9: Energy from Organic Molecules II Flashcards
Module 2, Lesson 3
In the first three stages of aerobic cellular respiration, each glucose molecule is oxidized to form…
(4 items)
6 molecules of carbon dioxide
4 molecules of ATP
10 molecules of NADH
2 molecules of FADH2
The fourth stage of cellular respiration is the…
Electron transport chain (ETC) and chemiosmosis
The majority of the ATP synthesized from glucose oxidation is made via…
Oxidative phosphorylation
The cell’s predominant method of synthesizing ATP from glucose is…
Oxidative phosphorylation
The electron transport chain involves the…
Orderly extraction of energy from electrons
True or false:
The ETC enables the cell to extract all the energy from electrons at once.
False
Like respiration of glucose, the ETC occurs over several steps.
Once all their energy has been extracted, electrons are transported to the…
Final electron acceptor
During aerobic respiration, the final electron acceptor is…
Molecular oxygen
True or false:
The electron transport chain directly produces ATP.
False
The electron transport chain produces a proton gradient, which is then used to produce ATP.
The electron transport chain involves a series of ____ and ____.
Membrane-bound protein complexes and lipid-soluble electron carriers.
The electron transport chain occurs in the…
Inner mitochondrial membrane
The ETC includes three ____ that harvest energy from electrons and pass the lower-energy electrons onward.
Transmembrane enzyme complexes
The transmembrane protein complexes use the energy from electrons to…
Pump protons from the mitochondrial matrix to the intermembrane space.
The ETC ensures that there are ____ protons in the intermembrane space than in the matrix.
More
(greater concentration)
List the three transmembrane enzyme complexes.
- NADH dehydrogenase
- bc1 complex
- Cytochrome oxidase complex
After harvesting energy, NADH dehydrogenase transfers electrons to…
A lipid-soluble electron carrier
(abbreviated “Q”)
The lipid-soluble elctron carrier “Q” transfers electrons to…
the bc1 complex
The bc1 complex transfers electrons to…
Cytochrome C
Cytochrome C transfers electrons to…
the cytochrome oxidase complex
At the end of the electron transport chain, molecular oxygen is reduced to form…
1 molecule of water
True or false:
The electrons in FADH2 only pass through two of the transmembrane complexes.
True
Which transmembrane enzyme complex does FADH2 electrons skip?
NADH dehydrogenase
Instead of giving its electrons to NADH hydrogenase, FADH2 transfers them to…
Ubiquinone
The purpose of the electron transport to chain is to…
Create a proton concentration gradient
The purpose of chemiosmosis is to…
Produce ATP by moving protons
The proton concentration gradient represents…
Potential energy
The force created by the proton gradient is similar to that created by…
Osmosis
ATP formation during chemiosmosis is driven by the ____ force.
Proton-motive
True or false:
The inner mitochondrial membrane is relatively impermeable to ions.
True
This is why protons require assistance to cross it.
____ moves protons across the inner membrane.
ATP synthase
The movement of protons across the inner membrane during chemiosmosis is an example of…
Facilitated diffusion
During chemiosmosis, protons are moved ____ their concentration gradient.
Down
ATP synthase is made up of a ____ connected to a ____.
Membrane-bound channel protein ; enzymatic head portion
1 ATP molecule is produced for every ____ protons.
Four
The electrons from one molecule of FADH2 can power the movement of ____ protons.
Six
Each FADH2 molecule has enough energy to produce ____ ATP molecules.
1.5
The electrons from one NADH molecule can power the movement of ____ protons.
Ten
Each NADH molecule has enough energy to generate ____ molecules of ATP.
2.5
Glycolysis produces…
2 ATP
Pyruvate oxidation produces…
No ATP
(directly)
The Krebs cycle produces…
2 ATP
The electron transport chain and chemiosmosis produce…
28 ATP
Prokaryotes produce a total of ____ ATP from the aerobic respiration of one glucose molecule.
32
Eukaryotes produce a total of ____ ATP from the aerobic respiration of one glucose molecule.
30
Why do eukaryotes produce less ATP from aerobic respiration of glucose?
Moving each NADH molecule into the mitochondria requires 1 ATP
True or false:
Cells require oxygen to be able to use the electron transport chain.
False
Some cells can still use the ETC even in the absence of oxygen.
____ cellular respiration is performed in the absence of oxygen.
Anaerobic
In anaerobic respiration, ____ replace molecular oxygen as the final electron acceptors.
Inorganic molecules
List three inorganic molecules that can replace oxygen as the final electron acceptor.
- Sulfur
- Carbon dioxide
- Inorganic metals
Anaerobic respiration generates ____ ATP than aerobic respiration, because…
Less ; the replacement molecules have less affinity for electrons than oxygen.
____ occurs when cells extract energy from organic molecules using an organic molecule as the final electron acceptor.
Fermentation
True or false:
Cells can perform glycolysis without oxygen.
True
Fermentation enables glycolysis to continue by…
Regenerating NAD+
When bacteria perform fermentation, the final electron acceptor is…
Pyruvate or a derivative of pyruvate
When eukaryotes perform fermentation, the final electron acceptor is often ____ or ____.
Yeast or pyruvate (lactic acid)
When yeast is used as the final electron acceptor, it produces…
Carbon dioxide, ethanol, and NAD+
Many muscle cells in animals can transfer electrons from NADH to pyruvate, producing…
Lactic acid
Lactic acid fermentation is useful because…
It allows some ATP production to continue as long as glucose is available.
What causes the burning sensation felt due to muscle fatigue?
A buildup of lactic acid in the muscle cells, as a result of fermentation
True or false:
Glucose is the only source of energy for cells.
False
Cells can also extract energy from several types of macromolecules.
List three macromolecules that serve as major energy sources for the cell.
- Polysaccharides
- Proteins
- Lipids
no, not glucose - glucose is not a macromolecule!
During catabolism of proteins, the proteins are broken down into…
Amino subunits
During catabolism, the amino group is removed from an amino acid via a ____ reaction.
Deamination
During the catabolism of fats, they are broken down into…
Fatty acids and glycerol
Fatty acids are converted into a 2-carbon acetyl group using…
Beta (β) oxidation
The respiration of 6-carbon fatty acids produces 20% ____ energy than glucose.
More
The molecules formed by the oxidation of macromolecules then enter…
The Krebs cycle