Chapter 9: Cellular Respiration

 Living cells require
 Organisms use their main energy source
 Cellular respiration is the process of as
 Energy is released in the process of respiration when the cells of plants and animals

 The breakdown of organic molecules is
 Aerobic respiration consumes
 Anaerobic respiration is similar to aerobic respiration but
 Fermentation is a

 Cellular respiration includes both but is often used to refer to
 Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace cellular respiration with the :

during chemical reactions  The
 This released energy is used to
 Chemical reactions that transfer electrons between reactants are called
 In oxidation, a substance
 In reduction, a substance
 In cellular respiration, the
, or is
, or is

 In cellular respiration, glucose and other organic molecules are broken down in a series of steps

• As an electron acceptor, NAD + functions as an
• Each NADH (the reduced form of NAD + )
• NADH passes the electrons to the

 Unlike an uncontrolled reaction, the electron transport chain passes electrons in a series of steps instead of one explosive reaction
• O
2 pulls electrons
• The energy yielded is

1) Glycolysis - Anaerobic
2) Citric Acid Cycle - Aerobic
3) Oxidative phosphorylation - Aerobic

1) Glycolysis
•
2) Citric Acid Cycle
•
QuickTime™ and a
TIFF (Uncompressed) decompressor are needed to see this picture.
3) Oxidative
Phosphorylation (ETC)
•

 “Splitting of sugar”
 Breaks down glucose
(C
6
H
12
O
6
) into

 Occurs in the
 NAD picks up H+ and electrons to form NADH
2

Reactants



Location:
Products
Simple Summary
Summary total



• **

 In the presence of O
2
,
 Before the citric acid cycle can begin,
 In the mitochondria matrix…
1) Pyruvic Acid loses a C to form
2) The lost carbon
3)Acetic acid binds with

 Takes place within the
 There are , each catalyzed by a specific enzyme
 The acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate
 The next seven steps

 2 molecules of CO2 are
 NAD+ and FAD (flavin adenine dinucleotide - another ion carrier)
 The NADH and FADH
2 produced by the cycle relay electrons extracted from food
 The cycle generates
 Recall that two molecules of pyruvate are formed during glycolysis resulting in

Location:
Reactants

Products




Kreb’s Summary
Kreb's Summary 2


•
 Takes place in the
 A series of molecules that excited electrons pass along,
 Most of the chain ’ s components are which exist in
,

 Following glycolysis and the citric acid cycle,
NADH and FADH
2 extracted from food account for most of the energy
 These two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via
 The carriers alternate as they accept and donate electrons
 Electrons
 They are finally passed to O
, forming
2

2
 Dump the electrons and protons they’ve gathered throughout glycolysis and the citric acid cycle
 Again,
• O2 + 2e- + 2H+  H2O
 Electrons are passed through a number of proteins
 The chain ’ s function is to break the large freeenergy drop from food to O
2 into smaller steps that release energy in manageable amounts


 Electron transfer in the ETC causes proteins to
 H + then moves back across the membrane, passing through channels in
 ATP synthase uses the exergonic flow of H + to drive
 This is an example of
chemiosmosis,

ETC Summary

Reactants


Location:
Product

•
•
Simpler ETC Summary
Best ETC Summary

Song I Found...

Total ATP from 1 molecule of glucose in
Stage ATP
+ 4 Total
Glycolysis (b/c 2 are used in the first step)
CA Cycle
ETC
_________________
TOTAL
During cellular respiration, most energy flows in this sequence:
Glucose -> NADH -> electron transport chain -> proton-motive force -> ATP

 Most cellular respiration requires
 Glycolysis can produce ATP

 Fermentation uses instead of an electron transport chain to generate ATP
 2 Types:
, glycolysis couples with to produce ATP
•
•

 In lactic acid
fermentation,
 Lactic acid fermentation by some fungi and bacteria is used
 Human muscle cells use lactic acid fermentation

 Example: Burning feeling in muscles during a workout
• From oxygen debt
•
• Lactate

 In alcohol
fermentation, pyruvate is
• Bacteria and fungi
(yeast)
 Alcohol fermentation by yeast is used in

 Obligate anaerobes carry out fermentation or anaerobic respiration and
 Yeast and many bacteria are facultative
anaerobes, meaning that
Review

 Catabolic pathways funnel electrons from many kinds of organic molecules into cellular respiration
 Glycolysis accepts a wide range of

• Amino groups can feed
 Fats are digested to
• Fatty acids are broken down by beta oxidation and yield
 An oxidized gram of produces more than twice as much ATP as an oxidized gram of

 is the most common mechanism for control
• If ATP concentration begins to , respiration
• When there is
ATP, respiration of
 Control of catabolism is based mainly on

1.
Define cellular respiration and state its importance as a life process.
2.
Differentiate between aerobic respiration, anaerobic respiration, and fermentation.
3.
State and explain the chemical equation for cellular respiration.
4.
Define oxidation and reduction and explain the idea of redox reactions.
5.
Explain the use of NAD+ as a coenzyme.
6.
Explain the electron transport chain (ETC).
7.
Name the 3 major stages of cell respiration, along with their locations.
8.
Explain glycolysis, stating the reactants, products, and major activities.
9.
Explain the bridge reaction, stating the reactants, products, and major activities.
10. Explain the Kreb’s cycle, stating the reactants, products, and major activities.
11. Explain glycolysis, stating the reactants, products, and major activities.
12. Explain the ETC, stating the reactants, products, and major activities.
13. Explain the role of oxygen in the ETC.
14. Define chemiosmosis and explain its role in cellular respiration.
15. Differentiate between lactic acid fermentation and alcohol fermentation.
16. Differentiate between oblicate anaerobes and facultative anaerobes.
17. Explain the role of macromolecules in cellular respiration.
18. Explain how cell respiration is regulated.