SfM - Proteins

Question 1

what is a protein?

Answer 1

macromolecule, made of amino acids, arranged in a particular structure to carry out a specific function

Question 2

what do proteins do?

Answer 2

involved in biological processes
structural - actin=scaffold, keratin=skins
functional=enzymes/antibodies

Question 3

how are amino acids made?

Answer 3

composed of either DNA or RNA nucleotides
DNA = a, c, g & t
RNA = a, c, g & uracil
Three nucleotides code for AAs

Question 4

how many AAs are there in the body?

Answer 4

20

Question 5

what is an amino acid composed of?

Answer 5

amine group and carboxylic acids. have a variable R group

Question 6

are amino acids chiral?

Answer 6

yes, every aa except glycine has 4 different groups surrounding the carbon

Question 7

are aa’s affected by pH?

Answer 7

low pH AA’s are cations (+)

high pH AA’s are anions (-)

Question 8

what are aliphatic AA’s?

Answer 8

AA’s with hydrocarbon chain in R group

alanine, valine, iso/leucine

Question 9

what are aromatic AA’s?

Answer 9

AA’s with benzene ring in R group

phenylalanine, tyrosine, tryptophan

Question 10

sulphur-containing AA’s?

Answer 10

cysteine, methionine

Question 11

basic AAs

Answer 11

long hydrocarbon chain that finishes in NH

arginine, lysine, histidine

Question 12

acidic AAs

Answer 12

AAs have a C=O or C-O

aspartate, glutamate

Question 13

polar AAs

Answer 13

AAs have carboxyl group in R group

serine, threonine, asparagine, glutamine

Question 14

what is a proteins primary structure?

Answer 14

the sequence of AAs bonded in polypeptide chain

Question 15

what is secondary structure?

Answer 15

the 3D spatial arrangement of AAs and their bonding (H-bond)
alpha helix
beta pleated sheet

Question 16

what is the tertiary structure?

Answer 16

when functional groups (R chain) on AAs, interact with another - van der waals, ionic, hydrogen, disulphide, hydrophobic interactions
all functional proteins exist in this form

Question 17

what is the quaternary structure?

Answer 17

every polypeptides interact with one another

haemoglobin contains 4 tertiary polypep structures and 4 iron containing heme groups

Question 18

how does denaturation affect proteins?

Answer 18

chemical bonds in the protein are broken down - functionality is lost as it needs to be 3D (v.rare for denaturation to break primary structure)

Question 19

what are the main functions of proteins?

Answer 19

structural, enzymatic, contractile, defensive, storage, storage, receptors, hormonal, transport

Question 20

what is a glycoprotein?

Answer 20

proteins with 1 or more carbohydrates covalently attached

involved in stability, solubility, cell signalling

Question 21

what is a lipoprotein?

Answer 21

proteins combine with fat/lipids to form lipoproteins

found in cell membranes, transport hydrophobic molecules

Question 22

what is a metalloprotein?

Answer 22

protein molecules with a metal ion within their structures i.e haemoglobin
involved in enzymes, signal transduction, storage, transport

Question 23

in what form can proteins exist?

Answer 23

globular, fibrous and membranous

Question 24

globular proteins tend to be…

Answer 24

used in storage, hormones, transporters and structural

Myeloma is cancerous blood cells - globular proteins spill out

Question 25

fibrous proteins tend to be…

Answer 25

involved in muscle fibres and connective tissue

Scurvy - lack of vitamin C means collagen can’t be created

Question 26

membranous proteins tend to be…

Answer 26

membrane transporters, enzymes, cell adhesion molecules

Xanthelasma - LDL receptors not functioning or produced = lipid deposits under skin