Biochemistry 460 Lecture 26 - Glycolysis 1
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- What is lactose intolerance caused by?
- It is caused by reduced levels of the digestive enzyme lactase, which is required to hydrolize the dissacharide sugar lactose to form glucose and galactose.
- What does purified lactase enzyme, which is commercially available, accomplish for its users?
- It reduces the symptoms that occur when bacteria of the Lactobacillus family convert lactose to methane and hydrogen gases in the small intestine.
- What 3 reasons causes glycolysis to be considered one of the core metabolic pathways in nature?
- Glycolytic enzymes are highly conserved amongst all living organisms. It is the primary pathway for ATP generation under anaerobic conditions. Metabolites of glycolysis are precursors for a large number of interdependent pathways, including mitochondrial ATP synthesis.
- What does Glycolysis accomplish for the cell?
- It generates a small amount of ATP which is critical under anaerobic conditions. It generates pyruvate, a precursor to acetyl CoA, lactate, and ethanol (yeast)
- What is the overall net reaction of glycolysis?
- Glucose + 2 NAD+ + 2ADP + 2 Pi --> 2 Pyruvate + 2 NADH + 2H+ + 2 ATP + 2 H2O
- What are the key enzymes in glycolysis?
- Hexokinase - commitment step in glycolysis, inhibited by glucose-6-P. Phosphofructokinase - activated by AMP and F-2,6-BP, inhibited by ATP and citrate. Pyruvate kinase - activated by AMP and fructose-1,6-bisphosphate, inhibited by ATP and acetyl CoA
- What are examples of glycolysis in real life?
- A deficiency in the hexokinase-related enzyme glucokinase, leads to a rare form of diabetes which is caused by the inability of liver and pancreatic cells to phosphorylate glucose inside cells when blood glucose levels are elevated.
- What does glycolysis generate?
- It generates a small amount of ATP
- Where does glycolysis take place?
- It takes place entirely in the cytosol
- Does glycolysis require oxygen?
- It does not require oxygen
- Does complete oxidation of glucose to CO2 and H2O require oxygen?
- Yes
- How many ATP does glycolysis yield?
- It yields 2 ATP out of the total 32 (6%)
- Coupled reactions accomplish what for glycolysis?
- Coupled reactions allow reactions that would normally have positive delta G values to instead have negative values.
- The five enzymatic reactions of glycolysis first accomplish what task?
- Using ATP as the phosphate donor, they create phosphorylated compounds that are negatively charged and cannot diffuse out of the cell.
- The five enzymatic reactions of glycolysis accomplish what after using ATP as the phosphate donor to create phosphorylated compounds?
- The aldolase reaction in step 4 splits the six carbon fructose-1,6-BP compound into two halves.
- What is reaction 2 of glycolysis?
- It is the isomerization of glucose-6-P to fructose-6-P by phosphoglucose isomerase
- What does phosphoglucose isomerase accomplish?
- It interconverts an aldose and a ketose through a multi-step pathway that involves opening and closing of the ring structure.
- What is reaction 4 of glycolysis?
- It is the cleavage of fructose-1,6-BP into glyceraldehyde-3-P and dihydroxyacetone-P by aldolase
- What is reaction 5 of glycolysis?
- It is the isomerization of dihydroxyacetone-P to glyceraldehyde-3-P by triose phosphate isomerase.