bio paper 1

• Rf value = distance travelled by solute/distance travelled by solvent (liquid)
• cellulose has 1,4 glycosidic bonds while amylopectin (starch) and glycogen have 1,4 and 1,6 glycosidic bonds
• b-glucose and a-glucose are isomers which means that they have the same chemical formula but different arrangement of atoms in space
• a-glucose has the hydrogen atom ABOVE the ring while b-glucose has the hydrogen atom BELOW the ring
• the properties of water are solvent, cohesion, high specific heat capacity, high latent heat of vaporisation and a metabolite (in hydrolysis)
• ATP is made up of 3 phosphate groups, 1 ribose sugar and 1 adenine
• ribosomes are formed from ribosomal RNA and proteins
• Food breakdown in the mouth

  1. Physical/mechanical breakdown by chewing to increase surface area

  2. Salivary amylase hydrolyses glycosidic bonds to produce maltose from starch

  3. Mineral salts in saliva keep pH neutral
• Food enters the stomach

  Stomach acid causes amylase to denature
• Food breakdown in the small intestine

  1. Food surrounded by pancreatic juice containing pancreatic amylase

  2. Pancreatic amylase hydrolyses any remaining starch into maltose

  3. Alkaline salts produced by pancreas and intestinal wall maintain neutral pH
• Food movement in the ileum

  1. Pushed by muscle contraction

  2. Epithelial lining produces maltase, a membrane-bound disaccharide, which hydrolyses maltose into a-glucose
• cotransport uses a carrier protein
• permeability of cell membranes is investigated by the leaking of pigment from beetroot into water which is measured by a colorimeter. At higher temperatures the cell membrane is more fluid so more pigment escapes.
• aseptic techniques include: leaving bunsen on to create convection current, sterilising surface and instruments, opening agar lid towards flame and flaming bottle neck
• root tips are soaked in hydrochloric acid to hydrolyse cellulose cell wall so the stain can diffuse into cells and they can be more easily squashed. It also stops mitosis.
• coverslips are pressed down to spread out cells so that the layer is thin enough for light to pass through
• in the hydrolysis of triglycerides by lactase in milk, fatty acids are produced which decrease the pH
• if oxygen affinity is lower it can be offloaded more readily
• oxyhaemoglobin forms when o2 and haemoglobin bind
• bohr effect is the fact that in high co2 concentrations, haemoglobin changes shape to have a lower affinity for oxygen so it offloads it to respiring cells readily
• RBCs are adapted by having no nucleus so there is more space for oxygen and having a biconcave shape that increases its surface area to volume ratio for faster diffusion ]
• the lungs have a high partial pressure of oxygen so oxygen binds to haemoglobin
• cooperative binding is the idea that haemoglobin changes shape when the first oxygen binds
• high co2 concentration makes the dissociation curve move to the right
• foetal haemoglobin (myoglobin) and animals at high altitude have a higher affinity for oxygen and a curve shifted to the left
• underground animals and those with a high metabolic rate (e.g. birds) have a lower affinity for oxygen and a curve shifted to the right
• the mammalian circulatory system is closed because blood stays within blood vessels and double because blood goes through the heart twice, once when deoxygenated and once when oxygenated
• coronary arteries cover the heart to supply the heart muscle with oxygen
• pulmonary artery delivers deoxygenated blood from the heart to the lungs
• pulmonary vein delivers oxygenated blood from the lungs to the left side of the heart
• cardiac output = heart rate x stroke volume. Cardiac output is the volume of blood pumped out of the heart each minute
• counter current principle

  • water and blood flow in opposite directions (antiparallel)
  • maintains favourable concentration gradient for diffusion
  • water always meets blood with a lower concentration of oxygen so oxygen diffuses down conc gradient
  • diffusion can occur continuously along whole length of lamellae
• monoglycerides and fatty acids associate with bile salts to form micelles. Micelles allow them to be transported to the ileum lining by making them soluble in water.
• At the ileum lining, micelles break down and monoglycerides and fatty acids can diffuse
• DNA is highly coiled around histones to form chromosomes
• locus is the fixed position of a gene on a chromosome
• codon is on mRNA and triplet is on DNA
• start and stop codons initiate translation
• proteome is the full range of proteins a cell is able to produce
• homologous chromosomes have the same genes but not the same alleles