B1

• DNA bases

  • Adenine
  • Cytosine
  • Thymine
  • Guanine
  • A pairs with T
  • C pairs with G
• Nucleotides

  • Base ( A C T G )
  • sugar
  • Phosphate
• Proteins

  • DNA codes for specific production of proteins
  • made up of amino acids
  • each protein has different functions
  • each amino acid codes in triplets
• mRNA


  single strand of DNA

  1. DNA contains gene coding for protein
  2. two DNA strands zip
  3. Transcription- DNA acts as a template to make mRNA, base pairings makes it complementary
  4. mRNA moves out of nucleus into cytoplasm to ribosome
  5. Translation- Amino acid that matches triplet code on the mRNA are joined together to make protein
  6. transfer RNA (tRNA) RNA molecule brought to ribosome
• Aerobic respiration


  Glucose + Oxygen --> Carbon dioxide + water

  • exothermic reaction
• Anaerobic respiration


  - without oxygen

  glucose --> lactic acid

  lactic acidc- builds up in muscle and is painful
• Oxygen debt

  • oxygen required to break down lactic acid
  • Breathe in more oxygen
• Anaerobic respiration with plants

  Glucose --> ethanol + Carbon dioxide
• Carbohydrates

  • molecule containing Carbon, Oxygen and hydrogen
  • break down into monomers of sugar (starch)
  • digested by Amylase enzymes in mouth and intestines
  • made in salivary glands, pancreas and small intestines
• Proteins

  • polymers made up of long chains of amino acids
  • carbon, nitrogen, hydrogen and oxygen atoms
  • broken down by protease enzymes in stomach and small intestine
  • Made in stomach, pancreas and small intestines
• Lipids

  • fats and oils
  • made into glycerol and three fatty acids
  • NOT Polymers as they don't form chains
  • Carbon, hydrogen and oxygen
  • broken down by ligase enzymes in small intestines
  • made in pancreas and small intestines
• > Iodine solution diffuses through membrane into starch solution

  > Starch cannot diffuse out of the membrane

  
• Animal cell


  Nucleus- contains DNA

  Cell membrane- controls what comes into and out of the cell

  Cytoplasm- where most chemical reactions take place

  Mitochondria- cell respiration and contains enzymes needed for reactions involved

  Ribosomes- where proteins are made from
• Plant cell


  Nucleus- contains DNA

  Cell membrane- controls what comes into and out of the cell

  Cytoplasm- where most chemical reactions take place

  Mitochondria- cell respiration and contains enzymes needed for reactions involved

  Ribosomes- where proteins are made from

  permanent Vacuole- contains cell sap (mixture of sugars, salts, water)

  Rigid cell walls- made of cellulose to support the cell

  Chloroplast- where photosynthesis occurs

  Cell wall- made of cellulose provides more structure
• Prokaryotic cells


  Chromosomal DNA- controls cell activity and replication, floats freely in cytoplasm

  Plasmids- small loop of extra DNA that aren't part of chromosome, contains genes

  Cell membrane- controls what goes in and out and supported by a cell wall

  Ribosomes

  Cytoplasm

  Unicellular
• Temperature effects enzymes

  • higher temperature the faster due to more kinetic energy
  • Too high damages cells and causes them to denature by changing active site and won't be able to bind to it's substrate
  • Optimum temp- highest rate of enzyme reaction
• pH effects enzyme

  • measure of acidity
  • too high, too low will lower rate of reaction
  • Some of the bonds holding enzyme together break changing shape of active site and substrate won't fit- denatured
  • Optimum pH
• Light effects photosynthesis

  • light transfers energy
  • light increases= photosynthesis increases but up to a point
  • beyond it will make no difference
• light intensity

  • inversely proportional
  • Distance increases, light intensity decreases
  • 1/ distance (squared)
• Carbon dioxide effects photosynthesis 


  Co2 Is needed for photosynthesis

  Increases to a certain point
• Temperature affects photosynthesis

  • too low- enzyme activity is slower
  • too hot- denatures enzymes
  • Experiments best in waterbacth
• Photosynthesis 


  carbon dioxide + water -(light/chlorophyll)-> glucose + oxygen

  • endothermic reaction
  • chlorophyll, water, carbon dioxide and sunlight
• Magnification


  image height/ object height
• Measurements

  Centimetre= 1 x10 -2 (cm)

  Millimeter = 1 x10 -3 (mm)

  Micrometer= 1 x10 -6

  Nanometer= 1 x10 -9

  Picometer= 1 x10-12
• what is glucose stored as

  • starch
• Amino acids

  • order of bases decides order of amino acids in a protein
  • Each amino acid is coded by a sequence of three bases
  • Complementary bases- triplet code