Cellular Respiration

Question 1

Anabolic

Answer 1

Use of energy to build macromolecules (Endergonic)

Question 2

Catabolic

Answer 2

The breakdown of complex organic molecules to generate energy: releases energy (Exergonic)

–>Think of cat tearing the cat tower

Question 3

Cellular Respiration

Answer 3

The major CATABOLIC pathway to produce energy from food

Question 4

Oxidation

Answer 4

LOSS of electrons

(INCREASES CHARGE)

Question 5

Reduction

Answer 5

GAINS electrons

(REDUCES/Decreases CHARGE)

Question 6

Cell Respiration General Formula

Answer 6

Sugar + O2 —> H2O + CO2 + Energy

Sugar –> CO2 = Oxidation

O2 –> Water = Reduction

Question 7

In cell respiration, sugar is…

Answer 7

OXIDIZED (Loses electrons which releases energy)

Question 8

NAD+

Answer 8

Nicotinamide Adenine Dinucleotide –> A COENZYME

Question 9

NAD+ vs NADH

Answer 9

NAD+ = Oxidized form (loss of electron)

NADH = Reduced form (gain of electron)

Question 10

NADH

Answer 10

An energy storage molecule (stores electrons) that is tapped to produce ATP

Question 11

Dehydrogenase

Answer 11

Enzyme that convert NAD+ to NADH

Question 12

NAD+ –> NADH =

Answer 12

Reduction

Question 13

NADH –> NAD+ + H+ =

Answer 13

Oxidation

Question 14

4 main steps to cellular respiration:

Answer 14

1) Glycolysis
2) Intermediate Step (Pyruvate Oxidation)
3) Kreb’s Cycle
4) Oxidative Phosphorylation

Question 15

Glycolysis

Answer 15

The splitting of sugar

Question 16

Steps of glycolysis

Answer 16

10 steps total:

–> First 5 steps = energy investment phase (uses 2 ATP)

–> Second 5 steps = Energy Payoff Phase (produces 4 ATP)

Question 17

Glycolysis Products

Answer 17

1) 2 NET ATP
2) 2 NADH
3) 2 Pyruvate

Question 18

Pyruvate

Answer 18

A 3 carbon molecule that is the product of glycolysis

–>In the presence of oxygen, pyruvate is further broken down to produce more energy

Question 19

Substrate-Level Phosphorylation

Answer 19

An enzyme transfers a phosphate group (NOT Pi) from an organic molecule (substrate) to ADP = produces ATP

Question 20

Last Step of Glycolysis (example of substrate-level phosphorylation)

Answer 20

PEP + ADP –> Pyruvate + ATP

(mediated by pyruvate kinase)

Question 21

Pyruvate Kinase

Answer 21

Takes phosphate from PEP to convert ADP to ATP (while also producing pyruvate)

Question 22

Intermediate Step

Answer 22

(AKA Pyruvate Oxidation) –> The conversion of pyruvate to Acetyl-CoA

Question 23

Intermediate Step PROCESS

Answer 23

1) Pyruvate is translocated to mitochondrion
2) Pyruvate is oxidized to release CO2
3) Acetalaldehyde remains (2C) and is oxidized to convert NAD+ to NADH

4) Acetyl group is left and this combines with Coenzyme A to produce Acetyl-CoA

Question 24

Intermediate Step Products

Answer 24

1) 2 Acetyl CoA
2) 2 NADH
3) 2 CO2

Question 25

CO2 is FIRST produced when/where in cell respiration?

Answer 25

In the oxidation of pyruvate (intermediate step)

Question 26

Coenzyme A

Answer 26

CoA: a sulfur containing compound that binds to acetyl to produce Acetyl-CoA

Question 27

Kreb’s Cycle

Answer 27

8 total steps that oxidizes pyruvate products completely to produce materials needed for the ETC and OXPHOS

Question 28

Kreb’s Cycle takes in the following molecules:

Answer 28

1) Acetyl-CoA
2) ADP
3) NAD+
4) FAD+

Question 29

Kreb’s cycle produces:

Answer 29

1) 4 CO2
2) 6 NADH
3) 2 ATP
4) 2 FADH2

Question 30

Kreb’s cycle occurs how many times per one molecule of glucose?

Answer 30

2 times

Question 31

Electron Transport Chain

Answer 31

A collection of molecules that donate and accept electrons: Produces a proton gradient that powers ATP synthase

–> Creates conditions needed for ATP synthesis (BUT DOES NOT PRODUCE ATP ITSELF)

Question 32

Oxygen serves as a __________ in the electron transport chain

Answer 32

Oxygen acts as the final electron acceptor in the ETC which produces water (waste product)

Question 33

Oxidative Phosphorylation

Answer 33

Occurs in Complex V or ATP synthase which converts ADP to ATP (powered by the proton gradient created from the ETC)

Question 34

ETC proton gradient creation

Answer 34

The complexes of the ETC pump H+ protons from the MT matrix into the IMS

–> These protons then come back to the matrix by diffusing through ATP synthase and thus powering the production of ATP

Question 35

Uncoupling

Answer 35

AKA Uncoupled Respiration

–> When the ETC is disconnected from OXPHOS = Minimal to no ATP production BUT gradient still forms

Question 36

Uncoupling can occur do to (2 possibilities):

Answer 36

1) ATP synthase is inhibited
2) Membrane permeabilizes (has holes) which leads to proton leak

Question 37

Proton Leak

Answer 37

H+ protons leak back into the matrix through holes rather than through ATP synthase

–> Causes the proton gradient to not be able to be maintained

Question 38

Benefits of uncoupled respiration

Answer 38

Uncoupled respiration still produces energy but in a different form: HEAT

–> Used in brown fat which contains THERMOGENIN (uncoupler) to increase heat production in hibernating animals and newborns

Question 39

Cell Respiration in Prokaryotes

Answer 39

**ETC STILL OCCURS SARAH
–> Their ETC simply occurs on their plasma membrane

–> More energy efficient because it does not require NADH to be trafficked into mitochondria (which uses ATP)

Question 40

Fermentation

Answer 40

Anaerobic respiration: Energy produced without using O2

–> Mainly just glycolysis

Question 41

Why does the ETC not function without O2?

Answer 41

Because O2 is the final electron acceptor, without this the ETC cannot run –> Therefore OXPHOS cannot go

Question 42

Lactic Acid Fermentation

Answer 42

Pyruvate is reduced BY NADH DIRECTLY (no further breakdown of Pyruvate!!!)

(NADH is oxidized to NAD+)

–> Produces lactate as a waste product

Question 43

Alcohol Fermentation

Answer 43

1) Pyruvate is broken down to acetalaldehyde (2C)
(RELEASES CO2)

2) Acetalaldehyde is reduced by NADH = ETHANOL production

(NADH is oxidized to NAD+)

Question 44

Which fermentation process produces CO2?

Answer 44

Alcohol Fermentation

Question 45

Pyruvate represents a __________ in the energy producing system that controls where the process goes

Answer 45

FORK –> Energy production can either go in aerobic or anaerobic directions

Question 46

Phosphofructokinase (PFK)

Answer 46

An enzyme (early in the glycolysis process)

–> Involved in feedback regulation of respiration

Question 47

PFK is inhibited by

Answer 47

1) ATP
2) Citrate

–> Stops glycolysis from happening and thus stops the energy production process as a whole

Question 48

PFK is activated by

Answer 48

AMP

Question 49

PFK is regulated by ___________

Answer 49

Allosteric regulation

Question 50

> AMP when…

Answer 50

< ATP