Biochemistry Quiz: Krebs Cycle & Glycogen Metabolism

<p>It inhibits glycogenolysis. (B)</p> Signup and view all the answers

<p>Glucagon (D)</p> Signup and view all the answers

<p>It's the active glucose form incorporated into glycogen. (A)</p> Signup and view all the answers

<p>It acts as a storage mechanism for glucose, preventing dramatic changes in osmotic pressure. (C)</p> Signup and view all the answers

<p>Glucagon and adrenaline (D)</p> Signup and view all the answers

<p>To provide energy for muscle contraction (B)</p> Signup and view all the answers

<p>Leucine (C)</p> Signup and view all the answers

<p>It allows the body to produce glucose from non-carbohydrate sources (D)</p> Signup and view all the answers

<p>The kidneys (C)</p> Signup and view all the answers

<p>To produce NADPH and precursors for nucleotide synthesis (D)</p> Signup and view all the answers

<p>To facilitate an ordered sequence of biochemical reactions (D)</p> Signup and view all the answers

<p>Ribulose 5-phosphate (D)</p> Signup and view all the answers

<p>To convert lactate from muscles into glucose in the liver. (B)</p> Signup and view all the answers

<p>They release energy and reducing power while synthesizing ATP. (B)</p> Signup and view all the answers

<p>Glycogen and glucose (C)</p> Signup and view all the answers

<p>Reductive and energy consuming (C)</p> Signup and view all the answers

<p>They have mixed catabolic and anabolic functions (A)</p> Signup and view all the answers

<p>A molecule involved in the synthesis, degradation, and conversion of essential metabolites. (D)</p> Signup and view all the answers

<p>Two molecules of pyruvate and molecules of ATP and NADH. (C)</p> Signup and view all the answers

<p>In the cytosol (B)</p> Signup and view all the answers

<p>Because it both produces energy and generates metabolic intermediates. (C)</p> Signup and view all the answers

<p>To rapidly produce energy in muscle tissue during intense activity. (A)</p> Signup and view all the answers

<p>It diffuses into the blood and is transported to the liver. (C)</p> Signup and view all the answers

<p>Lactate dehydrogenase (A)</p> Signup and view all the answers

<p>Muscle cells lack the enzyme glucose-6-phosphatase. (A)</p> Signup and view all the answers

<p>To convert lactate back into glucose via gluconeogenesis. (A)</p> Signup and view all the answers

<p>Pyruvate (A)</p> Signup and view all the answers

<p>Beta-oxidation (B)</p> Signup and view all the answers

<p>Phosphoenolpyruvate carboxykinase (PEPCK) (A)</p> Signup and view all the answers

<p>To convert glucose 6-phosphate into free glucose. (A)</p> Signup and view all the answers

<p>Absorption of extracellular fluid. (D)</p> Signup and view all the answers

<p>To act as an acceptor and transporter of amino groups. (B)</p> Signup and view all the answers

<p>Covalent bond. (D)</p> Signup and view all the answers

<p>Alanine and α-ketoglutarate. (D)</p> Signup and view all the answers

<p>It is both a cytosolic and mitochondrial enzyme. (B)</p> Signup and view all the answers

<p>It increases their expression. (B)</p> Signup and view all the answers

<p>Lysine. (C)</p> Signup and view all the answers

<p>Carbamoyl phosphate synthetase I (D)</p> Signup and view all the answers

<p>N-acetylglutamate (C)</p> Signup and view all the answers

<p>Citrulline (B)</p> Signup and view all the answers

<p>Argininosuccinate synthetase (B)</p> Signup and view all the answers

<p>Fumarate (C)</p> Signup and view all the answers

<p>Arginase (B)</p> Signup and view all the answers

<p>Birds and reptiles (B)</p> Signup and view all the answers

<p>Metabolism (B)</p> Signup and view all the answers

A sequence of chemical reactions that occur in organisms, where the final product of one reaction serves as the initial substrate for the next reaction.

Metabolic pathways that release energy and reducing power (like NADH) producing ATP. Examples are glycolysis and beta-oxidation

Metabolic pathways that use energy (ATP) and reducing power to synthesize complex molecules. Examples are gluconeogenesis and the Calvin cycle.

Metabolic pathways that can act as both catabolic and anabolic. Example: the Krebs cycle, which generates both energy (ATP) and reducing power, as well as building blocks for biosynthesis.

Central metabolic pathways that participate in the synthesis, degradation, and conversion of essential metabolites.

A metabolic pathway that oxidizes glucose to produce energy for the cell. It occurs in the cytosol and involves ten consecutive enzymatic reactions converting glucose into two pyruvate molecules.

The ability to do work and cause change in matter. It takes different forms, such as heat, light, electricity, and movement.

A set of interconnected metabolic pathways that enable interconversions between metabolic intermediates at the beginning of anabolic pathways or at the end of catabolic pathways.

A cyclical metabolic pathway, occurs in the mitochondria, to produce energy in the form of ATP. It requires oxygen and involves the oxidation of acetyl-CoA.

The process of breaking down glycogen into glucose, releasing glucose into the bloodstream.

The process of synthesizing glycogen from glucose, storing glucose in the form of glycogen.

A metabolic pathway that converts non-carbohydrate precursors, such as lactate, pyruvate, glycerol, and amino acids, into glucose.

A hormone that stimulates glycogenolysis, increasing blood glucose levels.

A hormone that stimulates glycogenesis, decreasing blood glucose levels.

A storage form of glucose found primarily in the liver and muscles. It is a branched polymer of glucose, acting as a reservoir for glucose.

Gluconeogenesis mainly occurs in the liver (90%) and kidneys (10%), ensuring a constant supply of glucose for the brain, muscles, and red blood cells.

The Pentose Phosphate Pathway (PPP) is a linear metabolic pathway that creates NADPH, essential for reducing power, and ribose-5-P, a crucial precursor for nucleotide synthesis.

The first part of the PPP converts glucose into a pentose sugar called ribulose 5-P, generating NADPH along the way. The second part involves rearranging sugars to create precursors for glucose synthesis.

This cycle involves a continuous exchange of glucose and lactate between the muscle and liver. During intense exercise, muscles produce lactate, which is sent to the liver for conversion back into glucose and released back into the bloodstream.

Muscle glycogen stores are used for muscle contraction, and glucose from the bloodstream can also be used as fuel. During intense exercise, when oxygen is limited, lactate is produced as a byproduct.

Glucose is the primary fuel source for the brain, and it requires a constant supply to function properly. Gluconeogenesis helps maintain blood glucose levels to ensure brain function.

Red blood cells rely entirely on glucose for their energy needs. Gluconeogenesis ensures a steady supply of glucose to support their essential functions.

A metabolic pathway where lactate produced in muscles during anaerobic glycolysis is transported to the liver and converted back into glucose for energy.

The Cori Cycle allows for the rapid production of energy in muscles, particularly during high-intensity exercise when oxygen is limited.

During intense exercise, muscle cells produce lactate as a byproduct of anaerobic glycolysis. This lactate diffuses into the blood and travels to the liver.

In the liver, the lactate is converted back into pyruvate, which can then be used for gluconeogenesis, the process of creating new glucose.

Muscle cells lack the enzyme glucose-6-phosphatase, which is necessary for glucose to leave the cell. This means that glucose produced in the Cori Cycle cannot be directly released back into the bloodstream from muscle cells.

The Cori Cycle prevents lactic acidosis in muscle cells by removing lactate from the muscle and converting it into glucose in the liver.

The Cori Cycle links glycolysis, glycogenolysis, gluconeogenesis, and lactic acid fermentation. It is a complex pathway involving multiple metabolic processes.

The Cori Cycle is crucial for maintaining muscle function during strenuous activity. It ensures that muscle cells have a continuous supply of energy, even in low oxygen conditions.

An enzyme that catalyzes the first step of the urea cycle, converting ammonia and bicarbonate to carbamoyl phosphate.

A compound involved in the urea cycle that provides the nitrogen atom for urea synthesis. It is formed from glutamate.

An enzyme that catalyzes the second step of the urea cycle, transferring the carbamoyl group from carbamoyl phosphate to ornithine, forming citrulline.

An amino acid that serves as a carrier in the urea cycle, carrying ammonia to be converted into urea.

An amino acid produced in the urea cycle when ornithine combines with carbamoyl phosphate.

An enzyme that catalyzes the third step of the urea cycle, where citrulline condenses with aspartate to form argininosuccinate.

An unstable intermediate formed during the third step of the urea cycle when citrulline reacts with aspartate.

An enzyme that catalyzes the fourth step of the urea cycle, where argininosuccinate is broken down into arginine and fumarate.

The process of transferring the α-amino group from an amino acid to an α-ketoacid, resulting in the amino acid becoming a ketoacid and the ketoacid accepting the amino group becoming the corresponding amino acid.

A coenzyme essential for transaminase activity, firmly bound to the enzyme (covalent bond). It acts as an acceptor and transporter of the amino group.

An intermediate compound formed when pyridoxal phosphate binds to an amino acid, crucial for transferring the amino group.

The most abundant transaminase found in the liver and heart, catalyzing the transfer of an amino group from glutamate to pyruvate, producing alanine and α-ketoglutarate.

Another transaminase found in both the cytosol and mitochondria, essential for the transfer of an amino group from glutamate to oxaloacetate, producing aspartate and α-ketoglutarate.

Amino acids obtained from various sources like food, protein breakdown, and de novo synthesis.

The process of removing an amino group from an amino acid, resulting in the formation of a ketoacid and ammonia.

A process where an amino group is transferred from one molecule to another, often involving the use of transaminases, such as GPT/ALT and GOT/ASAT.