Quiz #3 (Ch 6.5-7)

Which of the following statements best describes a characteristic feature of diffusion?

It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

Which of the following statements best describes how unsaturated fatty acids increase membrane fluidity at lower temperatures?

The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.

Which of the following statements best describes the structure of a membrane based on the fluid mosaic model?

The membrane is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins.

The force driving simple diffusion is ________, while the energy source for active transport is ________.

a concentration gradient; ATP hydrolysis

A defect in which of the following molecules would dramatically reduce the rate of diffusion of water across cell membranes?

aquaporins

Which of the following is a common trait of chloroplasts and mitochondria?

both contain their own DNA

An organelle in a newly discovered cell contains thylakoids, DNA, and ribosomes. These findings suggest that this organelle is most likely similar to which of the following organelles?

chloroplasts

An early step in the evolution of eukaryotic cells most likely involved which of the following events?

endosymbiosis of an oxygen-using bacterium in a larger bacterial host cell-the endosymbiont evolved into mitochondria

Cyanide binds to at least one molecule involved in producing ATPATP. In a cell exposed to cyanide, most of the cyanide will be in

mitochondria

Which of the following membrane activities requires energy from ATP hydrolysis?

movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Mitochondria are found in __________.

plant and animal cells