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True or False: Photoheterotrophs use light and inorganic carbon sources for obtaining energy.
False.
Explanation: photoheterotrophs use light and organic carbon sources for energy, as they cannot fix carbon on their own
Which of the following is the main purpose of fermentation?
A) to make NADH
B) to make ATP
C) to make NAD+
D) to make glucose
C. to make NAD+
Explanation: the main reason for fermentation is to regenerate NAD+ from NADH under anaerobic conditions. This regeneration is essential for continuing glycolysis, which produces ATP. Without NAD+, glycolysis would halt, and the cell would be unable to generate energy
Which of the following is FALSE about the process of oxidative phosphorylation in eukaryotes?
A) it requires a PMF (proton motive force)
B) it produces around 26-28 ATP molecules
C) the final electron acceptor is O2
D) it takes place in the cytoplasmic membrane
D. it takes place in the cytoplasmic membrane.
Explanation: oxidative phosphorylation in eukaryotes takes place in the inner mitochondrial membrane, not the cytoplasmic membrane.
Which of the following is NOT a function of the proton motive force (PMF)?
A) catalyzing chemical reactions in metabolic pathways
B) synthesizing ATP thru ATP synthase
C) powering flagellar movement
D) facilitating transport of nutrients across the membrane
A. catalyzing chemical reactions in metabolic pathways.
Explanation: "A" is NOT a direct function of the PMF, because it does not catalyze chemical reactions in metabolic pathways. Rather, it provides energy for other processes.
During the transition (bridge) reaction, what are the two pyruvates from glycolysis converted into? What binds to them?
the pyruvates are converted into acetyl groups, and coenzyme A binds to them
Homolactic fermentation uses pyruvate and NADH to create which products?
lactic acid and NAD+
Which of the following molecules is reduced?
A) NAD+
B) O2
C) NADPH
D) FAD
C. NADPH
Explanation: This is reduced to NADH when it gains electrons (and usually a hydrogen ion) during processes like glycolysis and the Krebs cycle.
The ATP molecules produced at the energy payoff phase of glycolysis are formed via...?
A) transition phosphorylation
B) substrate-level phosphorylation
C) oxidative phosphorylation
D) photophosphorylation
B. Substrate-level phosphorylation
True or false? Anaerobic respiration uses an inorganic molecule (such as nitrate, sulfate, etc.) as the final electron acceptor.
True.
Which of the following processes is NOT involved in the conversion of organic nitrogen to nitrogen gas?
A) denitrification
B) ammonification
C) nitrification
D) nitrogen fixation
D. Nitrogen fixation.
Explanation: Nitrogen fixation does not convert organic nitrogen compounds into nitrogen gas. Rather, it takes N₂ from the atmosphere and makes it available as ammonia (NH4)
True or false? The enzyme responsible for CO2 fixation during the Calvin cycle is called RuBisCO.
True.
Explanation: the enzyme responsible for CO₂ fixation during the Calvin cycle is called RuBisCO (ribulose bisphosphate carboxylase/oxygenase).
True or false? Glycolysis and the Krebs Cycle are "connected by" the transition (bridge) reaction.
True.
Explanation: The transition/bridge reaction converts pyruvate (end product of glycolysis) into acetyl CoA, which then enters the Krebs Cycle
What is the net gain of ATP (or GTP) from ONE turn of the Krebs cycle?
1 ATP (or GTP)
Explanation: Each "turn" processes one acetyl CoA, in which one molecule of ATP (or GTP) is produced through substrate-level phosphorylation.
In which part of the chloroplast do light-independent (Calvin cycle) reactions occur?
the stroma.
Explanation: the stroma is a fluid-filled space surrounding the thylakoid membranes where enzymes and substrates for the Calvin cycle are located.
Which process occurs in the mitochondria?
A) Photosynthesis
B) Glycolysis
C) Krebs Cycle
D) Fermentation
C. Krebs cycle
Explanation: The Krebs cycle occurs in the mitochondria. Glycolysis occurs in cytoplasm, while fermentation can occur in the cytoplasm or anaerobic environments.
What is the net gain of ATP from glycolysis?
A) 1 ATP
B) 2 ATP
C) 4 ATP
D) 36 ATP
B. 2 ATP
Explanation: Glycolysis produces a net gain of 2 ATP molecules per glucose molecule, despite producing 4 ATP initially (with 2 ATP used in the process; 4-2 = 2 net gain).
True or false? Photosynthesis occurs in the mitochondria of plant cells.
False.
Explanation: Photosynthesis occurs in chloroplasts of plant cells (specifically: the thylakoid membranes and stroma)
True or false? The Calvin cycle requires light directly to occur.
False.
Explanation: The Calvin cycle does not require light directly; it uses ATP and NADPH produced during the light-dependent reactions, which can occur in the dark. The Calvin cycle is also called the "dark cycle".
True or false? In aerobic respiration, the final electron acceptor is oxygen.
True.
Explanation: In aerobic respiration, oxygen acts as the final electron acceptor in the electron transport chain, forming water as a byproduct
What are organic molecules that help enzymes work correctly?
coenzymes
Which of the following products is made during Embden-Meyerhof (EMP) glycolysis?
A) Pyruvate
B) NAD+
C) 2-carbon acetyl
D) CO2
A. pyruvate
Explanation: This is the end product of the EMP pathway of glycolysis, where one glucose molecule is converted into two molecules of pyruvate
During the catabolism of glucose, which of the following is produced only in the Krebs cycle?
A) FADH2
B) ATP
C) NADH
D) NADPH
A. FADH2
Explanation: while ATP and NADH are produced in the Krebs cycle, they are also produced in glycolysis, as well
The EMP pathway of glycolysis produces how many pyruvate molecules and NADH molecules per glucose molecule?
2 pyruvate; 2 NADH
The enzymes responsible for catalyzing triglycerides are known as...
lipases
Explanation: Lipases are a group of enzymes that hydrolyze triglycerides into glycerol and free fatty acids.
Which is the location of electron transports systems in prokaryotes?
the cytoplasmic/plasma membrane
A stack of thylakoids is called a...?
granum (grana)
An apoenzyme and holoenzyme are considered to be ________ and _________, respectively.
inactive ; active
True or false? ATP synthase is involved in both oxidative phosphorylation and photophosphorylation.
True.
A competitive inhibitor should most structurally resemble...?
the substrate
Explanation: competitive inhibitors bind to the active site, competing with the substrate for access. So, they often share a similar structure or functional groups with the substrate, allowing them to fit into the active site.
True or false? Competitive inhibitors bind to the allosteric site.
False.
Explanation: Competitive inhibitors bind to the active site of an enzyme. In contrast, allosteric inhibitors bind to an allosteric site (a different site from the active site), causing a change in the enzyme's shape that affects its activity.
Which of these is NOT a reason that a cell may perform anaerobic respiration?
A) If it lacks a cytochrome oxidase for passing electrons to oxygen
B) If it lacks the transition reaction to convert pyruvate to acetyl CoA
C) If it lacks the required amount of oxygen to carry out aerobic respiration
D) If it lacks the enzymes to minimize the damaging effects of oxygen radicals
B. If it lacks the transition reaction to convert pyruvate to acetyl CoA.
Explanation: a cell that lacks the transition reaction can still undergo anaerobic respiration by using glycolysis and fermentation to generate energy, though with a lower yield of ATP compared to aerobic respiration.
Which trait do aerobic and anaerobic respiration have in common?
A) they both use O2 as the final electron acceptor
B) they both yield H2O as a final product
C) they both yield 30-32 ATP molecules per glucose molecule
D) they both utilize an electron transport chain
D. they both utilize an electron transport chain
Explanation: they both use the ETC. Aerobic uses O2 as the final acceptor, and anerobic uses nitrate, sulfate, etc. as final acceptor.
ATP synthase is located in the _________ for eukaryotes, and the _________ for prokaryotes.
inner mitochondrial membrane ; plasma membrane
In prokaryotes, which direction are hydrogen ions pumped by the electron transport system of photosynthetic membranes?
to the outside of the plasma membrane
Chemiosmosis is defined as the flow of _________ across a membrane-bound enzyme complex called _________.
hydrogen ions ; ATP synthase
True or false? The type of photosynthesis carried out by cyanobacteria is oxygenic photosynthesis.
True.
Using oxidative photosynthesis, cyanobacteria uses water and CO2 to produce energy-rich organic molecules, and produces O2 as a byproduct.
Organisms that convert inorganic CO2 into organic compounds are known as...?
autotrophs
What is the main purpose of the Calvin cycle (light-independent)?
to synthesize glucose from CO2
Which of the following are two products of the light-dependent reaction?
A) glucose and NADPH
B) NADPH and ATP
C) glucose and O2
D) glyceraldehyde-3 phosphate and CO2
B. NADPH and ATP
Explanation: the three main products from the light dependent reactions are NADPH, O2, and ATP.
Glycolysis most commonly occurs by which pathway?
the Embden-Meyerhof-Parnas (EMP) pathway
Fermenting organisms make ATP through the process of ________.
glycolysis.
Explanation: fermenting organisms make ATP through glycolysis. In glycolysis, one molecule of glucose is broken down into two molecules of pyruvate, producing a net gain of 2 ATP through substrate-level phosphorylation
Do both aerobic and anaerobic respiration utilize an electron transport chain (ETC)?
Yes.
Which of the following molecules is a primary donor of electrons in the electron transport chain (ETC)?
A) ATP
B) H2O
C) NADH
D) Acetyl-CoA
C. NADH
Explanation: NADH is generated during glycolysis, the transition reaction, and the Krebs cycle. It donates electrons to the ETC, initiating the process of electron transport.
What are the two byproducts of alcoholic fermentation?
ethanol and CO2
After extracellular protease degradation and deamination, the remaining molecules of the protein can enter...?
the Krebs cycle
Explanation: via protease degradation, the protein is broken down into peptides and amino acids. And, the carbon "leftovers" can be converted into intermediates (i.e. acetyl CoA, pyruvate, etc.) that can then enter the Krebs Cycle.
Which of the following is NOT a photosynthetic pigment molecule?
A) phycocyanins
B) thylakoids
C) carotenoids
D) chlorophylls
B. thykaloids.
Explanation: Thylakoids are structures within chloroplasts where the light-dependent reactions can occur, but they are NOT pigment molecules themselves.
True or false? The second phase of glycolysis is known as the "energy payoff" phase.
True.
True or false? The loss of an electron from a molecule is called reduction.
False.
Explanation: the loss of an electron from a molecule is called oxidation.
Where do the light-dependent reactions of photosynthesis take place?
the thykaloid membranes
Which of the following is NOT a product of the Krebs cycle?
A) ATP
B) NADH
C) FADH₂
D) Glucose
D. glucose.
Explanation: The Krebs cycle does not produce glucose; it generates ATP, NADH, and FADH₂ from the breakdown of acetyl CoA.
What role do NADH and FADH₂ play in cellular respiration?
A) They are end products of glycolysis.
B) They serve as electron carriers to the electron transport chain.
C) They are produced in the light-dependent reactions.
D) They are used to fix carbon in the Calvin cycle.
B. they serve as electron carriers to the electron transport chain
Explanation: NADH and FADH₂ transport electrons to the electron transport chain; they contribute to ATP production through oxidative phosphorylation.
