proteins

Question 1

what is a protein

Answer 1

macromolecule consisting of aminos acids arranged in a particular structure that enables it to carry out specific function

Question 2

structural protein example

Answer 2

actin within a cell or keratin in skin

Question 3

whats transcription

Answer 3

DNA—-> mRNA

-comes before translation

Question 4

whats translation

Answer 4

mRNA—> protein synthesis

-mRNA used by cell as a code to make chains of AA’s that go onto form proteins

Question 5

whats does uracil replace in mRNA

Answer 5

thymine

Question 6

how many naturally occurring AA’s are there

Answer 6

20

Question 7

describe an AA’s structure

Answer 7

amine group and carboxylic group and R group which is different each time

Question 8

amine group

Answer 8

N-H2

Question 9

what does chiral mean

Answer 9

its mirror image is not the same as itself

Question 10

how are AA’s affected by a low Ph

Answer 10

carboxylic acid group takes up a hydrogen, and becomes slightly positive

the reverse is true at a high Ph

Question 11

aliphatic amino acids

Answer 11

R group consisting of hydrocarbon chains

eg. glycine

Question 12

aromatic amino acids

Answer 12

R group consisting of hydrocarbon ring

eg. phenylalanine

Question 13

sulphur containing amino acids

Answer 13

contains a sulphur group

Question 14

di-sulphide bridges

Answer 14

covalently bonded linkages that are contained between 2 sulphur containing AA’s and help increased strength

Question 15

acid amino acids

Answer 15

eg. glutamate

Question 16

basic amino acids

Answer 16

eg. lysine

Question 17

polar amino acids

Answer 17

can carry a charge at the end of the R group

eg. serine

Question 18

miscellaneous amino acid

Answer 18

proline- has a unusual ring shape

Question 19

primary strcuture

Answer 19

sequence in which AA monomers are bonded together to form a polypeptide chain
-amino acid sequence

Question 20

peptide bond

Answer 20

c=O, NH2

Question 21

secondary struture

Answer 21

local interactions between stretches of a polypeptide chain

• alpha helices
• beta plated sheets

Question 22

tertiary structure

Answer 22

overall 3D arrangement when R groups of different amino acids interact

• van der waals, ionic, hydrogen, disulphide bridges and hydrophobic interactions
• functional proteins can’t exist without tertiary structure

Question 23

quaternary structure

Answer 23

more than one polypeptide chains join together

eg. HAEMOGLOBIN

Question 24

functions of proteins

Answer 24

enzymes
structural
receptors
hormones
transport
storage
defensive
contractile

Question 25

conjugated proteins

Answer 25

protein to which another chemical group eg. carbohydrate is attached, by covalent bonding or other interactions

Question 26

glycoproteins

Answer 26

proteins with 1 or more carbohydrate molecules covalently attached

Question 27

ogliosaccharide

Answer 27

when a few carbohydrate monomers exist together in a chain, the carbohydrate is termed this

Question 28

glycosylation

Answer 28

when carbohydrate molecules are attached to a protein

Question 29

effects of glycosylation

Answer 29

stability
solubility
cell signalling
orientation

Question 30

lipoproteins

Answer 30

proteins that combine with lipids

Question 31

functions of lipoproteins

Answer 31

found in cell membranes to transport hydrophobic molecules eg. cholesterol

Question 32

apolipoprotiens

Answer 32

when lipoproteins form complexes with other lipoproteins

transport fat around body, blood and CSF

Question 33

metalloportines

Answer 33

protein molecules with a metal ions within their structures

Question 34

example of metalloprotiens

Answer 34

haemoglobin

Question 35

describe haemoglobin structure

Answer 35

• quaternary structure
• 4 polypeptide chains- 2 alpha and 2 beta subunits
• each subunit contains haem, and within each is 1 iron

Question 36

what are the 3 categories proteins can be divided into functionally

Answer 36

globular
fibrous
membranous

Question 37

globular proteins functions

Answer 37

storage
enzymes
hormones
transporters
structural