8: Energy From Organic Molecules I Flashcards

Module 2, Lesson 2

1
Q

Depending on how they obtain energy, organisms are classified as either…

A

Autotrophs or heterotrophs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

____ convert solar energy into chemical energy.

A

Autotrophs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Autotrophs store chemical energy as…

A

ATP or organic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

List three examples of autotrophs.

A
  1. Plants
  2. Algae
  3. Photosynthetic bacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

____ rely on the chemical energy stored in the bonds of organic molecules.

A

Heterotrophs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Heterotrophs convert chemical energy into…

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

True or false:

Only heterotrophs can extract chemical energy from organic molecules.

A

False

Both autotrophs and heterotrophs are capable of this.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

____% of species are heterotrophs.

A

95

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

List four examples of heterotrophs.

A
  1. Animals
  2. Fungi
  3. Most protists
  4. Most prokaryotes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

All cells can use ____ to extract energy from the chemical bonds in organic molecules.

A

Cellular respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Cellular respiration involves two enzyme-catalyzed reactions, ____ and ____.

A

Oxygenation and dehydrogenation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Dehydrogenation involves…

A

The loss of both protons and electrons
(the loss of one or more hydrogen atoms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The energy contained in electrons is harvested via a series of…

A

Redox reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

During a redox reaction, the ____ and ____ are transferred to another molecule.

A

Electrons and most of their energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to the energy lost by electrons during transfer?

A

It is either lost as heat or converted to ATP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

After multiple redox reactions, the energy-depleted electrons are transferred to…

A

A final electron acceptor molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The transfer of electrons often relies on…

A

Electron carriers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Most electron carriers are…

A

Cofactors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are cofactors?

A

Small chemicals that assist enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

All electron carriers are easily and reversibly ____ and ____.

A

Oxidized and reduced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

List two examples of electron carriers.

A

NAD+ (reduces to NADH)
FAD (reduces to FADH2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What two forms of energy are generated via cellular respiration?

A
  1. ATP
  2. Electron energy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

NAD+ has ____ energy than NADH.

A

Greater

24
Q

____ is a fundamental energy source for cells.

A

Glucose

24
Q

When glucose is oxidized in the process of molecular oxygen (O2), respiration becomes…

A

Aerobic

25
Q

During the aerobic respiration of glucose, ____ is the final acceptor for harvested electrons.

A

Oxygen

26
Q

Cellular respiration of glucose produces chemical energy as…

A

ATP and heat

27
Q

True or false:

It is more efficient for a cell to convert the chemical energy of glucose to ATP all at once.

A

False

Glucose is so energy efficient that if a cell did this, it would likely combust.

28
Q

Glucose oxidation happens over ____ stage(s).

A

Four

29
Q

List the four stages of glucose oxidation.

A
  1. Glycolysis
  2. Pyruvate oxidation
  3. Krebs cycle
  4. Electron transport chain & chemiosmosis
30
Q

In eukaryotes, glycolysis occurs in the…

A

Cytosol

31
Q

In eukaryotes, pyruvate oxidation, the Krebs cycle, and chemiosmosis occur in the…

A

Mitochondria

32
Q

In prokaryotes, the process of glucose oxidation occurs in either the…

A

Cytoplasm or plasma membrane

33
Q

During glycolysis, 1 molecule of glucose is converted into….

A

2 molecules of pyruvate

34
Q

What are the two phases of glycolysis?

A
  1. Energy input
  2. Energy production
35
Q

During the first phase of glycolysis…

A

Glucose splits into 2 molecules of G3P.

36
Q

The first phase of glycolysis is ____, while the second is ____.

A

Endergonic ; exergonic

37
Q

During the second phase of glycolysis…

A

Each molecule of G3P is converted into a pyruvate molecule

38
Q

For each glucose molecule, glycolysis produces…

A

2 pyruvate molecules
4 ATP molecules
2 NADH molecules
2 water molecules

39
Q

Glycolysis results in a net gain of ____ ATP molecules.

A

Two

40
Q

List the two means of producing ATP.

A
  1. Substrate-level phosphorylation
  2. Oxidative phosphorylation
41
Q

During substrate-level phosphorylation…

A

An enzyme transfers an inorganic phosphate to ADP, creating ATP.

42
Q

The energy contained in the inorganic phosphate is ____ during substrate-level phosphorylation.

A

Maintained

43
Q

When ____ is present, eukaryotes and aerobic prokaryotes can synthesize much more ATP.

A

Oxygen

44
Q

True or false:

Glycolysis requires oxygen to proceed.

A

False

However, the cell can perform aerobic respiration if there is oxygen present.

45
Q

Pyruvate oxidation occurs in the ____ of a mitochondrion.

A

Matrix
(innermost area)

46
Q

For every molecule of pyruvate, pyruvate oxidation produces…

A

1 molecule of carbon dioxide
1 molecule of NADH
1 molecule of acetyl-CoA

47
Q

The Krebs cycle is also sometimes called the…

A

Citric acid cycle

48
Q

The Krebs cycle contains a total of ____ steps, divided into ____ phases.

A

Nine ; three

49
Q

During the Krebs cycle…

A

Acetyl-CoA is oxidized.

50
Q

The Krebs cycle occurs in the ____ of a mitochondrion.

A

Matrix

51
Q

List the three main steps of the Krebs cycle.

A
  1. Acetyl-CoA and oxaloacetate combine to form citrate.
  2. Citrate is rearranged and forms a 4-carbon succinate.
  3. Oxaloacetate is regenerated from succinate.
52
Q

In addition to succinate, the second step of the Krebs cycle produces…

A

2 carbon dioxide molecules
2 NADH molecules
1 ATP molecule

53
Q

In addition to oxaloacetate, the third step of the Krebs cycle produces…

A

1 NADH molecule
1 FADH2 molecule

54
Q

In total, for each molecule of acetyl-CoA, the Krebs cycle produces…

A

2 molecules of carbon dioxide
3 molecules of NADH
1 molecule of FADH2
1 molecule of ATP
1 oxaloacetate

55
Q

For each glucose molecule, ____ acetyl-CoA molecules enter the Krebs cycle.

A

Two