Chapter 8 practice problems/review
what are the characteristics of fermentation that distinguish it from aerobic respiration. Multiple select question.
-does not require oxygen -results in the formation of lactate in animal cells -produces a limited amount of ATP
A single "turn" of the Krebs cycle will yield
1 ATP, 3 NADH, 1 FADH2
what are the stages of cellular respiration in order?
1. glycolysis 2. preparatory reaction 3. citric acid cycle 4. electron transport chain
If oxygen is not present, pyruvate cannot be fully broken down. In this instance, what is the net gain in ATP for each glucose molecule that enters glycolysis?
2 ATP
what are the outputs of the citric acid cycle per glucose molecule?
2 ATP 2 FADH2 6 NADH 4 CO2
The NET result of a single glycolysis run is the formation of
2 NADH and 2 ATP
what are the inputs of the citric acid cycle?
2 acetyl CoA 2 ADP + (P) 6 NAD+ 2 FAD
The overall process of glycolysis results in the production of
2 molecules of pyruvate and 2 molecules of ATP.
what are the inputs of fermentation?
2 phosphate groups 2 ADP glucose
In glycolysis, glucose is converted to
2 pyruvate
what are the outputs for glycolysis?
2 pyruvate, 2 ATP 2 NADH
what is the acetyl group?
2-carbon molecule that matches up with a 4-carbon molecule
what are the outputs of the citric acid cycle?
4 CO2 6 NADH 2 FADH2 2 ATP
During cellular respiration, how many molecules of CO2 will be produced from one molecule of glucose?
6
Provide the correct reactant to complete this chemical equation: C6H12O6 + _____ → 6 CO2 + 6 H2O + 36 ATP (energy)
6 O2
what is citrate?
6-carbon molecule produced when an acetyl group matches up with a 4-carbon molecule; oxidized after it forms
Which of the following statements about cellular respiration is accurate? A. Cellular respiration requires oxygen and produces carbon dioxide. B. Cellular respiration is the same process as photosynthesis. C. Cellular respiration requires carbon dioxide and produces oxygen.
A. Cellular respiration requires oxygen and produces carbon dioxide.
The electron transport chain produces 32-34 molecules of _________
ATP
The enzyme responsible for the synthesis of ATP is
ATP synthase
cellular respiration: what produces 32-34 ATP?
ATP synthase
what is the enzyme used to synthesize ATP?
ATP synthase
FAD + 2e- + 2H+ ==> FADH2 NAD + 2E- + H+ --> NADH Both equations above are examples of ______________ reactions because _____________ are accepted. In this case, both FAD and NAD⁺ are ________________. When these reactions occur within the cell, the __________ energy electrons added to the ______________ are supplied to the ________________. Both of these reactions are part of a larger set of individual metabolic reactions that make up the process of _________________.
Both equations above are examples of reduction reactions because electrons are accepted. In this case, both FAD and NAD⁺ are coenzymes. When these reactions occur within the cell, the high energy electrons added to the coenzymes are supplied to the electron transport chain. Both of these reactions are part of a larger set of individual metabolic reactions that make up the process of cellular respiration.
what are all of the products produced during the citric acid cycle of cellular respiration.
CO2 FADH2 ATP NADH
what are the end products of the prep reaction?
CO2 acetyl CoA
What are possible outputs of fermentation?
CO2 alcohol lactate
Cellular respiration is the process by which cells obtain ______________ by breaking down nutrients. This breakdown is accomplished by intake of ____________ and release of ___________ ____________. Cellular respiration involves the complete breakdown of ______________ to carbon dioxide and water. _______________ breakdown is completed in the ________________ of the cell. This breakdown is done through a series of _______________ reactions. The breakdown results in production of the high-energy molecule ___________
Cellular respiration is the process by which cells obtain energy by breaking down nutrients. This breakdown is accomplished by intake of oxygen and release of carbon dioxide. Cellular respiration involves the complete breakdown of glucose to carbon dioxide and water. Glucose breakdown is completed in the mitochondria of the cell. This breakdown is done through a series of oxidation-reduction reactions. The breakdown results in production of the high-energy molecule ATP
Which process of cellular respiration produces the most ATP?
ETC
Which electron carriers bring electrons to the electron transport chain in cellular respiration?
FADH2 NADH
what is an advantage of lactic acid fermentation over cellular respiration?
Fermentation provides a rapid burst of energy when oxygen supplies are limited.
What happens to glucose during cellular respiration?
Glucose is oxidized during cellular respiration.
Describe each: Glycolysis The prep reaction The citric acid cycle The ETC
Glycolysis: occurs outside the mitochondria with or without oxygen present The prep reaction: occurs in the matrix of the mitochondria; produces 1 ATP per turn The citric acid cycle: occurs in the matrix of the mitochondria; occurs twice per glucose molecule
What happens to the end product of glycolysis, pyruvate, if oxygen is not available?
It is broken down in the cytoplasm in a process called fermentation.
what is the cristae the location of?
Location of the electron transport chain
what is the matrix the location of?
Location of the prep reaction and the citric acid cycle
Where does the citric acid cycle occur?
Matrix of the mitochondria
During fermentation pathways, what molecule is regenerated that is essential for glycolysis to continue, allowing the production of a small amount of ATP in anaerobic conditions?
NAD+
In the preparatory reaction, pyruvate undergoes oxidation when it loses electrons that are used to reduce??
NAD+
Which molecule is regenerated during fermentation, making it available to continue serving as a coenzyme in glycolysis?
NAD+
what are the outputs of the ETC?
NAD+ ATP FAD H2O
Which of the following best describes the reduction of the coenzyme NAD?
NAD+ + H --> NADH
what are the coenzymes which function as energy carriers during cellular respiration.
NAD+ and FAD
It is important that NAD+ is regenerated during fermentation because
NAD+ is required for glycolysis to continue.
what are the inputs of the ETC?
NADH ADP FADH2 O2
What are the products of glycolysis?
NADH ATP pyruvate (pyruvic acid)
The electrons that are transferred through the electron transport system initially belonged to
NADH2 and FADH2
what are all of the phases of cellular respiration that are classified as aerobic.
The citric acid cycle The electron transport chain The prep reaction
During which phases of cellular respiration is CO2 produced?
The citric acid cycle The prep reaction
When is fermentation more advantageous than aerobic respiration?
When a quick burst of energy is needed and oxygen is in limited supply
A hydrogen atom consists of
a proton and an electron
Before entering the Krebs cycle, pyruvate is converted to
acetyl CoA
Which of the following is an input to the citric acid cycle?
acetyl groups
The preparatory reaction, citric acid cycle and the electron transport chain all occur in the presence of oxygen and are therefore _______.
aerobic
The construction of ATP by the addition of a phosphate molecule to ADP is an example of?
anabolism
Based on the number of ATP generated during the electron transport chain for every one glucose molecule, how many ATP would be generated if 10 glucose molecules were broken down?
between 320 and 340 ATP molecules
fermentation, cellular respiration or both?: involve an initial energy expenditure?
both
The removal of a phosphate molecule from ATP that forms ADP is an example of _________
catabolism
fermentation, cellular respiration or both?: consists of glycolysis followed by the krebs cycle and the ETC
cellular respiration
fermentation, cellular respiration or both?: net gain of 32 ATP
cellular respiration
fermentation, cellular respiration or both?: occurs when oxygen is in ample supply
cellular respiration
Short, fingerlike projections formed by the folding of the inner membrane of mitochondria are called _________.
cristae
Where is the electron transport chain located?
cristae of mitochondria
During cellular respiration NAD+ and FAD usually carry high energy electrons to the _______ to produce ATP.
electron transport chain
Under aerobic conditions, the end-product of glycolysis is further reduced to yield more ATP. true or false?
false
The energy that is released when hydrogen ions pass through ATP synthase provides the energy needed to form ADP and phosphate from ATP. true or false?
false; ATP is formed from ADP and P in a reaction that requires energy. ADP and P result when ATP is broken down, or hydrolyzed; this reaction releases energy.
The citric acid cycle is responsible for producing the bulk of the ATP generated during cellular respiration. true or false?
false; The citric acid cycle only produces 2 ATP molecules. The electron transport chain produces 32-34 ATP molecules.
The overall goal of the electron transport chain is to break down glucose molecules into pyruvate, producing 2 ATP molecules. true or false?
false; The overall goal of the electron transport chain is to harvest the energy in electrons carried by NADH and FADH2 molecules.
The terminal electron acceptor in the electron transport chain is water. true or false?
false; The terminal electron acceptor in the electron transport chain is oxygen, which produces water.
True or false: Mitochondria creates energy when it converts a carbohydrate into ATP.
false; a sugar to ATP
The reactions that make up cellular respiration occur entirely within the mitochondria of cells. true or false?
false; the reactions that make up cellular respiration occur both in the cytoplasm and the mitochondria of cells.
The anaerobic process that produces a limited amount of ATP in the absence of oxygen is called ____________
fermentation
fermentation, cellular respiration or both?: net gain of 2 ATP
fermentation
fermentation, cellular respiration or both?: occurs when oxygen is in low supply
fermentation
fermentation, cellular respiration or both?: produces lactate, alcohol or one of many other products depending on the species
fermentation
fermentation, cellular respiration or both?: products do not enter the citric acid cycle or ETC
fermentation
what is NADH and FADH2?
formed during the oxidation of citrate electron carriers
Cellular respiration is best described as a metabolic process that uses energy from ______ to produce ATP.
glucose
Glycolysis produces two pyruvate molecules due to the breakdown of the sugar __________
glucose
Glycolysis produces two pyruvate molecules due to the breakdown of the sugar _______________
glucose
what are the inputs for glycolysis?
glucose 2 NAD+ 2 ADP + P 2 ATP
cellular respiration: glucose is __________ to carbon dioxide
glucose is oxidized to carbon dioxide
What are the inputs of glycolysis?
glucose, NAD+, ADP
during the process of glycolysis describe the roles of : glucose pyruvate NADH 4 ATP 2 ATP
glucose: broken down into two 3-carbon pyruvate molecules pyruvate: 3-carbon molecule; two are produced from each glucose molecule broken down NADH: formed from the oxidation of glucose 4 ATP: produced as a result of the oxidation of glucose 2 ATP: used during the process
Which stage of cellular respiration breaks down glucose into two 3-carbon pyruvate molecules?
glycolysis
cellular respiration: what step(s) produces 2 ATP?
glycolysis and citric acid cycle
Cellular respiration: where does glycolysis occur? what happens in the mitochondrial matrix? what happens in the cristae of the mitochondria?
glycolysis--> cytoplasm prep rxn & krebs cycle--> mitochondrial matrix cristae---> ETC
When electrons move through an electron transport chain, they move from a ______ to a _____ energy level.
higher; lower
Where is the ETC found?
inner membrane of mitochondria
The movement of protons through ATP synthase occurs from the
intermembrane space to the matrix.
what are the energy investment steps of glycolysis? what are the energy harvesting steps in glycolysis? what is the net gain ?
investment: -2 ATP harvesting: +2 ATP net gain: 2 ATP
Under anaerobic conditions, the end-product of glycolysis is converted to
lactic acid
where does the citric acid cycle take place?
matrix of mitochondria
Cytochromes can best be described as
membrane proteins that constitute part of the electron transport chain.
Proton pumps are protein complexes that
move hydrogen ions across cell membranes.
ATP
one molecule of this is produced per turn of the cycle
Cells obtain energy by ________ food molecules such as glucose.
oxidizing
The final electron acceptor at the end of the electron transport chain is _______.
oxygen
cellular respiration: oxygen is ___________ to water
oxygen is reduced to water
The role that mitochondria play in the cell is that of a ______.
powerhouse
cellular respiration: what step(s) produces no ATP?
prep rxn and proton pumps of the ETC
During the prep reaction, _____ is converted into acetyl-CoA
pyruvate
During the preparatory reaction of cellular respiration, a 3-carbon molecule called _______________ is converted into acetyl-CoA.
pyruvate
The 3-carbon end product of glycolysis is ______.
pyruvate
during the preparatory reaction phase of cellular respiration describe the roles of: pyruvate acetyl group carbon dioxide
pyruvate: 3-carbon molecule broken down to a 2-carbon and a 1-carbon molecule acetyl group: 2-carbon molecule produced when pyruvate is broken down carbon dioxide: 1-carbon molecule released when pyruvate is broken down
The purpose of the preparatory reaction is to break down ________ into ________ so it can enter the citric acid cycle.
pyruvate; acetyl CoA
Because one molecule loses electrons while another gains them during the process of cellular respiration, this reaction is considered a(n) ________ reaction.
redox
Electrons move along a series of carrier molecules from a higher to lower energy level during which phase of cellular respiration?
the electron transport chain
As protons move through the proton pump,
they build up on one side of the membrane, producing a concentration gradient.
As the hydrogen ions move down their concentration gradient, energy is released. true or false?
true
NADH serves as an electron carrier that can donate its hydrogen to other molecules. true or false?
true
The Krebs cycle occurs in the mitochondrion. true or false?
true
The NADH and FADH2 molecules that are used during the reactions of the electron transport chain are derived from glycolysis, the preparatory reactions, and the citric acid cycle. true or false?
true
True or false: Oxygen is required during aerobic respiration for the electron transport chain to remain functioning.
true
When oxygen accepts electrons, water is produced as a by-product. true or false?
true
Whenever a molecule is oxidized, another molecule must be reduced. TRUE OR FALSE?
true
carbon dioxide
two of these are released for each citrate that is broken down
Which of the following are produced during cellular respiration? choose all that apply: glucose water carbon dioxide fats and lipids oxygen protein energy (ATP)
water CO2 energy (ATP)