Martini Chapter 2 - Part 2

Martini Chapter 2 - Part 2

1. Carbohydrates 1:2:1 ratio

   • contain carbon, hydrogen and oxygen in a 1:2:1 ratio
   • Monosaccharides
     • Simple sugars
     • contains 3 to seven carbon atoms
     • isomers have the same molecular formula but a different arrangement in space
   • Disaccharides and Polysaccharides
     • 2 simple sugars joined together are disaccharides
     • condensation reactions occur to join simple sugars together to form dissaccharides and polysaccharides, it requires the removal of a water molecule
     • di and polysaccharides have to be hydrolysed before the energy stored in the simple sugars can be used
     • polysaccharides are more than 2 simple sugars joined together

2. Lipids 1:2 ratio

   • they contain carbon to hydrogen in the ratio 1:2, they also contain oxygen.
   • most lipids are insoluble
   • lipids are an important energy storage providing double that of carbohydrates
   • when there are excess lipids they are stored as fat reserves
   • Fatty Acids
     • long carbon chains with hydrogen atoms attached
     • one end of the chain is a carboxyl group
     • the carboxyl group is the only part of the molecule that reacts with water as it is the only hydrophilic part of the molecule
     • saturated fatty acids have no double carbon carbon bonds there is complete saturation of hydrogen atoms
     • unsaturated fatty acids have double carbon carbon bonds
     • monounsaturated means there is only one double bonds
     • polyunsaturated means there are multiple double bonds
   • Eicosanoids
     • lipids derived from arachidonic acid - a fatty acid that must be absorbed in the diet as it can't be made in the body
     • Leukotrienes are produced mainly by cells that coordinate responses to injury and disease
     • Prostaglandins are short chain fatty acids that have a ring of 5 carbons.
       • They are released by cells to coordinate local cellular activities
       • local hormones, they only effect the area they are released in
   • Glycerides
     • fatty acids are joined to a backbone of glycerol
     • the number of fatty acids determines whether it is a mono, di or tri glyceride
     • Energy Source - they can be broken down into their parts to provide energy
     • Insulation - fat deposits under the surface of the skin act as insulation
     • Protection - a fat deposit around an organ provides a cushion against trauma
   • Phospholipids and Glycolipids
     • A phospholipid is a diglyeride that is attached to a nonlipid group by a phosphate group
     • A glycolipid is a carbohydrate attached to a diglyceride
     • the heads of both are hydrophilic and the tails hydrophobic so a micelle forms
     • A bylayer can be formed to make the membrane of a cell, it is mostly made of phospholipids
   • Steriods
     • large lipid molecules that share a distinctive carbon framework
     • the bits that make them different are the different groups that attach to them
     • the plasma membrane contains cholesterol which is needed to maintain the plasma membrane
     • steriod hormones are involved in sexual function
     • steriod hormones are important in the regulation of tissue metabolism and mineral balance
     • derivatives called bile salts are required for the processing of dietary fats

3. Proteins are formed from amino acids

   • Types
     • Structural - create a 3D framework for the body
     • Contractile - responsible for muscle contraction
     • Transport - molecules that can't travel in the blood are transported by a transport protein
     • Buffering - provide a buffering system to stop pH change in the blood
     • Enzymes - accelerate metabolic reactions
     • Hormones - influence the actions of every cell in the body or specific organs/organ systems
     • Defense - tough waterproof proteins to protect against the outside environment and antibodies to protect against disease
   • Protein Structure
     • long chains of amino acids
     • There are 20 differnt amino acids that make up all the proteins in the body
     • Amino Acids
       • central carbon atom
       • hydrogen atom
       • amino group
       • carboxyl group
       • R group
       • The R group is what maes each amino acid differnt and changes the function of the amino acid
       • water soluble
       • form peptide bonds with each other
   • Protein Shape
     • Primary structure - sequence of amino acids in a single polypeptide
     • Secondary structure - formation os a simple 3D shape, a helix or a pleated sheet
     • Tertiary structure - the secondary structure bends and folds around itself and forms a complex 3D shape uses various bonds to keep its position. The strongest bond is the disulphide bond.
     • Quaternary structure - tertiary structures bonding with each other to form a protein complex
     • Fibrous and Globular proteins
       • Fibrous - extended sheets are strands. Tough, durable, insoluble and structural
       • Globular - compact, rounded and only function when in an aqueous solution
     • Portein Shape and Function
       • shape determines function
       • shape depends on the order of amino acids
       • local environmental conditions can effect the shape of proteins e.g. pH can break bonds
   • Enzyme function
     • reactants in enzyme reactions are substrates
     • the active site is specific to certain substrates and weak bonds form between the 2 to help the reaction happen
     • how it happens
       • 1 - the substrates bond to the active site
       • 2 - the substrates are then bonded together in the enyzme substrate complex
       • 3 - the binding of the substrates changes the shape of the active site
       • 4 - the enzyme releases the product and starts all over again
     • Characteristics
       • Specificity - enzymes can only catalyze specific reactions because of their unique active sties. There are multiple enzymes that can catalyze the same reaction that are called isozymes.
       • Saturation limits - the rate of reaction is limited by the concentration of both enzyme and substrate. The higher the concentration the higher the chance of a successsful collison and reaction taking place.
       • Regulation - enzymes are effected by changes in the environment so the cell can change them to alter whether the enzyme is active or inactive
     • Cofactors and Enzyme Function
       • cofactor - ion or molecule that must bind to the enzyme before the substrate can
       • cofactors alter the shape of the active site
       • Coenzymes - nonproteins organic molecules that act as cofactors
     • Temperature and pH on enzyme action
       • optimum conditions exist for enzymes and if the conditions stay far from the set point then the enzyme will stop working and in extreme conditions will denature
       • denature - an irriversable change in the structure of an enzyme that means it no longer functions
   • Glycoproteins and Proteoglycans
     • combinations of proteins and carbohydrates
     • glycoproteins - large proteins with small carbohydrate groups
     • GPs are antiobdies, enzymes, hormones or protein components of blood plasma
     • glycoproteins in plasma membranes identify normal and abnormal cells and start the immune response
     • GPs also secrete mucins that absorb water to become mucus
     • Proteoglycans are polysaccharides linked to polypeptides

4. DNA and RNA

   • nucleic acids - organic molecules made up of carbon, hydrogen, oxygen, nitrogen and phosphorus
   • DNA is the building blocks to life they code for everything in the body and all the characteristics that make people different
   • RNA is used to copy DNA so the information stored on the DNA can be used to make proteins
   • Structure of Nucleic acids
     • Nucleotides - pentose sugar, phosphate group and nitrogenous base
     • the pentose sugar is either ribose (RNA) or deoxyribose (DNA)
     • the 5 bases
       • T - thymine
       • A - adenine
       • G - guanine
       • C - cytosine
       • U - uracil
     • A and G are purines - double ringed molecules
     • T, C and U are pyrimidines - single ringed molecules
     • T is only found in DNA and U only in RNA
     • The phosphate group and sugar form the backbone of the DNA (the sides of the ladder)
     • The bases form the rungs of the ladder with A and T bonding and C and G bonding only
   • RNA and DNA
     • RNA is a single chain of nucleotides
     • there are 3 types of RNA: mRNA - messenger, tRNA - transfer, rRNA - ribosomal
     • DNA is a double strand of nucleotides held together with hydrogen bonds
     • Complementary base pairs are the only pairs that occur A and T(or U), C and G.

5. ATP

   • ATP can be broken down to ADP and then AMP releasing energy each time
   • high energy compound
   • the attachment of a phosphate group on to another molecule is called phosphorylation
   • ATP is made up of adenine bonded to ribose which is then bonded to a chain of 3 phosphates
   • to convert from ADP to ATP you have to use ATPase