Biochemistry

Question 1

disaccharides

Answer 1

are soluble in water and can be transported across a barrier

lactose, maltose, sucrose, cellobiose

Question 2

polysaccharides

Answer 2

cellulose and glycogen

Question 3

first law of thermodynamics

Answer 3

energy is neither created nor destroyed

Question 4

second law of thermodynamics

Answer 4

when energy is converted from one form to another, some of that energy becomes unavailable to do work

Question 5

entropy

Answer 5

free energy will tend towards an unusable state after multiple transformation

Question 6

exergonic reactions

Answer 6

the total free energy of the products is less than the total free energy of the reactants
delta g is negative
can occur spontaneously
energy liberated can be used to do work

Question 7

endergonic reactions

Answer 7

reactions in which the total free energy of the products is more than the total free energy of the reactants
delta g is positive
cannot occur spontaneously
they need an input of energy to proceed

Question 8

coupling of processes

Answer 8

many cellular processes are unfavourable

driven by coupling to highly favourable processes

Question 9

metabolism

Answer 9

all reactions in the body

Question 10

catabolism

Answer 10

breaking down

releases energy

Question 11

anabolism

Answer 11

synthesising

uses energy

Question 12

amphipathic molecules

Answer 12

have regions which are either hydrophilic/hydrophobic
polar head
non polar tail

Question 13

zwitterions

Answer 13

amino acids without charged side groups exist as zwitterions in neutral solution
contains 2 titratable groups
2 pka values
buffers at both pka

Question 14

primary protein structure

Answer 14

sequence of amino acids

Question 15

secondary protein structure

Answer 15

alpha helix
proline breaks alpha helix due to angle
beta strands and sheets
triple helix

Question 16

tertiary protein structure

Answer 16

arrangement of atoms in space
fibrous/globular
forces stabilising - covalent disulphide bonds, electrostatic interactions, hydrogen bonds, complex formation with metal ions

Question 17

quaternary protein structure

Answer 17

multiple polypeptide chains

Question 18

polymerisation

Answer 18

a phosphodiester bond is formed between a free 3 prime OH and a 5 prime triphosphate
consumes 2 high energy bonds
new nucleotides only added to a free 3 prime end

Question 19

helicase

Answer 19

needed to unwind DNA helix

Question 20

proofreading and repair

Answer 20

DNA polymerase 3 prime to 5 prime endonuclease activity

Question 21

processing the ends of mRNA

Answer 21

addition of 5 prime cap

addition of poly a tail

Question 22

aminoacyl tRNA synthetases

Answer 22

binds amino acid to their corresponding tRNA molecule highly specific

Question 23

3 ribosome binding sites

Answer 23

exit
peptidyl
aminoacyl

Question 24

types of mutations

Answer 24

point 
missense
nonsense 
silent 
frameshift

Question 25

chromosomal mutations

Answer 25

deletion
duplication
inversion
translocation

Question 26

isozymes

Answer 26

are forms of enzymes that catalyse the same reaction but have different properties and structure

Question 27

zymogens

Answer 27

inactive precursor of an enzyme

Question 28

low Km

Answer 28

means that an enzyme only needs a little substrate to work at half maximal velocity. efficient

Question 29

high Km

Answer 29

means that an enzyme needs a lot of substrate to work at half maximal velocity. inefficient