question

Meiosis starts with a single diploid cell and produces

answer

four haploid cells

question

A cell preparing to undergo meiosis duplicates its chromosomes during

answer

interphase.

question

During prophase I of meiosis,

answer

homologous chromosomes stick together in pairs.

question

The correct order of events during meiosis is

answer

prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II.

question

During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur?

answer

prophase I.

question

Nucleoli are present during _____.

answer

interphase

question

Cytokinesis often, but not always, accompanies _____.

answer

telophase (Cytokinesis often, but not always, accompanies telophase.)

question

Chromosomes become visible during _____.

answer

prophase (The chromatin fibers become discrete chromosomes.)

question

Centromeres divide and sister chromatids become full-fledged chromosomes during _____.

answer

anaphase (During anaphase, sister chromatids separate and daughter chromosomes migrate to opposite poles.)

question

Spindle fibers attach to kinetochores during _____.

answer

prometaphase (Attachment of spindle fibers to kinetochores is one of the events of pro metaphase.)

question

When the separate chromosomes are being pulled from one place to another? This animation illustrates the events of _____.

answer

Anaphase

question

In animal cells ______ involves the formation of a cleavage furrow

answer

Cytokinesis

question

Events of________ include the condensation of chromatin and the dispersal of nucleoli.

answer

Prophase

question

During _______ chromosomes align along the metaphase plate.

answer

Metaphase

question

The events of _________ include the attachment of spindle fibers to kinetochores.

answer

Prometaphase

question

_____ in plant cells involves the formation of a cell plate.

answer

Cytokinesis

question

During_______ both nuclear envelopes and nucleoli re-form.

answer

Telophase

question

When a cleavage furrow appears and eventually pinch into 2 cells. This animation illustrates the events of _____.

answer

cytokinesis as it occurs in animal cells

question

When the chromosomes become visible? This animation illustrates the events of _____.

answer

Prophase

question

When chromosomes align laterally (along the metaphase plate: imaginary line located midway between the poles of the duplicated chromosomes and the original chromosomes), before they separate. This animation illustrates the events of _____.

answer

Metaphase

question

When the chromosomes break the nuclear envelope, and attach to microtubules. This animation illustrates the events of _____.

answer

prometaphase

question

When a cell plate divides into 2 cells. This animation illustrates the events of _____.

answer

Cytokinesis as it occurs in Plant Cells

question

When the sister cells are completely divided through Cytokinesis. This animation illustrates the events of _____.

answer

telophase

question

During prophase a homologous pair of chromosomes consists of _____.

answer

two chromosomes and four chromatids

question

During _____ the cell grows and replicates both its organelles and its chromosomes.

answer

interphase

question

During _____ both the contents of the nucleus and the cytoplasm are divided.

answer

the mitotic phase (encompasses both mitosis and cytokinesis)

question

Which of these phases encompasses all of the stages of mitosis but no other events?

answer

Mitosis

question

DNA replication produces two identical DNA molecules, called _____, which separate during mitosis.

answer

sister chromatids

question

After chromosomes condense, the _____ is the region where the identical DNA molecules are most tightly attached to each other.

answer

centromeres

question

During mitosis, microtubules attach to chromosomes at the ______.

answer

kinetochores

question

In dividing cells, most of the cell's growth occurs during ______.

answer

interphase

question

The _____ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.

answer

mitotic spindles

question

During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called _____.

answer

chromatin

question

In most eukaryotes, division of the nucleus is followed by ______, when the rest of the cell divides.

answer

cytokinesis

question

The _____ are the organizing centers for microtubules involved in separating chromosomes during mitosis.

answer

centrosomes

question

The key structures involved in mitosis of an animal cell

answer

The two SISTER CHROMATIDS of each duplicated chromosome beginning to attach to the MITOTIC SPINDLE by means of their KINETOCHORES. The CENTROSOMES anchor the MIT at opposite ends of the cell. CENTROMERE is the region of the chromosome where chromatids are most closely attached to each other.

question

Cell Cycle Phases: Interphase consists of the G1, S, and G2 subphases, and that the M phase consists of mitosis and cytokinesis.

answer

A. Non dividing cells exit cell cycle B. At this point, cell commits to go through the cycle. C. DNA replicates D. Centrosome replicates E. Mitotic spindle begins to form. F. Cell divides, forming two daughter cells.

question

Phases of the cell cycle

answer

The first step in preparing for division is to replicate the cell's DNA in the S phase. In the G2 phase, the centrosome replicates. In early M phase, the centrosomes move away from each other toward the poles of the cell, in the process organizing the formation of the mitotic spindle. At the end of the M phase when mitosis is complete, the cell divides (cytokinesis), forming two genetically identical daughter cells.

question

Once a cell passes the ______ checkpoint, it usually completes the cell cycle--that is, it divides.

answer

G1

question

As the chromosomes of a parent cell are duplicated and distributed to the two daughter cells during cell division, the structure of the chromosomes changes.

answer

1. N Y Y Y N 2. N N N Y Y 3. N Y Y Y Y

question

Changes in DNA structure during the cell cycle:

answer

Sister chromatids form when DNA replicates in the S phase. The sister chromatids become individual chromosomes once they separate in early anaphase. Similarly, the cellular DNA content doubles in the S phase when the DNA replicates. However, the cell's DNA content does not return to its normal (undoubled) levels until after cytokinesis is complete and two daughter cells have formed. The condensation state of the DNA is not related to the presence or absence of sister chromatids. The DNA condenses in prophase and remains condensed until after the sister chromatids separate and the new daughter cells begin to form. In late telophase/cytokinesis, the emphasis shifts to cell growth and DNA replication for the next cell cycle. For these processes to occur, the DNA needs to be de-condensed so it is accessible to the cellular machinery involved in transcription.

question

In ______ the microtubules of the spindle apparatus begin to assemble from individual tubulin subunits. As the identical chromatids of each pair of sister chromatids condense during this stage, they are held together by cohesin proteins.

answer

Prophase

question

In_____ is marked by fragmentation of the nuclear envelope, expansion of the spindle into the nuclear region, and attachment of some spindle fibers to the chromosomes via the kinetochores.

answer

Prometaphase

question

_________,marked by the alignment of chromsomes along the metaphase plate, is brought about by kinetochores aligning and then remaining motionless relative to the poles of the cell.

answer

Metaphase

question

In ______ , the cohesin proteins are cleaved, and the kinetochores move toward the poles of the cell, separating the sister chromatids.

answer

Anaphase

question

As _______ proceeds, the kinetochore microtubules of the spindle disassemble. As the chromosomes reach the poles of the cell, the nuclear envelopes of the two new daughter nuclei form.

answer

Telophase

question

What phase is this?

answer

Cytokinesis

question

During prophase, the microtubules of the mitotic spindle ______.

answer

lengthen

question

During anaphase, the nonkinetochore microtubules ______ and move past each other, and the kinetochore microtubules ______.

answer

lengthen, shorten

question

During telophase, the non kinetochore microtubules ______.

answer

disassemble

question

Roles of the mitotic spindle

answer

1. Will this cell elongate during mitosis? (yes) 2. Will the sister chromatids separate from each other? (yes) 3. Will the chromosomes move to the poles of the cell? (no)

question

Comparing chromosome separation in bacteria and eukaryotes

answer

bacteria only: *Chromosome separation begins at the origin of replication on DNA. Eukaryotes only: * Before separation, duplicated chromosomes condense. * Nuclear envelope fragments, permitting chromosome separation. * 2 copies of the duplicated chromosome are attached at their centromeres before separation. Both Bacteria and Eukariotes: * Chromosomes replicate before cell division. * Replicated chromosomes separate by attaching to some other structural feature of the cell.

question

Cytokinesis in plant cells

answer

*Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. *The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells.

question

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

answer

They have uncoiled to form long, thin strands.

question

Kinetochores

answer

They are sites at which microtubules attach to chromosomes.

question

Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division?

answer

cleavage

question

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

answer

large cells containing many nuclei

question

Cells divide by constriction of a ring of proteins

answer

bacteria: TRUE animals: TRUE plants: FALSE

question

The presence of a cell wall prevents the cell from dividing by constriction

answer

bacteria: FALSE animals: FALSE plants: TRUE

question

Tubulin or tubulin-like molecules function in binary fission (in bacteria) or cytokinesis (in animals and plants).

answer

bacteria: TRUE animals: FALSE plants: TRUE

question

Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle?

answer

G1

question

_____ is a carcinogen that promotes colon cancer.

answer

Fat (A diet high in fat increases the risk of both colon and breast cancer.)

question

Carcinogens

answer

cigarette smoke testosterone UV light Fat (All of these substances can cause cancer.)

question

One difference between cancer cells and normal cells is that cancer cells

answer

continue to divide even when they are tightly packed together.

question

The decline of MPF activity at the end of mitosis is due to

answer

the degradation of cyclin.

question

Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of micro-tubules, its effectiveness must be related to

answer

disruption of mitotic spindle formation.

question

The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B?

answer

cleavage furrow formation and cytokinesis

question

How do cancer cells differ from normal cells?

answer

Cancer cells may be immortal.

study help–Mastering Biology Chapter 8 – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards