Biology Chapter 12 Review Questions

Which of the following statements best describes how cytokinesis differs between plant and animal cells?

Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.

What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle?

centrosome

Cytochalasin B is a chemical that disrupts microfilament formation. With which aspect of cell division would cytochalasin B interfere?

cleavage

Which of the following events characterizes the beginning of anaphase?

enzymatic cleavage of cohesin

If there are 24 centromeres in a cell at anaphase of mitosis, how many chromosomes will be found in each daughter cell following cytokinesis?

12

If a cell at metaphase of mitosis contains 32 sister chromatids, how many chromosomes will be present in a G1 cell?

16

In a diploid cell with four chromosome pairs (2n = 8), how many sister chromatids will be found in a nucleus at prophase of mitosis?

16

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 10 picograms of DNA per nucleus. Approximately how many picograms of DNA would be found in a nucleus at prophase of mitosis?

20

Beginning with a fertilized egg (zygote), how many cells will be present in the embryo following five rounds of cell division?

32

In a diploid cell with four chromosome pairs (2n = 8), how many centromeres will be found in a nucleus at G2 of the cell division cycle?

8

A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain? See Concept 12.1 (Page)

92

Which of the following structures or molecules is required in order for motor proteins to facilitate movement of chromosomes toward the poles in mitosis?

ATP as an energy source

Certain unicellular eukaryotes, including diatoms and some yeasts, have mechanisms of nuclear division that resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?

Chromosomes are segregated by a mitotic spindle, but the nuclear envelope remains intact during division.

Eukaryotic chromatin is composed of which of the following macromolecules?

DNA and proteins

Which statement provides the best description of the interphase portion of the cell cycle?

During interphase, a cell is metabolically active.

If a eukaryotic cell is in the G1 phase of the cell cycle, which statement about the cell's chromosomes must be correct?

Each chromosome is made of a complex of DNA and associated proteins.

The mass of DNA per nucleus in a certain fungus ranges from 4 to 10 picograms. Nuclei with 5 picograms of DNA are most likely derived from cells in which of the following parts of the cell cycle?

G1

Which of the following correctly matches a phase of the cell cycle with its description?

G1, follows cell division

Amount of DNA per nucleus over the cell division cycle.G1 is represented by which numbered part(s) of the cell division cycle in the accompanying figure?

I and V

Amount of DNA per nucleus over the cell division cycle. Which region of the accompanying figure represents S phase?

II

The unlettered circle at the top of the accompanying figure shows a diploid nucleus with four unreplicated chromosomes. The circles labeled 1 to 5 show various combinations of these chromosomes.Which chromosomal configuration would be observed at prometaphase of mitosis?

II

Amount of DNA per nucleus over the cell division cycle. Which numbered regions of the accompanying figure represent the DNA content associated with cells at metaphase?

III only

A research team used a culture of lymphocytes with radioactively labeled T nucleotides to study the cell cycle. They found that the lymphocytes incorporated the labeled nucleotide at a significantly higher rate after a pathogen was introduced into the culture. Which of the following conclusions is most consistent with the results?

Infection causes lymphocytes to divide more rapidly.

Amount of DNA per nucleus over the cell division cycle.

Line 2 contains more DNA than line 1.

Which of the following statements describing kinetochores is correct?

They are sites at which microtubules attach to chromosomes.

Which chromosomal configuration would be observed in one daughter cell after telophase of mitosis?

V

Which of the following statements best describes a cleavage furrow?

a groove in the plasma membrane between daughter nuclei

Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely ________.

a plant cell in the process of cytokinesis

Which of the following statements describes a characteristic feature of metaphase?

alignment of chromosomes on the equator of the cell

In which phase of mitosis do the sister chromatids become daughter chromosomes?

anaphase

The drug cytochalasin B blocks the polymerization of actin microfilaments. Which of the following events of the cell cycle in animal cells would be most directly disrupted by cytochalasin B?

cleavage furrow formation and cytokinesis

Which of the following occurs in binary fission but not in mitosis with cytokinesis?

duplicated chromosomes attach to the plasma membrane

Students in a biology lab isolated cells in various phases of the cell cycle. A population of cells that have twice the DNA of G1 phase cells was most likely isolated from which of the following part of the cell cycle?

in the G2 phase

Students in a biology lab isolated cells in various phases of the cell cycle. A population of cells that have 1 1/2 times the DNA of G1 phase cells was most likely isolated from which of the following parts of the cell cycle?

in the S phase

Why is it difficult to observe individual chromosomes with a light microscope during interphase?

interphase chromosomes are long, thin strands unlike the condensed chromosomes visible in mitosis

In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What would result from this?

large cells containing many nuclei

Which of the following cellular events occur in the G1 phase of the cell division cycle?

normal growth and cell function

At which phase of the cell cycle do centrioles begin to move apart in animal cells?

prophase

Which of the following events would be most likely to produce cells with several nuclei?

repeated mitosis without cytokinesis

Which of the following events occurs during interphase of the cell cycle?

replication of the DNA

If the cell whose nuclear material is shown in the accompanying figure continues toward completion of mitosis, which of the following events would occur next?

segregation of daughter chromosomes

The mitotic spindle plays a critical role in which of the following processes?

separation of sister chromatids

Movement of the chromosomes during anaphase would be most directly affected by a drug that prevents which of the following events?

shortening of microtubules

After DNA replication, each duplicated chromosome consists of two of which of the following structures?

sister chromatids

What is the name of the region on duplicated chromosomes where the sister chromatids are most closely attached to each other?

the centromere

FtsZ is a bacterial protein that forms a contractile ring involved in binary fission. Its function is analogous to which of the following structures in eukaryotic cells?

the cleavage furrow of eukaryotic animal cells

Why do some species employ both mitosis and meiosis, whereas other species use only mitosis?

they need both if they are reproducing sexually