bio

• stimulus to sensory neurone to relay neurone to motor neurone to effector to response
• senseory neurone sends electrical impulse, electrical impulse passed to relay neurone in spinal cord, relay synapses with motor and motor neurone carries impulse to muscle and then reponds
• when an object is too close, ciliary muscle will tighten, suspensory ligament will loosen, thicker lens so more light can refract
• when an object is too far, ciliary muscle will loosen, suspensory ligament will be contract so less light can refract
• progesterone 


  Maintains the Uterus lining to cushion fertilised Egg cell
• Oestrogen 


  initiate development of secondary sexual characteristics, building uterus lining
• oestrogen 


  develops the uterus lining
• progesterone


  maintains and thickens the uterus lining
• Alleles are different versions of a gene
• A gene is a short length of DNA found on a chromosome that codes for a protein
• chromosomes are thread like structures of DNA carrying genetic information in the form of genes
• • There are three main factors that limit the rate of photosynthesis:
  • Temperature
  • Light intensity
  • Carbon dioxide concentration
• alleles are different forms/variations of the same gene
• adrenaline is the fight or flight hormone that increases heart rate and blood pressure
• insulin lowers level of glucose in blood
• How adrenaline prepares the body for movement

  1. Increase in heart rate

  2. Increase in breathing rate

  3. Diverting blood flow towards muscles and away from non-essential parts of the body

  4. Dilation of the blood vessels inside muscles

  5. Breaking down of stored glycogen to glucose in the liver and muscle cells
• Increase in heart rate and breathing rate

  Ensures glucose and oxygen can be delivered to muscle cells (and carbon dioxide can be taken away from muscles cells) at a faster rate
• Diverting blood flow towards muscles and away from non-essential parts of the bodyensures an increased supply of the reactants of respiration (glucose and oxygen)
• Dilation of the blood vessels inside muscles

  Ensures more blood can circulate through them (again, supplying more glucose and oxygen)
• If the blood glucose concentration gets too high:

  • Cells in the pancreas detect the increased blood glucose levels
  • The pancreas produces the hormone insulin, secreting it into the blood
• Transgenic means the transfer of genetic material from one species to a different species
• Ligase is an enzyme that is able to join two different fragments of DNA together. The sticky ends of the DNA fragments are complementary to each other, allowing ligase to bind them together, sealing the gene into the plasmid.
• • Large surface area to allow faster diffusion of gases across the surface
  • Thin walls to ensure diffusion distances remain short
  • Good ventilation with air so that diffusion gradients can be maintained
  • Good blood supply to maintain a high concentration gradient so diffusion occurs faster
• • Some fungi store carbohydrates as glycogen
• Blood consists of red blood cells, white blood cells, platelets and plasma
• Phagocytes carry out phagocytosis by engulfing and digesting pathogens
• Lymphocytes produce antibodies

  • Antibodies are Y-shaped proteins with a shape that is specific (complementary) to the antigens on the surface of the pathogen
• Carbon dioxide and water from aerobic respiration in cell Urea produced by the breakdown of excess proteins (amino acids) in the liver
• • Their cells contain a nucleus with a distinct membrane
  • Some have features making them more like animal cells e.g. Plasmodium (the protoctist that causes malaria)
• renal artery supplies kidney with blood
• Plasmodium (the protoctist that causes malaria)
• fertilisation


  fuse of nucleus of pollen and nucleus of ovum]\
• Auxin produced in tip of shoot, diffuses back down the shoot, auxin moves away from light source causes growth on the dark side of the shoot
• • During times of fear or stress, Adrenaline is produced by Adrenal glands and secreted into the bloodstream
  • As a result, Liver cells convert Glycogen into Glucose to increase blood glucose levels
  • Additionally, breathing and heart rate increases to increase blood flow
  • Hence, the increase in breathing and heart rate allows more Glucose and Oxygen to be transported in the bloodstream to respiring cells for 'fight or flight' response to occur