Creation of Protein

 Once the mRNA leaves the nucleus it enters the cytoplasm  Ribosomes form around the mRNA  mRNA is fed through the Ribosome and each codon is matched up to the corresponding tRNA anticodon  The tRNA brings the amino acids, a chain is formed  Occurs in a 5’ – 3’ direction

 A strand of RNA that has turned into a double loop by base pairing  Each amino acid has a specific tRNA activating enzyme that binds a specific amino acid to the tRNA  20 different tRNA enzymes, each matching up to a specific amino acid  Energy from ATP is needed to attache the amino acid to the tRNA  Contains the anti-codon used to match up to the mRNA template

 Ribosomes are made up of rRNA and protein  Two subunits – large and small  Three binding sites for tRNA on the surface of the ribosomes  Two tRNA molecules can bind at the same time to the ribosome.  Also a binding site for mRNA

1. Initiation – translation begins (Start codon) 2. Elongation – chain of amino acids grows 3. Translocation – newly formed protein is folded 4. Termination – sequence ends (Stop codon)

 Sometimes, one strand of mRNA can be translated by more than one ribosome at a time  This results in a polysome

 Free ribosomes – located in cytoplasm  Typically synthesize proteins made for use within the cell itself  Bound ribosomes – located on the RER  Synthesize proteins primarily for secretion or for lysosomes

 Long chains of amino acids  Functions:  Blood  Muscle, tissue, hair, nails  Antibodies  Hormones  Enzymes

 Primary Structure  The number and sequence of amino acids in a polypeptide  Typically anywhere between 50 – 1,000 peptides long  Secondary Structure  The regular repeating structures ▪ Α-helix ▪ Β-pleated sheets

 Tertiary Structure  The three dimensional conformation of a polypeptide  Essentially, the 3-dimensional folded formation of a protein  Includes the intramolecular bonds formed between amino acids  Quaternary Structure  How two or more polypeptides link together to form a single protein ▪ Prosthetic group – non-polypeptide structure that some polypeptides contain ▪ Conjugated protein – Proteins with a prosthetic group

 Long, narrow shape  Insoluble in water  Examples:  Collagen – structural protein ▪ Strengthens bones, tendons, skin ▪ Causes these tissues to create long tough fibres  Myosin – movement ▪ Myosin + actin cause contraction in muscle fibres ▪ Results in muscle movement

 Round shaped proteins  Typically soluble in water  Examples:  Haemoglobin ▪ Binds with oxygen in the bloodstream and transports to tissues  Immunoglobulin ▪ Antibodies

 Polarity based on the R group  Hydrophilic R groups = polar  Hydrophobic R groups = non-polar  Polarity determines the location and distribution of proteins located in the cell and what function it might have  Creation of hydrophilic channels through the cell membrane  Influences specificity of active sites in enzymes

Polar amino acids are forced to stay on the internal/external of the cell wall Non polar amino Acids are able to Cross the cell membrane And make channel proteins

 Polar amino acids act within the active site of an enzyme initiates a chemical reaction  Substrate and enzyme interact to form an activated complex  Weakened state allows for transitions to occur

 Hormones – Insulin  Regulates glucose uptake in cells  Immunoglobulin – Antibodies  Immune response  Enzyme – Amylase  Breaks down glucose  Gas transport – Haemoglobin  Brings oxygen to the tissues