BIOL 303: Test 3
Types of ETC carriers
- Flavoproteins: polypeptides bound to either flavin adenine dinucleotide or flavin mononucleotide - Cytochromes: contain heme groups bearing Fe or Cu ions - Copper ions (3) located within protein complex - Coenzyme Q: lipid-soluble molecule made of 5-carbon isoprenoid units - Iron-Sulfur proteins: contain Fe association with inorganic sugar
The three catalytic sites of ATP synthase ___________.
- have different substrate binding affinities - have different product binding affinities -at any one time are present in different conformations - pass sequentially through their three different conformations
How NADH enters mitochondria
- malate-asparate shuttle, which allows electrons to move across the impermeable membrane between cytosol and the mitochondrial matrix - glycerol-3-phosphate shuttle: translocates electrons by oxidizing cytoplasmic NADH to NAD+
On average, how many ATPs would be made if 6 NADH and 4 FADH2 molecules donated their high-energy electrons to the mitochondrial electron transport chain?
26
How many catalytic sites does ATP synthase possess?
3
Cyanide poisons the ETC. Which of the following could still be produced by the mitochondria in the presence of cyanide? A-ATP B - Proton gradient C - Water D - NAD+
A - ATP
Which of the following contributes to the gel-like component of the extracellular matrix? A - Glycosaminoglycans B - Laminins C - Collagen D - Hemidesmosomes
A - Glycosaminoglycans
What is an electron acceptor? A - The molecule that is reduced in a redox reaction B - A reducing agent C - NADH & FADH2 D - A molecule with low electron affinity E - None of the above
A - The molecule that is reduced in a redox reaction
Glycolysis
A metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and release energy for the body in the form of ATP
Lactic Acid Fermentation
A series of anaerobic chemical reactions using pyruvic acid that supplies energy when oxygen is scarce
Which of the following statements is FALSE about cytochrome oxidase?
Activity of the enzyme leads to production of oxygen.
Which of the following is/are carbon product(s) of pyruvate processing AND Kreb's cycle I. Acetyl CoA II. CO2 III. NADH IV. ATP A - I only B - II only C - I & II D - II, III & IV
B - II only
Which of the following is true of oxidative phosphorylation? A - FADH2 enters the electron transport chain through complex I, FADH2 dehydrogenase B - NADH enters the electron transport chain through complex I, NADH dehydrogenase C - FADH2 enters the electron transport chain through complex II, cytochrome bc1 D - NADH enters the electron transport chain through complex II, succinate dehydrogenase
B - NADH enters the electron transport chain through complex I, NADH dehydrogenase
Which of the following processes cannot be used by human cells to produce ATP in the absence of oxygen? A - lactic acid fermentation B - ethanol fermentation C - creatine phosphate hydrolysis D - increase productivity of fast-twitch muscle fibers
B - ethanol fermentation
You have a petri dish coated in fibronectin. Which combination of cells and ECM contents will likely prevent adhesion of cells to the cell plate? A - Cell culture, excess proteoglycans B - Cell culture, excess actin and myosin (for adherens junctions) C - Cell culture, excess laminins D - Cell culture, excess collagen
C - Cell culture, excess laminins
Bullous pemphigoid is an autoimmune disease which creates blisters on the patient's skin. This is likely linked to malfunction of: A - Tight junctions B - Desmosomes C - Hemidesmosomes D - Collagen
C - Hemidesmosomes
Which of the following are held together by homophilic adhesion molecules that could be disrupted by agents that sequester calcium ions? I. Desmosomes II. Hemidesmosomes III. Adherens junctions IV. Tight junctions A - I only B - II & III C - III only D - II, III & IV
C - III only
Which of the following is not a sign of a mitochondrial disease or disorder? A - Loss of apoptotic regulation B - Maternal inheritance of the disorder C - Increased succinate dehydrogenase function D - Premature aging
C - Increased succinate dehydrogenase function
Which of the following is not true of mitochondria? A - It is the site the of aerobic cellular respiration. B - It contains its own mitochondrial DNA which is maternally inherited. C - It is the site of lactic acid fermentation in the absence of oxygen. D - It is involved in apoptotic pathways.
C - It is the site of lactic acid fermentation in the absence of oxygen.
Which of the following is true of ATP synthase? A - It utilizes revolutionary catalysis, which describes movement of the alpha subunit powered by proton motive force B - It utilizes rotational catalysis, which describes movement of the alpha subunit powered by proton motive force C - It utilizes rotational catalysis, which describes movement of the gamma subunit powered by proton motive force D - It utilizes revolutionary catalysis, which describes movement of the gamma subunit powered by proton motive force
C - It utilizes rotational catalysis, which describes movement of the gamma subunit powered by proton motive force
Which of the following describes a function of the ECM? A - Physical support of the cell through strength and turgor in the interior side of the plasma membrane B - Serving as a molecular "soup" for cells to swim in C - Mediating intercellular communication which contributes to intracellular activity D - Limiting the rate of reactions through increased cellular interactions
C - Mediating intercellular communication which contributes to intracellular activity
Warburg Effect
Cancer cells will consistently use lactic acid fermentation and aerobic glycolysis even when oxygen is available and will not use oxidative phosphorylation; glycolysis only produces 2 ATP; so cancer cells need a ton of glucose
________ were responsible for the accumulation of significant levels of atmospheric oxygen on Earth between 2.4 and 2.7 billion years ago.
Cyanobacteria
Which of the following is an energetic product of glycolysis AND Kreb's cycle? A- ATP, FADH2 B - NADH, FADH2 C - ATP, CO2
D - ATP, NADH
Which of the following contains the correctly matched junction and function? A - Tight junctions- allow the passage of small water-soluble molecules from cell to cell B - Adherens junctions- connects the actin filaments in one cell to actin filaments in the next cell C - Desmosomes- anchors intermediate filaments in a cell to the extracellular matrix D - Focal adhesions- anchors intermediate filaments in a cell to a petri dish
D - Focal adhesions- anchors intermediate filaments in a cell to a petri dish
Which of the following explains FADH2 behavior as an electron carrier? A - FADH2 is a stronger reducing agent than NADH, allowing it to bypass Complex I of the ETC B - FAD holds higher energy electrons that must be coupled with a reaction of lower redox potential C - Oxidation of FADH2 is paired to the succinate-fumarate redox reaction because FAD is a lower affinity electron acceptor and succinate-fumarate reaction has a more negative redox potential D - Oxidation of FADH2 is paired to the succinate-fumarate redox reaction because FAD is a higher affinity electron acceptor and succinate-fumarate reaction has a more positive redox potential
D - Oxidation of FADH2 is paired to the succinate-fumarate redox reaction because FAD is a higher affinity electron acceptor and succinate-fumarate reaction has a more positive redox potential
Which of the following correctly pairs the metabolic process with its location and products? A - Glycolysis occurs in the cytosol and produces 2 acetyl coA and 2 ATP B - TCA cycle occurs in the inner mitochondrial membrane and produces 4 CO2, 6 NADH, 2 FADH2, and 2 ATP C - The ETC is on the outer mitochondrial membrane and produces water and a proton gradient D - The ETC is on the inner mitochondrial membrane and produces water and a proton gradient.
D - The ETC is on the inner mitochondrial membrane and produces water and a proton gradient.
Which of the following statements is incorrect with respect to the chemiosmotic coupling hypothesis? A - ATP synthesis is a function of electron transport and oxidative phosphorylation. B - Coupling of ATP synthesis to electrons transfer is via the electrochemical H+ gradient across a membrane. C - Energy from electrons transport is responsible for the active transport system. D - The active transport system pumps protons into the mitochondrial matrix out of the intermembrane space. E - The electrochemical gradient of protons creates a lower pH outside the inner mitochondrial membrane relative to the inside.
D - The active transport system pumps protons into the mitochondrial matrix out of the intermembrane space.
Complexes I and II each transfer electrons immediately to ______.
E - Coenzyme Q/ Ubiquinone
ATP Synthase
F1 particle contains 3 catalytic sites; F0 protein is embedded in the inner membrane; H+ moves through the F0 particle; ATP synthase is highly conserved
Cristae
Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.
Integrin
Integrate intra- and extracellular environments; cell-cell and cell-substratum interactions; consists of 2 non-covalently linked polypeptide chains; can be in active (elongated) or inactive (tight) conformation
Bind change mechanism for ATP synthase
Movement of protons through ATP synthase alters the binding affinity of the active site; Each active site goes through distinct conformations that have different affinities for substrate and product
Types of electron carriers found in the electron transport chain of the inner mitochondrial membrane do NOT include:
NAD
Which of the following are reduced coenzymes?
NADH and FADH2
Which of the following statements about mitochondrial diseases is TRUE?
Oxygen radicals formed in mitochondria cause an increased mutation rate in mtDNA relative to nuclear DNA.
Which of the following BEST describes the mechanism by which ATP is synthesized by ATP synthase using the energy of proton movement?
Protons move through the Fo subunit and rotate the γ subunit, inducing changes in the conformation of the β subunit catalytic sites and allowing formation and release of ATP.
Anaerobic respiration
Respiration in the absence of oxygen. This produces lactic acid.
Aerobic respiration
Respiration that requires oxygen
Mitochondrial matrix
The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle.
Inner Mitochondrial Membrane
The inner mitochondrial membrane is the innermost membrane of the mitochondria. Oxidative phosphorylation and chemiosmosis take place at the inner mitochondrial membrane, which produces ATP via the flow of protons across the membrane.
Which one of the following statements is FALSE regarding action of the Fo portion of ATP synthase?
The movement of electrons through the membrane drives the rotation of the ring of c subunits.
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.
What advantage do the cristae confer on the mitochondria?
They greatly increase the surface area for aerobic respiration machinery.
TCA cycle
a series of metabolic reactions that break down molecules of acetyl CoA to carbon dioxide and hydrogen atoms
In what form does a portion of the product of glycolysis enter the TCA cycle?
acetyl CoA
The composition of the inner mitochondrial membrane is MOST like that of:
bacterial plasma membranes.
Glycoproteins function
cellular organization and interaction
Extracellular matrix
components: proteins, polysaccharides; functions: physical support, movement, growth/proliferation, cell-cell interactions
The Fo portion of the ATP synthase:
contains a channel through which protons can move from the intermembrane space to the mitochondrial matrix.
Match the ETC complex to the type of electron carriers they use: a.) Complex I, FADH2 b.) Complex II, NADH c.) Complex III, FADH2 d.) Complex IV, Oxygen
d.) Complex IV, Oxygen
Which of the following is NOT a feature of oxidative phosphorylation?
direct transfer of phosphate from a substrate molecule to ADP, also known as substrate-level phosphorylation)
According to the rotational catalysis model, _______ energy stored in the proton gradient is transduced into ________ energy of a rotating stalk, which is transduced into __________ energy stored in ATP.
electrical; mechanical; chemical
During aerobic exercise, muscle fibers first use glycogen for energy and then they switch to use of:
free fatty acids.
Fibrous proteins
functions: structure; collagen: fibrous glycoproteins, quaternary structure is triple helix; bundled into fibrils (multiple molecules overlap)
Protoglycans
gel-like, glycosaminoglycans linked to proteins, an form large extended structures
Write the net reaction for glycolysis and the TCA cycle
glycolysis: glucose+NAD+ +2ADP+2Pi→2pyruvate+2ATP +2NADH+2H+ +2H2O TCA cycle: acetyl CoA + 2 H2O + FAD + 3 NAD+ + GDP + Pi → 3 CO2 + FADH2 + 3 NADH + 3 H+ + GTP + HS-CoA
ATP synthase is located:
inner mitochondrial membrane
Mitochondrial disease
linked to mutations in mtDNA, inherited from mother, can lead to the release of reactive oxygen species into the cell which can damage cellular structure and nuclear DNA
Cadherins
mediates adhesion between different types of cells, adhesion is reliant of Ca2+ being bound to cadherin extracellular domain
At the end of the electron transport chain, low-energy electrons are transferred to ______, which is the terminal electron acceptor, forming ______.
molecular oxygen (O2); water (H2O)
Types of electron carriers for the electron-transport chain include all of the following EXCEPT __________
molybdenum.
To what is the 2-carbon fragment of acetyl CoA added to make citric acid at the start of the Krebs cycle?
oxaloacetate
Most of the ATP made during cellular respiration is generated through ________.
oxidative phosphorylation.
Anaerobic metabolism provides energy for muscle contraction when the supply of ___________ is limited.
oxygen
What are the two components of the proton-motive force?
pH gradient and voltage
In what molecule is most of the energy of glucose stored at the end of glycolysis?
pyruvate
Mitochondria functions
regulate apoptosis pathway, energy metabolism, uptake and release of calcium for signaling, maintains redox balance to prevent oxidative damage, synthesizes amino acids and heme groups, mtDNA replication
Which of the following would NOT be found as part of the mitochondrial matrix?
ribosomes larger than those in the cytoplasm of the cell
The F1 portion of mitochondrial ATP synthase:
synthesizes ATP
Outer Mitochondrial Membrane
the membrane that separates the contents of the mitochondrion from the rest of the cell, creating a cellular compartment with the ideal conditions for aerobic respiration.
Observations of mitochondria within living cells have shown that:
they can exist as a highly branched, interconnected tubular network.
Each pair of electrons transferred from NADH to oxygen by means of the electron-transport chain releases sufficient energy to drive the formation of approximately how many molecules of ATP?
three