CHAPTER 8 Cellular Energy
8-3 Cellular Respiration
JOURNALExplain how Cellular Respiration is related to Photosynthesis.
anaerobic processaerobic respirationaerobic processglycolysisKrebs cyclefermentationCellular EnergyVocabulary
Cellular Respiration: WhatThe process that releases energy from food in the presence of oxygen. Sugar + oxygen carbon dioxide + water + energy Opposite of photosynthesis!
Cellular Respiration: WhyFunction: Harvest electrons from carbon compounds (glucose), and use that energy to make ATP, which provides energy for cells to do work.
Cellular Respiration: Where
Cellular EnergyOccurs in two main parts.Glycolysis Aerobic respiration Cellular Respiration: How
Aerobic vs. AnaerobicAerobic pathways that require oxygenAnaerobic does not directly require oxygen
Cellular Respiration Overview Video
GlycolysisGlucose is broken down in the cytoplasm through the anaerobic process of glycolysis.You must put energy in to get energy out!
GlycolysisGlycolysis has a net result of two ATP, two NADH and two pyruvate. Most of the energy from the glucose is still contained in the pyruvate.
Glycolysis ReviewWhere does glycolysis take place?CytoplasmWhat are the energy carrying molecules in involved in glycolysis?ATP, NADHWhat is the main molecule being broken down? What is it broken down into?Glucose pyruvate (pyruvic acid)Does glycolysis require oxygen?No. It is anaerobic.
In the presence of oxygen, pyruvate is transported into the mitochondrial matrix, where it is eventually converted to carbon dioxideKREBS CYCLE
Krebs CycleThe series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle.
Pyruvate reacts with CoA to from acetyl-CoA. CO2 is released and NADH is formed.Acetyl CoA forms Citric AcidCitric Acid is broken down. Two CO2 molecules are released. One ATP, three NADH and one FADH2 are formed.
Remember, two pyruvates are formed during glycolysis. Both go through the Krebs cycle. So for every ONE glucose molecule, there are two turns of the Krebs Cycle!
Net Yield = -six CO2, -two ATP, -eight NADH, -two FADH2Krebs Cycle(Citric Acid Cycle)
Electron TransportFinal step in the breakdown of glucosePoint at which (the most) ATP is produced Produces 32 ATP
In eukaryotes, one molecule of glucose yields 36 ATP under ideal conditions
Cellular Respiration Totals
So what happens when oxygen is not available?
The cell can still undergo Glycolysis to produce ATP, but without oxygen the electron transport chain does not work, so waste builds up.
Cellular EnergyAnaerobic Respiration(Fermentation)The anaerobic pathway that follows glycolysisOccurs in the cytoplasmTwo main typesLactic acid fermentation Alcohol fermentation
Lactic AcidAlcoholOccurs in yeast and some bacteriaProduced by skeletal muscles when the body cant supply enough oxygen; causes fatigue and soreness
Still Unsure? Watch this three-part series.Part 1: Introduction and Glycolysis
Part 2: The Krebs Cycle
Part 3: Electron Transport Chain
JOURNALList the three parts of cellular respiration. At which stage is oxygen crucial? What type of pathway is this (aerobic or anaerobic)?
Comparing Photosynthesis and Cellular RespirationPhotosynthesis removes carbon dioxide from the atmosphere and cellular respiration puts it back. Photosynthesis releases oxygen into the atmosphere, and cellular respiration uses that oxygen to release energy from food.
Comparing photosynthesis and cellular respiration
Quick lab, page 264How does exercise affect disposal of wastes from cellular respiration?After completing the lab, read pages 264-265 in your textbook for further information.
JOURNALCreate a table or diagram that demonstrates the processes of photosynthesis and cellular respiration. Try to name what type of organism each process occurs in, which organelle each process takes place in, what is needed for each process and what is a result of each process (what goes in, what comes out?)