Biology Chapter 6
If a cell's carbohydrate supplies run low, ______ monomers of proteins can be converted into molecules that enter the pathways of cellular respiration.
amino acid
Plants conduct photosynthesis. Which of the following conduct cellular respiration?
animals and plants
The Krebs cycle produces ATP, NADH, FADH2, and releases ______, which contains the carbon atoms remaining from the original 6-carbon glucose molecule.
carbon dioxide
Select the molecules that are products of the Krebs cycle.
carbon dioxide NADH ATP FADH2
electron transport in prokaryotes
cell membrane
Select all of the cellular activities that require ATP.
cell movement active transport protein synthesis
When protons diffuse across a membrane through ATP synthase, energy is transferred to phosphorylate an ADP, making ATP in the process called ______ phosphorylation.
chemiosmotic
The first product of the Krebs cycle is the 6-carbon molecule citrate; hence, the Krebs cycle is also known as the ______ cycle.
citric acid
In the picture, the arrows point to mitochondrial folds called
cristae
What increases the surface area of the inner mitochondrial membrane?
cristae
Glycolysis occurs in the ______ of all living cells.
cytosol
Krebs cycle in prokaryotes
cytosol
In what step of aerobic cellular respiration do electrons pass through a series of membrane proteins, and the energy released by their passage is used to created a hydrogen ion gradient?
electron transport chain
Oxygen accepts electrons and combines with hydrogen atoms to form water at the last protein complex in the electron transport chain. Nearby the electron transport chain, the A T P synthase channel protein is also embedded in the inner mitochondrial membrane. What pathway of aerobic respiration is shown in the picture?
electron transport chain
What pathway of aerobic cellular respiration generates ATP by chemiosmotic phosphorylation?
electron transport chain
What step of aerobic respiration generates the most ATP?
electron transport chain
NADH and FADH2 transfer energy-rich ______ from the molecules of glycolysis and the Krebs cycle to the electron transport chain of aerobic respiration.
electrons
True or false: Glucose is the only food molecule that can enter the pathways of aerobic respiration and lead to the production of ATP.
false
The glycerol and fatty acid components of ______ molecules present in food can be converted into pyruvate and acetyl CoA, respectively, which then enter the pathways of aerobic respiration.
fat
Two pathways that cells use to make ATP from glucose without oxygen are anaerobic respiration and
fermentation.
Cellular respiration harvests energy from ______ and uses the energy to power the synthesis of ______ from ADP and a phosphate group.
food molecules; ATP
Before the NADH and FADH2 produced during glycolysis and the Krebs cycle are "cashed in" during the electron transport chain, the net number of ATP molecules produced per glucose molecule is ______ molecules.
four
Aerobic respiration captures energy from the oxidation of ______ and reduction of ______ and stores the captured energy in the bonds of ATP.
glucose; oxygen
During what step of cellular respiration is glucose split into two 3-carbon pyruvate molecules?
glycolysis
The monomers of starch and glycogen food molecules first enter aerobic respiration at what step?
glycolysis
Select all of the following steps of cellular respiration that generate ATP by substrate-level phosphorylation—that is, without a proton gradient.
glycolysis Krebs cycle
Approximately 32% of the potential energy in a molecule of glucose is captured in ATP through aerobic respiration; the remainder is lost as
heat
In the electron transport chain, energy from electron transfers powers the pumping of ______ into the intermembrane compartment by some of the proteins in the chain.
hydrogen ions
Glycolysis can occur
in both aerobic and anaerobic conditions.
The Krebs cycle not only produces ATP and electron carriers, but intermediate molecules formed in the Krebs cycle can also be used
in pathways that manufacture amino acids or fats.
electron transport in eukaryotes
inner mitochondrial membrane
Within mitochondria, the electron transport chain and ATP synthase proteins are located in the
inner mitochondrial membrane.
The area between the outer and inner membranes of a mitochondrion is called the ______ compartment.
intermembrane
What space of the mitochondrion is the arrow pointing to in the picture?
intermembrane compartment
The arrow is pointing to what component of a mitochondrion?
matrix
The fluid enclosed within the inner membrane of a mitochondrion is called the
matrix
Within mitochondria, the Krebs cycle takes place in the
matrix
In the cells of protists, plants, fungi, and animals, the Krebs cycle and the electron transport chain take place in organelles called
mitochondria.
Krebs cycle in eukaryotes
mitochondrial matrix
Pyruvate is the product of glycolysis, and after it moves into the ______, it is oxidized to form ______ that enters the Krebs cycle.
mitochondrial matrix; acetyl CoA
What organelle in a eukaryotic cell provides most of the cell's ATP?
mitochondrion
In aerobic respiration, the final electron acceptor, ______, combines with hydrogen ions to form water.
oxygen
In substrate-level phosphorylation, a molecule donates a(n) ______ group to ADP to form ATP, and a ______ is not required.
phosphate; proton gradient
glycolysis
produces 4 ATP but requires 2 ATP; so net 2 ATP are produced
Select molecules that have stored potential energy and that can be used in aerobic respiration to generate ATP.
proteins carbohydrates lipids
In the electron transport chain, electrons are shuttled through a series of membrane proteins, which creates a gradient of _________________ ions across the inner mitochondrial membrane.
proton or hydrogen
In glycolysis, a glucose molecule is split into two molecules of ______, and energy is harvested as ATP and NADH.
pyruvate
Select all of the following that are reactants of pyruvate oxidation during the "transition step" of cellular respiration.
pyruvate NAD+
Cellular respiration is an oxidation-reduction reaction that ______ energy, which the cell uses to synthesize ______.
releases; ATP
Select all the food molecules that can be broken down into glucose monomers, which enter aerobic respiration at the beginning of glycolysis.
starch glycogen
How is ATP formed during the Krebs cycle?
substrate-level phosphorylation
What method is used to generate ATP in glycolysis?
substrate-level phosphorylation
When the electron carrier molecules NADH and FADH2 enter ______, electrons are removed, and the energy pumps protons into the intermembrane compartment of the mitochondrion.
the electron transport chain
How do organisms make ATP?
using potential energy stored in molecules
Select reactions that occur during the first stage of glycolysis, called the energy investment stage, which consists of the first five reactions.
-A 6-carbon intermediate is split into two 3-carbon molecules. -Phosphate is transferred to glucose
Select all of the following that cause the difference between the theoretical and actual yields of ATP in aerobic respiration.
-ATP is spent transporting pyruvate and ADP into the mitchondrial matrix. -Protons leak across the inner mitochondrial membrane without using ATP synthase
Select all of the following that are products in the overall equation for aerobic respiration.
-CO2 (carbon dioxide) -ATP (adenosine triphosphate)
Select all of the following that are stages of aerobic cellular respiration.
-Krebs cycle -electron transport chain -glycolysis
Select reactions that occur during the second stage of glycolysis, called the energy harvest stage and consisting of reactions 6 through 10.
-Two molecules of pyruvate are produced. -ATP is generated by substrate-level phosphorylation. -NAD+ is reduced to NADH.
Select all of the following that are encoded by mitochondrial DNA.
-proteins of the electron transport chain -ATP synthase
Select all of the following that are true of ATP synthesis.
-requires an input of energy (endergonic reaction) -a phosphate group is added to ADP
Rank the 3 groups of reactions of aerobic respiration in the order they occur, beginning with the first stage of cellular respiration at the top.
1. glycolysis 2. Krebs cycle 3. electron transport chain
How many molecules of ATP are produced in the Krebs cycle per every two molecules of acteyl CoA that enter the Krebs cycle?
2 ATP
Krebs cycle
2 ATP
Although the theoretical yield of ATP per one molecule of glucose in aerobic respiration is about 36 ATP, the actual yield is about ______ ATP per glucose.
30
electron transport
34 ATP
theoretical total
36 ATP
The oxidation of glucose during aerobic respiration yields ATP, NADH, and FADH2 molecules. In theory, the ATP yield during the electron transport chain is ______ molecules of ATP per NADH and ______ molecules of ATP per FADH2.
3; 2
ATP synthase is an enzyme that forms a channel for hydrogen ions to diffuse across a membrane and power the formation of
ATP
Mutations to mitochondrial DNA may cause severe disorders if the genes that code for electron transport proteins or ATP synthase are affected because ______ may not be generated.
ATP
Organisms in oxygen-rich environments use aerobic cellular respiration to generate
ATP
The potential energy stored in food (such as glucose) is used by all organisms to make the energy-carrying molecule ________________, which powers cellular activity.
ATP
What molecule powers most energy-requiring cell activities, including active transport, movement of chromosomes and flagella, muscle contraction, and the synthesis of organic molecules?
ATP
Select all of the following that are required for glycolysis to occur.
ATP glucose
What enzyme uses the energy of a proton gradient to add a phosphate to ADP?
ATP synthase
Glycolysis generates 4 ________molecules per glucose, but requires an input of ___________ ATP molecule(s), producing a net of 2 ATP molecules per glucose.
ATP; 2
Shark
Blood is circulated through gills, and water passing by blood vessels causes diffusion of oxygen into blood vessels and diffusion of carbon dioxide out of blood vessels.
Aerobic cellular respiration requires that ______ diffuses out of cells, and ______ diffuses into cells.
CO2; O2
Select all of the following that have been produced from the original glucose molecule after glycolysis, oxidation of pyruvate, and the Krebs cycle occur, but before molecules enter the electron transport chain.
FADH2 CO2 NADH ATP
Select all the products of glycolysis and the Krebs cycle that carry electrons to the electron transport chain in aerobic respiration.
FADH2 NADH
Select all of the electron-carrier molecules produced by the Krebs cycle.
FADH2 (flavin adenine dinucleotide) NADH (nicotinamide adenine dinucleotide)
Bacteria
Gases diffuse across cell membrane.
human
Inhaling and exhaling of air causes diffusion of oxygen into blood vessels and diffusion of carbon dioxide out of blood vessels at the lungs
In aerobic respiration, what group of reactions releases CO2, ATP, NADH, and FADH2?
Krebs cycle
Intermediates from what pathway can be used in the manufacture of amino acids and fats?
Krebs cycle
Select all of the molecules that are reactants of glycolysis.
NAD+ glucose
What electron carrier molecule is generated during the reactions of glycolysis?
NADH
The electron transport chain accepts energy-rich electrons from ______ and ______ produced in the previous reactions of aerobic respiration.
NADH FADH2
The electron transport chain harnesses the potential energy of the molecules ______, which donate electrons to proteins in the electron transport chain.
NADH and FADH2
The molecules ______ that are produced by glycolysis and the Krebs cycle must move to the inner mitochondrial membrane to enter the electron transport chain.
NADH and FADH2
The rearrangement and oxidation of intermediates in the Krebs cycle transfers electrons to what molecules?
NADH and FADH2
The first protein in the electron transport chain accepts electrons from ______, and the second protein in the electron transport chain accepts electrons from ______.
NADH; FADH2
What happens to the carbon atoms in the two-carbon acetyl group that enters the Krebs cycle?
They are released as CO2.
True or false: Plants use a portion of the glucose they produce in photosynthesis to make ATP in cellular respiration.
True
The potential energy of ______ is used to power the production of ATP in chemiosmotic phosphorylation.
a proton gradient
What molecule carries potential energy originally present in the chemical bonds of glucose and enters the Krebs cycle?
acetyl CoA
What product of pyruvate oxidation enters the Krebs cycle?
acetyl CoA
Select all of the following that are products of the "transition step" in aerobic cellular respiration.
acetyl CoA CO2 NADH
C6H12O6 + 6O2 → 6CO2 + 6H2O + 36ATP is the overall equation for what process?
aerobic respiration
What cellular process uses glucose and oxygen to produce ATP?
aerobic respiration
