Lecture 17&18- proteins and amino acids

Question 1

The biological world stages

Answer 1

Biosphere -> domains of life + viruses -> phylum, genus, species, strain -> cells -> molecular biology

Question 2

It is suggested that …. evolved through ….

Answer 2

Eukaryotes
Archea

Question 3

Alanine

Answer 3

ALA
A

Question 4

Arginine

Answer 4

Arg
R

Question 5

Asparagine

Answer 5

Asn
N

Question 6

Aspartic acid

Answer 6

Asp
D

Question 7

Cysteine

Answer 7

Cis
C

Question 8

Glutamic acid

Answer 8

Glu
E

Question 9

Glycine

Answer 9

Gly
G

Question 10

Histidine

Answer 10

His
H

Question 11

Isoleucine

Answer 11

Ile
I

Question 12

Leucine

Answer 12

Leu
L

Question 13

Lysine

Answer 13

Lys
K

Question 14

Methionine

Answer 14

Met
M

Question 15

Phenylalanine

Answer 15

Phe
F

Question 16

Proline

Answer 16

Pro
P

Question 17

Serine

Answer 17

Ser
S

Question 18

Threonine

Answer 18

Thr
T

Question 19

Tryptophan

Answer 19

Trp
W

Question 20

Tyrosine

Answer 20

Tyr
Y

Question 21

Valine

Answer 21

Val
V

Question 22

In vertebrates, … of the 20 amino acids can be made in cells and … cannot be synthesised in human cells

Answer 22

11
9

Question 23

All amino acids except … have the same structure:
-….. carbon atom (chiral in all amino acids except glycine
-…… group
-….. group
-…… group

Answer 23

Alpha
Carboxyl
Amine
R

Question 24

Chirality/ handedness

Answer 24

The object or molecule can’t be superimposed on it’s mirror image by any translations or rotations

Question 25

Amino acids are always ....-isomers

Answer 25

L

Question 26

Aliphatic

Answer 26

R-group chain isn't branched

Question 27

Aromatic

Answer 27

R-group os based on a benzene ring (hydrophobic)

Question 28

Polar

Answer 28

The R-group carries a small charge, both positive and negative

Question 29

Charged

Answer 29

The R-group is ionisable creating positive or negative charge depending on pH and type of R group

Question 30

In ..... amino acids have two ionisable groups: ..... and .....

Answer 30

Solution Carboxyl Amine

Question 31

Amphoteric

Answer 31

An acid can both donate and accept protons

Question 32

pKa

Answer 32

Acid dissociation constant measure of how easily the proton is lost How well something mops up protons As dissociation increases, pKA decreases Low pKa = strongly acidic

Question 33

..... & ... have delocalised charge

Answer 33

Arg His

Question 34

.... & .... are polar- form H-bonds

Answer 34

Ser Thr

Question 35

Zwitterion

Answer 35

An ion that contains 2 functional groups, 1 +ve and 1 -ve

Question 36

Hydropathy values

Answer 36

How well a protein mixes with water High value= hydrophobic

Question 37

AA with aromatic R groups

Answer 37

Phe, Tyr, Trp

Question 38

AA with small R-groups

Answer 38

Gly, Ala

Question 39

AA with kinks

Answer 39

Pro

Question 40

AA with thiol group

Answer 40

Cys

Question 41

Electrostatic/ ionic interactions

Answer 41

Occur between oppositely charged atoms Strongest as ionic bonds formed between fully/ formally charged atoms

Question 42

Proteins with R-groups with charged atoms for ionic bonds

Answer 42

Asp, Glu, Lys, Arg, His

Question 43

Example of essential ionic bond in enzyme activity

Answer 43

ATPase ATP -> ADP ATPase hydrolyses ATP and a phosphate group is lost lysine amino acid R-group bonds ionically to ATP

Question 44

Polar bonds: hydrogen bonding

Answer 44

Specialised type of polar interaction Involves slightly electropositive H atom and an electronegative acceptor atom Mostly form between H, O & N

Question 45

Salvation shell

Answer 45

Formed by water around proteins Formed by a network of hydrogen bonds

Question 46

Van der Waals interactions

Answer 46

Temporary dipole formed Can induce a dipole on adjacent atoms

Question 47

Hydrophobic forces

Answer 47

Not bonds Hydrophobic molecules crowd together in water Allows hydrophobic packing

Question 48

AA that are hydrophobic

Answer 48

Val, Leu, Ile, Met

Question 49

hydrophobic AA stick together in....

Answer 49

Cores

Question 50

Hydrophobic forces Increase with increasing .... and .....

Answer 50

Temperature Salt