Chapter 6

Question 1

Basic Characteristic of Life

Answer 1

Use Energy

Energy flows in and out of organisms

Question 2

Catabolism

Answer 2

How cells make ATP

Catabolic pathways generate energy
Catabolism
Breaks down complex organic compounds / to component parts (small/large)

Cellular Respiration
Energy generation

Question 3

Respiration provides…to cells

Answer 3

Oxygen

Which is required for cellular respiration

Question 4

Cellular Respiration

Answer 4

Transforming stored chemical energy into a form that a living cell can use

Both aerobic and anaerobic respiration
Often used to refer to aerobic respiration

Carbohydrates, fats, and proteins are all consumed as fuel
Usually traced by glucose

C6H12O6 + 6 O2 = 6 CO2 + 6 H2O + Energy (ATP + heat)

C6H12O6 is glucose

Focuses on two things:
Oxygen
Energy

3 main steps

Question 5

3 Main Steps of Cellular Respiration

Answer 5

1. Glycolysis
   2 ATP, 2 NADH, 2 Pyruvate
2. Citric Acid Cycle
   2 ATP, 6 NADH, 2 FADH, 4 CO2
3. Oxidative Phosphorylation
   28 ATP per glucose / 14 per pyruvate

Question 6

Glycolysis

Answer 6

2 phases:
investment
payoff

Occurs in the cytoplasm

Takes glucose and breaks it into 2 pyruvate molecules

Net production per glucose:
2 ATP, 2 NADH, 2 Pyruvate

Question 7

Citric Acid Cycle

Answer 7

Pyruvate provided by Glycolysis

Occurs in the mitochondria

Takes Acetyl-CoA, joins with oxaloacetate
Forms citrate

Net production per glucose:
2 ATP, 6 NADH, 2 FADH, 4 CO2

Question 8

Oxidative Phosphorylation

Answer 8

No oxygen = no process

Occurs in the mitochondria inner membrane

Two components:
Electron Transport Chain
Chemiosmosis

Takes all the electron carriers

Net production per glucose:
28 ATP per glucose / 14 per pyruvate

Question 9

Electron Transport Chain

Answer 9

Takes extra electrons

Added to oxygen to make water

Question 10

Terminal Electron Acceptor

Answer 10

Accepts oxygen

Question 11

Aerobic

Answer 11

With oxygen

Question 12

Anaerobic

Answer 12

Without oxygen

Question 13

ATP Synthase

Answer 13

High concentration gradient of H+ on one side

Located in the mitochondria inner membrane

H+ re-enters the mitochondria through ATP synthase
“spins” a rotor generating energy to make ATP

Chemiosmosis lets H+ back in

Question 14

Anaerobic Respiration

Answer 14

Limited to prokaryotes (bacteria/archaea)

Allows cells to generate ATP in the absence of oxygen

Bacteria/Archaea use a compound other than O2 as the terminal electron acceptor, even compounds considered toxic

Still uses glycolysis

Electron Transport Chain still active

Question 15

Fermentation

Answer 15

Not energy efficient
No energy = DEAD

Eukaryotes/prokaryotes can still generate energy in the absence of oxygen

Terminal Electron Acceptor is an organic molecule
Usually pyruvate or acetaldehyde

Two main types:
Alcohol Fermentation
Lactic Acid Fermentation

Question 16

Alcoholic Fermentation

Answer 16

Carried out by yeast and bacteria

Transfers electrons from NADH to acetaldehyde
Generates ethanol

Beer, wine
Bakers yeast

Question 17

Lactic Acid Fermentation

Answer 17

Carried out by prokaryotic and eukaryotic cells

Transfers electrons from NADH to pyruvate
Generates lactic acid

Yogurt, cheese
Pickled foods

Human muscle cells also carry out this process when O2 levels are low
During heavy activity
Act like facultative anaerobes

Causes the build-up of lactic acid in muscles
Can cause cramping

Question 18

Regulation of Cellular Respiration

Answer 18

Cells don’t like to waste energy

Shuts down pathways if not needed

If energy (ATP) is plentiful respiration is slowed

Key enzyme controlling the pathways is phosphofructokinase

Question 19

Anabolism / Biosynthesis

Answer 19

Cells need to build complex molecules, not just break them down

Energy generated and stored as ATP is used for biosynthesis

Intermediates from glycolysis, citric acid cycle, and other catabolic pathways can be used