4PY013

• Lipids can be saturated (single bond) or unsaturated (double bond)
• glycerol + 3 fatty acids -> triglyceride + 3 water

  DEHYDRATION REACTION
• Integral proteins - span membrane and interact with hydrophobic hydrocarbons
• Peripheral proteins - interact with integral proteins and interact with hydrophilic head and can move through the membrane
• Membrane lipids are amphipathic - contain both hydrophilic and hydrophobic regions
• 3 common types of membrane lipids:

  • phospholipids - lipid containing phosphate group
  • glycolipids - sugar containing lipid
  • cholesterol - steroid
• Glycerophospholipid - fatty acid, glycerol, phosphate and alcohol
• Saturated lipids reduce fluidity of a membrane
• Unsaturated lipids increase the fluidity of the membrane
• Cholesterol inserts into gaps and regulates membrane fluidity
• Steroids are lipids that have four rings, e.g. cholesterol, testosterone and estrogen
• Cholesterol is made in the liver
• Sugars are carbohydrates that are used for energy stores, fuels and metabolic intermediates
• Monosaccharides are simple sugars, e.g. glucose, fructose
• Trioses are the smallest monosaccharides that have 3 carbons and are aldehydes or ketones
• trioses: D - glyceraldhyde, L - glyceraldehyde and dihydroxyacetone
• Epimers are sugars differing in configuration around only 1 chiral carbon
• Epimers - glucose and mannose and glucose and galactose but not galactose and mannose
• Glycoside - any molecule in which a sugar group is bonded through its anomeric carbon to another group via a glycosidic bond
• Monosaccharides are joined to alcohols and amines through glycosidic bonds
• When sugars react with alcohols they form O-glycosidic bonds
• Glycosidic bonds can join monosaccharides to each other to make disaccharides
• a-D-glucopyranose + a-D-glucopyranose = maltose
• a-D-glucopyranose + B-D-fructofuranose = sucrose
• B-D-Galactopyranose + a-D-glucopyranose = lactose
• Nucleotide - base + sugar + phosphate group
• Adenine, guanine, cytosine and thymine are bases found in nucleotides
• Base + sugar = adenosine, cytidine, thymidine, guanosine
• Base + sugar + 1 phosphate = adenosine monophosphate
• Base + sugar + 2 phosphate = adenosine diphosphate
• Base + sugar + 3 phosphate = adenosine triphosphate
• Proteins are coded and regulated by genes
• There are 20 different types of amino acid, but make around 20,000 proteins
• amino acids divided in four groups:

  • Neutral Non-polar (no charge, no polarity)
  • Neutral Polar (no charge but have a di-pole)
  • Acidic ( -ve charge  due to carboxyl group)
  • Basic (+ve charge due to amine group)
• PrImary structure - linear chain of amino acids
• DNA is deoxyribosenucleic acid and is double stranded and is for genetic coding
• RNA is ribonucleic acid and is a single strand and is for translation and transcription
• The bases in DNA and RNA are held together by hydrogen bonds
• Phosphodiester bonds link the triphosphate of one nucleotide to the deoxyribode sugar of the next nucleotide to form a single strand of DNA
• Inside the helix the bases are stacked one on top of the other and are stabilised by the hydrophobic effect and stacked bases are attracted to each other through van der waals force