Choose the single correct response in each of the following questions 1) The act
ID: 195966 • Letter: C
Question
Choose the single correct response in each of the following questions 1) The activity of the enzyme hexokinase is directly regulated by a. glucose b. glucose-6-phosphate ATP d. citrate e. AMP 2) The Krebs Cycle a. can occur in red blood cells b. produces Acetyl Co c produces 3 NADH, 1 FADH, 1 ATP for every turn d. produces 3 molecules of ATP per cycle e. produces more FADH than NADH 3) After a meal, high levels of insulin would serve to in the liver a. increase glycogen synthase activity b. decrease glucokinase activity c. increase aldosterone release d. decrease the ICF 9smolarity of hepatocytes e. increase glycogen phosphorylase activity Glycolysis metabolism of glucose a. produces more ATP than does aerobic metabolism of glucose b. produces 1 pyruvate c. is regulated by the enzyme glucose-6-phosphatase d. generates 2 glyceraldehyde 3-phosphate molecules e. uses no ATP 5) The process where fats are broken down into glycerol and fatty acids is called a. elycerolyeis b. glycolysis c. lipogenesis d. lipolysis e. gluconeogenesis 6) Each single cycle of -oxidation produces a. glucose b. 1 NADH, 1 FADH, 1 Acetyl CoA c. 1 NADH, 1FADH, 1 ATP d. 3 NADH, 1 FADH, 1 ATP e. pyruvateExplanation / Answer
Q.1 the activity of hexokinase enzyme is regulated by b. Glucose 6 phosphate.
The reactions performed by hexokinase is irreversible, so it is very important to have these enzymes being regulated. Their activities are regulated by reversible bindings of allosteric effectors or by covalent modifications. It is regulated only by excess glucose 6 phosphate. If G6 accumulates in the cell there is feedback inhibition of hexokinase till G6 is consumed.
Q.2 Kreb cycle c. Produces 3 NADH, 1FADH, 1 ATP at each turn.
In the first step of the cycle, acetyl CoA combines with a 4 carbon acceptor molecule, oxaloacetate to form a 6 carbon molecule called citrate after a quick rearrangement, this 6 carbon molecule releases two of it's carbon in the form of carbon dioxide in a pair of similar reactions, producing a molecule of NADH each time. The remaining 4 carbon molecule undergoes a series of additional reactions, first making an ATP molecule or in some cells, reducing the electron carrier FAD to FADH2 and finally generating another NADH.
Q.4 b. Produces 1 pyruvate
Glycolysis is a very important step. Here, glucose is metabolized and is converted into pyruvate with generation of ATP molecules.
Q.5 d. Lipolysis.
It is the process where fats are broken down into fatty acids and glycerol. Predominantly it occur in the apidose tissue.