UNIT 1

• Monomers of Carbs?

  Monosaccharides
• In Alpha Glucose which element is on the top

  Hydrogen on top, OH on bottom
• Disaccharides ( two monosaccharides joined )

  SUCROSE = Glucose + Fructose

  LACTOSE = Glucose + Galactose

  MALTOSE = Glucose + Glucose (both alpha)
• Condensation reaction: Joins two molecules together by removing water

  forms a glycosidic bond and releases water

  eg. disaccharide formation
• STARCH- formed via condensation reaction of alpha glucose and is main energy storage in plants

  • Made up of two polysaccharides Amylose and Amylopectin
  • Insoluble in water- doesn't affect water potential meaning water can't move in via osmosis and cause cell to swell and burst

  AMYLOSE= long and unbranched chain joined by 1,4 glycosidic bonds which make it coil therefore more compact and better for storing energy

  AMYLOPECTIN= Branched chain joined by 1,4 AND 1,6 glycosidic bonds. Side branches allow energy to be released quicker as enzymes can act upon them stimultaneously
• GLYCOGEN- formed via condensation reaction of Alpha glucose and is the main energy storage in ANIMALS

  • Lots of side branches meaning energy can be released quicker as enzymes can act simultaneously
  • Compact so can store lots of energy
  • Insoluble so won't affect water pot. and can't diffuse out of cells
  • Joined via 1,4 and 1,6 glycosidic bonds
• CELLUOSE- component of cell walls made up of long and unbranched chains of beta glucose joined via glycosidic bonds

  • Chains run parallel held by Hydrogen bonds which forms microfibrils - cross linkage form
  • stops cell from bursting from osmotic pressure
  • insoluble
• TESTING FOR FATS - Emulsion test

  1. Add 2cm of sample to 5cm of ethanol
  2. Shake sample to dissolve any lipid in sample
  3. Add 5cm of water and shake gently
  4. Pos test= cloudy emulsion
• alpha vs beta glucose

  Alpha - the hydrogen atom is above the carbon.

  Beta - the hydrogen atom is below the carbon. 
•  Explain five properties that make water important for organisms.

  • METABOLITE= acts as solvent so metabolic reactions can happen
  • High specific heat capacity =buffers changes in temperature
  •  Large latent heat of vaporisation = provides a cooling effect
  • Cohesive =supports columns of water as water molecules will stick together
• Describe the process of semi-conservative replication of DNA.

  1. DNA helicase unzips DNA, breaking H bonds
  2. Original strands act as templates
  3. Free DNA nucleotides line up in complementary pairs
  4. DNA Polymerase joins strands forming phosphodiester bonds and a new strand of DNA
  5. Each new strand contains 1 strand of the template and 1 strand of the new
•  Explain the arrangement of phospholipids in a cell-surface membrane.

  • is a bilayer
  • hydrophilic heads face point inwards (phosphate head)
  • hydrophobic tails face outwards (fatty acid tail)
•  Describe how an ester bond is formed in a phospholipid molecule.

  condensation reaction between fatty acid and glycerol
• State and explain the property of water that helps to prevent temperature increase in a cell.

  High specific heat capacity = buffers changes in temperature
• Describe the biochemical tests you would use to confirm the presence of lipid, non-reducing sugar and amylase in a sample.


  LIPID= EMULSION TEST = add ethanol , mix , then water then mix

  NON REDUCING SUGAR= BENEDICTS = do benedicts test, will stay blue, then boil with acid and neutralise with alkali . heat with Benedict's and will turn red

  AMYLASE= add bieuret , goes purple then add starch and test for reducing sugar
• Describe the primary structure of all proteins.

  sequence of amino acids that make up a polypeptide chain

  has peptide bonds
• Explain why phospholipids can form a bilayer but triglycerides cannot.

  phospholipid is polar

  triglycerides are not polar

  phosphate group attracts water to either side of bilayer
• Describe two other functions of bile salts.

  • emulsify fats and lipid
  • form micelles
  • inc SA of lipid
• Explain why triglycerides are not considered to be polymers.

  not made of repeating units
• The performance of the athletes might have been influenced by how they expected the caffeine to affect them. How could the researchers avoid this possibility?

  don't tell group what was in the drink
•  Suggest one explanation for the higher glycerol and fatty acid concentrations in the blood plasma of the athletes after they were given caffeine.

  breakdown of fats at a increased rate
• Galacto-oligosaccharides (GOS) are polymers of galactose.

  (a)  Explain why GOS are described as polysaccharides.

  galactose is a monosaccharide

  made up of monosaccharides joined via condensation
• Describe the role of ATP in the process of translation in protein synthesis.

  provides energy

  so amino acid joins to tRNA