Unit 1: Proteins Flashcards
What are proteins made up of?
amino acids
What determines the structure and the function of the protein?
The type and order of the amino acids
What is the structure of an amino acid?
has a central alpha carbon an amino group (NH2) a carboxyl group (COOH) an R group (variable) H atom
What is the R group of an amino acid?
It is the variable part of the amino acid structure and gives the amino acid unique chemical properties
What are the different R group classifications?
Acidic, basic, uncharged polar and non polar
what is an acidic side chain?
it is hydrophilic and is COOH group
what is a basic side chain?
it is hydrophilic and is NH2/NH3+ group
what is an uncharged polar chain?
is it hydrophilic and is OH or CONH2
what is a non-polar side chain?
it is hydrophobic and is a hydrocarbon including an aromatic ring
amino acids link together by which bond?
a covalent peptide bond
to form a peptide what reaction occurs?
condensation reaction between carboxyl group and amino group
what is a residue?
amino acids joined by peptide bonds
what bonds apart from peptide bonds are important in protein structure?
hydrogen bonds and ionic bonds
what is the primary structure of a protein?
the sequence of amino acids in a polypeptide chain
what determines the secondary and tertiary structure of a protein?
the primary structure
what are the two main types of secondary structure?
alpha helix and beta sheet
describe the alpha helix structure
polypeptide chain is coiled into a right handed helix held in place by hydrogen bonds between N-H bonds and C=O of another peptide bond
describe the beta sheet
polypeptide chain linked in a side to side configuration and can be parallel or antiparallel by hydrogen bonds between NH bonds and C=O of another.
what is a tertiary structure
The way in which a protein folds to give the final protein structure
what are van der waals
very weak attractions between the electron clouds of atoms
what are protein domains?
these are produced by any polypeptide chain that can fold independently into a compact, stable structure. protein is mad of one or more domains
what is a protein motif?
motifs are elements of secondary structure that form in a particular way
What is a prosthetic group?
final aspect to tertiary structure in proteins is the incorporation of non-protein groups e.g.. iron atom in catalase
what is a secondary structure due to?
hydrogen bonds between the atoms of the peptide bond
what is a tertiary structure due to?
interactions between the R groups
what is a quaternary structure
when protein has more than one polypeptide sub-unit
what is the function of an enzyme and give an example?
catalysis of bond breaking and bond making. e.g. amylase
what is the function of structural proteins and give an example?
provides mechanical support of cells and tissues. e.g. collagen
what is the function of a transport protein and give an example?
carries small molecules and ions. e.g. haemoglobin
what is the function of a motor protein and give an example
generates movement in cells and tissues. eg. myosin in skeletal muscle
what is the function of a storage protein and give an example
stores small molecules and ions. e.g. iron
what is the function of a signalling proteins and give an example
carries signals from cell to cell. eg. insulin
what are receptor proteins and give an example
detect signals and transmit to cell’s response machinery. eg. insulin receptor
what is a gene regulatory protein and give an example
bind to DNA to switch on or off genes. e.g. repressor protein in lac operon
what is the isoelectric point of a protein?
pH at which the protein has no overall charge
