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Flashcards in Chapter 9 Deck (37):
1

Energy enters an ecosystem as ____ and exits as ______

sunlight; heat

2

What releases the energy stored in glucose during cellular respiration? What is this released energy used for?

-The transfer of electrons
-Used to synthesize ATP

3

Cellular respiration is a ______ reaction

exergonic

4

Redox reaction

Reaction with transfer of electrons between reactants

5

Oxidation

A substances loses electrons and is oxidized

6

Reduction

A substance gains electrons and is reduced.

7

In this equation: Na + Cl = Na+ + Cl- Which is oxidized and which is reduced?

-Na is oxidized, Cl is reduced
Remember that Na loses electrons, and therefore has more protons. It has a positive charge. Cl gains electrons and has less protons that electrons. Its charge is reduced to negative.

8

Reducing agent

Electron donor; this would be the substance that is oxidized

9

Oxidizing agent

Electron receptor; this would be the substance that is reduced

10

Some redox reactions do not transfer electrons but change _______

electron sharing in covalent bonds

11

In cellular respiration, which is oxidized and which is reduced?

-Glucose is oxidized
-Oxygen is reduced

12

In a molecule of H2O, which atom is reduced?

Oxygen is reduced as electrons of covalent bonds tend to gravitate towards it more

13

Oxidation of glucose transfers electrons to a ____ free energy level

Lower; they lose potential energy along the way

14

What is NAD+

An electron carrier coenzyme

15

NAD+ functions as a _____ agent during cellular respiration

Oxidizing
-Remember that NAD+ receives electrons, therefore it is reduced. So, it is an oxidizing agent.

16

What does NADH represent?

Stored energy that is tapped to synthesize ATP

17

What electron transfer is coupled with the reduction of NAD+?

The oxidation of glucose
(Dehydrogenase enzymes remove 2 hydrogen atoms from glucose, thus oxidizing it, and then delivers 2 electrons and 1 proton to NAD+)

18

What do dehydrogenase enzymes do?

Oxidize glucose by removing 2 hydrogen atoms and delivers it to NAD+

19

The Electron Transport Chain passes electrons down the chain until it meets _____, which is the stable and electron acceptor

O2

20

The energy yielded from which process is used to generate ATP?

Electron Transport Chain

21

Which process generates the most ATP and why?

Oxidative phosphorylation and because it is powered by redox reactions

22

Which 2 processes generate the least ATP and why?

Glycolysis and Citric Acid Cycle because it is fueled by substrate-level phosphorylation

23

What is substrate-level phosphorylation?

Transfer of phosphate group from organic substrate to ADP

24

Glycolysis breaks glucose into __(number)__ molecules of _____

2 molecules of pyruvate

25

Where does glycolysis occur and what are its phases?

In cytoplasm, energy investment phase and energy payoff phase

26

What are the products of glycolysis?

-2 pyruvate and 2 H2O, 2 ATP, 2 NADH and 2 H+
(The 2 ATP is produced by substrate-level phosphorylation and the NAD+ is reduced to NADH)

27

What does the Citric Acid Cycle ultimately do?

Completely oxidizes glucose in the presence of oxygen

28

What happens before Krebs cycle begins and after glycolysis?

Carbon is lost as carbon dioxide, 2-carbon molecule combines with CoA to form acetyl CoA

29

What is the final electron acceptor in oxidative phosphorylation?

Oxygen

30

More H+ ions = _____ pH

Lower

31

The electron transport chain sends H+ from where to where?

Matrix to intermembrane space

32

How does the exergonic flow of H+ ions create ATP?

Catabolic pathway of H+ across membrane through ATP synthase conforms ADP and phosphate group

33

What is chemiosmosis?

Use of energy in an H+ gradient to drive work

34

What are the types of fermentation? What happens in these?

-Alcohol: CO2 released from pyruvate, then that is oxidized. Ethanol is final.
-Lactic: Pyruvate oxidized right away, creating lactate

35

Obligate anaerobe

Carry out fermentation and cannot survive in O2

36

What three organic molecules are often utilized to make ATP by cellular respiration?

Proteins, fats, carbohydrates

37

Why don't cells catabolize carbon dioxide?

CO2 is already completely oxidized