Cellular Respiration

Question 1

Cellular Respiration

Answer 1

Cells harvest chemical energy stored in organic molecules and use it to generate ATP

Question 2

What is the major source of fuel for animals?

Answer 2

Starch, breaks down into glucose

Question 3

Oxidation of glucose transfers…..

Answer 3

e- to a lower energy state, releasing energy to be used in ATP synthase

Question 4

Path of Electrons in energy harvest

Answer 4

Glucose—->NADH (electron carrier)—->ETC (electron transport chain)—->oxygen

Question 5

Energy Harvest

Answer 5

1. Each e- taken travels with a proton H+
2. Dehydrogenases (oxidizing agent for glucose) takes two e- and two protons from glucose
3. Transfers 2 e- and 1 proton to coenzyme NAD+ which reduces (gains electron) to NADH
4. NADH carries electron down the electron transport chain

Question 6

Electron Transport Chain

Answer 6

1. Sequence of proteins that shuttle electrons down a series of redox reactions
2. Releases energy used to make ATP
3. ETC transfers e- to O2 (the final electron acceptor) to make H20, releases energy

Question 6

Stages of cellular respiration

Answer 6

1. Glycolysis
2. Pyruvate oxidation and the citric acid cycle
3. Oxidative phosphorylation (ETC and chemiosmosis)

Question 7

Glycolysis

Answer 7

1. Starting point of cellular respiration
2. Occurs in the cytosol
3. Splits glucose into 2 pyruvates

Question 8

Two stages of glycolysis

Answer 8

1. Energy investment stage
2. Energy Payoff stage

Question 9

Energy investment stage

Answer 9

Cell uses ATP to phosphorylate compounds of glucose
2 ATP—> 2 ADP

Question 10

Energy payoff stage

Answer 10

Energy produced by substrate level phosphorylation
*Invest two ATP and get 4 ATP
*Net gain of two ATP
4 ADP + P—> 4 ATP
2 NAD+ + 4e- + 4H+ —> 2NADH + 2H+

Question 11

Net production of ATP during glycolysis

Answer 11

2 ATP

Question 12

Pyruvate oxidation

Answer 12

If oxygen is present, the pyruvate enters the mitochondria
*Pyruvate is oxidized into acetyl CoA
*Acetyl CoA used to make citrate in the citric acid cycle
*2CO2 and 2NADH are produced

Question 13

Citric Acid Cycle

Answer 13

*Also known as the krebs cycle, occurs in the mitochondrial matrix
*Turns acetyl CoA into citrate
*Releases CO2
*ATP synthesized
*Electrons transferred to NADH and FADH2

Question 14

Citric acid cycle inputs

Answer 14

2 Acetyl CoA

Question 15

Citric acid outputs

Answer 15

2 ATP
6 NADH
4 CO2
2 FADH2

Question 16

Oxidative phosphorylation consists of

Answer 16

1. ETC
2. Chemiosmosis- moving of chemicals down it’s gradient

Question 17

ETC

Answer 17

*Located in the inner membrane of the mitochondria
*Collection of proteins
*As electrons “fall” proteins alternate between reduced (accepts e-) and oxidized (donates e-)

Question 18

What increases the surface area for the reactions to occur?

Answer 18

Cristae, doesn’t produce ATP directly, helps manage the release of energy by creating several small steps for the fall of electrons

Question 19

Final electron acceptor?

Answer 19

Oxygen

Question 20

Major function of the ETC?

Answer 20

Creates a proton gradient across the membrane

Question 21

Chemiosmosis

Answer 21

-Uses hydrogen ions to power cellular work
-Moving of chemicals down their gradient

Question 22

ATP synthase

Answer 22

Enzyme that makes ATP from ADP + P, uses energy from the H+ gradient across the membrane

Question 23

H+ ions flow….

Answer 23

-Down their gradient through ATP synthase
-ATP synthase acts like a rotor, when H+ binds, it begins to spin
-Activates catalytic sites to turn ADP + P into ATP
-Produces about 26-28 ATP per glucose

Question 24

How is the proton gradient formed?

Answer 24

Flow of electrons from NADH and FADH2 powers the complexes in the ETC to pump H+ into the intermembrane space

Question 25

Glycolysis inputs

Answer 25

1 glucose

Question 26

Glycolysis outputs

Answer 26

2 pyruvate
2ATP
2 NADH

Question 27

Pyruvate oxidation inputs

Answer 27

2 Pyruvate

Question 28

Pyruvate oxidation outputs

Answer 28

2 acetyl CoA
2 CO2
2 NADH

Question 29

Oxidative phosphorylation inputs

Answer 29

10 NADH
10 FADH2

Question 30

Oxidative phosphorylation outputs

Answer 30

26-28 ATP

Question 31

Anaerobic respiration

Answer 31

1. Generates ATP using an electron transport chain
2. Takes place in prokaryotic organisms that live in environments with no oxygen
3. Final electron acceptors- sulfates or nitrates

Question 32

Fermentation

Answer 32

Generates ATP without an ETC, extension of glycolysis
1. Recycles NAD+
2. Occurs in the cytosol

Question 33

Two types of fermentation

Answer 33

1. Alchohol Fermentation
2. Lactic acid fermentation

Question 34

Alchohol fermentation

Answer 34

Pyruvate is converted into ethanol

Question 35

Lactic acid fermentation

Answer 35

Pyruvate is reduced directly by NADH to form lactate

Question 36

Muscle cells and lactic acid fermentation

Answer 36

1. When muscles run out of oxygen they can go through lactic acid fermentation to produce ATP
   *Causes burning sensation you feel when exercising

Question 37

Breakdown of lactate

Answer 37

-Muscles produce lactate, which goes into the blood, and is broken back to glucose in the liver
-When lactate is in the blood it lowers the PH
-If lactate builds up and is unable to be broken down it can lead to lactic acidosis- excessively low blood PH