Biology 100/101
Lecture 8: Respiration
(Print Version)

Announcements &
Assignments

Lecture Objectives

Web Resources

Photosynthesis
and Respiration

Overview of Cellular
Respiration

Glycolysis

Acetyl CoA
Bridge

Krebs Cycle

Electron
Transport Chain

Fermentation

Summary

Lecture Syllabus

IB 100/101 Home Page

Announcements & Assignments

Text Readings in Lewis

Chapter 6, The Energy of Life, Pages 92-101
Chapter 8, How Cells Release Energy, Pages 125-141

The "Reviewing Concepts" boxes are valuable summaries of the main ideas in these sections of the text.

You have open access (no log-in or password needed) to instructional materials on the Text web site. Select the text chapter you want and use the links to the e-learning modules or other available materials. There is also a collection of study materials called the "Essential Study Partner" that you may find useful.

Web Crossing

You may also ask questions and see answers to your classmates' questions in Web Crossing in the "Talk to Carl and Ed" discussion.

Objectives:

The content of today's lecture will help you complete this assignment:

After studying this material you should be able to:

  1. Explain how the process of respiration is involved in net primary production and an increase in plant biomass.

  2. Draw a diagram of part of a cell including a portion of cytoplasm and a mitochondrion. Describe the energy transformations that occur in the cytoplasm and mitchondria as chemical energy from glucose and other compounds is converted to the chemical bond energy of ATP.

  3. List the inputs (raw materials) and outputs (products) of glycolysis, the Krebs Cycle, and the respiratory (electron transport) chain.

  4. Describe the roles of ADP, ATP, NAD+, NADH, and a proton gradient in the enzyme reactions of the Krebs Cycle and the respiratory (electron transport) chain.

  5. Explain where in the respiratory pathway O2 is used and CO2 is produced.

  6. Describe the role of oxygen in the process of aerobic respiration.

  7. Explain how weight loss and CO2 production are inseparably linked.

  8. Explain how proteins and fats may be utilized by the enzymes involved in respiration.

  9. Explain the role of the respiratory pathways in the processing of compounds for biosynthesis.

  10. Compare the energy output (in the form of ATP) of the anaerobic pathways (alcoholic and lactic acid fermentation) to that of aerobic respiration.

Respiration Links

Respiration

Glycolysis Movie

Electron Transport Chain Movie

ATP Synthase Movie

Fermentation/Anaerobic Respiration


Photosynthesis: Summary

CO2 + H2O + --- Light
Energy		 ---> Simple
Carbohydrates
(Organic Compounds)		 + O2 + Heat

Cellular Respiration - The Basic Reaction

O2 + Simple
Carbohydrates
(Organic Compounds)		 ----> Heat + Usable
Chemical
Energy
(ATP)		 + CO2 + H2O

The Chemical reactions of Photosynthesis and Respiration are facilitated by the action of protein molecules called ENZYMES (Text, Pg. 100, fig. 6.16)

    Protein: A polymer of amino acids

    Enzyme: A protein that catalyzes a chemical reation.

Overview of Cellular Respiration

from text Pg. 130. fig. 8.5

What the heck is all this ATP used for, anyway???

Glycolysis occurs in the cytoplasm.

Glycolysis animation from Smith College.

Glycolysis "burns" glucose (6 carbons) to 2 molecules of pyruvic acid (3 carbons each) with a net gain of 2 ATP. (see Lewis, Pg. 131, fig. 8.6)

  • Glucose Activation

  • Enzyme Reactions

  • Production of ATP & NADH (ENERGY)

  • Production of Pyruvic Acid

Glycolysis, the first 5 steps from Access Excellence

Glycolysis, the last 5 steps from Access Excellence

Acetyl CoA Bridge to the Krebs Cycle

from text Pg. 132. fig. 8.7

  • The Pyruvic Acid molecules start to enter the mitochondria.

  • As it enters a mitochondrion a molecule of CO2 is split off the Pyruvic Acid molecule and the remaining two carbons are connected to a co-enzyme A molecule to produce Acetyl Coenzyme A (Acetyl CoA).

  • In the process, a molecule of NADH (ENERGY) is produced.

  • The Acetyl CoA actually enters the Krebs Cycle

    • Pyruvic
    Acid    		 + CoA + Enzyme
    Action    		 --> Acetyl
    CoA    		 + CO2 + NADH
    (ENERGY)

The Krebs Cycle occurs in the Mitochondria.

Krebs Cycle (Text, Pg. 132 figure 8.8)
Mitochondria (Text, Pg. 129 figure 8.4)

Acetyl CoA and Krebs animation (AKA Citric Acid Cycle) from Smith College

Breakdown of carbohydrates to make short-term chemical energy (NADH, a little ATP, and FADH2).

  • Acetyl CoA enters the Krebs cycle and combines with oxalic acid (4C) to produce citric acid (6C)

  • Citric Acid is broken down step-by-step

  • CO2 is released

  • NADH, FADH2, and a little ATP is made (ENERGY)

  • oxalic acid (4C) is regenerated

The Krebs Cycle (AKA Citric Acid Cycle) from Access Excellence

The Respiratory Chain or Electron Transport Chain (ETC)

Text Pg. 134, fig. 8.10

Electron Transport animation from Smith College

ETC occurs on the mitochondrial inner membrane.
Conversion of NADH & FADH2 to lots and lots of ATP.
(see Lewis, fig. 7.9 and 7.10)

Anaerobic Fermentation

Anaerobic Fermentation takes place in the absence of O2 in the cytoplasm. (see Lewis, figure 8.14, a, pg. 139)

Summary of Energy Production