Forms of the Ras protein found in tumors usually cause which of the following?
A) DNA replication to stop
B) DNA replication to be hyperactive
C) cell-to-cell adhesion to be nonfunctional
D) cell division to cease
E) growth factor signaling to be hyperactive

growth factor signaling to be hyperactive

A genetic test to detect predisposition to cancer would likely examine the APC gene for
involvement in which type(s) of cancer?
A) colorectal only
B) lung and breast
C) small intestinal and esophageal
D) lung only
E) lung and prostate

colorectal only

In colorectal cancer, several genes must be mutated in order to contribute to a cell
developing into a cancer cell, supporting Knudsen's hypothesis. Which of the following kinds of
genes would you expect to be mutated?
A) genes coding for enzymes that act in the colon
B) genes involved in control of the cell cycle
C) genes that are especially susceptible to mutation
D) the same genes that Knudsen identified as associated with retinoblastoma
E) the genes of the bacteria that are abundant in the colon

genes involved in control of the cell cycle

Muscle cells differ from nerve cells mainly because they
A) express different genes.
B) contain different genes.
C) use different genetic codes.
D) have unique ribosomes.
E) have different chromosomes.

express different genes

Cell differentiation always involves
A) the production of tissue-specific proteins, such as muscle actin.
B) the movement of cells.
C) the transcription of the myoD gene.
D) the selective loss of certain genes from the genome.
E) the cell's sensitivity to environmental cues, such as light or heat.

the production of tissue-specific proteins, such as muscle actin.

Apoptosis involves all but which of the following?
A) fragmentation of the DNA
B) cell-signaling pathways
C) activation of cellular enzymes
D) lysis of the cell
E) digestion of cellular contents by scavenger cells

lysis of the cell

Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body
parts and mirror-image duplication of posterior parts. This is evidence that the product of the
bicoid gene
A) is transcribed in the early embryo.
B) normally leads to formation of tail structures.
C) normally leads to formation of head structures.
D) is a protein present in all head structures.
E) leads to programmed cell death.

normally leads to formation of head structures.

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best
explains the presence of these potential time bombs in eukaryotic cells?
A) Proto-oncogenes first arose from viral infections.
B) Proto-oncogenes normally help regulate cell division.
C) Proto-oncogenes are genetic "junk."
D) Proto-oncogenes are mutant versions of normal genes.
E) Cells produce proto-oncogenes as they age.

Proto-oncogenes normally help regulate cell division.