GRE Subject Test: Biochemistry, Cell, and Molecular Biology : Help with Catabolism
Study concepts, example questions & explanations for GRE Subject Test: Biochemistry, Cell, and Molecular Biology
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Example Questions
Example Question #1 : Help With Catabolism
__________ is an enzyme used to help break down glycogen. The end product is __________.
Glycogen phosphatase . . . glucose-6-phosphate
Glycogen phosphatase . . . glucose-1-phosphate
Glycogen phosphorylase . . . glucose-1-phosphate
Glycogen phosphorylase . . . glucose-6-phosphate
Glycogen phosphorylase . . . glucose-1-phosphate
Phosphorylases are enzymes that attach phosphate groups to acceptors by breaking a chemical bond. Phosphatases are enzymes that remove phosphate groups.
Glycogen catabolism occurs by activation of glycogen phosphorylase, which then catalyzes the reaction of glycogen into glucose-1-phosphate (and a glycogen chain that is one glucose shorter).
Example Question #2 : Help With Catabolism
__________ helps transfer fatty acids into the mitochondrial matrix.
Fatty acid transferase
Carnitine
Biotin
Acyl-CoA
Carnitine
Carnitine is ultimately responsible for helping fatty acids enter into the mitochondrial matrix. Acyl-CoA is actually the activated fatty acid that is being transferred. Carnitine reacts with acyl-CoA, and the newly formed acyl carnitine is moved into the mitochondrial matrix by a translocase.
Biotin is a vitamin that has many functions, including aiding in fatty acid synthesis. There is no protein that is actually called fatty acid transferase.
Example Question #3 : Help With Catabolism
Which of the following statements about catabolic pathways are not true?
Polysaccharides eventually release energy in the form of NADH and ATP
Macromolecules are only involved in catabolic pathways
Lipids are broken down into glycerol and fatty acids
Polysaccharides are hydrolyzed to glucose, which can then pass through glycolysis and the citric acid cycle
Proteins are hydrolyzed into their amino acids, which feed into glycolysis or the citric acid cycle
Macromolecules are only involved in catabolic pathways
Macromolecules, such as peptides, polysaccharides, lipids, and proteins can be broken down to provide energy as well as operate in reverse through anabolic pathways. Anabolic and catabolic processes can occur simultaneously. All of the other answers are true.
Example Question #4 : Help With Catabolism
Which of the following cellular processes is defined as a catabolic reaction?
Gylcolysis
Gluconeogenesis
Protein synthesis
Glycogenesis
Gylcolysis
A catabolic reaction is defined as a reaction in which a large molecule is broken down into smaller subunits. Of the following options, all listed are anabolic except for glycolysis. Glycolysis is the process of converting a glucose molecule into 2 pyruvate molecules, which classifies it as catabolic in nature.
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