Regulation of Energy Metabolism Part 3
48 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary storage form of excess fructose in the liver?

  • Glycogen
  • Glucose
  • Triglycerides (correct)
  • Proteins

    • Fructose stimulates a significant insulin release, similar to glucose.

    False (B)

    What is the name of the lipoprotein that carries triglycerides from the liver to peripheral tissues?

    Very-low-density lipoprotein (VLDL)

    Fructose is a ______, the simplest form of carbohydrate.

    <p>monosaccharide</p> Signup and view all the answers

    What is the primary fate of accumulated citrate in the liver during high fructose consumption?

    <p>Converted to acetyl CoA for fatty acid synthesis (B)</p> Signup and view all the answers

    Match the following components to their roles in triglyceride synthesis from fructose:

    <p>DHAP = Provides the glycerol backbone for the triglyceride molecule Acetyl CoA = Derived from citrate, used in fatty acid synthesis VLDL = Transports triglycerides from the liver to peripheral tissues Citrate = Intermediate in the Krebs cycle, transported from mitochondria to cytosol</p> Signup and view all the answers

    All cells in the body can utilize fructose for energy production as they do with glucose.

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

    What is the name of the enzyme that converts citrate to acetyl CoA in the cytosol?

    <p>Citrate lyase</p> Signup and view all the answers

    What is gluconeogenesis primarily used for in the human body?

    <p>Synthesizing glucose from non-carbohydrate sources (B)</p> Signup and view all the answers

    Gluconeogenesis occurs mainly in the pancreas.

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

    Name one type of molecule that can be used in gluconeogenesis.

    <p>Amino acids</p> Signup and view all the answers

    Gluconeogenesis is often referred to as ________ glucose production.

    <p>endogenous</p> Signup and view all the answers

    Which of the following is the first step of gluconeogenesis?

    <p>Carboxylation of pyruvate to form oxaloacetate (B)</p> Signup and view all the answers

    ATP is required in the process of gluconeogenesis.

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

    What is the end product of gluconeogenesis that is released into the bloodstream?

    <p>Glucose</p> Signup and view all the answers

    Match the following metabolic processes with their definitions:

    <p>Gluconeogenesis = Synthesis of glucose from non-carbohydrate sources Glycolysis = Breakdown of glucose into components Endogenous Glucose Production = Internal glucose synthesis ATP = Energy currency of the cell</p> Signup and view all the answers

    Which of the following fatty acids has an aliphatic tail of 6 to 12 carbons?

    <p>Medium-chain fatty acids (B)</p> Signup and view all the answers

    Saturated fatty acids contain one or more double bonds in their structure.

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

    What is the common example of a saturated fatty acid mentioned?

    <p>stearic acid</p> Signup and view all the answers

    Very long chain fatty acids have aliphatic tails containing _____ or more carbons.

    <p>22</p> Signup and view all the answers

    Which configuration of unsaturated fatty acids causes the chain to bend and restricts conformational freedom?

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

    Match the following types of fatty acids with their characteristics:

    <p>Short-chain fatty acids = Up to 5 carbons Medium-chain fatty acids = 6 to 12 carbons Long-chain fatty acids = 13 to 21 carbons Very long chain fatty acids = 22 or more carbons</p> Signup and view all the answers

    The trans configuration of unsaturated fatty acids allows the adjacent hydrogen atoms to lie on the same side of the chain.

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

    Name a fatty acid that is known for having a pronounced bend due to multiple cis double bonds.

    <p>linoleic acid</p> Signup and view all the answers

    What is one way fatty acids are utilized in the body?

    <p>They are converted into ATP and heat. (D)</p> Signup and view all the answers

    Fatty acids can only be used for energy storage and not for gene regulation.

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

    What are the two-carbon molecules generated from the breakdown of fatty acids called?

    <p>Acetyl-CoA</p> Signup and view all the answers

    Fatty acids are transported intracellularly by _____ proteins.

    <p>fatty acid-binding</p> Signup and view all the answers

    Match the fatty acid function with its description:

    <p>Signal-transduction pathways = Regulating cellular responses to signals Energy storage = Stored as triacylglycerols in adipose tissues Hormone composition = Essential components of hormone structure Modification of proteins = Changing protein function and activity</p> Signup and view all the answers

    Which of the following indicates a saturated fatty acid?

    <p>Contains only single carbon-to-carbon bonds (A)</p> Signup and view all the answers

    Fatty acids can be formed from glucose under conditions of excess energy.

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

    What are the specialized fat cells that store energy in the form of triacylglycerols called?

    <p>Adipose tissue</p> Signup and view all the answers

    Which enzyme is responsible for converting fructose-6-phosphate to glucose-6-phosphate?

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

    Gluconeogenesis primarily occurs in the skeletal muscle.

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

    Name one enzyme that is unique to gluconeogenesis.

    <p>Pyruvate carboxylase</p> Signup and view all the answers

    Fructose is a dietary monosaccharide that can be found in __________.

    <p>fruits and vegetables</p> Signup and view all the answers

    What is the primary function of gluconeogenesis?

    <p>To maintain blood glucose levels during fasting or exercise. (A)</p> Signup and view all the answers

    Match each enzyme to its respective function in gluconeogenesis:

    <p>Pyruvate carboxylase = Converts pyruvate to oxaloacetate PEP carboxykinase = Converts oxaloacetate to phosphoenolpyruvate Fructose 1,6-bisphosphatase = Converts fructose 1,6-bisphosphate to fructose 6-phosphate Glucose 6-phosphatase = Converts glucose-6-phosphate to glucose</p> Signup and view all the answers

    Uptake of fructose by the liver is regulated by insulin.

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

    Glucose is formed from glucose-6-phosphate in the cell’s __________ via the enzyme glucose-6-phosphatase.

    <p>endoplasmic reticulum</p> Signup and view all the answers

    What is the first step in the catabolism of fructose?

    <p>Phosphorylation by fructokinase (A)</p> Signup and view all the answers

    Fructose 1-phosphate is not further metabolized in the liver.

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

    Which enzyme is responsible for splitting fructose 1-phosphate?

    <p>Aldolase B</p> Signup and view all the answers

    The triose __________ is produced from glyceraldehyde by triokinase.

    <p>glyceraldehyde 3-phosphate</p> Signup and view all the answers

    Match the enzymes with their functions in fructose metabolism:

    <p>Fructokinase = Phosphorylates fructose Aldolase B = Splits fructose 1-phosphate Glycerol 3-phosphate dehydrogenase = Reduces DHAP to glycerol 3-phosphate Glyceraldehyde kinase = Converts glyceraldehyde to glyceraldehyde 3-phosphate</p> Signup and view all the answers

    Which of the following statements is true regarding fructose metabolism?

    <p>Fructose 1-phosphate needs to be hydrolyzed for further metabolism. (A)</p> Signup and view all the answers

    Glycogen synthesis from fructose is less efficient than from glucose.

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

    What happens to the intermediates of fructose metabolism once liver glycogen is replenished?

    <p>They are directed toward triglyceride synthesis.</p> Signup and view all the answers

    Study Notes

    Regulation of Energy Metabolism (Part 3)

    • Gluconeogenesis is the creation of new glucose from non-carbohydrate sources.
    • It's the opposite of glycolysis, which breaks down glucose.
    • Gluconeogenesis primarily takes place in the liver, with smaller amounts occurring in the kidneys and small intestine.
    • This process is important for maintaining blood sugar levels during periods without food intake (e.g., fasting or starvation).

    Gluconeogenesis Pathway

    • The pathway begins in the mitochondria or cytoplasm of the liver or kidneys.
    • Two pyruvate molecules are carboxylated to form oxaloacetate, needing one ATP molecule.
    • Oxaloacetate is reduced to malate by NADH for transport out of the mitochondria.
    • Malate is oxidized back to oxaloacetate.
    • Oxaloacetate forms phosphoenolpyruvate using the enzyme PEPC.
    • Phosphoenolpyruvate converts to fructose-1,6-bisphosphate and then to fructose-6-phosphate
    • Fructose-6-phosphate turns into glucose-6-phosphate with phosphoglucoisomerase.
    • Glucose-6-phosphate is converted to glucose by the enzyme glucose-6-phosphatase in the endoplasmic reticulum.
    • In this process ATP becomes ADP.

    Gluconeogenesis Functions

    • Human bodies produce glucose to maintain healthy blood sugar (for ATP production in cells).
    • Gluconeogenesis happens when a person hasn't eaten in a while (during periods of starvation or prolonged exercise).
    • The body utilizes molecules like amino acids, lactate, pyruvate, and glycerol when carbohydrate sources are limited.
    • Glucose produced through gluconeogenesis is released into the bloodstream for energy use by other body parts.
    • This process is also sometimes called endogenous glucose production (EGP).

    Fructose Metabolism

    • Fructose is a naturally occurring sugar found in fruits, vegetables, and sucrose.
    • It is a monosaccharide.
    • Fructose metabolism is different than glucose.
    • The first step is phosphorylation of fructose to fructose-1-phosphate by fructokinase.
    • Fructose-1-phosphate can be isomerized into glyceraldehyde-3-phosphate or converted into glycerol 3-phosphate. The resulting intermediate will be part of the gluconeogenic or fatty acid synthesis pathways.
    • Fructolysis is a specific pathway for fructose breakdown.
    • Fructose, unlike glucose, doesn't signal a substantial insulin release.
    • Fructose is transported into cells via a different transporter than glucose.

    Fatty Acids

    • Fatty acids are carboxylic acids with long aliphatic chains.

    • They can be saturated (no C=C double bonds) or unsaturated (one or more C=C double bonds, either cis or trans).

    • Unsaturated fatty acids can have cis or trans configurations, affecting their rigidity and bendability.

    • Unsaturated fatty acids with many cis bonds bend more.

    • These are crucial components of cell membranes and triglycerides.

    • Fatty acids are crucial for energy sources and storage.

    • Fatty acid metabolism results in ATP production, gene expression, and the creation of different lipid classes for energy storage.

    • The process begins with uptake of free fatty acids via fatty acid-binding proteins, activation to acyl-CoA and then transport to mitochondria or peroxisomes.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Regulation Of Energy Metabolism (Part 3) PDF

    Description

    This quiz explores the process of gluconeogenesis, detailing how new glucose is created from non-carbohydrate sources. It highlights the significance of this metabolic pathway in maintaining blood sugar levels during fasting. Test your understanding of the steps involved and the locations where gluconeogenesis occurs in the body.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser