B 1.2 - Proteins 2

• What are proteins?


  polymers (and macromolecules) made of monomers called amino acids
• what aspect of proteins determines its characteristics

  sequence, type and number of the amino acids within a protein determines its shape and therefore its function
• what do proteins form

  EnzymesCell membrane proteins (e.g. carrier)HormonesImmunoproteinsTransport proteinsStructural proteinsContractile proteins
• What are amino acids?

  monomers of polypeptides and are the building blocks of proteins
• what does each amino acid have

  central carbon atom called the alpha carbon, with single covalent bonds to 4 other atoms
• How many amino acids are there?

  20
• what is the general structure of an amino acid

  (NH2)(R) - C - (H)(COOH)amino group, R group, carboxyl group
• What is an R group?

  any group in which a carbon or hydrogen atom is attached to the rest of the molecule - it is a variable group and is how propertied of amino acids differ
• What is a peptide bond?

  covalent bond between two amino acids
• how do you form a peptide bond?

  condensation reaction where OH group and H is lost to form water and the C and N bond together
• how do you form a dipeptide bond

  two amino acids re linked by a condensation reaction
• What is a hydrolysis reaction?

  A covalent bond is broken by adding a molecule of water.
• what are polypeptides

  Chains of amino acids which are the main component of proteins
• how many amino acids can our cells synthesise

  11 amino acids - non-essential amino acids
• What are essential amino acids?

  one that cannot be synthesized in sufficient quantities by the animal thus must be obtained from the diet
• what are non-essential amino acids

  acids that can be synthesized by an animal using metabolic pathways that transform one amino acid into another
• how do we get the remaining 9 amino acids


  consume them in out diet
• histidine is found in

  rice, wheat, legumes, potato's, cantaloupe
• Valine

  legumes, spinach, broccoli, sesame, hemp seeds
• Tryptophan


  oats, spinach, soybeans, sweet potatos
• Threoine


  watercress, spirulina, pumpkin, leafy greens, hemp, chia seeds
• Phenylalanine


  avocado, beans, rice, almonds, seaweed, pumpkin, spirulina
• methioninr


  sunflower seeds, hemp seeds, chia seeds
• Lysine

  beans, soy, quinoa, pumpkin seeds, seitan, pistachios
• lsoleucine

  lentils, beans, oats, rye, soy, quinoa, brown rice, cabbage
• Leucien


  peas, pea protein, whole grain rice, sesame seeds, pumpkin, seaweed
• what do ribosomes do

  link amino acids together one at a time, until a polypeptide is fully formed
• how do ribosomes link amino acids together

  they receive instructions in the form of genetic code thus do not make random sequences
• What are polypeptides?

  long chains of amino acids
• what does the structure of amino acids do

  they can vary
• What does the genetic code do?

  codes for the number and order of amino acids in a polypeptide
• Where are polypeptides made?

  ribosomes, when stop codon is reached the amino acid chain is ended
• what determines which amino acid is added

  the mRNA codon
• What is the role of proteins on reactions

  Speeding up cellular reactions, or catalysis, is performed by enzymes
• What is the role of proteins on blood clotting

  blood proteins interact with oxygen to form a gel-like scab across a wound
• what is the role of proteins in skin, hair, tendons blood vessels etc

  Strengthening fibres in skin, hair, tendons, blood vessels e.g. collagen, keratin
• what is the role of proteins in transport

  Transport of vital metabolites e.g. oxygen which is carried by haemoglobin
• what is the role of proteins in cytoplasm

  Formation of the cytoskeleton, a network of tubules within a cell that cause chromosomes to move during the cell cycle
• what is the role of proteins in cells

  Cell adhesion, where cells in the same tissue stick together
• how can we determine the number of amino acids in a polypeptide

  20^n