2.4

living organisms synthesize many different proteins with a wide range of functions.

Catalysis Muscle contraction cytoskeletons Tensile strengthening blood clotting transport of nutrients & gases cell adhesion membrane transport hormones Receptors packing of DNA immunities

Insulin

A hormone - signals many cells to absorb glucose to help reduce glucose concentration in blood. affected cells have a receptor (proteins) on their surface to which insulin can to which insulin can (reversibly) bind to. secreted by β cells in the pancreas and transport by the blood. the pancreas of type 1 diabetes don't produce insulin so they must inject themselves periodically

collagen

A number of different forms all are rope - like proteins made of three polypeptides wound together about a quarter of all protein in the human body is collagen forms a mesh of protein in blood vessel walls that resists tearing. gives strength to tendons ligament, skin and in blood vessel walls. forms part of teeth and bones helps to prevent cracks and fractures to bones and teeth

Rhodopsin

A pigment that absorbs light Membrane proteins of rod cells if the retina Consists of the opsin polypeptide surrounding a retinal the prosthetic group Retinal molecule absorbs a single proton of light --> changes shape --> changes to the opsin --> the rod cell sends a nerve impulse to the brain. Even very low light intensities can be detected

Polypeptides And proteins.

A polypeptide is an unbranched chain of amino acids The number of amino acids is variable and can be over 10,000 however most have been between 50 and 2000 amino acids. Chain of fewer than 40 amino acids are used to be called peptides rather than polypeptides or proteins. Amino acids can be linked together and any sequence giving a huge range of possible polypeptides. if we consider polypeptide with 100 amino acids the number of possible sequences is 20100 amino acids Only a small proportion of the possible sequence of amino acids is ever made by living organisms. The amino acid sequence of a polypeptide is coded by a gene. the sequence of bases in the DNA of the gene determines the sequence of amino acids in the polypeptide. Proteins have either single polypeptides or more than one polypeptides linked together.

Immunoglobulins

Also known as antibodies. Two antigen (a molecule on the pathogen which provokes an immune response) binding sites - one on each 'arm' Binding sites vary greatly between immunoglobulins (hypervariable) to enable them to respond a huge range of pathogens. Other parts of the immunoglobulin molecule cause a response, e.g. acting as a marker to phagocytes (which engulf the pathogen)

Peptide bonds and polypeptides

Amino acids are linked together by condensation reactions. the new bonds between the amine of one group and the amino acid of the carboxyl group of the next is a peptide bond. A molecule consisting of two amino acids together is a dipeptide.

Amino acids

Amino acids have a central atom with four different atoms linked to it The R group of an amino acid is variable this means that there are hundreds of different types of amino acids but living organisms can make only 20 of them, these are produced on the ribosomes.Some organisms contain an extra to polypeptides Making the total on some organisms 22.

spider silk

Different types of silk with different functions dragline silk is stronger than steel and tougher than kevlar when first made it contains regions where the polypeptide forms parallels arrays some regions seem like a disordered tangle when the stretched polypeptide gradually extends making the silk extensible and very resistant to breaking.

Difference between fibrous and globular proteins and the properties of proteins

Fibrous proteins and globular proteins differ in size, shape, solubility, appearance as well as in function. Fibrous proteins consist of repetition of a single unit to form chains that act as connective tissues and give strength and joint mobility. Globular proteins are spherical in shape and consist of long chains with numerous branches and offshoots which make them great as transport proteins.

How does the R group make a protein soluble or insoluble

If the R group is folded into the core of the molecule from the surrounding water, molecules. this makes them soluble (globular) If the R group is exposed it makes the molecule insoluble (fibrous)

Primary structure

Order/ sequence of the amino acids of which the protein is composed formed by covalent peptide bonds between adjacent amino acids controls all subsequent levels of structure

what are thermophile

Organisms that live in relative hot condition In order that they can survive their proteins are stable at higher than normal temps

Proteins and Proteomes

Proteomes are all the proteins produced by a cell Or an organism.A genome is all of its genes. The genome of an organism is fixed. The protein is variable because different cells in organisms make different proteins. Even in a single cell the proteins that are made very over time spent on cell activities. Within a species there are strong similarities in the proteome but also differences. it is unique because of differences in the activity but also because of small differences in the amino acid sequence of proteins. with the possible exception of identical twins no one has identical proteins so every person has a unique protein and with age the problem of identical twins change.

explain the denaturing of proteins by extreme heat or pH

The 3d conformation of proteins is stabilized by bond or interactions between or groups of amino acids while the molecule most of these bonds and if your actions are relatively weak and they can be disrupted or broken. this results in a change to the confirmation of the proteins which is called denaturation. denaturation is permanent. soluble proteins often become insoluble he's can cause denaturation: vibrations within a molecule can cause the molecules to break intermolecular bonds for interactions.

Secondary structure

The chains of amino acids fold or turn upon themselves Held together by hydrogen bonds between (non adjacent) amine (N-H) and carboxylic (C-O) groups. H bonds provide a level of structural stability fibrous proteins

Quaternary structure

The interaction between multiple polypeptides of prosthetic group. A prosthetic group is an inorganic compound involve in a protein Fibrous & globular protein.

Tertiary structure

The polypeptide folds and coils to form a complex 3D shape Caused by interactions between R groups (H-bonds, disulphide bridges ionic bonds and hydrophilic/hydrophobic, interactions) ertiary structure may be important for the function Globular proteins

sequence of amino acids determines?

The sequence of amino acids determine how the folding is done and so determines the protein conformation. each time a polypeptide with a particular sequence of amino acids is synthesized on a ribosome, the confirmation will tend to be precisely the same. the structure is stabilized by intermolecular bonds between the amino acids in the polypeptides between the amino acid and the polypeptides that are brought together by folding process.

Rubisco

full name ribulose bisphosphate carboxylase enzyme- catalyses the reaction that fixes CO2 from the atmosphere. provides the source of carbon from which all carbon compounds are produced found in high concentration in leaves and algal cells

What are white smokers?

hydrothermal vents produce hot CO2 gas found in deep oceans temps over 100 degrees but organisms live around it