Chapter 7 biology 1107
aerobic respiration
A catabolic pathway for organic molecules, using oxygen (O2) as the final electron acceptor in an electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms. With oxygen
Fermentation
A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid.
Acetyl CoA
Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme.
How do anaerobic and aerobic respiration differ in ATP output?
Aerobic respiration is far more energy-efficient than anaerobic respiration. Aerobic processes produce up to 38 ATP per glucose. Anaerobic processes yield only 2 ATP per glucose.
Which of the following substances is/are involved in oxidative phosphorylation? - ATP - ADP - oxygen - all of the listed substances - none of the listed substances
All of the listed substances are involved in oxidative phosphorylation
Gaseous hydrogen burns in the presence of oxygen to form water: 2H2 + O2 → 2H2 O + energy Which molecule is oxidized and what kind of bond is formed?
Hydrogen, polar.
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of _____.
NADH
The reduced form of the electron acceptor in glycolysis is ______.
NADH
Which of the following is a correct description in sequence of events and cellular respiration?
Oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation
During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction?
Oxygen
Which of the following statements is true of the bonds in a water molecule?
Oxygen holds electrons more tightly than hydrogen does, and then the charge is zero
Once the electron donor in glycolysis gives up it's electrons, it is oxidized to a compound called _____.
Pyruvate
Pyruvate oxidation (bridge step)
Pyruvate decarboxylation or pyruvate oxidation, also known as the link reaction, is the conversion of pyruvate into acetyl-CoA by the enzyme complex pyruvate dehydrogenase complex. pyruvate oxidation takes place in the mitochondrial matrix (in eukaryotes). In prokaryotes, it happens in the cytoplasm. Pyruvate—three carbons—is converted to acetyl CoA, a two-carbon molecule attached to coenzyme A. A molecule of coenzyme A is a necessary reactant for this reaction, which releases a molecule of carbon dioxide and reduces a NAD+ to NADH.
What are common components of aerobic/cellular respiration in the mitochondria and photosynthesis in the chloroplast? (I.e. electron transport chain, redox reactions, ATP synthase, etc....)
They both use oxygen, both produce a large amount of ATP, both go through the same stages, both use glucose
In mitochondrial electron transport, what is the direct roll of O2?
To function as the final electron acceptor in the electron transport chain
How many molecules of ATP are gained by substrate level Phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen?
four
In glycolysis, the carbon-containing compound that functions as the electron donor is _______.
glucose
Of the metabolic pathways listed below, which is the most universal metabolic process Associated with cellular respiration?
glycolysis
The electron transport chain involved in cellular respiration is located in/on the _______.
inner membrane of the mitochondrion
Molecular oxygen (O2) has what role in aerobic cellular respiration?
it is the final electron acceptor at the end of the electron transport chain
Most of the ATP produced in aerobic cellular respiration comes from which of the following processes?
oxidative phosphorylation
The ATP that is generated in glycolysis is produced by substrate level phosphorylation, A very different mechanism than the one used to produce ATP during oxidative phosphorylation. Phosphorylation reactions involve the addition of a phosphate group to another molecule. Correct statements
- One of the substrates in a molecule derived from the breakdown of glucose - an enzyme is required in order for the reaction to occur. - A bond must be broken between an organic molecule and phosphate before ATP can form
The ATP that is generated in glycolysis is produced by substrate level phosphorylation, A very different mechanism than the one used to produce ATP during oxidative phosphorylation. Phosphorylation reactions involve the addition of a phosphate group to another molecule. Incorrect statements
- The phosphate group added to ADP to make ATP comes from free inorganic phosphate ions - The enzymes involved in ATP synthesis must be attached to a membrane to produce ATP
Citric acid cycle
A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) two carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotic cells; together with the graph family pyruvate oxidation, the second major stage and cellular respiration. A glucose (six carbons) molecule enters glycolysis and produces two three carbon molecules (pyruvate). Each pyruvate is broken down into a two carbon acetyl-CoA molecule that enters the citric acid cycle. Each acetyl-CoA molecule produces three and one in the citric acid cycle.
ATP synthesis
A complex of several membranes proteins that functions in chemiosmosis with adjacent electron transport chain's, using the energy of a hydrogen ion (the proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membrane of prokaryotic cells ATP synthesis involves the transfer of electrons from the intermembrane space, through the inner membrane, back to the matrix. ... The combination of the two components provides sufficient energy for ATP to be made by the multienzyme Complex V of the mitochondrion, more generally known as ATP synthase. The function of ATP synthase is to produce ATP. ATP is necessary to power all cellular processes, so it is constantly being used by cells and constantly needs to be produced. Each ATP synthase can produce about 100 molecules of ATP every second. Oxygen and glucose are both reactants in the process of cellular respiration. The main product of cellular respiration is ATP; waste products include carbon dioxide and water.
Which of the following statements is not true of most cellular redox reactions? - A hydrogen atom is transferred to the atom that loses an electron - The reactant that is oxidized loses electrons - changes in potential energy can be released as heat - The electron acceptor is reduced
A hydrogen atom is transferred to the Atom that loses an electron
beta oxidation
A metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA.
Electron transport chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP. Consist of a number of molecules, mostly proteins, built into the inner membrane of the mitochondria of eukaryotic cells and the plasma membrane of aerobically Respiring prokaryotes. In the electron transport chain, electrons are passed from one molecule to another, and energy released in these electron transfers is used to form an electrochemical gradient. In chemiosmosis, the energy stored in the gradient is used to make ATP. reactants: Hydrogen ions, oxygen, NADH, FADH2 Products:Water and ATP( 2 e- + 2 H+ 1/2 O2= H20) · Complex I.
Glycolysis
A series of reactions that ultimately splits glucose into pyruvate. Glycolysis occurs in almost all living cells, serving as the starting point of fermentation or cellular respiration. Glycolysis means "sugar splitting" It takes place in the cytoplasm of both prokaryotic and eukaryotic cells. Glycolysis produces 2 ATP, 2 NADH, and 2 pyruvate molecules: Glycolysis, or the aerobic catabolic breakdown of glucose, produces energy in the form of ATP, NADH, and pyruvate, which itself enters the citric acid cycle to produce more energy. Glucose is the reactant; while ATP and NADH are the products of the Glycolysis reaction.
If muscle cells in the human body consume O2 faster than it can be supplied which of the following is likely to result? - The muscle cell will have trouble making enough ATP to meet demands - The cell will not be able to carry out oxidative phosphorylation - The cell will consume glucose at an increased rate - The muscle cells will have trouble making enough ATP to meet demands and the sale will not be able to carry out oxidative phosphorylation - all of the listed events will occur
All of the listed will occur
Chemiosmosis
An energy coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Under aerobic conditions, most ATP synthesis in cells occur by chemiosmosis.
Cytochromes
An iron-containing protein that is a component of electron transport chains in the mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells
facultative anaerobe
An organism that makes ATP by aerobic respiration if oxygen is present but that switches to anaerobic respiration or fermentation if oxygen is not present.
obligate anaerobes
An organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it.
What are two types of anaerobic respiration?
Anaerobic respiration occurs when the amount of oxygen available is too low to support the process of aerobic respiration. There are two main types of anaerobic respiration, alcoholic fermentation and lactic acid fermentation.
Which term describes to Adams when they form a bond in which electrons are completely transferred from one Adam to the other?
Anion and cation
How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATP synthesis in glycolysis or the citric acid cycle.)
Both electron transport and ATP synthesis would stop.
What are the aerobic stages of cellular respiration in which stages are shared or not with anaerobic respiration's?
Cellular respiration occurs in three stages: glycolysis, the Krebs cycle, and electron transport. Glycolysis is an anaerobic process. The other two stages are aerobic processes. The products of cellular respiration are needed for photosynthesis, and vice versa.
Before amino acid can feed into glycolysis or the citric acid cycle, their amino groups must be removed, a process called __________. The nitrogenous waste is excreted from the animal in the form of ammonia (NH3), urea, or other waste products
Deamination
What is the difference between ATP made by substrate level phosphorylation and oxidative phosphorylation?
During respiration, most energy flows in this sequence: glucose→NADH→electron transport chain→proton-motiveforce→ATP. We can do some bookkeeping to calculate the ATP profit when cellular respiration oxidizes a molecule of glucose to six molecules of carbon dioxide. The three main departments of this metabolic enterprise are glycolysis, the citric acid cycle, and the electron transport chain, which drives oxidative phosphorylation. The tally adds the 4 ATP produced directly by substrate-level phosphorylation during glycolysis and the citric acid cycle to the many more molecules of ATP generated by oxidative phosphorylation. Each NADH that transfers a pair of electrons from glucose to the electron transport chain contributes enough to the proton-motive force to generate a maximum of about 3 ATP. A third variable that reduces the yield of ATP is the use of the proton-motive force generated by the redox reactions of respiration to drive other kinds of work. For example, the proton-motive force powers the mitochondrion's uptake of pyruvate from the cytosol. However, if all the proton-motive force generated by the electron transport chain were used to drive ATP synthesis, one glucose molecule could generate a maximum of 28 ATP produced by oxidative phosphorylation plus 4 ATP (net) from substrate-level phosphorylation to give a total yield of about 32 ATP (or only about 30 ATP if the less efficient shuttle were functioning). Overall, glycolysis is exergonic, and some of the energy made available is used to produce 2 ATP (net) by substrate-level phosphorylation. If oxygen is present, then additional ATP is made by oxidative phosphorylation when NADH passes electrons removed from glucose to the electron transport chain. But glycolysis generates 2 ATP whether oxygen is present or not—that is, whether conditions are aerobic or anaerobic.
Which term describes the decree to which an element attracts electrons?
Electronegativity
Which of the following best describes the electron transport chain of cellular respiration?
Electrons are passed from one carrier to another, releasing a little energy at each step.
What is the movement of H+ ions by NADH & FADH2 through ATP synthases and how many ATP this makes
Establishing the H+ gradient across the inner mitochondrial membrane is a major function of the electron transport chain. The chain is an energy converter that uses the exergonic flow of electrons from NADH and FADH2 to pump H+ across the membrane, from the mitochondrial matrix into the intermembrane space. The H+ has a tendency to move back across the membrane, diffusing down its gradient. And the ATP synthases are the only sites that provide a route through the membrane for H+. As we described previously, the passage of H+ through ATP synthase uses the exergonic flow of H+ to drive the phosphorylation of ADP. Thus, the energy stored in an H+ gradient across a membrane couples the redox reactions of the electron transport chain to ATP synthesis. chemiosmosis is an energy-coupling mechanism that uses energy stored in the form of an H+ gradient across a membrane to drive cellular work There are three reasons we cannot state an exact number of ATP molecules generated by the breakdown of one molecule of glucose. First, phosphorylation and the redox reactions are not directly coupled to each other, so the ratio of the number of NADH molecules to the number of ATP molecules is not a whole number. We know that 1 NADH results in 10 H+ being transported out across the inner mitochondrial membrane, but the exact number of H+ that must reenter the mitochondrial matrix via ATP synthase to generate 1 ATP has long been debated. Based on experimental data, however, most biochemists now agree that the most accurate number is 4 H+. Therefore, a single molecule of NADH generates enough proton-motive force for the synthesis of 2.5 ATP. The citric acid cycle also supplies electrons to the electron transport chain via FADH2, but since its electrons enter later in the chain, each molecule of this electron carrier is responsible for transport of only enough H+ for the synthesis of 1.5 ATP. These numbers also take into account the slight energetic cost of moving the ATP formed in the mitochondrion out into the cytosol, where it will be used.
What is the equation fo cellular respiration and is it an endergonic or exergonic reaction?
Exergonic; C6H12O6 + 6O2 → 6CO2 + 6H2O.
NADH and FADH2 are both electron carriers that donate their electrons to the electron transport chain. The electrons ultimately reduce O2 to water in the final step of electron transport. However, the amount of ATP made by electrons from an NADH molecule is greater than the amount made by electrons from an FADH2 molecule. Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2?
Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.
Alcohol fermentation
Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing carbon dioxide. Products are ethanol and carbon dioxide Ex) yeast
lactic acid fermentation
Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide Products are lactate Ex) cheese and yogurt
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the _____.
H+ concentration across the membrane holding ATP synthase.
What chemicals will disrupt the ETC and how will this affects cellular respiration?
If the electron transport chain is disrupted, no more protons (H+) will be pumped into the intermembrane space, therefore its H+ concentration will decrease, and its pH will increase. The most important known inhibitors of the ETC are Amytal, Rotenone, Antimycin A, CO, Sodium Azide, and Cyanides.
Where do the reactions of glycolysis occur in a eukaryotic cell?
In the cytosol
What kind of van is formed when lithium and fluorine combine to form lithium fluoride?
Ionic
_______ is the compound that functions are the electron acceptor in glycolysis.
NAD+
When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle also eventually stop working. Which of the following is the best explanation for this?
NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue.
Cellular respiration
The catabolic pathways of aerobic and anaerobic respiration, which write down organic molecules and use an electron transport chain for the production of ATP
What are redox reactions?
The chemical reaction involving the complete or partial transfer of one or more electrons from one reacted to another; short for reduction-oxidation reaction
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes?
The citric acid cycle Both NADH and FADH2 are produced during the citric acid cycle.
Reduction
The complete or partial addition of electrons to a substance involved in a redox reaction
Oxidation
The complete or partial loss of electrons from a substance involved in a redox reaction
Oxidizing agent
The electron acceptor in a redox reaction.
Reducing agent
The electron donor in a redox reaction.
substrate-level phosphorylation
The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.
Why is the citric acid cycle called a cycle?
The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the pathway
Where do the reactions of the citric acid cycle occur in eukaryotic cells?
The matrix of the mitochondrion
How do you identify oxidizing agent and reducing agents?
The oxidizing agent is a substance that causes oxidation by accepting electrons; therefore, its oxidation state decreases. The reducing agent is a substance that causes reduction by losing electrons; therefore its oxidation state increases.
Proton-motive force
The potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H+) across a biological membrane during chemiosmosis
oxidative phosphorylation
The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.
anaerobic respiration
Without oxygen An- without
Why am I muscle in liver cells produce more ATP than other cells?
liver cells and muscle cells contain a lot of mitochondria. Muscle cells are assiciated with a large number of mitochondria as they require more ATP (energy) to function than other cells. They need this because of their frequent contraction and relaxation, which requires more ATP than average cells. Human muscle cells make ATP by lactic acid fermentation when oxygen is scarce. This occurs during strenuous exercise, when sugar catabolism for ATP production outpaces the muscle's supply of oxygen from the blood. Under these conditions, the cells switch from aerobic respiration to fermentation. The lactate that accumulates was previously thought to cause the muscle fatigue and pain that occurs a day or so after intense exercise. However, evidence shows that within an hour, blood carries the excess lactate from the muscles to the liver, where it is converted back to pyruvate by liver cells. Because oxygen is available, this pyruvate can then enter the mitochondria in liver cells and complete cellular respiration. Next-day muscle soreness is more likely caused by trauma to small muscle fibers, which leads to inflammation and pain.
A molecule becomes oxidized when it __________.
loses an electron
When a compound donates (loses) electrons, that compound becomes _______. Such a compound is often referred to as an electron donor.
oxidized
Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?
pyruvate, ATP, and NADH
When a compound accepts (gains) electrons, that compound becomes ______. Such a compound is often referred to as an electron acceptor.
reduced
