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 Vocabulary 1.Acetyl CoA 2.Aerobic respiration 3.Alcoholic fermentation 4.Anaerobic 5.Cellular respiration 6.Citric acid 7.Fermentation 8.Glycolysis 9.Kilocalorie 10.Krebs cycle 11.Mitochondrial matrix 12.Oxaloacetic acid 13.Pyruvic acid 14.Lactic acid fermentation 15.NAD+---NADH, FAD+---FADH 2 Read Pgs 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 15 th !

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 C 6 H 12 O 6 + 6O  6CO 2 + 6H 2 O + 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.

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 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 mith.edu/department s/Biology/Bio231/kre bs.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

Net Energetics of Cellular Respiration Per Molecule of Glucose Stages of Cellular Respiration Net ATP produced NADH produced FADH2 produced CO2 produced Glycolysis2200 Grooming of Pyruvic acid 0202 Kreb’s Cycle 2624 E.T.C Net # of molecules 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 and hand in on Thursday, April 16 th –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