2.4 proteins Flashcards
what are proteins?
proteins are POLYMERS made from AA (which are the monomers)
what determines the properties of proteins?
determinded by the R group on the AA
H
l
amino group – C – carboxyl group
(NH2) l (COOH)
R
How many common (made by ribosomes) AA are there
20
RECALL HOW TO DRAW PEPTIDE BOND FORMATION
carboxyl grp from AA + amino grp from AA – dehydration recation –> peptide bond between C=O and N-H + H2O
how are amino acid polypeptide sequences arranged
- prod in ribosomes
- AA linked tgt in sequence dictated by genes (sequences of DNA carrying info for expression)
what are the bare bones of the process from DNA to polypeptide production
DNA –transcription–> RNA –translation–> polypeptide
what is the start codon?
AUG
What are the stop codons
UAA
UAG
UGA
what are the 4 levels of protein structure?
- primary
- secondary
- tertiary
- quaternary
what is primary protein structure
a sequence of AA along the polypeptide chain (w peptide bonds), determined from genetic info
what is secondary structure of a protein
- parts of polyp chain COIL onto itself, forming ALPHA HELICES
- other parts can fold into BETA PLEATED STRUCTURE
- stabilised by HYDROGEN BONDS btw AA
what is tertiary protein structure
- overall THREE DIMENSIONAL SHAPE of a protein
- from bonds formed between R groups
- eg. disulphide bridge betw 2 sulfur-containing AAs
what is quarternary structure of protein
- when 2 OR MORE polypeptide chains ASSOCIATE to form resultant protein
- not all proteins
- eg collagen (triple helix), haemoglobin (4 polyp chains)
are all enzymes proteins?
no! some enzymes are made of RNA.
protein function: enzymatic
its just an enzyme man cmon lock and key
substrate in active site then products
proetin function: storage, 2 examples
examples
- egg albumin
- casein in milk (makes it white)
protein functions: hormonal, 3 ex
- insulin
- glucagon
- adrenaline
protein function: contractile and motor, 2 ex
both found in muscle cells
- actin
- myosin
protein functions: defensive, 1 ex
antibodies – clump onto bacteria
protein functions: transport, 1ex
electron transport chain proteins
protein functions: receptor
on plasma membrane, receives signal molecule –> relay molecules –> response
protein function: structural, 1 ex
collagen
define PROTEOME
the sum of all proteins that can be produced by the species
define GENOME
the sum of all genes encoded within the DNA of that species
