BaP

Question 1

How many bonds do the following elements form?

Hydrogen, Oxygen, Sulfur, Phosphorus, Carbon, Nitrogen

Answer 1

H-H
O=O
S has 2 bonds
P has 5 bonds
C has 4 bonds
N has 3 bonds

Question 2

What is the history of the RNA World theory?

Answer 2

First used by Gilbert (1986), but the same idea was mentioned by Crick, Orgel, and Woese’s ‘The Genetic Code’ (1967)

Question 3

What are some experiments used to investigate the origins of life?

Answer 3

Miller-Urey (1953). 10% carbon in their system was in organic compounds, and 2% in amino acids specifically.

Oro (1962). Made amino acids in solution of water, ammonia, hydrogen cyanide

Question 4

How much of cellular RNA is tRNA? How much is rRNA? (Why so little mRNA?)

Answer 4

15% is tRNA
80% is rRNA
(mRNA only synthesised when needed, and then degraded)

Question 5

At what rate is Cytosine deaminated to Uracil?

Answer 5

250 bases per day

Question 6

How wide is the DNA double helix? How many base pairs per turn?

Answer 6

2nm

10.4 bp/ turn

Question 7

What is normal rate of mutation? What is it plus proofreading? What is it plus later mismatch repair?

Answer 7

1/10^5
1/10^7
1/10^9

Question 8

What enantiomer form do carbs take in life?

Answer 8

D

Question 9

What enantiomer form do amino acids take in life?

Answer 9

L

Question 10

What is the start codon? (and protein)

Answer 10

AUG (Methionine in euks, N-methionine in proks)

Question 11

What are the 3 stop codons?

Answer 11

UAA
UAG
UGA

Question 12

What is Km?

Answer 12

Measure of affinity of an enzyme for its substrate

Question 13

What is Kcat?

Answer 13

the turnover number (max reactions one active site can do in a given time)

Question 14

What is Vmax?

Answer 14

enzyme conc x Kcat (=max rate of reaction for that enzyme concentration)

Question 15

What is Eo?

Answer 15

Reduction potential (tendency for a molecule to be reduced (+ve, affinity for electrons) or oxidised (-ve, will donate electrons))

Question 16

What is Keq?

Answer 16

The equilibrium constant of a reaction (value of reactants/products when at chemical eqm)

Question 17

At what wavelength does Photosystem II absorb light?

Answer 17

680nm

Question 18

At what wavelength does Photosystem I absorb light?

Answer 18

700nm

Question 19

What are the monomers of the disaccharide trehalose?

Answer 19

alpha glucose and another alpha glucose but rotated through 180*

Question 20

What bonds and monomers make up the polysaccharide dextran?

Answer 20

alpha 1,6 glycosidic bonds between alpha glucose molecules

Question 21

What are the smallest aas? (2)

Answer 21

Glycine

Proline (kink)

Question 22

What are the two types of hydrophobic aas?

Answer 22

Aliphatic (chain)

Aromatic (one C and then ring)

Question 23

What are the essential aas for humans? (10)

Answer 23

(Very Many Hairy Little Pigs Live In the Torrid (Air))
Valine- aliphatiic
Methionine -aliphatic
Histidine- basic, +vely charged
Leucine- aliphatic
Phenylalanine- aromatic
Lysine- basic, +ve
Isoleucine- aliphatic
Threonine- polar, uncharged
Tryptophan- aromatic
(Arginine)- basice, +ve

Question 24

What is the aldehyde group?

Answer 24

HC=O

/

Question 25

What is the ketone group?

Answer 25

/
C=O
/

Question 26

Name 3 aldohexoses

Answer 26

D-glucose
D-mannose
D-galactose

Question 27

Name 3 aldopentoses

Answer 27

D-ribose
D-arabinose
D-xylose

Question 28

Name a ketohexose

Answer 28

D-fructose

Question 29

Name a ketopentose

Answer 29

D-ribulose

Question 30

What are stereoisomers?

Answer 30

Have the same bonding but different 3D orientations

Question 31

What are enantiomers?

Answer 31

mirror images of eachother!

Question 32

What are diastereomers?

Answer 32

stereoisomers that aren’t mirror images of eachother

Question 33

What are epimers?

Answer 33

Diastereomers (not mirror images) but they only differ at one chiral centre, and are fixed.

Question 34

Which anomer of glucose is the most common in solution?

Answer 34

The beta form (64%)

Question 35

Why does the hydroxyl on C1 of beta glucose take the equatorial position when in a chair conformation?

Answer 35

Because this position is always more stable- it minimises the axial strain.