Cellular Respiration Overview
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Questions and Answers

How many NADH are produced by glycolysis?

2

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation

Which of these is NOT a product of glycolysis?

  • ATP
  • NADH + H+
  • FADH2 (correct)
  • Pyruvate
  • In glycolysis, what starts the process of glucose breakdown?

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

    In glycolysis there is a net gain of _____ ATP.

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

    For each glucose that enters glycolysis, _____ NADH enter the electron transport chain.

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

    In cellular respiration, most ATP molecules are produced by _____

    <p>oxidative phosphorylation</p> Signup and view all the answers

    The final electron acceptor of cellular respiration is _____

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

    During electron transport, energy from _____ is used to pump hydrogen ions into the _____.

    <p>NADH and FADH2, intermembrane space</p> Signup and view all the answers

    The proximate (immediate) source of energy for oxidative phosphorylation is _____

    <p>kinetic energy that is released as hydrogen ions diffuse down their concentration gradient</p> Signup and view all the answers

    Which of the following molecules is broken down in cellular respiration, providing fuel for the cell?

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

    Which energy-rich molecule produced by cellular respiration directly powers cell work?

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

    Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

    <p>glycolysis → acetyl CoA → citric acid cycle → electron transport chain</p> Signup and view all the answers

    What is the correct general equation for cellular respiration?

    <p>C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy</p> Signup and view all the answers

    Which of the following processes takes place in the cytosol of a eukaryotic cell?

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

    In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

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

    Which statement describes glycolysis?

    <p>This process splits glucose in half and produces 2 ATPs for each glucose.</p> Signup and view all the answers

    Which statement describes the citric acid cycle?

    <p>This process produces some ATP and carbon dioxide in the mitochondrion.</p> Signup and view all the answers

    Which statement describes the electron transport chain?

    <p>This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.</p> Signup and view all the answers

    The transfer of _____ from one molecule to another is an oxidation-reduction reaction, or redox reaction.

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

    In cellular respiration, glucose becomes _____ to carbon dioxide (CO2) as it loses electrons.

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

    In cellular respiration, oxygen becomes _____ to water (H2O) as it gains electrons.

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

    In cellular respiration, organic molecules become oxidized as _____ picks up electrons and H+ and becomes reduced to NADH.

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

    NADH delivers electrons to an electron transport chain, which passes the electrons through carrier molecules in a series of redox reactions to the final electron acceptor, _____.

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

    The energy released from the redox reactions in the electron transport chain is used by the cell to make _____.

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

    In muscle cells, fermentation produces _____.

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

    When proteins are used as a source of energy for the body, the proteins are converted mainly into intermediates of glycolysis or the citric acid cycle.

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

    Which of the following statements about the energy yield of aerobic respiration is false?

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

    Most NADH molecules generated during cellular respiration are produced during __________.

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

    Describe how food molecules reach the body's cells and fuel cellular respiration. Start with the ingestion of food on the left.

    <ol> <li>Eating food provides fuel and building blocks for your body. 2. After food is broken down in the digestive system, it is transported to cells via the circulatory system. 3. Fuel molecules are broken down further in glycolysis and the citric acid cycle (also called the Krebs cycle). 4. ATP is produced with the help of the electron transport chain.</li> </ol> Signup and view all the answers

    As electrons move through the mitochondrial space, what happens?

    <p>the pH of the intermembrane space changes.</p> Signup and view all the answers

    Which of the following statements about the energy yields from cellular respiration is true?

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

    During cellular respiration, NADH delivers its electron load to which molecule?

    <p>the first electron carrier molecule</p> Signup and view all the answers

    NADH is also used by cells when making certain molecules. Based on your knowledge of the role of NADH in cellular respiration, what do you think NADH's role is in biosynthesis of molecules?

    <p>reducing molecules</p> Signup and view all the answers

    In cellular respiration, which of the following outcomes is the result of electrons moving through the electron transport chain?

    <p>A proton gradient is formed.</p> Signup and view all the answers

    In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive carbon. The mice were closely monitored, and in a few minutes, radioactive carbon atoms showed up in __________.

    <p>carbon dioxide</p> Signup and view all the answers

    The electron transport chain is, in essence, a series of redox reactions that conclude cellular respiration. During these redox reactions, __________.

    <p>electrons are transferred through a series of electron acceptors embedded within the inner mitochondrial membrane.</p> Signup and view all the answers

    Inputs of cellular respiration

    <p>Fuel = Glucose Gas we inhale = O2</p> Signup and view all the answers

    Outputs of cellular respiration

    <p>Gas we exhale = CO2 Water = H2O Energy parts that cells use to do the work = ATP</p> Signup and view all the answers

    Sunlight is essential for the varied life on Earth because it provides __________.

    <p>the energy necessary to power the rearrangement of chemical bonds in H2O and CO2</p> Signup and view all the answers

    Which of the following is the role of cellular respiration?

    <p>to harvest energy from organic molecules</p> Signup and view all the answers

    Cellular respiration is a series of chemical reactions that harvest energy in the form of ______ from ______ and other organic molecules.______ and ______ are also released.

    <p>ATP, glucose, CO2, water</p> Signup and view all the answers

    A person's basal metabolic rate (BMR) is equal to about __________.

    <p>1,300-1,500 Calories/day</p> Signup and view all the answers

    Given the relatively modest number of calories burned by any but the most vigorous activities, why can most people consume more than 2,000 kilocalories per day yet maintain a healthy body weight?

    <p>A large proportion of the energy consumed in food is needed to maintain the body's functions, so only a fraction of food energy needs to be burned in exercise.</p> Signup and view all the answers

    A molecule that functions as the electron donor in a redox reaction __________.

    <p>loses electrons and becomes oxidized</p> Signup and view all the answers

    In cellular respiration, ______ is oxidized when it loses electrons in hydrogen atoms, and ______ is reduced as it gains electrons in hydrogen atoms.

    <p>glucose, oxygen</p> Signup and view all the answers

    In cellular respiration, glucose __________ electrons and oxygen __________ electrons.

    <p>loses, gains</p> Signup and view all the answers

    What is the role of the dehydrogenase enzyme at the beginning of the electron transport chain in cellular respiration?

    <p>It transfers two electrons from the glucose molecule to NAD+, reducing it to NADH.</p> Signup and view all the answers

    How does the electron transport chain run?

    <p>electron transfers by higher-energy molecules to lower-energy molecules, which releases energy used to synthesize ATP.</p> Signup and view all the answers

    Oxidative phosphorylation could not occur without glycolysis and the citric acid cycle because __________.

    <p>these two stages supply the electrons needed for the electron transport chain.</p> Signup and view all the answers

    The main function of glycolysis and the citric acid cycle is...

    <p>to supply oxidative phosphorylation, the last stage of cellular respiration, with electrons carried by NADH and FADH2.</p> Signup and view all the answers

    Which of the following statements about glycolysis is correct?

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

    In glycolysis, how many ATP are invested? How many ATP are produced?

    <p>2 invested, 4 produced, net of 2</p> Signup and view all the answers

    Glycolysis begins with __________ and ends with __________.

    <p>one molecule of glucose, two molecules of pyruvate</p> Signup and view all the answers

    How many carbon atoms are in glucose?

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

    How many carbon atoms are in pyruvate?

    <p>3</p> Signup and view all the answers

    At what point in cellular respiration is the first molecule of CO2 produced?

    <p>in the reaction that creates acetyl CoA (coenzyme A) from pyruvate</p> Signup and view all the answers

    Each glucose molecule yields __________ molecule(s) of ATP during the citric acid cycle.

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

    Each turn of the citric acid cycle generates one ATP molecule as well as which energy-rich molecules?

    <p>3 NADH and 1 FADH2</p> Signup and view all the answers

    In oxidative phosphorylation, electrons are passed from one electron carrier to another. The energy released is used to __________.

    <p>pump protons (H+) across the mitochondrial membrane</p> Signup and view all the answers

    What does the proton pump do?

    <p>moves H+ across the inner mitochondrial membrane to the intermembrane space.</p> Signup and view all the answers

    What 'powers' ATP synthase, allowing it to catalyze the conversion of ADP to ATP in the presence of phosphate?

    <p>the flow of H+ ions down their concentration gradient</p> Signup and view all the answers

    Evidence suggests that heat-generating brown fat is most active in __________.

    <p>babies and lean people exposed to cold temperatures</p> Signup and view all the answers

    About how much ATP is produced by the metabolism of one molecule of glucose in cellular respiration?

    <p>32 molecules</p> Signup and view all the answers

    During fermentation, __________ that was produced during glycolysis is converted back to __________.

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

    Why are wine barrels and beer fermentation vats designed to keep air out?

    <p>Facultative anaerobes prefer aerobic pathways.</p> Signup and view all the answers

    Which of the following statements about glycolysis is INCORRECT?

    <p>Glycolysis became a universal cellular process about the time that significant levels of O2 appeared in the atmosphere.</p> Signup and view all the answers

    Fat is the most efficient fuel molecule because __________.

    <p>with their numerous hydrogen atoms, fats provide an abundant source of high-energy electrons</p> Signup and view all the answers

    Let's look at the big picture here: Fueled by the ATP generated during cellular respiration, the intermediates of glycolysis and the citric acid cycle, such as pyruvate and acetyl CoA, are siphoned off and used to __________.

    <p>build proteins, fats, and carbohydrates</p> Signup and view all the answers

    What process regulates the rate of cellular respiration?

    <p>feedback inhibition</p> Signup and view all the answers

    Study Notes

    Glycolysis Overview

    • Glycolysis produces 2 NADH per glucose molecule.
    • ATP is generated via substrate-level phosphorylation; a phosphate is transferred from glyceraldehyde phosphate to ADP.
    • ATP investment in glycolysis: 2 ATP are used, producing a total of 4 ATP; net gain is 2 ATP.
    • Initiation of glucose breakdown requires ATP.
    • Glycolysis is the first step, yielding 2 pyruvate molecules from one glucose (6 carbon atoms).
    • It takes place in the cytosol of eukaryotic cells, outside the mitochondria.

    Cell Respiration Processes

    • The primary stages of cellular respiration: glycolysis → acetyl CoA formation → citric acid cycle → electron transport chain.
    • Cellular respiration's overall equation: C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy.
    • Glucose is oxidized to carbon dioxide, while oxygen is reduced to water.
    • NAD+ is reduced to NADH during these processes, which then delivers electrons to the electron transport chain.

    Citric Acid Cycle Insights

    • Each glucose molecule enters two turns of the citric acid cycle, yielding 2 ATP, 6 NADH, and 2 FADH2.
    • Carbon dioxide is released during the conversion of pyruvate to acetyl CoA, marking the first carbon dioxide release in cellular respiration.
    • The cycle captures energy-rich molecules that transport electrons to the electron transport chain.

    Electron Transport Chain and Oxidative Phosphorylation

    • Most ATP in cellular respiration comes from oxidative phosphorylation, utilizing energy released by electron transport.
    • The final electron acceptor is oxygen, which combines with electrons and protons to form water.
    • Energy from NADH and FADH2 drives hydrogen ion pumping into the intermembrane space, creating a proton gradient.
    • ATP synthesis occurs as protons flow back down their gradient through ATP synthase.

    Anaerobic Processes and Fermentation

    • In muscle cells, fermentation produces lactate and regenerates NAD+ from NADH.
    • The preference of facultative anaerobes for aerobic pathways explains the design of fermentation vessels to keep air out, ensuring alcohol production.

    Energy and Metabolism Insights

    • A person's basal metabolic rate (BMR) is approximately 1,300-1,500 Calories/day, supporting essential functions.
    • Fat is a highly efficient fuel due to its high hydrogen content, which provides abundant high-energy electrons.
    • Metabolism in cells involves utilizing ATP and other intermediates for building proteins, fats, and carbohydrates.

    Regulatory Mechanisms

    • Feedback inhibition regulates the rate of cellular respiration, ensuring that metabolic pathways respond to the energy needs of the cell.
    • Signals from reactive products control enzymatic activities and energy usage efficiency.

    General Highlights

    • Cellular respiration's efficiency surpasses that of car engines in harnessing energy from fuels.
    • A glucose molecule generally produces approximately 32 ATP through various stages.
    • Understanding energy transformation and regulation is key in biology, impacting health and metabolism.

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    Description

    This quiz covers the key processes of cellular respiration, including glycolysis, the citric acid cycle, and electron transport chain. Understand how glucose is transformed into ATP through these metabolic pathways, with a focus on energy yield and oxidation processes. Ideal for students studying biology or biochemistry.

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