Cell Biology - Chapter 4 + 5

Which of the following processes is driven by chemiosmosis?

• ATP hydrolysis

• substrate-level phosphorylation

• oxidative phosphorylation

• reduction of NAD+ to NADH

In a plant, which of the following reactions produce molecular oxygen (O2)?

• neither the light reactions nor the Calvin cycle

• the light reactions and the Calvin cycle

• the light reactions alone

• the Calvin cycle alone

The oxygen released by photosynthesis is produced by which of the following processes?

• the electron transfer system of photosystem II

• chemiosmosis

• the electron transfer system of photosystem I

• splitting water molecules

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

• H2O → plastoquinone → cytochrome b6-f → plastocyanin → ferredoxin → NADPH → Calvin cycle

• NADPH → electron transport chain → O2

• NADPH → O2 → plastoquinone → CO2

• NADPH → chlorophyll → photosystem I → Calvin cycle

Which electron carrier(s) function in the citric acid cycle?

• NADH and FADH2

• NAD+ only

• ADP and ATP

• the electron transport chain

The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol, and the free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?

• There is no CO2 or water produced as products of glycolysis.

• Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis.

• Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat.

• Most of the free energy available from the oxidation of glucose is used in the production of ATP in glycolysis.

An electron-driven proton pump in the respiratory chain that accepts electrons from cytochrome c and generates water using molecular oxygen as an electron acceptor.

• NADH dehydrogenase complex

• cytochrome c oxidase complex

• iron–sulfur center

• cytochrome c reductase

Which of the following events takes place in the electron transport chain?

• the breakdown of an acetyl group to carbon dioxide

• substrate-level phosphorylation

• the breakdown of glucose into six carbon dioxide molecules

• the harnessing of energy from high-energy electrons derived from glycolysis and the citric acid cycle

The affinity of a redox pair for electrons, generally measured as the voltage difference between an equimolar mixture of the pair and a standard reference

• free energy

• redox potential

• redox pairs

• redox reaction

Process in bacteria and mitochondria in which ATP formation is driven by the transfer of electrons from food molecules to molecular oxygen, with the intermediate generation of a proton gradient across a membrane.

• chemiosmotic coupling

• electrochemical gradient

• proton-motive force

• oxidative phosphorylation