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Example Question #131 : Catabolic Pathways And Metabolism
Which of the following processes occurs in the cytoplasm of a cell?
All of these occur in the cytoplasm
Glycolysis
Krebs cycle
Oxidative phosphorylation
Electron transport chain
Glycolysis
Glycolysis is the only of the above choices that occurs in the cytoplasm. The remaining occur in different parts of the mitochondria. The Krebs cycle occurs in the mitochondrial matrix. Both oxidative phosphorylation and the electron transport chain occur along the inner mitochondrial membrane.
Example Question #51 : Glycolysis
When during cellular respiration is created?
The Krebs cycle
The electron transport chain
Glycolysis
The non-oxidative phase of the pentose phosphate pathway
The oxidative phase of the pentose phosphate pathway
The oxidative phase of the pentose phosphate pathway
in unrelated to the Krebs cycle and the electron transport chain.
is produced during the pentose phosphate pathway, which is a branch off of glycolysis. The first phase of the pentose phosphate pathway is called the oxidative phase, and is where
is created. During the second phase, five-carbon sugars are created, the most important being ribose-5-phosphate.
Example Question #133 : Catabolic Pathways And Metabolism
Which statement is false regarding glycolysis?
2 NADH are produced
2 Pyruvate are produced.
Hexokinase catalyzes the conversion of glucose to glucose-6-phosphate.
Every step is irreversible.
Glucose is oxidized.
Every step is irreversible.
In glycolysis, glucose is oxidized, and the final products are 2 pyruvate, 2 ATP, and 2 NADH. The first step is irreversible, and is the conversion of glucose to glucose-6-phosphate by the enzyme hexokinase. The only remaining answer choice is "every step is irreversible." That statement is false. Steps 1,3, and 10 are irreversible, but the remaining steps are reversible.
Example Question #134 : Catabolic Pathways And Metabolism
How does fructose get metabolized by the body?
I. Fructose-1-phosphate is converted to glyceraldehyde.
II. Fructose is converted to fructose-1-phosphate by fructokinase in the liver.
III. Glyceraldehyde-3-phosphate from fructose is used in both glycolysis and gluconeogenesis.
II and III
I, II, and III
I and III
III only
II only
I, II, and III
Fructose is mainly metabolized by the liver from sugar, honey and fruits. Fructose can be converted to fructose-1-phosphate and then to dihydroxyacetone phosphate (DHAP) and glyceraldehyde.
Example Question #141 : Catabolic Pathways And Metabolism
Which of the following is false of NADPH?
It is created during the oxidative phase of the pentose phosphate pathway.
It is typically consumed during anabolic reactions.
All of these
It is easily discriminated from NADH in the body.
It protects the cell from oxidative stress.
All of these
NADPH is a molecule created during the oxidative phase of the pentose phosphate pathway. It is used in anabolic reactions, specifically in the formation of fatty acids. Another important role is that it acts as an anti-oxidant. Finally, NADPH is easily discriminated from NADH in the body because of an additional attached phosphate group. This allows the body to regulate the concentrations of the two similar molecules independently.
Example Question #142 : Catabolic Pathways And Metabolism
Which of the following are true about lactate dehydrogenase?
I. Lactate dehydrogenase converts reversibly pyruvate to lactate under anaerobic conditions.
II. Lactate dehydrogenase is also important in gluconeogenesis by converting lactate to pyruvate.
III. Lactate dehydrogenase oxidizes NADH to prevent its accumulation in anaerobic conditions.
IV. There are 5 lactate dehydrogenase isoenzymes that differ in their tissue distribution.
I, II, and III
I and IV
I and II
I, II, III and IV
II, III, and IV
I, II, III and IV
A dehydrogenase is an enzyme that removes hydrogen ions from a molecule, thereby oxidizing it.Lactate dehydrogenase converts lactate to pyruvic acid and NADH to NAD+ in glycolysis.The reaction is reversible, in which case it provides pyruvate for gluconeogenesis.Lactate dehydrogenase is present in most tissues with some isoforms more frequent than others. For example, isoenzyme LDH-1 is found in the heart, red blood cells, and brain.
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