Biology Ch 3

The transport of water across a membrane from a solutionof lower solute concentration to a solution of higher solute concentration is best describe as:

a) osmosis.

Hydrophobic molecules can pass freely through the plasma membrane, but molecules with electrical charges (such as ions and polar molecules) are impeded by the hydrophobic core. For this reason, plasma membranes can be considered:

a) partially permeable.

Which of the following statements about prokaryotes is incorrect?

b) Prokaryotes have circular pieces of DNA within their nuclei.

Cell walls:

b) are not completely solid, having many small pores.

In plant cells, chloroplasts:

b) are the site of conversion of light energy into chemical energy.

The largest structure in a eukaryotic cell is the Nucleus and it is surrounded by two membrane(s).

b) nucleus; two

Given that a cell's structure refl ects its function, what function would you predict for a cell with a large Golgi apparatus?

b) secretion of digestive enzymes

Which of the following statements about mitochondria is correct?

c) Most plant cells contain mitochondria.

The movement of molecules across a membrane from an area of high concentration to one of low concentration is best described as:

c) passive transport.

In an experiment, you measure the concentration of a polar molecule inside and outside a cell. You find that the concentration is high and gradually increasing inside the cell. You also measure the ATP concentration inside the cell and find that it is dropping.

d) active transport

Drugs called beta-blockers do all of the following except:

d) bind to the cytoplasmic side of a receptor protein.

Cellular "fingerprints":

d) can help the immune system distinguish "self " from "non-self."

Which of the following allows the passage of small molecules between animal cells?

d) gap junctions

The cytoskeleton:

d) helps to coordinate intracellular movement of organelles and molecules.

Which of the following statements about the cell theory is correct?

e) Both a) and b) are correct. a) All living organisms are made up of one or more cells. b) All cells arise from other, pre-existing cells

Which of the following facts supports the claim that mitochondria developed from bacteria that, long ago, were incorporated into eukaryotic cells by the process of phagocytosis?

e) Mitochondria have their own DNA.

Which one of the following organelles is not found in both plant and animal cells?

e) central vacuole

Which of the following organelles is not present in animal cells?

e) chloroplast