2A-2B Flashcards
Proteome
complete set of proteins produced by a single cell or organism
What roles do proteins play?
Act as enzymes that control cellular processes;
Fibres in cells that provide structural support and movement
Define a Polypeptide
A chain of amino acids bonded by peptide bonds between the amino group of one amino acid and the carboxyl group of the other
Polymer
Chemically linked smaller units called monomers (amino acids)
What is the R-group
R group determines the interaction between other molecules
R group is the part that varies between amino acids and plays an important role in establishing interactions between proteins
Describe a Condensation Reaction
Amino acids join to form polypeptides by releasing H2O
Describe Hydrolysis
This reaction requires H2O to be added breaking polypeptides into their amino acids
Describe the primary structure of proteins
Linear sequence of amino acids linked by peptide bonds
Describe the secondary structure of proteins
Describes the three-dimensional form of local segments of a polypeptide chain. It is the result of the interactions between nearby amino acids and includes (most importantly) α-helices and β-pleated sheets
Describe α – helix
A spiral molecule that is held together by H bonds between neighbouring CO & NH groups
Describe β - pleated sheets
Folds in the polypeptide chain which are also the result of H bonds between amino acids
Describe the tertiary structure of proteins
Involves the way that random coils, alpha helices and beta sheets fold with respect to each other.
Various types of interactions can occur between the R groups of amino acid residues.
Describe the quaternary structure of proteins
It is made of more than a single polypeptide chain, each with its own primary, secondary and tertiary structure. Those polypeptides are held together by hydrogen bonds and the mutual attraction between polar amino acid side chains
Final product can be:
globular e.g. Haemoglobin
fibrous e.g. collagen
Describe the nucleus
Control centre of cells
Enclosed by double membrane
Contains genetic material called DNA
Nucleoli contiaing RNA (involed in formation of ribosomes)
Outer membrane forms endoplasmic reticulum
How is DNA formed?
Nucleotide polymers form by condensation polymerisation
A phosphodiester bond is formed
Polynucleotide extends in the 5’ → 3’ direction
Describe mRNA
Carries genetic info form the nucleus to the ribosmes (for protein synthesis)
Describe tRNA
Carry amino acids to ribosomes for protein formation
Describe rRNA
Helps make ribosomes
Main structural component
