Multiple Choice

Which of the following is an organism that obtains its energy from the transfer of electrons originating from chemical compounds and its carbon from an inorganic source?

1. chemoautotroph
2. chemoheterotroph
3. photoheterotroph
4. photoautotroph

Which of the following molecules is reduced?

1. NAD⁺
2. FAD
3. O₂
4. NADPH

Enzymes work by which of the following?

1. increasing the activation energy
2. reducing the activation energy
3. making exergonic reactions endergonic
4. making endergonic reactions exergonic

To which of the following does a competitive inhibitor most structurally resemble?

1. the active site
2. the allosteric site
3. the substrate
4. a coenzyme

Which of the following are organic molecules that help enzymes work correctly?

1. cofactors
2. coenzymes
3. holoenzymes
4. apoenzymes

During which of the following is ATP not made by substrate-level phosphorylation?

1. Embden-Meyerhof pathway
2. Transition reaction
3. Krebs cycle
4. Entner-Doudoroff pathway

Which of the following products is made during Embden-Meyerhof glycolysis?

1. NAD+
2. pyruvate
3. CO₂
4. two-carbon acetyl

During the catabolism of glucose, which of the following is produced only in the Krebs cycle?

1. ATP
2. NADH
3. NADPH
4. FADH₂

Which of the following is not a name for the cycle resulting in the conversion of a two-carbon acetyl to one ATP, two CO₂, one FADH₂, and three NADH molecules?

1. Krebs cycle
2. tricarboxylic acid cycle
3. Calvin cycle
4. citric acid cycle

Which is the location of electron transports systems in prokaryotes?

1. the outer mitochondrial membrane
2. the cytoplasm
3. the inner mitochondrial membrane
4. the cytoplasmic membrane

Which is the source of the energy used to make ATP by oxidative phosphorylation?

1. oxygen
2. high-energy phosphate bonds
3. the proton motive force
4. P_i

A cell might perform anaerobic respiration for which of the following reasons?

1. It lacks glucose for degradation.
2. It lacks the transition reaction to convert pyruvate to acetyl-CoA.
3. It lacks Krebs cycle enzymes for processing acetyl-CoA to CO₂.
4. It lacks a cytochrome oxidase for passing electrons to oxygen.

In prokaryotes, which of the following is true?

1. As electrons are transferred through an ETS, H⁺ is pumped out of the cell.
2. As electrons are transferred through an ETS, H⁺ is pumped into the cell.
3. As protons are transferred through an ETS, electrons are pumped out of the cell.
4. As protons are transferred through an ETS, electrons are pumped into the cell.

Which of the following is not an electron carrier within an electron transport system?

1. flavoprotein
2. ATP synthase
3. ubiquinone
4. cytochrome oxidase

Which of the following is the purpose of fermentation?

1. to make ATP
2. to make carbon molecule intermediates for anabolism
3. to make NADH
4. to make NAD⁺

Which molecule typically serves as the final electron acceptor during fermentation?

1. oxygen
2. NAD⁺
3. pyruvate
4. CO₂

Which fermentation product is important for making bread rise?

1. ethanol
2. CO₂
3. lactic acid
4. hydrogen gas

Which of the following is not a commercially important fermentation product?

1. ethanol
2. pyruvate
3. butanol
4. penicillin

Which of the following molecules is not produced during the breakdown of phospholipids?

1. glucose
2. glycerol
3. acetyl groups
4. fatty acids

Caseinase is which type of enzyme?

1. phospholipase
2. lipase
3. extracellular protease
4. intracellular protease

Which of the following is the first step in triglyceride degradation?

1. removal of fatty acids
2. β-oxidation
3. breakage of fused rings
4. formation of smaller peptides

During the light-dependent reactions, which molecule loses an electron?

1. a light-harvesting pigment molecule
2. a reaction center pigment molecule
3. NADPH
4. 3-phosphoglycerate

In prokaryotes, in which direction are hydrogen ions pumped by the electron transport system of photosynthetic membranes?

1. to the outside of the plasma membrane
2. to the inside (cytoplasm) of the cell
3. to the stroma
4. to the intermembrane space of the chloroplast

Which of the following does not occur during cyclic photophosphorylation in cyanobacteria?

1. electron transport through an ETS
2. photosystem I use
3. ATP synthesis
4. NADPH formation

Which of the following are two products of the light-dependent reactions?

1. glucose and NADPH
2. NADPH and ATP
3. glyceraldehyde 3-phosphate and CO₂
4. glucose and oxygen

Which of the following is the group of archaea that can use CO₂ as their final electron acceptor during anaerobic respiration, producing CH₄?

1. methylotrophs
2. methanotrophs
3. methanogens
4. anoxygenic photosynthesizers

Which of the following processes is not involved in the conversion of organic nitrogen to nitrogen gas?

1. nitrogen fixation
2. ammonification
3. nitrification
4. denitrification

Which of the following processes produces hydrogen sulfide?

1. anoxygenic photosynthesis
2. oxygenic photosynthesis
3. anaerobic respiration
4. chemoautrophy

The biogeochemical cycle of which of the following elements is based on changes in solubility rather than redox chemistry?

1. carbon
2. sulfur
3. nitrogen
4. phosphorus