proteins lec 4

Question 1

globular proteins structure?solubility?

Answer 1

tertiary structure gives 3D arrangement
somewhat spherical
water soluble
(hydrophobic sidechains face inwards , hydrophilic face outwards)

Question 2

what is the function of the tertiary structure

Answer 2

to recognise specific molecules

Question 3

tertiary structure easy/hard to unfold/denature/misfold

Answer 3

easy to unfold/denature due to weak interactions

Question 4

tertiary structure stability ?

Answer 4

marginally stability favoured in evolution as they can readily unfold/denature and be used for the production of more vital proteins

Question 5

what’s the driving force of protein folding?

Answer 5

hydrophobic effect

Question 6

_____ can’t interact favorably with water

Answer 6

hydrophobic side chain Val, Leu, Phe

Question 7

During ____ the chain _____

Answer 7

protein folding

clusters together in the protein interior

Question 8

_____ carries oxygen in ____

Answer 8

myoglobin

muscle

Question 9

___ has # helices

Answer 9

myoglobin
8
most are amphipathic

Question 10

_____ side chains ___ proteins

Answer 10

hydrophobic

buried inside

Question 11

____ are ___ portions buried in ___ core of membrane

Answer 11

membrane proteins
hydrophobic
hydrophobic

Question 12

_____ are interactions between protein structures. (explain)

Answer 12

van der waals
weak intermolecular attractions between uncharged molecules
numerous interactions

Question 13

_____ hold secondary structure together

Answer 13

hydrogen bonds

Question 14

hydrogen bonds provide ___ for proper folding of __

Answer 14

geometric restrains

protein

Question 15

___ bonds can form between backbone C=O and N-H groups, or side chains _____

Answer 15

hydrogen

Ser, Asn, Thr, Asp

Question 16

hydrogen bonds can form between ___

Answer 16

backbone
C=O
N-H groups
side chains (Ser, Thr, Asn, Asp)

Question 17

ion pairs def

Answer 17

electrostatic attraction between oppositely charged side chains

Question 18

In ___charge depends on pH, so interactions disrupted by ____ ___

Answer 18

ion pairs
pH
change

Question 19

Disulphide bonds def?

Answer 19

covalent link between two cysteine residues (-SH HS- to -S-S-)

Question 20

_______ don’t cause folding but provide extra stability

Answer 20

Disulphide bonds

Question 21

metal ion coordination def?

Answer 21

ions with interactions on several parts of a amino acid chain, causing folding

Question 22

proteins denature easily since __

Answer 22

they are only marginally stable

Question 23

during protein denaturing ______

Answer 23

the interactions are disrupted, therefore, results in unfolding, causing the protein to lose function

Question 24

Examples of denaturing agents ?

Answer 24

pH - charge
Temp- all interactions
organic solvents and detergents - hydrophobic interactions
reducing agents - disulphide bonds

Question 25

What denaturing agent affects:
charge
hydrophobic interactions
disulphide bonds

Answer 25

pH
detergents and organic solvents
reducing agents