Mixed 3 Flashcards
How many cytochrome c molecules are involved in the reduction of one O2 molecule?
A. 2
B. 8
C. 4
D. 3
C. 4
Which complex in the electron transport chain accepts electrons from FADH2?
A. Complex I
B. Complex II
C. Complex III
D. Complex IV
B. Complex II
How many moles of O2 are reduced by one mole of NADH?
A. 2
B. 0.5
C. 0.25
D. 1
B. 0.5
The redox reaction of NADH and O2 forming NAD+ and H2O in the electron transport chain take place primarily in which area in the mitochondrion?
A. Outer mitochondrial membrane
B. Cristae
C. Matrix
D. Inner mitochondrial membrane
C. Matrix
Which of the following does not explain the highly negative phosphorylation potential?
A. Charge repulsion
B. Solvation effects
C. Entropy
D. Resonance
C. Entropy
What is the charge of ATP inside the cell?
A. -4
B. -1
C. 0
D. -3
E. -2
A. -4
True or False: All substrate-level phosphorylation reactions are coupled reactions.
True
Which of the following statements is FALSE about phosphorylation reactions?
A. Substrate-level phosphorylations take place in the cytosol while oxidative phosphorylations occur in the outer mitochondrial membrane.
B. Oxidative phosphorylations take more time than substrate-level phosphorylation.
C. Oxidative phosphorylations harvest more energy from a specific source than substrate-level phosphorylation.
D. Substrate-level phosphorylations require a phosphorylated compound while oxidative phosphorylations require electron transporters.
A. Substrate-level phosphorylations take place in the cytosol while oxidative phosphorylations occur in the outer mitochondrial membrane.
Which of the following electron transfer DOES NOT occur in the electron transport chain?
A. Transfer of hydrogen atom (H+ + e—)
B. Transfer of hydride (H—)
C. Transfer of superoxide radical (O2—)
D. Direct transfer of electron/s
C. Transfer of superoxide radical (O2—)
On electron acceptors in the electron transport chain, which of the following statements is TRUE?
A. NAD accepts two electrons and FAD accepts one electron in their complete reduction reactions.
B. NAD accepts one electron and FAD accepts two electrons in their complete reduction reactions.
C. Both NAD and FAD accepts two electrons in their complete reduction reactions.
D. Both NAD and FAD accepts one electron in their complete reduction reactions.
C. Both NAD and FAD accepts two electrons in their complete reduction reactions.
Consider the following sentences.
A. NAD+ absorbs at both 260 nm and 340 nm.
B. NAD+ absorbs at 340 nm but not at 260 nm.
C. NADH absorbs at both 260 nm and 340 nm.
D. NADH absorbs at 260 nm but not at 340 nm.
Which of the above sentences are true?
A. A and C
B. C only
C. A only
D. B and D
B. C only
Which of the following does not explain the highly exergonic hydrolysis of ATP in the biochemical standard state?
A. The phospholinkage in ATP is unstable inside the cell.
B. The products are well solvated.
C. There is resonance in at least one of the products.
D. The process relieves charge repulsion in the ATP molecule.
A. The phospholinkage in ATP is unstable inside the cell.
Even though the linkage is unstable primarily because of charge repulsion, this is kept stable by mechanisms inside the cell, e.g. interaction with Mg2+ ions.
True or False: The hydrolysis of ATP is more exergonic inside the cell than if it were to take place in the biochemical standard state.
True. The cell ensures that the concentration of the reactants are greater than the concentration of the products thereby giving a more exergonic process.
In the neurons, electrons from NADH enters the electron transport chain via ___ ?
A. Complex III
B. Complex IV
C. Complex I
D. Complex II
A. Complex III
The electrons bypass Complex II and are passed to mitochondrial glycerol-3-phosphate dehydrogenase via FAD which reduce ubiquinone.
An organism has 9 c subunits in the c ring of its Fo in the ATP synthase. What is the proton cost per ATP for this organism?
A. 3.7
B. 4.0
C. 2.5
D. 4.3
B. 4.0
One full rotation of the ATP synthase pumps 9 protons back to the matrix producing 3 ATP molecules at the same time. For the transport of ATP and the substrates ADP and Pi, 1 ATP molecule is needed. Add 9 + 3 = 12. 12 protons/3 ATP gives a value of 4.0
An organism has 9 c subunits in the c ring of its Fo in the ATP synthase. What is the P/O ratio for this organism?
A. 4.0
B. 3.0
C. 2.5
D. 2.7
C. 2.5
Using the consensus that 1 molecule of NADH leads to pumping of 10 protons to the intermembrane space and the previously calculated proton cost per ATP of 4.0:
10 (protons/NADH) x (ATP/4 protons) = 2.5 ATP/NADH
An organism has 9 c subunits in the c ring of its Fo in the ATP synthase. How many ATP molecules are stoichiometrically produced from 1 molecule of FADH2 in its mitochondria?
A. 2.0
B. 1.5
C. 3.0
D. 2.5
B. 1.5
Using the fact that the oxidation of 1 FADH2 in the electron transport chain starts at Complex III, 6 protons are pumped to the intermembrane space. With the computed proton cost per ATP of 4.0:
6 (protons/FADH2) x (ATP/4 protons) = 1.5 ATP/FADH2
An organism has 9 c subunits in the c ring of its Fo in the ATP synthase. Furthermore, the organism was exposed to a compound that inhibits its Complex III. In this case, how many ATP molecules are stoichiometrically produced from 1 molecule of NADH in its mitochondria assuming that oxygen is still being reduced in the electron transport chain?
A. 2.5
B. 1.5
C. 1.0
D. 3.0
C. 1.0
Which steps in glycolysis are irreversible?
A. Step 10
B. Step 8
C. Step 3
D. Step 7
E. Step 9
F. Step 6
G. Step 1
H. Step 4
I. Step 2
J. Step 5
A, C, G
What are the fates of pyruvate, the end-product of glycolysis? Select all that apply.
A. fermented to alcohol
B. converted to acetyl-CoA that enters the Kreb’s cycle
C. serves as precursor for some anabolic pathways
D. fermented to lactic acid
All choices.
How many ATP molecules are produced when 6 molecules of glucose enter glycolysis?
12
How many molecules of NADH are produced if 12 molecules of glucose enter the glycolytic pathway?
24
If 12 molecules of glucose enter the glycolytic pathway, how many ATP molecules can be generated in the electron transport chain from the NADH produced in the pathway assuming that there are 10 c subunits in the Fo complex of the organism?
55
Glycolysis converts one glucose molecule into what?
A) 2 ATP, 2 pyruvate, 2 NADH
B) 3 ATP, 2 pyruvate, 2 NADH
C) 2 ATP, 2 pyruvate, 10 NADH
D) 3 ATP, 2 pyruvate, 10 NADH
A) 2 ATP, 2 pyruvate, 2 NADH
True or False: The citric acid cycle occurs twice for each glucose molecule.
True
In the presence of oxygen, pyruvate is converted into what during pyruvate oxidation?
A) Lactate
B) Acetyl CoA
C) Oxaloacetate
D) Glucose
B) Acetyl CoA
True or False: The electron transport chain produces the majority of ATP in cellular respiration.
True
What is the terminal electron acceptor in the electron transport chain?
A) NADH
B) Oxygen
C) FADH2
D) Carbon dioxide
B) Oxygen
What is Saccharomyces cerevisiae commonly known as?
A) Brewer’s yeast
B) Baker’s yeast
C) Wine yeast
D) All of the above
D) All of the above
True or False: Sucrose is a disaccharide composed of glucose and fructose.
True
Which enzyme converts sucrose into glucose and fructose?
A) Amylase
B) Invertase
C) Maltase
D) Zymase
B) Invertase
True or False: Flour contains amylase which breaks up starch.
True
What is the expected result for a bottle setup with 200 mL water + 1 tbsp yeast?
A) Release CO2
B) No release of CO2
B) No release of CO2
In the absence of oxygen, what does yeast switch to for metabolism?
A) Respiration
B) Fermentation
B) Fermentation
True or False: Anaerobic respiration in yeast produces alcohol and CO2.
True
What enzyme converts pyruvate to acetaldehyde in yeast?
A) Alcohol dehydrogenase
B) Pyruvate decarboxylase
C) Maltase
D) Invertase
B) Pyruvate decarboxylase
Which enzyme is involved in the digestion of milk proteins in young mammals?
A) Pepsin
B) Renin
C) Amylase
D) Lipase
B) Renin
True or False: Renin is replaced by pepsin as the major enzyme in the stomach over time.
True
True or False: High total acidity in gastric juice can lead to hyperacidity and duodenal ulcers.
True
What are the components of the pancreatic solution used in the small intestine digestion experiment?
A) Lipase, proteases, and pancreatic amylase
B) Lipase and bile salts
C) Proteases and amylase
D) Lipase, proteases, and invertase
A) Lipase, proteases, and pancreatic amylase
What role do bile salts play in lipid digestion?
A) Emulsification of lipids
B) Breaking down proteins
C) Converting starch to glucose
D) Hydrolyzing sucrose
A) Emulsification of lipids
True or False: Orlistat is an inhibitor of lipase.
True
Which enzyme mechanism involves His-263 and Ser-152 in lipid digestion?
A) Pancreatic lipase
B) Pepsin
C) Amylase
D) Renin
A) Pancreatic lipase
True or False: The presence of oxygen in yeast metabolism leads to fermentation.
False
True or False: The enzyme enolase is inhibited by fluoride.
True
What is the role of oxygen in the electron transport chain (ETC)?
A) Electron donor
B) Final electron acceptor
C) Proton donor
D) ATP producer
B) Final electron acceptor
Which step in glycolysis produces ATP?
A) Glucose to glucose-6-phosphate
B) Fructose-6-phosphate to fructose-1,6-bisphosphate
C) 1,3-bisphosphoglycerate to 3-phosphoglycerate
D) Phosphoenolpyruvate to pyruvate
E) A and D
F) C and D
G) B and D
F) C and D
In the absence of oxygen, what happens to NADH produced during glycolysis?
A) It is used in the citric acid cycle
B) It accumulates in the cell
C) It transfers its electrons to pyruvate or acetaldehyde
D) It is converted back to NAD+ in the electron transport chain
C) It transfers its electrons to pyruvate or acetaldehyde
True or False: Citrate is an allosteric inhibitor of phosphofructokinase.
True
Which molecule is produced at the end of glycolysis?
A) Lactate
B) Acetyl-CoA
C) Pyruvate
D) Ethanol
C) Pyruvate
What is the effect of sodium fluoride on glycolysis?
A) It inhibits hexokinase
B) It inhibits phosphofructokinase
C) It inhibits enolase
D) It inhibits pyruvate kinase
C) It inhibits enolase
During fermentation, pyruvate is converted into which compound in yeast?
A) Lactate
B) Acetaldehyde
C) Ethanol
D) Acetyl-CoA
C) Ethanol
True or False: NADH produced in glycolysis is used directly in the citric acid cycle.
False
Which enzyme converts fructose-6-phosphate to fructose-1,6-bisphosphate in glycolysis?
A) Hexokinase
B) Phosphofructokinase
C) Aldolase
D) Triose phosphate isomerase
B) Phosphofructokinase
What gas is produced during the alcohol fermentation process?
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Hydrogen
B) Carbon dioxide
True or False: The citric acid cycle operates under anaerobic conditions.
False
In an aerobic setup, which gas is released at the conversion of isocitrate to α-ketoglutarate in the citric acid cycle?
A) Oxygen
B) Carbon dioxide
C) Nitrogen
D) Methane
B) Carbon dioxide
True or False: Yeast can undergo both aerobic respiration and anaerobic fermentation.
True
What is the expected outcome when yeast is added to a sugar solution and oxygen is depleted?
A) Continued aerobic respiration
B) Switch to anaerobic fermentation
C) Yeast inactivity
D) Increased oxygen production
B) Switch to anaerobic fermentation
Which enzyme converts pyruvate to acetaldehyde during alcohol fermentation?
A) Pyruvate dehydrogenase
B) Alcohol dehydrogenase
C) Pyruvate decarboxylase
D) Lactate dehydrogenase
C) Pyruvate decarboxylase
What is the function of maltase in yeast?
A) Converts maltose into glucose
B) Converts sucrose into glucose and fructose
C) Converts glucose into ethanol
D) Converts starch into maltose
A) Converts maltose into glucose
True or False: Amylase is an enzyme present in flour that breaks down starch into glucose.
True
What is the main product of anaerobic respiration in yeast?
A) Lactate
B) Ethanol
C) Acetate
D) Glucose
B) Ethanol
True or False: Inhibitors such as sodium fluoride and sodium citrate have no effect on glycolysis.
False
What is the role of NADH in glycolysis?
A) ATP production
B) Electron carrier
C) CO2 production
D) Oxygen consumption
B) Electron carrier
During glycolysis, which molecule is converted into pyruvate?
A) Glucose
B) Fructose
C) Sucrose
D) Lactose
A) Glucose
True or False: The citric acid cycle generates more ATP directly than glycolysis.
False
Which of the following is a product of the electron transport chain?
A) NAD+
B) FADH2
C) CO2
D) H2O
D) H2O
What is the first step in the glycolysis pathway?
A) Conversion of glucose to glucose-6-phosphate
B) Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
C) Conversion of pyruvate to acetyl-CoA
D) Conversion of ATP to ADP
A) Conversion of glucose to glucose-6-phosphate
True or False: The conversion of pyruvate to lactate regenerates NAD+ in lactic acid fermentation.
True
Which enzyme catalyzes the final step of glycolysis?
A) Hexokinase
B) Pyruvate kinase
C) Phosphofructokinase
D) Enolase
B) Pyruvate kinase
What is the net gain of ATP molecules from one molecule of glucose during glycolysis?
A) 1
B) 2
C) 3
D) 4
B) 2
True or False: The production of CO2 is an indicator of anaerobic respiration in yeast.
True
What happens to the glucose-6-phosphate in glycolysis?
A) It is converted to fructose-6-phosphate
B) It is converted to glucose
C) It is converted to pyruvate
D) It is converted to acetyl-CoA
A) It is converted to fructose-6-phosphate
Which step of glycolysis is inhibited by high levels of ATP?
A) Glucose to glucose-6-phosphate
B) Fructose-6-phosphate to fructose-1,6-bisphosphate
C) 1,3-bisphosphoglycerate to 3-phosphoglycerate
D) Phosphoenolpyruvate to pyruvate
B) Fructose-6-phosphate to fructose-1,6-bisphosphate
True or False: The electron transport chain is located in the mitochondrial matrix.
False. The ETC is situated in the inner mitochondrial membrane
What is the primary purpose of the electron transport chain?
A) To generate CO2
B) To produce ATP
C) To produce NADH
D) To produce glucose
B) To produce ATP
Which of the following compounds is not a direct product of the citric acid cycle?
A) ATP
B) NADH
C) FADH2
D) Glucose
D) Glucose
True or False: The electron transport chain can function without oxygen.
False
Which compound acts as the final electron acceptor in the electron transport chain?
A) CO2
B) H2O
C) NADH
D) O2
D) O2
In which part of the cell does glycolysis occur?
A) Mitochondria
B) Cytoplasm
C) Nucleus
D) Endoplasmic reticulum
B) Cytoplasm
Which class of secondary metabolites contains at least one nitrogen atom in an amine type structure?
A. Phenolics
B. Flavonoids
C. Alkaloids
D. Saponins
C. Alkaloids
True or False: Phenolics contain an aromatic ring with one or more hydroxyl groups.
True
What test is used to identify the presence of alkaloids using a picric reagent?
A. Wagner’s Test
B. Hager’s Test
C. Shinoda’s Test
D. Ferric Chloride Test
B. Hager’s Test
True or False: Flavonoids are a type of phenolics with two benzene rings separated by a propane unit.
True
Which solvent is effective for removing fat, oils, chlorophyll, and nonpolar triterpenoids?
A. Methanol
B. Hexane
C. Chloroform
D. Water
B. Hexane
What are the benefits of extracts obtained using hexane?
A. Anti-inflammatory and infection fighting
B. High antioxidative and cardioprotective properties
C. Effective against oxidative damage
D. Good medium for microbial growth
A. Anti-inflammatory and infection fighting
True or False: Methanol is not a good solvent for extraction because it has a high boiling point.
False
Which test uses dimethylthiazol-diphenyltetrazolium bromide to measure cell activity?
A. Trypan blue exclusion assay
B. MTT Assay
C. ATP bioluminescence assay
D. Bioautography
B. MTT Assay
What is the primary role of cholesterol in the body?
A. Act as a storage form of energy
B. Precursor of different hormones
C. Provide structural support to the bones
D. Enhance the taste of food
B. Precursor of different hormones
True or False: Lipids are soluble in water.
False
Which enzyme’s activity is described by the Lipoxygenase inhibition assay?
A. Succinate dehydrogenase
B. Acetylcholinestrase
C. Lipoxygenase
D. Methylene blue
C. Lipoxygenase
What type of test is Shinoda’s Test?
A. Test for Alkaloids
B. Test for Phenolics
C. Test for Flavonoids
D. Test for Saponins
C. Test for Flavonoids
