Biochem

Question 1

What is the deltaG (free energy) in an exergonic and an endergonic reaction and which can occur spontaneously?

Answer 1

Exergonic: -ve (can occur spontaneously)
Endergonic: +ve

Question 2

Where are steroid hormones synthesised?

Answer 2

Smooth ER

Question 3

Where are polypeptides synthesised?

Answer 3

Rough ER

Question 4

What does the golgi apparatus do?

Answer 4

Distributes materials from the ER and modifies proteins

Question 5

What is a eukaryote and a prokaryote?

Answer 5

Eukaryote = a normal cell
Prokaryote = single organism without a well defined nucleus

(YOUkaryote = what you are)

Question 6

What is included in a nucleoside and a nucleotide?

Answer 6

Nucleotide = phosphate + base + sugar
Nucleoside = base + sugar 

(NucleoSide = Sugar)

Question 7

What are the 3 types of RNA and their purpose?

Answer 7

rRNA = ribosomal RNA (combines with proteins to form ribosomes)
tRNA = transfer RNA (collects amino acids and transports them to the ribosomes)
mRNA = messenger RNA (carries DNA code to ribosomes for translation)

Question 8

What RNA subunit type synthesises all mRNA?

Answer 8

Pol II

Question 9

What are transcription factors?

Answer 9

Turn on and off genes during translation to RNA/proteins

Question 10

Which areas of a gene and coding and non-coding?

Answer 10

Coding = exons
Non-coding = introns

Question 11

What provides the energy for protein synthesis?

Answer 11

GTP

Question 12

What are enzymes called with and without a cofactor?

Answer 12

Without = apoenzymes
With = holoenzymes 
(cofactor = nonprotein compound required for the enzymes activity)

(WHOLEoenzyme = with)

Question 13

What effect do competitive and non-competitive binding have upon the Vmax and Km?

Answer 13

Competitive: Vmax constant, Km varies

Non-Competitive: Km constant, Vmax varies

Question 14

How does glucose enter cells?

Answer 14

By facilitated diffusion through GLUT

Question 15

What is the difference between catabolism and anabolism?

Answer 15

Anabolism = requires energy 
Catabolism = produces energy (breakdown of molecules)

Question 16

What enzyme phosphorylates glucose?

Answer 16

Hexokinase

Question 17

Where are GLUT1, 2, 3 and 4 found?

Answer 17

GLUT1: RBCs
GLUT2: GI tract
GLUT3: neurones
GLUT4: muscle cells

Question 18

Describe the citric acid cycle

Answer 18

Acetyl CoA
Citrate 
Isocitrate (=>CO2, NAD=>NADH+H)
Alpha-ketoglutarate (=>CO2, NAD=>NADH+H)
Succinyl CoA (GDP=>GTP)
Succinate (FAD=>FADH2)
Fumarate (H2O=>)
Malate (NAD=>NADH+H)
Oxaloacetate

Question 19

What are the products of each citric acid cycle?

Answer 19

3NADH+H
1FADH2
2CO2
1GTP (ATP)

Question 20

Which enzyme of the TCA cycle is not in the matrix of the mitochondria?

Answer 20

Succinate dehydrogenase (on inner mitochondrial membrane)
(Succinate => fumarate)

Question 21

How is ADP converted to ATP?

Answer 21

Flow of electrons back across the mitochondrial membrane into the mitochondria drives phosphorylation through ATPsynthase (FiFoATPase)

Question 22

What is the total amount of ATP produced from internal respiration?

Answer 22

30-32

Question 23

What is the electron carrier during oxidative phosphorylation?

Answer 23

Oxygen