Bioenergetics

Question 1

What is bioenergetics?

Answer 1

The flow and exchange of energy within a living system. Conversion of food to usable energy for cell work. (chemical to mechanical).

Question 2

What is metabolism

Answer 2

Sum of all chemical reactions that occur in the body

Question 3

What are anabolic reactions?

Answer 3

Synthesis of molecules (e.g. glucose being stored as glycogen)

Question 4

What is catabolism?

Answer 4

Breakdown of molecules (e.g. glycogen being broken down into glucose)

Question 5

The first law of thermodynamics

Answer 5

Energy cannot be created or destroyed, only transformed from one form to another.

Question 6

What is meant by an endergonic reaction?

Answer 6

Requires energy to be added to reactants (product has more energy than reactants)

Question 7

What is an exergonic reaction?

Answer 7

Energy is released (reactant has more energy than product)

Question 8

What is a coupled reaction?

Answer 8

The liberation of energy in an exergonic reaction that drives an endergonic reaction

Question 9

Oxidation is the ……….

Answer 9

removal of electron or addition of an oxygen

Question 10

Reduction is the ……….

Answer 10

Addition of an electron or removal of an oxygen

Question 11

NAD (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) plays an important role in the ………

Answer 11

Transfer of electrons (carrier molecules) during bioenergetic reactions

Question 12

What are enzymes?

Answer 12

Proteins (biological catalysts) that lower the activation energy needed to initiate a reaction causing the reaction to accelerate.

Question 13

Kinase function

Answer 13

Adds a phosphate group

Question 14

Dehydrogenase function

Answer 14

Remove hydrogen atoms

Question 15

Oxidase function

Answer 15

Catalyse oxidation-reduction reactions involving oxygen

Question 16

Isomerase function

Answer 16

Rearrangement of the structure of molecules

Question 17

What influences enzyme activity?

Answer 17

Temperature (eg. warm up to body temps exceeding 37)
pH (e.g. heavy exercise increases lactate threshold, increase H+, lows pH, decreases ATP production = muscular fatigue).

Question 18

ATP stands for

Answer 18

Adenosine triphosphate

Question 19

Synthesis of ATP (basic level)

Answer 19

ADP + Pi > ATP

Question 20

Breakdown of ATP (simple)

Answer 20

ATP — ATPase —-> ADP + Pi + Energy

Question 21

Intramuscular stores only have enough for ………….

Answer 21

less than 2 seconds of all out exercise

Question 22

What are the anaerobic pathways and there properties (substrate-level phosphorylation)?

Answer 22

Does not involve oxygen
Phosphocreatine system
Glycolytic system

Question 23

Aerobic pathway

Answer 23

Requires oxygen
Oxidative phosphorylation

Question 24

ATP-PC system:

Answer 24

Most rapid of the systems and simplest

PC + ADP —–creatine kinase—–> ATP + C

PC can be replenished but with a limited capacity for prolonged energy production (depleted after 10-15 secs all out activity)

Question 25

Net gain of ATP if glucose is the substrate

Answer 25

2 ATP

Question 26

Net gain of glycogen is the substrate

Answer 26

3 ATP are production

Question 27

How long can the glycolytic system last?

Answer 27

approx. 30 - 90 seconds

Question 28

What is the net result of ATP and by-products from one molecule of glucose?

Answer 28

2 ATP, 2 NADH, 2 Pyruvate (or 2 lactate)

Question 29

If sufficient O2 is available during glycolysis, what happens to NAD+ ?

Answer 29

H+ ions can bind to NAD+ to from NADH which allows the H+ ions to be shuttled into the mitochondria to be used in oxidated phosphorylation.

Question 30

If oxygen is insufficient, what happens to the later stages of glycolysis?

Answer 30

Pyruvate accepts the H+ ions to form lactate. This is catalysed by the enzyme lactate dehydrogenase which takes NADH + H+ and frees up NAD+. Allowing glycolysis to continue without O2.

Question 31

Aerobic ATP production is broken down into two sections ............

Answer 31

Krebs cycle (Citric acid cycle) and the Electron transport chain.

Question 32

Describe the citric acid cycle?

Answer 32

Pyruvic acid (3C) enters the mitochondria and is converted to acetyl-CoA (2C) (losing a carbon = CO2) Acetyl-CoA combines with oxaloacetate (4C) to form citrate (6C) Series of reactions occur to regenerate oxaloacetate Each turn of the cycle produces 1 ATP molecule (synthesised by GTP) and the releasing of high-energy electrons 3 NADH and 1 FADH2

Question 33

Beta oxidation (very basic description)

Answer 33

Process by which fatty acids are oxidised to produce Acetyl-CoA where it can then enter the citric acid cycle and ETC.

Question 34

ETC (oxidative phosphorylation)

Answer 34

Electrons are removed from the NADH and FADH2, getting passed along a series of carriers (cytochromes). This provides energy which pumps the H+ into the intermembrane space. Increased concentration of H+ ions in the intermembrane space results in the establishment of an electrochemical gradient. Hydrogen ions diffuse across the membrane through an enzyme ATP synthase which uses the kinetic energy from the hydrogen ion to resynthesise ATP from Pi and ADP.

Question 35

What occurs at the end of the electron transport chain?

Answer 35

O2 accepts the electrons and combines this with hydrogen to form water (H2O) (chemiosmotic hypothesis).

Question 36

What would happen is O2 was not available to accept the electrons?

Answer 36

Oxidative phosphorylation would not be able to function.

Question 37

What is the approximate amount of ATP produced form aerobic respiration from one molecule of glucose? And why?

Answer 37

32 ATP 4 ATP are produced during substrate level phosphorylation 10 NADH and 2 FADH2 produced 2.5 ATP per NADH, 1.5 ATP per FADH2

Question 38

What are stimulators and inhibitors of the ATP-PC system?

Answer 38

Rate-limiting enzyme is creatine kinase Stimulator is ADP Inhibitor is ATP

Question 39

What are the stimulators and inhibitors of the glycolytic system?

Answer 39

Rate limiting enzyme is phosphofructokinase Stimulator is AMP, ADP, Pi, pH increase Inhibitor is ATP, CP, Citrate, reduction pH

Question 40

Simulator and inhibitors of Kreb cycle?

Answer 40

Rate limiting enzyme is isocitrate dehydrogenase stimulator is ADP, Ca2+, NAD+ Inhibitor is ATP, NADH

Question 41

Stimulator and inhibitor of ETC

Answer 41

Cytochrome oxidase is rate limiting enzyme stimulator; ADP, Pi inhibitor; ATP

Question 42

Short-term, high intensity is predominately supplied by .....

Answer 42

ATP-PC system (<5 secs)

Question 43

Intense exercise lasting >5 secs

Answer 43

Glycolytic system

Question 44

Events lasting >45 secs

Answer 44

ATP production through ATP-PC, glycolysis and aerobic systems At 2 mins; balance between aerobic and anaerobic

Question 45

Prolonged exercise (>10mins)

Answer 45

ATP production primarily from aerobic metabolism.