Biochemistry Chapter 9 Flashcards

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Questions and Answers

Identify all correct statements about the basic function of fermentation.

Continued ATP production by glycolysis (correct)

Production of carbon dioxide

Regeneration of NAD+ (correct)

Breaking down fatty acids

What happens to most of the energy that the cell obtains from the oxidation of glucose?

It is stored in NADH and FADH2

What is likely to happen to an individual when they exhaust their ATP supply?

Catabolic processes will be activated to generate additional ATP

When a glucose molecule loses a hydrogen atom in an oxidation reduction reaction, what happens to the glucose molecule?

It is oxidized Signup and view all the answers

What is the most important result of the process of cellular respiration in biological systems?

Transforming the energy in glucose and related molecules into a chemical form that cells can use for work Signup and view all the answers

Why may carbohydrates and fats be considered high energy foods?

They contain many electrons associated with hydrogen atoms Signup and view all the answers

What is correct about the redox reactions of the electron transport chain?

The redox reactions are directly coupled to the movement of protons across a membrane Signup and view all the answers

Which metabolic process normally occurs in most cells regardless of oxygen availability?

Glycolysis Signup and view all the answers

Where is the energy released from the electron transport chain used to pump hydrogen ions?

Mitochondrial inter-membrane space Signup and view all the answers

What happens to the carbon in compounds that do not end up as CO2 during cellular respiration?

The carbon compounds are removed to serve as building blocks for other complex molecules Signup and view all the answers

How many molecules of ATP are produced from the complete oxidation of one glucose molecule in aerobic cellular respiration?

30-32 Signup and view all the answers

What is a primary function of both alcohol and lactic acid fermentation?

Oxidation of NADH to NAD+ Signup and view all the answers

What is the likely effect of removing oxygen from a facultative anaerobic organism's environment?

Glucose consumption increases, while the growth rate decreases Signup and view all the answers

Which process will be inhibited first when a cell is deprived of oxygen?

Electron transport chain Signup and view all the answers

Which metabolic processes take place in the cytosol of a eukaryotic cell?

Glycolysis and fermentation Signup and view all the answers

Which molecule is the lowest energy donor of electrons to the electron transport chain?

FADH2 Signup and view all the answers

Why is lactate used as an indicator of exercise capacity in endurance athletes?

Lactate levels increase when muscle cells need more energy Signup and view all the answers

What symptoms do dogs affected by canine phosphofructokinase deficiency display?

They are lethargic and readily tire from exercise Signup and view all the answers

How does ATP production change in healthy individuals during an eight-hour fast?

The individual's ATP production will not change significantly Signup and view all the answers

Upon completion of the citric acid cycle, where is most of the energy originally stored in glucose?

NADH Signup and view all the answers

In liver cells, why do mitochondria have increased surface area?

To allow for increased rates of oxidative phosphorylation Signup and view all the answers

What products result from the oxidation of pyruvate to acetyl-CoA?

NADH and CO2 Signup and view all the answers

Which process would reduce or eliminate the generation of a proton motive force in mitochondria?

Pumping of hydrogen ions from the mitochondrial matrix across the inner membrane Signup and view all the answers

Which molecules are generated through beta oxidation?

Fatty acids Signup and view all the answers

What molecules are produced from glycolysis per glucose molecule?

2 NADH, 2 Pyruvate, and 2 ATP Signup and view all the answers

What is a correct statement about cellular respiration?

Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level Signup and view all the answers

Which process is driven by chemiosmosis?

Oxidative phosphorylation Signup and view all the answers

What takes place in the electron transport chain?

The harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle Signup and view all the answers

Which statement about glycolysis is correct?

It represents the first stage in the chemical oxidation of glucose by a cell Signup and view all the answers

What supports the claim that glycolysis is likely one of the first metabolic pathways?

It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms Signup and view all the answers

What describes the results of the reaction C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy?

C6H12O6 is oxidized and O2 is reduced Signup and view all the answers

What summarizes ATP use in glycolysis?

Two molecules of ATP are used and four molecules of ATP are produced Signup and view all the answers

What happens to the molecule of NAD+ when it gains a hydrogen atom?

NAD+ becomes reduced Signup and view all the answers

Where do the electrons stripped from glucose in cellular respiration ultimately end up?

Water Signup and view all the answers

What does the synthesis of ATP by oxidative phosphorylation exemplify?

Coupling of an endergonic reaction to an exergonic reaction Signup and view all the answers

Under what conditions does plant cell mitochondria actively oxidize pyruvate in oxidative phosphorylation?

In all cells, with or without light Signup and view all the answers

What is correct about chemiosmotic synthesis of ATP?

It requires that electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane Signup and view all the answers

What type of molecule can yeast cells with defective mitochondria use for energy?

Glucose Signup and view all the answers

What is the result of energy obtained by fermentation in the absence of oxygen?

ATP, CO2, and ethanol Signup and view all the answers

In the reaction Pyruvate + NADH + H+ → lactate + NAD+, which molecule functions as the oxidizing agent?

Pyruvate Signup and view all the answers

What best describes the electron transport chain?

It consists of a series of redox reactions Signup and view all the answers

What is an example of allosteric regulation in glycolysis?

High levels of citric acid inhibit phosphofructokinase Signup and view all the answers

What must be present after disrupting inner mitochondrial membranes for electron transfer and ATP synthesis?

All of the electron transport proteins and ATP synthase Signup and view all the answers

What is the primary role of oxygen in cellular respiration?

It serves as the final acceptor for electrons from the electron transport chain Signup and view all the answers

Describe the path by which electrons move from high energy to lower energy molecules in aerobic respiration.

Glucose → NADH → electron transport chain → oxygen Signup and view all the answers

What type of cells carry out ATP synthesis by chemiosmosis?

All respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors Signup and view all the answers

How did a person on a strict diet and exercise regimen lose body fat?

It was released as CO2 and H2O Signup and view all the answers

What accurately describes the function of glycolysis in cellular respiration?

The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP Signup and view all the answers

What inhibits phosphofructokinase, a key enzyme in glycolysis?

ATP and citrate Signup and view all the answers

How are fatty acids converted to acetyl-CoA?

Directly entering the citric acid cycle Signup and view all the answers

What is consumed and produced in cellular respiration?

Glucose is consumed, and carbon dioxide is produced Signup and view all the answers

Study Notes

Fermentation and Cellular Metabolism

Fermentation's primary role is to regenerate NAD+, enabling glycolysis to continue ATP production.
Glycolysis and the citric acid cycle yield minimal ATP; most energy from glucose oxidation is stored in NADH and FADH2.

ATP Availability and Energy Production

Eukaryotic cells store enough ATP for approximately 30 seconds of activity; after depletion, catabolic processes kick in to generate more ATP.
The complete oxidation of one glucose molecule in aerobic cellular respiration produces about 30-32 molecules of ATP.

Oxidation-Reduction Reactions

Loss of a hydrogen atom from glucose in oxidation-reduction signifies the molecule is oxidized.
Carbohydrates and fats serve as high-energy foods due to their electrons associated with hydrogen atoms.

Electron Transport Chain and Proton Motive Force

The electron transport chain's redox reactions couple to proton movement across membranes.
Energy released during the electron transport chain pumps hydrogen ions into the mitochondrial inter-membrane space.

Glycolysis and Cellular Respiration

Glycolysis is universal and occurs regardless of oxygen presence, while fermentation and oxidative phosphorylation occur in specific scenarios.
Not all carbons in glycolysis and the citric acid cycle are converted to CO2; some serve as building blocks for complex molecules.

Fermentation Types and Processes

Both alcohol fermentation and lactic acid fermentation focus on the oxidation of NADH to NAD+.
In the absence of oxygen, yeast can ferment glucose, producing ATP, CO2, and ethanol.

Regulation and Inhibition in Metabolism

High citric acid levels inhibit phosphofructokinase (PFK), a crucial glycolytic enzyme, showcasing allosteric regulation.
The electron transport chain is characterized by a series of redox reactions, and its inhibition reduces proton motive force.

ATP Synthesis and Energy Sources

ATP production occurs by chemiosmosis in all respiring cells using the energy from proton flow through ATP synthase.
Mitochondrial membranes with increased surface area enhance oxidative phosphorylation efficiency.

Pyruvate Processing

Pyruvate is oxidized to acetyl-CoA, resulting in NADH and CO2 production.

Conditions Affecting Cellular Respiration

Removal of oxygen from facultative anaerobes increases glucose consumption but decreases growth rates.
During an eight-hour fast, ATP production changes little in healthy individuals.

Impacts of External Conditions

Lactate levels increase during anaerobic exercise, signaling the need for energy, but fatigue occurs if anaerobic conditions persist.
Mitochondria can convert fatty acids and amino acids to produce energy when glucose is not available.

Cellular Energy Yield from Metabolic Pathways

Glycolysis produces 2 NADH, 2 pyruvate, and 2 ATP from one glucose molecule.
In the absence of oxygen, glycolysis yields a net gain of 2 ATP per glucose molecule.

Energy and Nutrients in Metabolism

The majority of fatty acids are catabolized into acetyl-CoA, which enters the citric acid cycle for further metabolization.

Biological Energy Transformation

Glucose is oxidized, and O2 is reduced during cellular respiration, emphasizing the transformation of energy for cellular work.
The synthesis of ATP via oxidative phosphorylation exemplifies coupling endergonic reactions with exergonic reactions.

Metabolic Products and Weight Loss

During weight loss, fat is predominantly released as CO2 and H2O.
Each metabolic pathway plays distinct roles, with glycolysis initiating catabolism by converting glucose to pyruvate and yielding ATP.

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Description

This quiz features practice questions from Chapter 9 focusing on fermentation and energy production in cells. Test your understanding of the basic functions of fermentation and the processes of glycolysis and the citric acid cycle.