Cellular Respiration Chapter 5 Section 3

Key Terms Aerobic Anaerobic Glycolysis NADH Krebs Cycle FADH 2 Fermentation

Cellular Respiration Process cells use to harvest the energy in organic compounds (glucose). The breakdown of glucose during cellular respiration can be summarized by: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Energy ATP Enzymes

2 Types of Cellular Respiration Aerobic Metabolic processes that require oxygen and is more efficient at producing ATP.(36-38 ATP) Anaerobic Metabolic processes that do not require oxygen and does not produce as many ATP as the aerobic stage.(2 ATP)

Question: In what kinds organisms does cellular respiration take place?In what kinds organisms does cellular respiration take place?

Plants and Animals Plants - AutotrophsPlants - Autotrophs: self-producers. Animals - Heterotrophs: consumers.

Stages of Cellular Respiration 1.GLYCOLYSIS (fist step in both types of respiration) -- Enzyme- assisted anaerobic process that breaks down one six- carbon molecule of glucose to two three-carbon pyruvate ions, producing a net result of 2 ATP and a NADH, electron carrier, molecule. This step occurs in the cytoplasm.

Glycolysis cont… Uses 2 ATP molecules but produces 4 ATP molecules, so net gain of ATP is 2.

Aerobic Respiration 2a. When oxygen is present, pyruvate & NADH are used to make more ATP. Takes place in the Mitochondria. The pyruvate goes thru the Kreb’s Cycle and the Electron Transport Chain to produce the ATP.

Krebs Cycle Acetyl-CoA enters a series of enzyme-assisted reactions called the Krebs Cycle.

Electron Transport Chain In aerobic respiration, electrons donated by NADH and FADH2 pass through an electron transport chain.

Electron Transport Chain

What happens when there is not enough oxygen for aerobic respiration to occur? The electron transport chain does not function!

Anaerobic Respiration 2b. When oxygen is not present, anaerobic respiration, the pyruvate is converted by fermentation to either lactic acid (in animals) or ethanol (in yeast) & carbon dioxide and no more ATP are produced.

Fermentation When oxygen is not present, NAD + is recycled in another way. The recycling of NAD + using an organic hydrogen acceptor is fermentation.

Fermentation cont… “NO Oxygen” (called anaerobic).Occurs in cytosol when “NO Oxygen” is present (called anaerobic). glycolysis fermentationRemember: glycolysis is part of fermentation. Two Types:Two Types: 1.Alcohol Fermentation 2. Lactic Acid Fermentation

2.Alcoholic Fermentation The three- carbon pyruvate is broken down to ethanol, a two-carbon compound, through alcoholic fermentation.

Alcohol Fermentation Plants and Fungi  beer and winePlants and Fungi  beer and wine glucose Glycolysis CCCCCCCCCCCCC CCCCCC 2 Pyruvic acid 2ATP 2ADP + 2 2NADH P 2 NAD + CCCC 2 Ethanol 2CO 2 released 2NADH 2 NAD +

Alcohol Fermentation End Products: Alcohol fermentationEnd Products: Alcohol fermentation 2 - ATP (substrate-level phosphorylation) 2 - CO Ethanol’s

2 Types of Fermentation: 1.Lactic Acid Fermentation A three-carbon pyruavte is converted to a three-carbon lactate through lactic acid fermentation in muscle cells.

Lactic Acid Fermentation Animals (pain in muscle after a workout).Animals (pain in muscle after a workout). 2 Lactic acid acid 2NADH 2 NAD + CCCCCC Glucose Glycolysis CCCCCC 2 Pyruvic acid 2ATP 2ADP + 2 2NADH P 2 NAD + CCCCCCCCCCCCC

Lactic Acid Fermentation End Products: Lactic acid fermentationEnd Products: Lactic acid fermentation 2 - ATP (substrate-level phosphorylation) 2 - Lactic Acids

Production of ATP The total amount of ATP that a cell is able to harvest from each glucose molecule that enters glycolysis depends on the presence or absences of oxygen.

Production of ATP

Question: In addition to glucose, what other various food molecules are use in Cellular Respiration?In addition to glucose, what other various food molecules are use in Cellular Respiration?

Catabolism of Various Food Molecules Other organic molecules used for fuel. 1. Carbohydrates: polysaccharides 2. Fats: glycerol’s and fatty acids 3. Proteins: amino acids