Cell Biology Lecture Week 5
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Questions and Answers

A condensation reaction that produces a polysaccharide is an endergonic reaction.

True

Which of the following is NOT a feature of ATP?

  • Adenine
  • Three phosphates
  • Inorganic phosphate (correct)
  • Ribose
  • Hydrolysis of ATP is an exergonic reaction.

    True

    Which of the following is NOT a product of glucose oxidation?

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

    How many carbons are in glucose?

    <p>6</p> Signup and view all the answers

    Where does glycolysis occur in the cell?

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

    During glycolysis, how many ATP are made through substrate-level phosphorylation?

    <p>4 ATP</p> Signup and view all the answers

    What happens to pyruvate if oxygen is not available for the cell?

    <p>It is reduced in fermentation</p> Signup and view all the answers

    Which coenzyme acts as an electron and hydrogen carrier during glycolysis?

    <p>NAD+</p> Signup and view all the answers

    The energy released by the hydrolysis of ATP is often used to drive unfavourable reactions forward.

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

    Glucose is fully oxidized during glycolysis.

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

    Which of the following is NOT a product of glycolysis?

    <p>NAD+</p> Signup and view all the answers

    Where in the cell is pyruvate produced?

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

    Which type of fermentation reduces pyruvate, regenerates NAD+ and produces a gas in the process?

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

    What is the primary function of mitochondria in cells?

    <p>To facilitate aerobic respiration and produce ATP</p> Signup and view all the answers

    Why are muscle cells rich in mitochondria?

    <p>To meet the high energy demands of muscle contraction</p> Signup and view all the answers

    What is the role of the endoplasmic reticulum (ER) in mitochondrial fission?

    <p>It marks the location where the mitochondrion will split</p> Signup and view all the answers

    What is the function of the protein Drp1 in mitochondrial fission?

    <p>It forms a helix around the mitochondrion, facilitating the splitting process</p> Signup and view all the answers

    What molecule provides energy for the mitochondrial fission process?

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

    What is the primary function of the cristae in mitochondria?

    <p>To increase the surface area for ATP production</p> Signup and view all the answers

    Which molecules are able to pass through the porins in the outer mitochondrial membrane?

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

    What is the primary function of cardiolipins in the inner mitochondrial membrane?

    <p>To insulate the inner membrane</p> Signup and view all the answers

    Which of the following statements about the outer and inner mitochondrial membranes is correct?

    <p>Two of the above are correct</p> Signup and view all the answers

    What is the primary role of the intermembrane space in mitochondria?

    <p>To allow for the exchange of molecules between the cytosol and matrix</p> Signup and view all the answers

    What is the primary function of the matrix in the mitochondria?

    <p>Site of the citric acid cycle</p> Signup and view all the answers

    According to the endosymbiont theory, what was the relationship between the prokaryotic cell and the eukaryotic cell?

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

    How many proteins does a mitochondrion typically produce for its own needs?

    <p>About 13 proteins</p> Signup and view all the answers

    What is the main reason chloroplasts are considered plastids?

    <p>For their membranous structure</p> Signup and view all the answers

    Which organelle shares a similar inner and outer membrane structure with mitochondria?

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

    The matrix is the area between the inner and the outer membranes.

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

    The outer membrane contains porins, which are channels that allow unrestricted passage of moderately sized molecules like pyruvate.

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

    Glycolysis and fermentation both occur in the cytoplasm.

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

    Fermentation is the preferred method of ATP generation in the presence of oxygen.

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

    The mitochondria is where pyruvate undergoes oxidation to produce acetyl CoA.

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

    Glycolysis results in the production of 3 NADH molecules.

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

    The citric acid cycle occurs in the intermembrane space of the mitochondria.

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

    During the oxidation of pyruvate, carbon dioxide is released and NADPH is produced.

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

    What is the fate of pyruvate in the presence of oxygen?

    <p>Moves into the mitochondria for aerobic respiration</p> Signup and view all the answers

    What is the main role of pyruvate dehydrogenase in the oxidation of pyruvate?

    <p>Forms NADH and acetyl CoA</p> Signup and view all the answers

    Which section of cellular respiration involves the formation of 2 pyruvate, 2 ATP, and 2 NADH?

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

    Which molecule acts as a coenzyme during the conversion of pyruvate to acetyl CoA?

    <p>Coenzyme A</p> Signup and view all the answers

    What is the outcome if a cell lacks oxygen for cellular respiration?

    <p>Fermentation to produce small amounts of ATP</p> Signup and view all the answers

    What happens in Step 2 of the citric acid cycle?

    <p>Two carbon dioxide molecules are released</p> Signup and view all the answers

    Which molecule is very similar to NADH and is produced in the citric acid cycle?

    <p>FADH2</p> Signup and view all the answers

    What is the primary function of FADH2 in the citric acid cycle?

    <p>Transfer of electrons and hydrogens</p> Signup and view all the answers

    What is the role of GTP or ATP production in the citric acid cycle?

    <p>Generation of energy currency for cellular activities</p> Signup and view all the answers

    How many oxaloacetate molecules are regenerated at the end of one complete turn of the citric acid cycle?

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

    How many total NADH so far from one molecule of glucose at the end of the citric acid cycle?

    <p>10</p> Signup and view all the answers

    How many total FADH2 so far from one molecule of glucose at the end of the citric acid cycle?

    <p>2</p> Signup and view all the answers

    How many total CO2 so far from one molecule of glucose at the end of the citric acid cycle?

    <p>6</p> Signup and view all the answers

    How many total ATP (Net!) so far from one molecule of glucose at the end of the citric acid cycle?

    <p>4</p> Signup and view all the answers

    What is the primary function of Coenzyme Q in the electron transport chain?

    <p>Accepting electrons and acting as a shuttle between complexes</p> Signup and view all the answers

    Which type of proteins are involved in carrying electrons through the electron transport chain?

    <p>Flavoproteins, iron-sulfur proteins, and cytochromes</p> Signup and view all the answers

    Where are the mega complexes of the electron transport chain embedded?

    <p>In the inner mitochondrial membrane</p> Signup and view all the answers

    What is the alternate name for Coenzyme Q used in the text?

    <p>'Ubiquinone'</p> Signup and view all the answers

    Which protein acts as a shuttle moving electrons along between complexes in the electron transport chain?

    <p>Cytochrome C</p> Signup and view all the answers

    At which complex in the electron transport chain does NADH enter?

    <p>Complex 1</p> Signup and view all the answers

    How many hydrogen ions are pumped into the intermembrane space from the oxidation of one NADH molecule?

    <p>10</p> Signup and view all the answers

    At which complex does FADH2 enter the electron transport chain?

    <p>Complex 2</p> Signup and view all the answers

    Which of the following poisons blocks complex 4 of the electron transport chain?

    <p>All of the above</p> Signup and view all the answers

    Which component of the electrochemical gradient is established by the accumulation of positively charged hydrogen ions (protons) in the intermembrane space?

    <p>Both the pH difference and the voltage difference</p> Signup and view all the answers

    According to the chemiosmotic theory, what is the primary source of the proton gradient established across the inner mitochondrial membrane?

    <p>The electron transport chain</p> Signup and view all the answers

    What is the direction of proton movement across the inner mitochondrial membrane during ATP synthesis?

    <p>From the intermembrane space into the matrix</p> Signup and view all the answers

    Study Notes

    Cellular Respiration

    • Cells can survive using glycolysis to produce ATP, but aerobic respiration produces the most ATP
    • Aerobic respiration completely oxidizes glucose to carbon dioxide and produces a large amount of ATP
    • Mitochondria are the primary site of aerobic respiration and are often referred to as the "powerhouse of the cell"
    • Mitochondria are found in areas of high ATP demand, such as muscle cells
    • Mitochondria are dynamic, interconnected networks that can fuse and divide
    • The endoplasmic reticulum plays a role in mitochondrial fission

    Mitochondrial Structure

    • Mitochondria have two membranes: outer and inner
    • The outer membrane encapsulates the organelle, while the inner membrane folds inward to increase surface area
    • The matrix is the middle compartment, and the intermembrane space is the area between the two membranes
    • Cristae are the deep folds of the inner membrane, and cristae junctions are the narrow extensions
    • The outer membrane contains channel proteins called porins, which allow moderately sized molecules to move freely
    • The inner membrane has different chemical properties and is enriched with cardiolipin, a phospholipid that insulates the membrane

    Mitochondrial Function

    • Mitochondria have their own machinery to transcribe and translate proteins, but only produce about 5% of the proteins they need
    • The matrix contains ribosomes and circular DNA
    • The citric acid cycle takes place in the matrix
    • Mitochondria can produce ATP through aerobic respiration, using the electron transport chain and chemiosmosis

    Cellular Respiration Process

    • Glycolysis produces 2 pyruvate, 2 ATP, and 2 NADH
    • Pyruvate oxidation produces acetyl CoA, carbon dioxide, and NADH
    • The citric acid cycle produces 2 CO2, 3 NADH, 1 FADH2, 1 GTP (or ATP), and 1 oxaloacetate
    • Oxidative phosphorylation produces ATP using energy from redox reactions in the electron transport chain
    • The electron transport chain produces a proton gradient that drives ATP synthesis through chemiosmosis

    Electron Transport Chain

    • The electron transport chain is a series of protein complexes that use energy from NADH and FADH2 to pump hydrogen ions into the intermembrane space
    • The electron transport chain is composed of four mega complexes and uses CoQ and cytochrome C as electron carriers
    • The energy from the electron transport chain is used to generate a proton gradient across the inner mitochondrial membrane

    Chemiosmosis

    • The proton gradient established by the electron transport chain is used to drive ATP synthesis through chemiosmosis
    • The proton gradient is an electrochemical gradient, with a difference in concentration and charge across the membrane
    • The energy from the proton gradient is used to phosphorylate ADP to ATP through the process of chemiosmosis

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    Test your knowledge on how polysaccharides are formed through condensation reactions and why this process is considered endergonic.

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