Introduction to Biochemistry

Question 1

First law of thermodynamics

Answer 1

Energy is neither created nor destroyed

Question 2

Second law of thermodynamics

Answer 2

When energy is converted to a new form, some becomes unavailable to do work

Question 3

How is it possible for a +delta G reaction to occur

Answer 3

By pairing it with a -delta G reaction

Question 4

What are standard conditions

Answer 4

pH 7, 298 K, 1 atmosphere, I mol/l

Question 5

What delta value are readily reversible reactions near to.

Answer 5

Zero.

Question 6

What type of reactions are spontaneous, endergonic or exergonic

Answer 6

Exergonic

Question 7

What enzyme catalyses the conversion of glucose-6-phosphate to glucose-1-phosphate

Answer 7

Phosphoglucomutase

Question 8

NET gain of ATP from glycolysis

Answer 8

2 ATP

Question 9

What is the term given to the formation of new glucose from non-carbohydrate precursors

Answer 9

Gluconeogenesis. Remember, gluconeogenesis IS NOT simply the reverse of glycolysis

Question 10

What shape is a water molecule

Answer 10

Tetrahedral

Question 11

What type of substances do not dissolve in water - hydrophobic

Answer 11

Non-polar substances

Question 12

What characteristic of micelles allows them to dissolve in water

Answer 12

Their hydrophobic tails face inside, whereas their hydrophilic heads face outside

Question 13

What are stereoisomers

Answer 13

Non-superimposable mirror images of a molecule

Question 14

Give an example of a non-polar hydrophobic group

Answer 14

CH3 (methyl) groups

Question 15

What are the four ‘groups’ of amino acids

Answer 15

Polar, non-polar, acidic and basic

Question 16

In what direction do peptide chains extend in

Answer 16

From the N-terminal to the C-terminal

Question 17

What does the acid dissociation constant measure

Answer 17

The ability of an acid to donate a proton

Question 18

What is Ka

Answer 18

Ka = the acid dissociation constant. This equilibrium constant is a quantitative measure of the strength of an acid in a solution.

Question 19

What is the Henderson Hasselbalch equation used for

Answer 19

This equation links the Ka of an acid with the pH of a solution containing this acid. It can be used to calculate the properties of buffer solutions

Question 20

Under what circumstance will pH = pKa

Answer 20

When the concentration of an acid is equal to the concentration of conjugate base

Question 21

What are zwitterons

Answer 21

Electrically neutral molecules or ions

Question 22

At which point does a molecule have no net charge

Answer 22

The isoelectric point = pI

Question 23

Primary protein structure

Answer 23

The sequence of amino acids

Question 24

Secondary structure

Answer 24

The localised conformation of the polypeptide backbone

Question 25

Tertiary structure

Answer 25

3D structure of the polypeptide, including all of its sidechains

Question 26

Quaternary structure

Answer 26

The special arrangement of polypeptide chains in a protein with multiple subunits

Question 27

What are the 3 types of secondary protein structures

Answer 27

Alpha helix, beta sheets/stands and triple helix

Question 28

Symptom of weakened collagen

Answer 28

Bleeding gums

Question 29

What amino acid substitution causes sickle cell anaemia

Answer 29

Glutamic acid to valine

Question 30

Give 3 examples of conditions which arise when protein folding is slow and errors subsequently occur

Answer 30

Alzheimer’s, Parkinson’s and CJD

Question 31

Describe the structure of haemoglobin

Answer 31

4 subunits, two alpha and two beta chains, each with a haem group which can bind one oxygen each

Question 32

What is allosteric regulation

Answer 32

When the binding of one molecule changes the affinity for the other subunits (e.g. haemoglobin)