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occurring in the absence of oxygen.
Involving occurring in the presence of oxygen.
Mitochondria cannot detoxify free radicals so they rely on antioxidant enzymes and vitamins in the cells cytoplasm to do that.
oxygen-requiring metabolic path that breaks down carbohydrates to produce ATP.
Set of reactions in which glucose or another sugar is broken down to two pyruvate for a net yield of two ATP.
three-carbon end product of glycolysis
Metabolic pathway that breaks down carbohydrates to produce ATP; does not require oxygen.
How do cells access the chemical energy in carbohydrates?
- Most cells convert the chemical energy of carbohydrates to the chemical energy of ATP by aerobic respiration or fermentation. Aerobic respiration and fermentation pathways start in cytoplasm, with glycolysis.
- Fermentation is anaerobic and ends in the cytoplasm.
- Aerobic respiration requires oxygen. in eukariotes, it ends in mitochondria.
A reaction that transfers a phosphate group from a substrate directly to ADP, thus forming ATP.
What is glycolysis?
- Glycolysis is the first stage or carbohydrate breakdown in both aerobic respiration and fermentation.
- the reactions of glycolysis occurs in the cytoplasm.
- Glycolysis converts one molecule of glucose to two molecules of pyruvate, with a net energy yield of two ATP . Two NADH also form.
cycle pathway that, along with acetyl-CoA formation,breaks down pyruvate to carbon dioxide during aerobic respiration.
What Happens during the second stage of aerobic respiration?
- the second stage of aerobic resperation. acetyl-CoA formation and the Krebs cycle, occurs in the inner compartment(matrix) of mitochondria.
- the pyruvate that formed in glycolysis is converted to acetyl-CoA and CO2. Kerbs cycle reactions break down the acetyl-CoA and CO2.
- For two pyruvate molecules broken down in the second-stage reactions, two ATP form, ten coenzymes (eight NAD+;twoFAD) are reduced.
What happens during the third stage of aerobic respiration?
- In aerobic respirations third stage, electron transfer phosphorylation, energy released by electrons flowing through electron transfer chains is ultimately captured in the attachment of phosphate to ADP.
- the third stage reactions begin when coenzymes that were reduced in the first and second stages deliver electrons and hydrogen ions to electron transfer chains in the inner mitochondrial membrane.
- Energy released by electrons as they pass through electron transfer chains is used to pump H+ from the mitochondrial matrix to the intermembrane space. the H+ gradient that forms across the inner mitochondrial membrane drives the flow of hydrogen ions through ATP synthases, which results in ATP formation.
- About thirty-two ATP form during the thirs stage reactions, so a typical net yield of all three stages of aerobic respiration is thirty-six ATP per glucose.
Anaerobic carbohydrates breakdown pathway that produces ATP and ethanol. Begins with glycolysis; end reactions regenerate NAD+ so glycolysis can continue.
Anaerobic carbohydrate breakdown pathway that produces ATP and lactate.
What is Fermentation?
- ATP can form by carbohydrate breakdown in fermentation pathways, which are anaerobic.
- The end product of lactate fermentation is lactate. the end product of alcoholic fermentation is ethanol. both pathways have a net yield of two ATP per glucose molecule. the ATP forms during plycolysis.
- Fermentation reactions regenerate the coenzyme NAD+ without which glycolysis (and ATP production) would stop.
Can the body use organic molecules other than glucose for energy?
- Complex carbohydrates, fats, and proteins can be oxidized in aerobic respiration to yield ATP.
- First the digestive system and then individual cells convert molecules in food into intermediates of glycolysis or Kerbs cycle.