Pyruvate is reduced to lactate to recycle NADH, formed by glycolysis, to NAD+, so that glycolysis can continue. During strenuous activity, muscle tissue demands large quantities of ATP, compared with resting muscle.
Which of the following compound Cannot serve as the starting material for the synthesis of glucose via gluconeogenesis?
Fatty acids and ketogenic amino acids cannot be used to synthesize glucose. The transition reaction is a one-way reaction, meaning that acetyl-CoA cannot be converted back to pyruvate. As a result, fatty acids can’t be used to synthesize glucose, because beta-oxidation produces acetyl-CoA.
Which of the following is the cofactor involved in the reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase?
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a homotetrameric enzyme complex that catalyzes the oxidation of glyceraldehyde-3-phosphate and its subsequent phosphorylation to form 1,3-biphosphoglycerate (or d-glycerate 1,3-biphosphate). In the process, the cofactor NAD+ is reduced to NADH (Fig. 16.8).
Which of the following can serve as starting material for gluconeogenesis?
Gluconeogenesis begins in the mitochondria with the formation of oxaloacetate by the carboxylation of pyruvate. This reaction also requires one molecule of ATP, and is catalyzed by pyruvate carboxylase.
What is pyruvate fate?
The fate of pyruvate depends on the availability of oxygen. If oxygen is available, then pyruvate is shuttled into the mitochondria and continues through several more biochemical reactions called the “Citric Acid Cycle.” This is called aerobic metabolism.
What is the other fate of pyruvate?
Next, show that in aerobic conditions (the presence of oxygen), pyruvate has two possible fates: – The first is cellular respiration, which occurs in fed conditions – when glucose is abundant. – The second is gluconeogenesis, which occurs in fasting conditions – when glucose is in demand.
Which enzyme in glycolysis requires ATP as a substrate?
The first step of glycolysis is catalyzed by phosphofructokinase (PFK) and converts fructose-6-phosphate to fructose-1,6-bisphosphate. The two initial phosphorylations by hexokinase and PFK require ATP and are therefore irreversible. PFK is one of the key regulators in glycolysis.
Which of the following compounds Allosterically inhibits pyruvate kinase catalyzed reaction?
Phosphoglycerate kinase is the first step where ATP is produced First enzyme where substrate level phosphorylation occurs. Pyruvate is allosterically inhibited by: -ATP-Acetyl-CoA-Long chain fatty acids.
Which of the following enzyme’s activity is increased whenever the cell’s ATP supply is depleted?
Whenever the cell’s ATP supply is depleted, which of the following enzyme’s activity is increased? Explanation: Phosphofructokinase-1 is a regulatory enzyme; it is the major point of regulation in glycolysis. Its activity is increased whenever the cell’s ATP supply is depleted.
What stimulates gluconeogenesis?
Gluconeogenesis is stimulated by the diabetogenic hormones (glucagon, growth hormone, epinephrine, and cortisol). Gluconeogenic substrates include glycerol, lactate, propionate, and certain amino acids.
Which of the following is not the precursor of gluconeogenesis?
3. Which of the following is not the precursor of gluconeogenesis? Explanation: Only leucine or lysine is the substrate which is not used for gluconeogenesis as these amino acids produce only acetyl-CoA upon degradation. Animals cannot carry out gluconeogenesis by two acetyl carbon of acetyl-CoA.
What is the arrangement of skeletal muscle tissue?
Skeletal muscle tissue is arranged in bundles surrounded by connective tissue. Under the light microscope, muscle cells appear striated with many nuclei squeezed along the membranes.
How do skeletal muscles participate in thermal homeostasis?
Skeletal muscles generate heat as a byproduct of their contraction and thus participate in thermal homeostasis. Shivering is an involuntary contraction of skeletal muscles in response to lower than normal body temperature.
What are the characteristics of muscle tissue?
Muscle tissue is characterized by properties that allow movement. Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, such as two bones, contraction of the muscles cause the bones to move.
What percentage of your body is made up of skeletal muscle?
Forty percent of your body mass is made up of skeletal muscle. Skeletal muscles generate heat as a byproduct of their contraction and thus participate in thermal homeostasis.
