BIO 205 CH 11

Taxol is an anti-cancer drug that prevents uncontrolled cell proliferation by stabilizing microtubules, which causes arrest of the cell cycle. If dividing cells are treated with Taxol, at what stage of the cell cycle would you predict the arrest would occur? prophase anaphase telophase metaphase G1 of interphase

prophase

The CORRECT sequence of steps in the M phase of the cell cycle is: prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis. prophase, metaphase, anaphase, telophase, cytokinesis, nuclear division. prophase, prometaphase, metaphase, anaphase, telophase, nuclear division. prophase, metaphase, prometaphase, anaphase, nuclear division, telophase.

prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.

A gene associated with promoting normal cell division is called a(n): tumor suppressor. proto-oncogene or a tumor suppressor. oncogene. proto-oncogene.

proto-oncogene.

Cell division is regulated by: signals about the nutritional status of the cell. signals that indicate that DNA has been replicated. All of these choices are correct. growth factor signals. signals that indicate that the cell has reached a sufficient size.

All of these choices are correct.

How does a cell regulate the progression of the cell cycle? through the expression and synthesis of CDKs through the expression and synthesis of cyclin proteins through destruction of cyclins All of these choices are correct. through checkpoints

All of these choices are correct.

Studies of rapidly dividing embryonic animal cells revealed: that the production of cyclin proteins is followed by activation of CDK enzymes. a cyclic production of certain proteins in sync with the cell cycle. All of these choices are correct. a cyclic activation of protein kinases in sync with the cell cycle. that inhibition of protein production blocks mitosis.

All of these choices are correct.

The first oncogene to be discovered: was discovered in a Rous sarcoma virus that causes cancer. is a gene that contributes to uncontrolled cell division or cancer. All of these choices are correct. has a less-active normal counterpart called a proto-oncogene. is a protein kinase that acts to promote cell division.

All of these choices are correct.

Tumor suppressors oppose oncogenes by: slowing cell division. instructing defective cells to die. All of these choices are correct. repairing mutations. blocking the action of an oncogene.

All of these choices are correct.

Which of the following steps in prokaryotic binary fission is CORRECT? The cell continues to grow outward symmetrically, separating the two chromosomes. All of these choices are correct. Cell wall material is laid down at the midpoint to separate the two daughter cells. The two replicated chromosomes remain attached to the plasma membrane. DNA is replicated bidirectionally from a single point on the circular chromosome.

All of these choices are correct.

In what way is cytokinesis in plant cells similar to binary fission in a bacterium? A motor protein slides microtubules in a contractile ring at the plasma membrane between the two nuclei to separate the daughter cells. All of these choices are correct. A microtubulin-like structure constricts the plasma membrane between the two nuclei to separate the daughter cells. Cell wall material is deposited to separate the daughter cells. A ring of actin filaments constricts the plasma membrane between the two nuclei to separate the daughter cells.

Cell wall material is deposited to separate the daughter cells.

Which of the following is NOT true about the eukaryotic cell cycle? Interphase is typically the shortest of the two stages of the cell cycle. There are two stages to the cell cycle: M phase and interphase. The M phase consists of two events: mitosis and cytokinesis. Some cells pause between M phase and S phase for more than a year. There are three phases of interphase: the S phase and two gap phases.

Interphase is typically the shortest of the two stages of the cell cycle.

Which of the following statements is TRUE if a cell has a mutation in the p53 gene such that the p53 protein is no longer able to be phosphorylated? The cell would proceed through the cell cycle even in the presence of DNA damage. The cell would arrest, giving time for the DNA damage to be repaired. The amount of cytoplasmic p53 protein would increase in response to DNA damage. The kinase activity in the nucleus would decrease in response to DNA damage.

The cell would proceed through the cell cycle even in the presence of DNA damage.

A researcher is evaluating the expression of p53 in cells she is culturing in the laboratory. She notices that in a small group of cells, high levels of phosphorylated p53 occur in the nuclei. What can she deduce about these cells? Within these cells, the cell cycle has been halted at the G2/M transition. All of these cells have entered meiosis. These cells likely contain damaged DNA. These cells are normal. All of these cells have entered mitosis.

These cells are normal.

What happens to CDKs in the absence of cyclins? They are inactive and become phosphorylated. They are degraded. They are inactive. They become phosphorylated.

They are inactive.

Which one of the following would MOST likely contribute to uncontrolled cell proliferation (i.e., cancer)? a mutant DNA replication mechanism causing extra chromosome copies a mutant cyclin that cannot bind to its normal CDK binding partner a mutant kinetochore protein that causes reduced microtubule attachment a mutant CDK that was active in the absence of its cyclin binding partner a mutant enzyme needed for microtubule synthesis/polymerization

a mutant CDK that was active in the absence of its cyclin binding partner

What is a cyclin? a kinase a protein that activates kinases and a protein whose levels change with the cell cycle a protein that activates kinases a protein whose levels change with the cell cycle

a protein that activates kinases and a protein whose levels change with the cell cycle

In which phase of mitosis do sister chromatids separate? telophase prophase anaphase metaphase

anaphase

In which phase of mitosis do spindle microtubules shorten? telophase anaphase prophase metaphase

anaphase

The division of the cell's cytoplasm in a eukaryotic cell is known as: cell fission. both cytokinesis and mitosis.. cytokinesis. mitosis.

cytokinesis

Mitosis MOST likely evolved from what process? cytokinesis the cell cycle binary fission meiosis

binary fission

The region of a replicated chromosome where sister chromatids remain attached is called the: chiasmata centrosome centromere kinetochore

centromere

The amount of _____ is fairly constant throughout the cell cycle, but the amount of _____ varies. cyclins/cyclin-dependent kinases DNA/cyclins cyclins/DNA cyclin-dependent kinase/DNA

cyclin-dependent kinase/DNA

A phragmoplast functions to: break down the nuclear envelope. form a new cell wall. anchor microtubules to sister chromatids. stimulate the growth of the microtubule spindle.

form a new cell wall.

Malignancies develop stepwise over time because: it takes time for a benign tumor to be able to dissolve through its encapsulation before it can invade neighboring tissues. benign tumor cells divide slowly and in a stepwise pattern. All of these choices are correct. cells keep leaving the benign tumor and are destroyed in lymph nodes. it takes multiple mutations of multiple genes to allow cancer cells to develop.

it takes multiple mutations of multiple genes to allow cancer cells to develop.

In which phase of mitosis do chromosomes line up at the middle of the cell? metaphase prophase anaphase telophase

metaphase

The two molecules of double-stranded DNA in a replicated chromosome are called: bivalent chromosomes homologous chromosomes non-sister chromatids sister chromatids

sister chromatids

All of the following happen during mitosis EXCEPT: condensing of chromosomes. synthesis of DNA. formation of the spindle. separation of sister chromatids at the centromeres.

synthesis of DNA.

The centrosome is: a region of the chromosome where kinetochores attach. a region of the chromosome where sister chromatids are attached to each other. the microtubule organizing center for the mitotic spindle. a region of the chromosome where microtubules attach to chromosomes during mitosis. All of these choices are correct.

the microtubule organizing center for the mitotic spindle.

What is the function of histone proteins? to organize the microtubules that make up the spindle to connect chromosomes to the mitotic spindle to package DNA in eukaryotic chromosomes to attach sister chromatids together

to package DNA in eukaryotic chromosomes

p53 is an example of a(n): tumor suppressor. cyclin-dependent kinase. oncogene. proto-oncogene.

tumor suppressor.