Microvilli are found
(a) Mostly in muscle cells
(b) On the inside of plasma membranes
(c) In large numbers on cells that secrete hormones
(d) In cells that are actively engaged in absorption
(e) Only on cells lining the reproductive tract

Diffusion is important in body fluids, because it tends to

(a) Increase local concentration gradients

(b) Eliminate local concentration gradients

(c) Move substances against concentration gradients

(d) Create concentration gradients

How many amino acids are coded in the DNA segment:

CTC–ATA–CGA–TTC–AAG–TTA?

(a) 18

(b) 9

(c) 6

(d) 3

What are the four major functions of the endoplasmic reticulum?

When a cell is placed in a(n)___solution, the cell will lose water through osmosis. This process results in the___ of red blood cells

(a) hypotonic; crenation

(b) hypertonic; crenation

(c) isotonic; hemolysis

(d) hypotonic; hemolysis

List five important factors that influence diffusion rates.

Suppose that a DNA segment has the following nucleotide sequence:

CTC–ATA–CGA–TTC–AAG–TTA.

Which nucleotide sequences would a complementary mRNA strand have?

(a) GAG–UAU–GAU–AAC–UUG–AAU

(b) GAG–TAT–GCT–AAG–TTC–AAT

(c) GAG–UAU–GCU–AAG–UUC–AAU

(d) GUG–UAU–GGA–UUG–AAC–GGU