lecture 1

Question 1

what are the atomic numbers of Carbon, Hydrogen, Oxygen and Nitrogen (protons and electrons)

Answer 1

6, 1, 8, 7

Question 2

what are the atomic masses of Carbon, Hydrogen, Oxygen and Nitrogen

Answer 2

12, 1, 16, 14 (protons + neutrons)

Question 3

define a covalent bond

Answer 3

a bond that forms when two atoms share a pair of electrons

Question 4

define a non-covalent bond

Answer 4

an attraction between positive and negative charges

Question 5

what is a phosphodiester bond

Answer 5

a covalent bond joining the 3’ hydroxyl group of one nucleotide to the 5’ phosphate group of the next nucleotide

Question 6

what is electrostatic interaction

Answer 6

attraction between opposite charges (intermolecular and intramolecular)- molecules interact in ways to maximise favourable interactions

Question 7

what is ionic bonding

Answer 7

electrostatic attraction between oppositely charged ions

Question 8

give an example of electrostatic repulsion in biomolecules

Answer 8

DNA - negatively charges due to the negative charge on each phosphate group in the sugar-phosphate backbone

Question 9

describe van der Waals interactions in biomolecules

Answer 9

weak interactions between two dipolar atoms

Question 10

what is van der Waals distance and what happens when it reduces

Answer 10

the distance at which two molecules are attracted to each other, when it reduces, the electrons of the two molecules may overlap causing repulsion leading to a rigid DNA structure

Question 11

describe hydrogen bonding in biomolecules

Answer 11

interaction between an electropositive H in one molecule and an electronegative atom (O or N) in another molecule, it is the bond that joins base pairs in DNA

Question 12

what are hydrophobic interactions

Answer 12

water cannot form hydrogen bonds with non-polar molecules, instead the water molecules form hydrogen bonds around the non-polar molecule like a cage. when non-polar molecules come together (hydrophobic interaction) some of the water molecules from the cage are released

Question 13

what is a monomeric protein

Answer 13

a protein consisting of a single polypeptide chain

Question 14

what is an oligomeric protein

Answer 14

two or more polypeptide chains held together by non covalent interactions

Question 15

how do you calculate molecular weight

Answer 15

mass number x no. of atoms

Question 16

what is the average weight of an amino acid residue

Answer 16

110 Daltons

Question 17

what is the mass of a protein that consists of 150 amino acids

Answer 17

150 x 110 Da = 16500 Da (16.5 kDa)

Question 18

what is an enzyme

Answer 18

a protein that catalyses a biochemical reaction by lowering the activation energy of the reaction

Question 19

what does the Michaelis mention equation describe

Answer 19

the variation of enzyme activity as a function of the substrate concentration

Question 20

what happens to the rate of product formation at high substrate concentrations

Answer 20

enzymes are working at maximum capacity, adding substrate no longer affects the rate of product formation

Question 21

what happens to the rate of product formation at low substrate concentrations

Answer 21

as the substrate concentration increases, so does the rate of product formation

Question 22

what does an irreversible inhibitor do

Answer 22

binds strongly to an amino acid R group that participates in substrate binding or catalysis - permanently inactivating the enzyme

Question 23

what is a reversible inhibitor

Answer 23

inhibitory effects can be reversed at least to some extent by the presence of the substrate