Proteins Flashcards
what are the monomers of proteins
and what are polypeptides
amino acids
more than two amino acids joined together
strucuture of amino acid
what elements are amino acids made up of
R
H2N–C – COOH
I
H
Carbon, Oxygen, Hydrogen and nitrogen
and sometimes sulfur
when peptide bonds are formed between amino acids what molecule is released
water (condensation)
HOWEVER the opposite of this reaction “hydrolysis” would add water to break the peptidde bond
how is a peptide bond formed
“OH” from COOH and “H” from H2N bond to form
C-N (peptide bond)
what are the four levels of a proteins structure
primary
secondary
tertiary
quaternary
what is the primary structure
the sequence of amino acids
a change in just one amino acid could change the entire strcuture of a protein
what is the secondary strucuture
hydrogen bonds form between amino acids in the polypeptide chain
making them COIL into an alpha helix or FOLD into a beta pleated sheet
what is the tertiary strucuture
the coiled or folded chain is often
COILED AND FOLDED FURTHER
more bonds form between different parts of the polypeptide chain
what is the quaternary structure
some proteins are made up of several polypeptide chains
the quaternary structure is the way these polypeptide chains are assembled together
what bonds hold the amino acids in the primary/secondary/tertiary structure together
primary- Peptide bonds
secondary- Hydrogen bonds
tertiary- affected by several bonds
what is an ionic bond in a protein
attraction between negatively and positively cahrged R groups
what is a disulfide bond
sulfur atom in one cystesine bonds to a sulfur atom in another cytesine forming a disulfide bond
Hydrophobic and hydrophillic interactions
when hydroPHOBIC R groups are close together in a protein they tend to clump together, which means that the hydroPHILLIC R groups are more likely to be pushed to the outside which affects the way the protein folds
Hydrogen bonds
weak bonds form between slightly positively charged hydrogen atoms in some R groups and slightly negatively charged atoms in other R groups
what are the four types of bonds that could be in the tertiary strucuture
ionic bonds
Disulfide bonds
hydrophobic/hydrophillic interactions
hydrogen bonds
what is a good feature of globular proteins
they are soluble so can be easily transported in fluids
what is a conjugated protein
a protein group with a non protein group( prosthetic group) attached to it
the prosthetic group in haemoglobin is haem
what is insulin
whats its function
what is one of its best features
what bond holds insulin molecule together
a hormone
regulate blood glucose levels.
Its soluble so can be transported in the blood
Disulfide bond
Amylase
is am enzyme that catalyses the break down of starch
made up of a single chain of amino acids
what is the secondary structure of Amylase made up of
BOTH alpha-helix and beta pleated sheets
what are fibrous proteins
what are the three types of fibrous proteins
stuctural proteins
1) Collagen- found in animal connective tissue. Very strong
2) Keratin- found in skin,hairs,nails,feathers,horns. can be flexible as it is in skin or hard as it is in nails
3) Elastin- Found in elastic connective tissue, such as skin, large blood vessels and some ligaments. It is elastic so allows tissue to return to their original shape
