Metabolic Processes

Question 1

Thermodynamics

Answer 1

The study of the energy changes in a system.
Surroundings are defined as the universe outside a system
.

Question 2

First law of thermodynamics

Answer 2

Energy cannot be created or destroyed.
Law of conservation of energy → the same amount of energy is maintained during any process.
All energy that exists now has existed since the Big Bang.

Question 3

Second Law of Thermodynamics

Answer 3

The entropy of a system will increase over time.
Only applies to closed systems.

Question 4

Catabolism

Answer 4

The process of breaking down larger molecules to smaller molecules, which results in a net release of energy.

Question 5

Anabolism

Answer 5

Is the process of forming larger molecules from smaller molecules, which involves a net input of energy.

Question 6

Kinetic Energy

Answer 6

Energy of motion.

Question 7

Bond Energy

Answer 7

Energy required to break a bond.

Question 8

Biological Systems

Answer 8

Are open systems (able to exchange energy and matter with the environment)
Can be highly ordered for survival (decrease in entropy).

Question 9

G = H - TS

Answer 9

• G is the symbol for free energy: the energy associated with a chemical reaction that can be used to do work
• The difference in its enthalpy or energy in chemical bonds (H) and
• The product of the temperature and the entropy (S) of the system.

Question 10

Gibbs free energy

Answer 10

The energy is that is available to do useful work
A reaction will spontaneously occur is ΔG < 0 (exergonic reaction)
A reaction will not spontaneously occur if ΔG > 0 (endergonic reaction)

Question 11

Energy coupling

Answer 11

The transfer of energy from one reaction to another in order to drive the second reaction.

Question 12

Photosynthesis

Answer 12

CO2 + H2O → C6H12O10 + O2 (anabolic)

Question 13

Cellular respiration

Answer 13

C6H12O6 + O2 → CO2 + H2O + ATP + energy as heat (catabolic)

Glucose + oxygen -> carbon dioxide + water + ATP energy

Question 14

Entropy

Answer 14

Disorder of a system, the increasing disorder of the universe. The universe held all of the potential energy it will ever have when it formed.
Since then, it has become increasingly more disordered, with every energy exchange increasing the amount of entropy. Entropy is continuously increasing.

Question 15

Krebs cycle produces

Answer 15

2 ATP/GTP , 6 NADH, 2 FADH2, 4 CO2 (?)

Question 16

Stages of Aerobic Respiration

Answer 16

Glycolysis (10 steps), Pyruvate Oxidation, Krebs cycle (8 steps), oxidative phosphorylation

Question 17

Glycolysis Steps

Answer 17

Glucose, glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-biphosphate, dihydroxyacetone phosphate, 1,3-biphosphoglycerate, 3-phosphoglycerate, Phosphoanolpyruvate, pyruvate

Know: glucose -> pyruvate (enzyme = pyruvate kinase)

• G3P, BPG, 3PG, 2PG, PEP
• Enzyme PFK

Question 18

Glycolysis Produces

Answer 18

2 NAD+ converted into 2NADH, NET 2 ATP molecules

Question 19

What is glycolysis?

Answer 19

Does not require oxygen, products necessary for following aerobic pathways. Occurs within the cytoplasm and produces two 3-carbon compounds. Compounds are then converted into 2 pyruvate molecules.

Question 20

Acetyl-coenzyme A (CoA)

Answer 20

Produced during glycolysis and then carbon dioxide is released. Then enters the Krebs cycle.

Question 21

What is the Krebs cycle?

Answer 21

Takes acetyl CoA (x2) and makes NADH + FADH2, carries electrons to the ETC. Occurs in the mitochondrial matrix

Question 22

Steps of the Krebs cycle

Answer 22

Citrate, isocitrate, a-ketoglutarate, Succinyl-CoA, Succinate, Fumarate, Malate, oxaloacetate

Question 23

Oxidative Phosphorilation

Answer 23

Occurs at the inner mitochondrial membrane, NADH and FADH2 are oxidised by electron carriers and proteins embedded in the membrane. Released energy is used to create a proton gradient in the inter-membrane space.

Question 24

Pyruvate Oxidation

Answer 24

When oxygen is present, pyruvate produced from glycolysis is transported into the mitochondrial matrix
- A carbon is created off the pyruvate molecule and CO2 is released
- Remaining Acetyl group becomes associated with coenzyme A and forms acetyl-CoA
- Reaction is coupled with reduction of NAD+ to form NADH

Question 25

Products before oxidative phosphprilation

Answer 25

• 4 ATP (2 glycolysis, 2 Krebs)
• 6 NADH (2 glycolysis, 2 pyruvate, 2 Krebs)
• 2 FADH2 (2 krebs)

Question 26

Products in oxidative phosphorylation

Answer 26

NADH Total 30 ATP
FADH2 Total 4 ATP
- MAX 34 ATP

Question 27

Enzymes in oxidative phosphorylation (weakest-strongest)

Answer 27

NADH dehydrogenase, succinate dehydrogenase, cytochrome b-c1 complex, cytochrome oxidase complex

Question 28

Chemiosmosis

Answer 28

The process of moving ions (e.g. protons) to the other side of a biological membrane, and as a result, an electrochemical gradient is generated. This can then be used to drive ATP synthesis.

Question 29

Electron Transport Chain

Answer 29

Chain of proteins and e- carriers that pass e- along in order of increasing electronegativity. Energy is used to pump H+ into the intermembrane space. H+ flows through ATP synthase attaching phosphate to ADP to make ATP. Last thing to get reduced is oxygen.

Question 30

Lactate fermentation

Answer 30

Pyruvate is converted to lactate (or lactic acid when protonated) and reoxidized NAD+ (NAD+ can be used again in glycolysis).

Question 31

Oxygen Debt

Answer 31

Amount of oxygen required to eliminate lactate is called oxygen debt.

Question 32

Methanogens

Answer 32

Use ETC to generate a hydrogen ion gradient that provide energy. Uses hydrogen synthesised by other organisms as a source of energy and CO2 as e- acceptor.

Question 33

Fermentation

Answer 33

In glycolysis, NAD+ is reduced to NADH and pyruvate molecules are made (and net 2 ATP). The process that occurs in age absence of oxygen in which NAD+ and pyruvate are recycled to produce more ATP.

Question 34

Anoxic

Answer 34

Oxygen free

Question 35

Ethanol Fermentation

Answer 35

Facultative anaerobes can function both aerobically and anaerobically. In absence of oxygen, yeast and bacteria convert pyruvate to ethanol and CO2 via ethanol fermentation.