Cell Respiration Ch 7 Objectives: Identify the 2 major steps of cellular respiration Describe the major events in glycolysis Compare lactic acid fermentation with alcoholic fermentation Calculate the efficiency of glycolysis Cellular respiration is the process by which cells break down Both autotrophs and heterotrophs use cellular respiration to make CO2 and water from The of cellular respiration are the in photosynthesis; conversely, the of photosynthesis are in cellular respiration. Cellular respiration can be divided into two stages: Glycolysis Cellular respiration begins with, which takes place in the of cells. *(Cytoplasm is a collective term for the cytosol plus the organelles suspended within the cytosol.) During glycolysis, one -carbon glucose molecule is oxidized to form three-carbon pyruvic acid molecules. A net yield of molecules is produced for every molecule of glucose that undergoes glycolysis.
Fermentation If is not present, some cells can convert pyruvic acid into other compounds through additional biochemical pathways that occur in the cytosol. The combination of glycolysis and these additional pathways is. Fermentation does not produce ATP, but it does regenerate NAD+, which allows for the continued production of ATP through glycolysis. Cell respiration!!!! Fermentation
Lactic Acid Fermentation In lactic acid fermentation, an enzyme converts pyruvic acid into another three-carbon compound, called lactic acid. Alcohol Fermentation Some plants and unicellular organisms, such as yeast, use a process called alcoholic fermentation to convert pyruvic acid into ethyl alcohol and CO2.
Examples of Lactic acid fermentation: Examples of Alcohol fermentation: Through glycolysis, only about 2 percent of the energy available from the oxidation of glucose is captured as ATP. Much of the energy originally contained in glucose is still held in pyruvic acid. Glycolysis alone or as part of fermentation is not very efficient at transferring energy from glucose to ATP. Use Chapter 7, section 2 to fill in the rest of the notes! Aerobic respiration has 2 major stages: and What is chemiosmosis? (use pg 137) In prokaryotes, the reactions of the Kreb Cycle and the ETC take place in the. In Eukaryotic cells, these reactions take place inside the. The pyruvic acid made in diffuses across the double membrane of a mitochondrion and enters the mitochondrial matrix. What is the mitochondrial matrix? When pyruvic acid enters this matrix, it reacts with a molecule called coenzyme A to form acetyl coenzyme A (acetyl CoA).
Make a quick sketch of figure 7-9 on page 138. What is the Kreb Cycle? The Kreb Cycle It has 5 main steps: Step 1: A 2-carbon molecule of acetyl CoA combines with a 4-carbon compound, oxaloacetic acid to make a 6-carbon compound called. What does this reaction regenerate? Step 2: Citric acid releases a & to form a 5-carbon compound. Citric acid is oxidized because a hydrogen atom was lost with its electron. The electron in the hydrogen atom is transferred to NAD+ reducing it to. Step 3: The 5-carbon compound formed in step 2 also releases a & a forming a 4-carbon compound. Again, NAD+ is reduced to NADH. A molecule of is also made from ADP.
Step 4: The 4-carbon compound formed in step 3 releases a hydrogen atom to form another 4-carbon compound. THIS TIME...the hydrogen atom is used to reduce. Step 5: The 4-carbon compound formed in step 4 releases a hydrogen atom to regenerate, which keeps the kreb cycle operating! The electron in the hydrogen atom reduces NAD+ to NADH. One glucose molecule is broken down into turns of the Kreb Cycle! These 2 turns produce how many CO2 molecules? ATP molecules? NADH molecules? FADH2 molecules? What happens to the CO2? Where does the ATP go? How many ATP are made from the Kreb Cycle? In Glycolysis, there are 2 NADH produced. The conversion of pyruvic acid to acetyl CoA addes 2 more. Added to the 6 NADH from Krebs, that is a total of 10 NADH molecules for every glucose molecule. These 10 NADH molecules and the 2 FADH2 molecules drive the next stage of aerobic respiration.