ICT weel 1

4 main biomolecules & subunits

Polysaccharide (sugars), fats lipids membranes (fatty acids), proteins (amino acids), nucleic acid (nucleotides)

Sugars

Formula (CH2O)n, often in cyclic form. Two hydroxyl groups react and form disaccaride (condensation, water released)

Reverse reaction of condensation

hydrolysis, water is needed

Storage of fatty acids

In the form of triacylglycerol (TCA)

Phospholipid

Two fatty acids attached to a glycerol molecule, a phosphate and an additional polar molecule that togehter form the polar head

Nucleic acids

In DNA and RNA, used for storage of genetic information

Nucleotide consist of

C5 sugar, cyclic base containing nitrogen and one or more phosphate groups. Nucleotide without phosphate group is nuleoside

Sugar component

Ribose for RNA (ribose nucleic acid), Deoxyribose for DNA (deoxyribose nucleic acid)

Base component

Cytosine - guanine

thymine (DNA) / uracil (RNA) - adeinine

C, T and U are build of pyrimine = ring with 4 carbon & 2 nitrogen

A & G have 6-ring pyrimidine bound to an extra 5-ring purine

Phosphate component

Nucleoside is bound to 1, 2 or 3 phosphate groups (adenosine diphosphate = ADP)

Side of coupling a nucleotide in DNA

3’-hydroxyl group of sugar of a nucleotide with the 5’-phosphate group of the next nucleotide

Five prime end vs three prime end

One side of a single strand DNA molecule contains a free phosphate group attached to carbon-5

free hydroxyl group attached to carbon-3

Peptide bonds between amino acids are made by

Ribosomes, in which translation of mRNA into proteins accurs

Sugars form branched structures because

they have many hydroxyl groups which can bind other saccharides

Storage of fatty acids

Often next to glycerol (hydrophillic head) in a cell

Peptide bonds are fromed during

protein synthesis by ribosomes

Determination of amino acid sequence

The triplets in mRNA determines the order of amino acids in a protein

Alpha helices

The backbone is inside the helice, the side chains are directed to the exterior of the helix. Hydrogen bonds between C=O groups and N-H group of amino acids that is 4 amino acids further up along the chain. Hydrogen bonds stabilise the helix

Beta sheets

Side chains are above and below the plane, alternatively. Hydrogen bonds between C=O and N-H groups

Beta turns

Two beta-sheets that are connected, for a compact structure. Hydrogen bond between C=O and N-H of an amino acids 3 residues further up along the polypeptide chain

Bonds in tertiary structure

Hydrogen bonds and hydrophobic effect stabilize the tertiary structure. For more stability, disulfide bonds between two sulfur atoms can help. They share an electron. Extracellular proteins have multiple disulfide bonds often.

Exonuclease activity of RNases

It can degrade RNA by removing nucleotides

Visualizing structure of three-dimensional proteins

X-ray crystallography, where individual atoms are determined via x-ray scattering. Visible that distance between covalent bonds are 0.1-0.22nm.

Difference between chemical catalyst and biocatalysts (enzymes)

Enzymes can couple energy requiring reactions with energy providing reactions, as long as the energy providing is more than the energy requiring

Active site of enzyme

Also called catalytic centre, is the binding site at the surface or in a groove

Induced fit

The enzyme changes his catalytic centre, to enable the reaction the enzyme catalyses

Factors influencing enzymatic activity

pH, at different pH the side chains can be charged and starting repelling each other

Temperature, enzymes have an optimum temperature range for their biocatalytic function

Protein folding happens when

Spontaneous, no ATP required