benedicts test
• state role of nitrates

  NO3- used to make dna, amino acids etc
• what is water potential?

  pressure created by water molecules measured in kPa

  more solute= wp more negatived
• name 5 factors affecting diffusion rate?

  temperature

  diffusion distance

  size of molecule

  difference in concentration
• define tidal volume?


  volume of air breathed in and out during each breath at rest
• gas exchange in fish

  buccal cavity volume increases so water flows in

  water pumped over lamellae by operculum
• what causes the first lub when listening to a heartbeat?


  Closure of the atrioventricular valves.
• Vagus / parasympathetic nerve - decreases heart rate
• accelerator/sympathetic nerve increases heart rate