Cellular Respiration

How Cells Harvest Chemical Energy

Objectives

• Define cellular respiration• Describe the major events in glycolysis• Compare and contrast lactic acid

fermentation and alcoholic fermentation• Summarize the events of the Krebs cycle

and the electron transport chain• Relate aerobic respiration to the structure

of a mitochondrion

Define Vocabulary1. Acetyl CoA 2. Aerobic respiration 3. Alcoholic fermentation 4. Anaerobic 5. Cellular respiration 6. Citric acid7. Fermentation8. Glycolysis9. Kilocalorie 10. Krebs cycle 11. Mitochondrial matrix 12. Oxaloacetic acid13. Pyruvic acid 14. Lactic acid fermentation15. NAD+---NADH, FAD+---FADH2

Read Pgs. 131-136 for tomorrow!

Agenda

• Go over Vocabulary Definitions

• Notes: Mitochondrion structure, Glycolysis & Fermentation

• Complete Role of ATP in Cells PSSA Worksheet

What energy carrying compound is made inside the mitochondria?

What occurs during glycolysis?

How is lactic acid fermentation different from alcoholic fermentation?

• Acetyl CoA -two-carbon molecule• Aerobic respiration - process that produces large amounts of ATP• Alcoholic fermentation – form of anaerobic respiration which involves

the conversion of pyruvic acid to ethyl alcohol and carbon dioxide• Anaerobic - does not require oxygen• Cellular respiration - process in which cells make ATP by breaking

down organic compounds• Citric acid -six-carbon molecule in the Krebs cycle• Fermentation - the recycling of NAD+ under anaerobic conditions• Glycolysis - pathway in which two molecules of pyruvic acid are

produced• Kilocalorie - unit of energy• Krebs cycle -pathway that breaks down acetyl CoA producing carbon

dioxide, hydrogen atoms, and ATP• Mitochondrial matrix -the space inside the inner membrane of a

mitochondria• Oxaloacetic acid -four-carbon molecule that combines with Acetyl CoA• Pyruvic acid - three-carbon product of glycolysis• Lactic acid fermentation –form of anaerobic respiration which involves

the conversion of pyruvic acid to lactic acid

Vocabulary Quiz is scheduled for Wednesday, April 15th!

Enzymes

36 ADP + 36 P 36 ATP

All living organisms need Energy!

• Photoautotrophs get energy from sunlight• Heterotrophs get energy from organic

compounds• Chemoautotrophs get energy from

inorganic compounds

The ULTIMATE source of energy for plants and animals is the Sun!

ATP Regenerated through process of Chemiosmosis

The Organelle of Cellular Respiration

• Cellular respiration takes place in both plant and animal cells.

• The organelle in which it takes place is the mitochondrion. – This is also known as the ‘power-house’ of the cell.

Stages of Cellular Respiration

• Glycolysis

• If oxygen present: Aerobic Respiration

• If oxygen not present: Fermentation

C6H12O6 + 6O2 --- 6CO2+ 6H2O + energy

Step #1: Glycolysis

• Biochemical pathway

• Glucose is oxidized into two molecules of pyruvic acid

• Take place in the cytosol ( cytoplasm) of the cell

• Glucose is oxidized (looses electrons) into two molecules of pyruvic acid(pyruvate).

• Net gain of 2 ATP, 2 NADH

• Glycolysis is inefficient in energy-utilization.– Aerobes organisms performing respiration in

the presence of oxygen• must go through Kreb’s Cycle and Electron

Transport Chain in order to produce more energy after glycolysis

– Anaerobes organisms respiring in the absence of oxygen

• can survive and make use of the energy released from glycolysis itself

• Two forms of anaerobes are:– Facultative anaerobes – these can survive in aerobic

and anaerobic conditions. – Obligate anaerobes – Survive only as anaerobes.

http://www.science.smith.edu/departments/Biology/Bio231/glycolysis.html

Anaerobic Respiration

• Two forms of anaerobic respiration are:– Alcoholic fermentation

– Lactic Acid Fermentation

Alcoholic Fermentation

• Yeasts, anaerobic bacteria, etc… undergo alcoholic fermentation.

• In this process, the pyruvic acid from Glycolysis is converted to Ethanol and Carbon dioxide.

• Commercially, this is used for making wine, bread, beer

Lactic Acid Fermentation• This also occurs in human muscle cells during

stress / when oxygen is scarce.• In this process, the pyruvic acid from Glycolysis

is converted to Lactic acid. No Carbon dioxide is produced.

• Lactic acid produced can be changed back to pyruvic acid when oxygen levels return to normal

Review

• What energy carrying compound is made inside the mitochondria?

• What occurs during glycolysis?• How is lactic acid fermentation

different from alcoholic fermentation?

Read Pgs. 137-144 in book & complete Role or ATP PSSA

Worksheet.

Agenda

• Review Vocabulary

• Notes: Aerobic Respiration

• Complete Measuring Respiration PSSA worksheet

How is aerobic respiration different for prokaryotes and eukaryotes?

What is the main purpose of the Kreb’s Cycle?

How does the efficiency of aerobic respiration with anaerobic respiration compare?

Aerobic Respiration

• Oxygen must be present

• Carried out in:– Cytosol(cytoplasm) in prokaryotes– Mitochondrial matrix in eukaryotes

• Stages– Krebs cycle– Electron transport chain

Prior to the Krebs Cycle

• The 3-C containing pyruvic acid produced at the end of Glycolysis is too bulky to enter the mitochondria from the cytoplasm.

• Hence, it is ‘groomed’ (broken down further) with the help of Coenzyme A to form Acetyl Co A

• This Acetyl CoA can easily pass into the mitochondrial matrix, where it undergoes Kreb’s Cycle.

Krebs Cycle

• Biochemical pathway that takes place in the mitochondrial matrix

• Breaks down acetyl Co A into citric acid

• Produces carbon dioxide, hydrogen atoms, and ATP

• Main purpose is to capture H+

•NAD and FAD pick up Hydrogen atoms and take them to the Electron Transport Chain

http://www.science.smith.edu/departments/Biology/Bio231/krebs.html

Electron Transport Chain• Redox reactions release energy when electrons pass

through a cascade of electron carrier molecules. • NADH and FADH release protons to make ATP through

chemosmosis• Final electron acceptor is oxygen

– Allows e- to keep moving down transport chain, therefore ATP can be produced.

– Bonds with H+ and released as water .

Review of Stages for Aerobic Respiration

http://www.studystack.com/wordscramble-93931

Net Energetics of Cellular Respiration Per Molecule of Glucose

Stages of Cellular Respiration

Net ATP produced

NADH produced

FADH2 produced

CO2 produced

Glycolysis 2 2 0 0

Grooming of Pyruvic acid

0 2 0 2

Kreb’s Cycle

2 6 2 4

E.T.C. 34 0 0 0

Net # of molecules

38 10 2 6

Remember Anaerobic Respiration produces only 2 ATP!

Review

• How is aerobic respiration different for prokaryotes and eukaryotes?

• What is the main purpose of the Kreb’s Cycle?

• How does the efficiency of aerobic respiration with anaerobic respiration compare?

Complete Measuring Respiration PSSA worksheet

Agenda

• Vocabulary Quiz

• Pea Respiration Lab

• Complete Chapter Review Pg. 146-147 and hand in on Thursday, April 16th

– Understanding Key Concepts #5-11, 13,14– Critical Thinking #17-20– Standardized Test Preparation #1-8, Short

Response, Extended Response A & B

Agenda

• Vocabulary Quiz

• Pea Respiration Lab