Lecture 13: Aerobic Respiration

Question 1

what’re the results of this reaction?

C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy

Answer 1

C6H12O6 is oxidized and O2 is reduced

Question 2

how do we know what molecule is the most reduced?

Answer 2

the one with the most hydrogens

Question 3

What happens to matter and energy in Glycolysis?

Answer 3

matter: glucose (6 carbon) is oxidized to two pyruvate (3 C)
energy: NAD+ is reduced to NADH

Question 4

what happens to matter and energy in the citric acid cycle?

Answer 4

matter: 2 pyruvate (3C) are oxidized to CO2
energy: NAD+ and FAD are reduced to NADH and FADH2

Question 5

what happens to matter and energy in oxidative phosphorylation?

Answer 5

matter: O2 is reduced to H2O
Energy: NADH and FADH2 are oxidized to NAD+ and FAD
Energy: oxidation energy powers phosphorylation of ATP

Question 6

glycolysis

Answer 6

universal energy releasing pathway that occurs in the cytoplasm and in the absence of O2

Question 7

3 fates of glucose if ATP levels are high

Answer 7

1. converted to glycogen and stored in the liver
2. converted to lipids for long term energy storage
3. converted to a 5 C ribose for DNA and RNA

Question 8

where does the 6th C in the ribose go?

Answer 8

released through CO2

Question 9

glycolysis equation

Answer 9

C6H12O6 + 2ADP + Pi + NAD+ -> 2 pyruvate + 2ATP + 2 NADH

Question 10

Glycolysis process

Answer 10

step 1-3: energy investment phase (requires 2 ATP)
stept 7 & 10: energy payoff phase releases 4 ATP for net gain of 2 ATP (substrate level phosphorylation)
Step 6: 2 molecules of NAD+ are reduced to NADH
Step 10: end product is two molecules of pyruvate
* no CO2 is released, no O2 is required

Question 11

The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mole and the free energy for the reduction of NAD+ to NADH is +53 kcal/mole. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?

Answer 11

most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis

Question 12

Oxidation of pyruvate

Answer 12

pyruvate + NAD+ + Coenzyme A + H2O -> Acetyl CoA + NADH + H+ + CO2

Question 13

what does it mean that pyruvate is decarboxylated?

Answer 13

release of CO2

Question 14

Citric Acid Cycle

Answer 14

oxidation of acetyl to CO2, reduction of NAD+, FAD, phosphorylation of GDP

Question 15

How many molecules of CO2 are released during one turn of the citric acid cycle?

Answer 15

2; one CO2 released in step 3 and one released in step 4

Question 16

Describe the flow of energy in the citric acid cycle

Answer 16

energy is transformed by the oxidation of acetyl CoA and the reduction of NAD+ and FAD

Question 17

Combustion

Answer 17

glucose + O2 (light and heat released)

Question 18

what is the name of the first step of glucose oxidation in all cells?

Answer 18

glycolysis

Question 19

in the stepwise release of energy, where does the energy released in the small steps go?

Answer 19

• reduction of NAD+ and FAD
• Phosphorylation of ADP
• Phosphorylation of GDP

Question 20

what is the exact amount of the small activation energy required to begin the process of the respiration?

Answer 20

2 ATP

Question 21

Mitochondria Structure

Answer 21

Dual membranes:
-outer membrane and inner membrane
Dual Spaces:
-inner membrane space
-matrix space

Question 22

what are the dual membranes in the mitochondria evidence as?

Answer 22

of a endosymbiotic origin; an archer host engulfed a bacteria

Question 23

inner membrane of mitochondria

Answer 23

houses the electron transport chain and ATP synthase

Question 24

electron transport chain

Answer 24

4 protein complexes embedded in the inner mitochondrial membrane; stepwise and downward release of energy bound in NADH and FADH2; redox reactions between the electron and transport proteins transport e- and H+

Question 25

Flow of energy

Answer 25

• from the covalent bonds of glucose to reduction of IEAs
• IEAs donate electrons to the redox reactions of the electron transport chain
• energy released from ETC is used to pump protons and create an electrochemical gradient
• the proton gradient powers the phosphorylation of ADP to ATP

Question 26

chemiosmosis

Answer 26

• diffusion of protons across a membrane driving the synthesis of ATP
• transformation of potential energy of a proton gradient to covalent bonds of ATP
• occurs in mitochondria and chloroplasts

Question 27

where is ATP synthase found?

Answer 27

mitochondria and chloroplasts

Question 28

what happens to pyruvate in the presence/absence of O2

Answer 28

• presence of O2- CO2 and H2O produced

- absence of O2- lactic acid produced OR ethanol and CO2 produced

Question 29

alchohol fermentation

Answer 29

• preceded by glycolysis
• regenerates the NAD+ required by glycolysis
• done by yeasts and some plant cells

Question 30

why is beer fattening?

Answer 30

1. it contains a lot of energy in C-H bonds

2. beer can be metabolized into lipids

Question 31

alcohol fermentation equation

Answer 31

C6H12O6 + 2ADP + 2P(i) -> 2 ethanol + 2 CO2 +2ATP

Question 32

lactic acid fermentation

Answer 32

• preceded by glycolysis

- regenerates. NAD+

Question 33

lactic acid fermentation equation

Answer 33

C6H12O6 + 2 ADP + 2P(i) -> 2 lactic acid + 2ATP

Question 34

what gas exits the Carboy (fermentation thing)?

Answer 34

CO2

Question 35

what gas must not enter carboy?

Answer 35

O2

Question 36

If O2 enters carboy what will be produced?

Answer 36

CO2 and H2O