Ch 7

Question 1

Autotrophs

Answer 1

Capture energy and build organic molecules through photosynthesis

Question 2

Heterotrophs

Answer 2

Use pre-formed organic molecules for both energy and to build new organic molecules

Question 3

What is it that all organisms use to extract energy from organic molecules?

Answer 3

Cellular respiration

Question 4

What types of reactions are involved in cellular respiration?

Answer 4

Redox and dehydrogenations

Question 5

Dehydrogenation

Answer 5

Electron transfers accompanied by proton transfers

Question 6

What type of atom is transferred in cellular respiration?

Answer 6

Hydrogen

Question 7

NAD+ has a positive charge, so…

Answer 7

It attracts an electron, which makes it an electron carrier

But then it attracts a proton, which leads to a proton gradient (I think)

Question 8

How does NAD+ become NADH

Answer 8

It accepts 2 electrons and 1 proton

Question 9

The “goal” of respiration is

Answer 9

To generate ATP

Question 10

What’s the movement of electrons during respiration?

Answer 10

They’re shuttled via electron carriers (transport chains) to a final electron acceptor

Question 11

Aerobic respiration

Answer 11

Final acceptor is oxygen

Question 12

Anaerobic respiration

Answer 12

Final acceptor is an inorganic molecule (but not oxygen)

Question 13

Fermentation

Answer 13

Final acceptor is an organic molecule

Question 14

Proton gradient (which he said was important but didn’t bother to define in the slides)

Answer 14

A higher concentration of protons outside the inner membrane of the mitochondria than inside the membrane
The driving force behind ATP synthesis
Product of the electron transport chain

Question 15

Chemical formula for aerobic respiration

Answer 15

C6 H12 O6 + 6O2 –> 6CO2 + 6H2O

Question 16

Where does aerobic respiration occur?

Answer 16

Mitochondrial matrix

Question 17

What’s the first step of aerobic respiration and how many ATP are produced?

Answer 17

Glycolysis

4 ATP are produced but we used 2 ATP in the process so there’s a net gain of 2 ATP

Question 18

What is the second step of aerobic respiration and what is produced?

Answer 18

1 ATP molecule and 3 molecules of CO2

Most importantly it yields several molecules of NADH and FADH2

Question 19

Why is the Krebs cycle repeated

Answer 19

Bc only 1 pyruvate is needed for the cycle and 2 were produced during glycolysis
This means you get 6 CO2 and 2 ATP from this step total

Question 20

What is the third step of aerobic cellular respiration? What is produced?

Answer 20

Electron transport chain

32-34 ATP

Question 21

Three reactants and three products of glycosis?

Answer 21

R: one glucose, NAD+, 2 ATP
P: 2 pyruvate, NADH, 4 ATP

Question 22

Three reactants and products of the electron transport chain?

Answer 22

R: NADH, FADH2, O2
P: 1 NAD+, H2O, 32-34 ATP

Question 23

Two steps to anaerobic respiration?

Answer 23

Glycolysis and fermentation

Question 24

Fermentation (in anaerobic respiration)

Answer 24

Starts with private and ferments it into ethanol or lactate. Releases CO2 only (no ATP)

Question 25

Electron energy is used to make ATP from...

Answer 25

ADP and Pi

Question 26

What are the two ways cells make ATP from ADP and Pi?

Answer 26

Substrate-level phosphorylation | Oxidative phosphorylation

Question 27

Substrate-level phosphorylation

Answer 27

Transferring a phosphate directly from another molecule to ADP

Question 28

Oxidative phosphorylation

Answer 28

Use of ATP synthase enzyme and energy derived from proton gradient to make ATP AKA chemiosmosis

Question 29

Four stages of the oxidation of glucose

Answer 29

Glycolysis Pyruvate oxidation Krebs cycle Electron transport chain and chemiosmosis

Question 30

Where does anaerobic respiration occur?

Answer 30

Cytoplasm

Question 31

The fate of pyruvate depends on

Answer 31

O2 availability

Question 32

Three products of pyruvate oxidation

Answer 32

1 CO2 1 NADH 1 acetyl-CoA

Question 33

Where is the electron transport chain

Answer 33

Mitochondrial inner membrane

Question 34

When electrons are transferred some electron energy is lost. What happens to this energy?

Answer 34

It is used to pump protons across the membrane from the matrix to the inner membrane space, establishing a proton gradient

Question 35

Chemiosmosis

Answer 35

The accumulation of protons in the intermembrane space drives protons from that space into the matrix via diffusion

Question 36

Even tho some protons diffuse through but the membrane, most move to the matrix through...

Answer 36

The ATP synthase enzyme

Question 37

ATP synthase enzyme

Answer 37

A membrane bound enzyme that uses the energy of the proton gradient to synthesize ATP from ADP + Pi

Question 38

What is the theoretical energy yield of respiration

Answer 38

38 ATP per glucose for bacteria | and 36 ATP per glucose for eukaryotes

Question 39

What is the actual energy yield of respiration

Answer 39

30 ATP per glucose for eukaryotes

Question 40

Why is the actual yield less than the theoretical yield?

Answer 40

Leaky inner membrane and and use of the proton gradient for purposes other than the ATP synthesis

Question 41

What do anaerobic methanogens use to reduce CO2 to CH4 (methane)?

Answer 41

NADH

Question 42

What do anaerobic sulfur bacteria use to reduce inorganic sulphate to hydrogen sulfide?

Answer 42

NADH

Question 43

What do amino acids under go to remove amino groups?

Answer 43

Deamination

Question 44

What are fats broken down into?

Answer 44

Fatty acids and glycerol

Question 45

How are fatty acids converted into acetyl groups?

Answer 45

Beta-oxidation

Question 46

ATP and citrate both allosterically inhibit...?

Answer 46

Phosphofructokinase

Question 47

NADH inhibits...

Answer 47

Pyruvate dehydrogenase

Question 48

ATP inhibits...

Answer 48

Citrate synthetase

Question 49

Six steps of the evolution of metabolism

Answer 49

``` Ability to store chemical energy in ATP evolution of glycolysis Anaerobic photosynthesis Use of water in photosynthesis Evolution of nitrogen fixation Aerobic respiration ```