Question

1. The fluid mosaic model describes cell membranes as consisting of
A) a phospholipid bilayer with embedded carbohydrates
B) two layers of phospholipids with protein sandwiched between them
C) a protein bilayer with embedded phospholipids
D) carbohydrates, proteins, and phospholipids that can drift in the membrane
E) individual proteins that can drift in a phospholipid bilayer

2. When a poison, such as Paraderil found in flea dip, blocks the electron transport chain, the citric acid cycle soon grinds to a halt as well because
A) it runs out of ATP
B) the buildup of unused oxygen interferes with the citric acid cycle
C) it runs out of NAD+ and FAD
D) electrons are no longer available from the electron transport chain
E) it runs out of ADP

3. In the electron transport chain, in mitochondria, the electrons from ___ end up in ___, while the electrons transport chain in chloroplasts, the electrons from ___ end up in ___.
A) NADPH, water, water, NADH
B) NADH, water, water, NADPH
C) water, NADH, NADPH, water
D) water, CO2, CO2, water
E) water, NADH, water, NADPH

Answer 1

1) according to the fluid mosaic model, the plasma membrane consists of phospholipids, proteins and carbohydrates and these components in the plasma membrane can move from location to another.

D) carbohydrates, proteins, and phospholipids that can drift in the membrane.

2) NADH and FADH2 are oxidized via the electron transport chain if the electron transport is blocked NADH and FADH2 cannot be oxidized so it remains in the reduced state, during the citric acid cycle NAD+ and FAD+ are reduced to NADH and FADH2 respectively. if the electron transport chain is blocked, NAD+ and FAD+ cannot be regenerated. so the citric acid cycle cannot progress so the answer is

C) it runs out of NAD+ and FAD

3) the final electron acceptor in the electron transport chain in aerobic respiration is oxygen, the electrons from the NADH and FADH2 finally ends up in the oxygen to form water.

whereas in the plants the electrons lost from the PSII is replaced with electrons from the water, the photolysis of water release H+, electron and oxygen, these electron replaces the electrons in PSII, the electrons move through the electron transport chain and used to reduce NADP+ to NADPH.

so the answer is B) NADH, water, water, NADPH.