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Flashcards in Chapter 9 Deck (49)
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1
Q

Energy flows

A

Into an ecosystem as sunlight and leaves as heat

2
Q

Catabolic pathways yield

A

Energy by oxidizing organic fuels. Catabolic pathways release stored energy by breaking down complex molecules

3
Q

The breakdown of organic molecules is

A

Exergonic

4
Q

Fermentation

A

A partial degradation of sugars that occurs without O2

5
Q

Aerobic respiration

A

Consumes organic molecules and O2 and yields ATP

6
Q

Anaerobic respiration

A

Similar to aerobic respiration but consumes compounds other than O2

7
Q

Autotrophs

A

Are able to produce their own organic molecules through photosynthesis (plants, algae, some bacteria)

8
Q

Heterotrophs

A

Live on organic compounds produced by other organisms

9
Q

All organisms use

A

Cellular respiration to extract energy from organic molecules. Energy is contained within bonds of molecules

10
Q

Electrons can be

A

Transferred from one atom to another during some chemical reactions. Still retain the energy of their position in the atom

11
Q

Oxidation

A

LOSS of electrons

12
Q

Reduction

A

GAIN of electrons

13
Q

OIL RIG

A

Oxidation is loss, reduction is gain

14
Q

Reduction:

A

Reduces the positivity of an atom/ion

15
Q

Reducing agent

A

The electron donor

16
Q

Oxidizing agent

A

The electron receptor

17
Q

Cellular respiration is a series

A

Of reactions that are oxidation and also dehydrogenations. What is lost is a hydrogen atom

18
Q

Dehydrogenations

A

Lost electrons are accompanied by hydrogen ions

19
Q

NAD+

A

An electron carrier, accepts 2 electrons and 1 proton to become NADH. This reaction is reversible

20
Q

NADH will later

A

Pass the electrons to the electron transport chain

21
Q

Harvesting of energy from glucose has 3 stages

A

Glycolysis, pyruvate oxidation & citric acid cycle, and oxidative phosphorylation

22
Q

Glycolysis

A

Breaks down glucose into two molecules of pyruvate

23
Q

Pyruvate oxidation and Citric acid cycle

A

Complete the breakdown of glucose

24
Q

Oxidative phosphorylation

A

Accounts for most of the ATP synthesis because it is powered by redox reactions

25
Q

Substrate level phosphorylation

A

A smaller amount of ATP is formed in glycolysis and the Citric acid by this

26
Q

32 molecules of ATP

A

For each molecule of glucose degraded to CO2 and water by respiration, the cell makes up to this many

27
Q

ATP powers

A

Cellular work

28
Q

ATP hydrolysis

A

Drives endergonic reactions in two way: by coupling or by phosphorylating

29
Q

Coupling

A

Exergonic reactions with endergonic reactions so overall Delta G < 0

30
Q

Phosphorylating

A

By phosphorylating substrates and making them more reactive

31
Q

When glucose is oxidized yo CO2,

A

It ‘loses’ electrons. So glucose loses the potential energy that is associated with those electrons

32
Q

Glycolysis breaks down

A

6-carbon glucose into two 3-carbon molecules of pyruvate and occurs in the cytoplasm

33
Q

Glycolysis occurs

A

In the cytoplasm and occurs whether or not O2 is present

34
Q

Glycolysis consists of two phases:

A

Energy investment phase and energy payoff phase

35
Q

Energy investment phase

A

Two molecules of ATP are consumed. Glucose is phosphorylated twice.

36
Q

Energy payoff phase

A
  • Sugar is split to form 2 pyruvate molecules
  • 2 molecules of NAD+ are reduced to NADH
  • 4 molecules of ATP are formed by substrate level phosphorylation (net gain of 2 ATP)
37
Q

For glycolysis to continue

A

NADH must be recycled to NAD+ by either aerobic respiration or fermentation

38
Q

Aerobic respiration occurs

A

When oxygen is available as the final electron acceptor

39
Q

Fermentation occurs

A

When oxygen is not available or when an organic molecule is the final electron acceptor

40
Q

When oxygen is present

A

Pyruvate is oxidized to acetyl-CoA which enter the Citric Acid cycle

41
Q

Without oxygen, pyruvate is

A

Reduced to oxidize NADH back to NAD+

42
Q

Before the Citric acid cycle can begin,

A

Pyruvate must be converted to acetyl CoA.

43
Q

Acetyl-CoA

A

Consists of 2 carbons from pyruvate attached to coenzyme A. Proceeds to the Citric Acid Cycle

44
Q

The Citric acid cycle

A

Completes the breakdown of pyruvate to CO2

45
Q

The Citric acid cycle oxidized organic fuel derived from

A

Pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2 per turn

46
Q

First step of Citric Acid Cycle

A

Acetyl-CoA (2 carbons) +
Oxaloacetate (4 carbons) —>
Citrate (6 carbons)

47
Q

Remaining steps of Citric Acid Cycle

A
  • release 2 molecules of CO2
  • reduce 3 NAD+ to 3 NADH
  • reduce 1 FAD (electron carrier) to FADH2
  • produce 1 ATP
  • regenerate oxaloacetate
48
Q

Have to run Citric Acid Cycle

A

Twice for each glucose. Produce 2 acetyl-CoA per glucose

49
Q

After glycolysis, pyruvate oxidation, and the Citric Acid Cycle, glucose has been oxidized to:

A
  • 6 O2
  • 4 ATP
  • 10 NADH
  • 2 FADH2
    NADH & FADH2 (electron carriers) proceed to the electron transport chain