Chapter 5- Cellular respiration

Question 1

3 jobs of cellular respiration

Answer 1

1. Breaks down carbohydrates, lipids, and proteins
2. Converts energy that is liberated into ATP
3. Allows the cell to do work

Question 2

What is cellular respiration

Answer 2

• Collection of metabolic reactions within cells that breaks down food molecules (catabolic reactions) to produce ATP

Question 3

ATP

Answer 3

form of chemical energy required for thousands of biosynthetic reactions (anabolic reactions) taking place within the cell

Question 4

Where is energy coming from?

Answer 4

the sun

Question 5

Oxidation-Reduction (Redox) Reactions

Answer 5

Chemical reactions in which electrons are transferred from one atom or molecule to another

Question 6

LEO GER

Answer 6

loss of electrons= oxidation
gain of electrons = reduction

Question 7

Electron Sharing

Answer 7

Sometimes only the degree of electron sharing in covalent bonds changes (a relative loss or gain of electrons)

Question 8

Oxidation

Answer 8

partial or full loss of e- to a substance

Question 9

Reduction

Answer 9

partial or full gain of e- to a substance

Question 10

Redox reaction

Answer 10

coupled reactions: The oxidation reaction and the reduction reaction occur simultaneously

Question 11

Cellular respiration formula

Answer 11

C6H12O6 + 6O2 –> 6CO2 +6H2O + ENERGY

Question 12

3 stages of cellular respiration

Answer 12

1. glycolysis
2. pyruvate oxidation and the citric acid cycle
3. oxidative phosphorlation

Question 13

Where do glycolysis, pyruvate oxidation and citric acid cycle, and oxidative phosphorylation occur?

Answer 13

glycolysis - cytosol
Pyruvate oxidation and the citric acid cycle- mitochondria
Oxidative phosphorylation- mitochondria

Question 14

where do most cellular respiration reactions occur

Answer 14

mitochondria

Question 15

does glycolysis require O2

Answer 15

no

Question 16

how many reactions in glycolysis

Answer 16

series of 10 chemical reactions, each catalyzed by a different enzyme

Question 17

What does glycolysis convert

Answer 17

converts glucose (6 carbons) in to 2 pyruvate molecules (3 carbons each)

Question 18

Phases of glycolysis

Answer 18

Phase I: Glucose → Fructose 1,6 Bisphosphate
Phase II: Fructose-1,6-Bisphosphate → Glyceraldehyde 3-phosphate
Phase III: glyceraldehyde 3-phosphate → Pyruvate

Question 19

Phase I of glycolysis

Question 20

Phase II of glycolysis

Question 21

Phase III of glycolysis

Question 22

Substrate level phosphorylation

Answer 22

a phosphate group is transferred from a high-energy donor directly to ADP, forming ATP

Question 23

When is most of the ATP produced duringing cellular respiration

Answer 23

oxidative phosphorlation

Question 24

When is most of the ATP produced during cellular respiration

Answer 24

oxidative phosphorylation

Question 25

What happens in the mitochondrial membrane

Answer 25

- electron transfer - ATP synthesis by ATP synthase

Question 26

What happens in the mitochondrial matrix

Answer 26

pyruvate oxidation and the citric acid cycle

Question 27

Phosphofructokinase

Answer 27

catalyzes the second ATP-consuming step of the pathway

Question 28

Pyruvate Oxidation

Answer 28

Pyruvate (3C) is oxidized to an acetyl group (2C) * CO2 is produced * Electrons removed are accepted by (or used to reduce) NAD+ to form NADH * Acetyl group linked to Co-Enzyme A (CoA)

Question 29

is pyruvate oxidation aerobic or anaerobic?

Answer 29

aerobic

Question 30

What does each pyruvate molecule produce

Answer 30

1 acetyl group 1 NADH 1 CO2

Question 31

What does pyruvate oxidation link

Answer 31

glycolysis and the citric acid cycle

Question 32

what happens to the acetyl group after pyruvate oxidation

Answer 32

Acetyl groups attached to coenzyme A * Delivered to citric acid cycle

Question 33

Citric Acid cycle

Answer 33

Acetyl groups completely oxidized to CO2 * Electrons removed in a series of oxidations * Accepted by NAD+ or FAD (which get reduced to NADH and FADH2) * Some ATP made by substrate-level phosphorylation

Question 34

Produced from the citric acid cycle

Answer 34

Each acetyl group that enters the cycle and gets oxidized produces * 2 CO2 * 1 ATP (by substrate-level phosphorylation) * 3 NADH * 1 FADH2

Question 35

What do electrons pass from in the ETC

Answer 35

NADH and FADH2 --> O2

Question 36

What does the ETC include

Answer 36

- 4 protein complexed 2 smaller shuttle carriers

Question 37

how do electrons move along the ETC

Answer 37

spontaneously

Question 38

what protein complexes are in the Respiratory ETC

Answer 38

3 major protein complexes I, II, Iv

Question 39

What do the respiratory ETC protein complexes do

Answer 39

* Pump H+ from Matrix to IMS * Contain prosthetic groups that cycle between reduced and oxidized states

Question 40

What do the electrons do in the respiratory ETC

Answer 40

* Depleted of energy * Delivered to oxygen as final electron acceptor

Question 41

Chemiosmotic synthesis of ATP

Answer 41

involves the ATP synthase complex, which uses the energy of the proton gradient to catalyze the synthesis of ATP.

Question 42

Why does fermentation occur

Answer 42

In eukaryotic cells, low oxygen levels result in fermentation

Question 43

What is fermentation

Answer 43

the pathway of respiration that oxidizes fuel molecules in the absence of oxygen

Question 44

what are the two types of fermentation

Answer 44

lactate fermentation and alcohol fermentation

Question 45

where does lactic acid fermentation occur

Answer 45

animals and bacteria

Question 46

how is lactic acid fermentation produced?

Answer 46

electrons from NADH are transferred to pyruvate to produce lactic acid and NAD+

Question 47

Where does alcohol fermentation occur?

Answer 47

plants and fungi

Question 48

how does alcohol fermentation happen?

Answer 48

Electrons from NADH are transferred to pyruvate to produce ethanol and NAD+

Question 49

Facultative aerobes:

Answer 49

Can grow in presence of oxygen and can grow using fermentative pathways

Question 50

is oxygen dangerous

Answer 50

yes, it can be a ROS (reactive oxygen species) - superoxide and peroxide - strong oxidizing agents

Question 51

Defence against ROS

Answer 51

* Antioxidant defence system * Enzymes * Superoxide dismutase and catalase * Nonenzymes * Antioxidants: vitamin C and vitamin E

Question 52

In eukaryotes what is the terminal electron acceptor

Answer 52

oxygen

Question 53

what does aerobic respiration happen in

Answer 53

prokaryotes - bacteria eukaryotes - plants

Question 54

How much ATP is required for glycolysis (input)

Answer 54

2

Question 55

At the end of glycolysis, the energy from glucose has been stored in

Answer 55

2 pyruvate 2 ATP (NET) 2 NADH