Chapter 6

During which phase of mitosis does the nuclear envelope re-form?

telophase

which stage of the mitosis is this: -chromosomes arrive at opposite poles and begin to decondense -nuclear envelope material surrounds each set of chromosomes -the mitotic spindle breaks down

telophase

A human bone marrow cell in the prophase stage of mitosis contains 46 chromosomes. Therefore, there are a total of __________ sister chromatids in this cell.

92

Imagine that a human skin cell went through mitosis but did not undergo cytokinesis. How many chromosomes would be in the cell?

92

What is the difference between a benign tumor and a malignant tumor?

Benign tumors do not metastasize; malignant tumors do

Which of the following statements regarding prokaryotes is false? Which of the following statements regarding prokaryotes is false? A. Prokaryotic cells are generally smaller and simpler than eukaryotic cells. B. In prokaryotes, daughter chromosomes are separated by an active movement away from each other and the growth of a new plasma membrane between them. C. Prokaryotic chromosomes are more complex than those of eukaryotes. D. Most prokaryotes reproduce by binary fission.

C. Prokaryotic chromosomes are more complex than those of eukaryotes.

Which of the following statements regarding cell division is false? A. Cell division is the basis of both sexual and asexual reproduction. B. Cell division is necessary for development to occur. C. Cell division can reproduce an entire organism. D. Cell division is common in eukaryotes but rare in prokaryotes.

Cell division is common in eukaryotes but rare in prokaryotes.

Which of the following occurs during interphase? A. a reduction in the size of the nuclear membrane B. separation of newly formed DNA to opposite ends of the cell C. cell growth and duplication of the chromosomes D. cytokinesis

Cell growth and duplication of the chromosomes

what are the parts of interphase?

G1 S G2

where are the three checkpoints located and their regulations?

G1-all conditions for cell division favorable G2-all chromosomes have been replicated without any damage M-near the end of the metaphase are chromotids, correctly connected to spindle fibers

During binary fission, each copy of the duplicating chromosome moves to opposite ends of the cell. What does this achieve?

It ensures that each daughter cell receives one copy of the chromosome.

During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?

Metaphase

what gene suppresses tumors?

P53 gene

Which of the following features likely accounts for the difference between plant and animal cell cytokinesis? A. Plant cells have cell walls. B. Plant cells have two sets of chromosomes; animal cells have one set of chromosomes. C. Animal cells lack chloroplasts. D. Animal cells lack the microfilaments required for forming a cleavage furrow.

Plant cells have cell walls

what may occur if cells are cancerous?

-cell cycle regulation stops operating normally -mutation is passed to daughter cells -mutated cells aren't functional -tumor may occur

what are the characteristics of binary fission?

-not as complicated as eukaryotes -very rapid -single circular DNA chromosomes -chromosome not enclosed in nucleus

A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA in one of the grasshopper daughter cells?

100 units

how many chromosomes do gametes (sex cells) have?

23

how many human cells are homologous pairs?

23

A human somatic cell contains __________ chromosomes.

46

How many chromosomes do humans have in somatic cells?

46

Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?

The sequences are identical.

The stage of mitosis during which the chromosomes move toward separate poles of the cell is _____.

anaphase

which stage of mitosis is this: -Cohesin proteins binding the sister chromatids together break down -sister chromatids (now chromosomes) are pulled toward opposite poles -non-kinetochore spindle fibers lengthen, elongating the cell

anaphase

names for the animal and plant cells stage for cytokinesis

animal cells-cleavage furrow plant cells-cell plate

Definition of mutagenic agent

anything in the environment that may lead to cell mutations

Eukaryotic chromosomes differ from prokaryotic chromosomes in that they

are housed in a membrane-enclosed nucleus.

In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____.

are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes

what is the cell division function for prokaryotes?

asexual reproduction

A cell replicates its entire chromosomal DNA only __________.

before it is about to divide

A cleavage furrow forms in an animal cell during _____.

cytokinesis

The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called

cytokinesis

what stage of the cell cycle does the daughter cells separate?

cytokinesis

what are cell division functions in multicellular organisms?

development growth repair

In bacterial cells, binary fission involves __________.

distribution of a copy of the single parental chromosome to each daughter cell

A benign tumor differs from a malignant tumor in that a benign tumor

does not metastasize

cause of cancerous cells

error (mutation) in a gene (DNA sequence)

wht genomic DNA cell does this description fit: several double-stranded, linear DNA molecules called chromosomes

eukaryotic cells

You see a cell with several nuclei and you know that something is different about cell division. What is the most likely explanation?

failure of cytokinesis following mitosis

Which of the following is a feature of plant cell division that distinguishes it from animal cell division? A. production of four (rather than two) new cells per mitotic division B. formation of a cell plate C. lack of cytokinesis D. formation of a cleavage furrow

formation of a cell plate

During asexual reproduction, yeast cells can produce

genetically identical offspring

Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are

homologous chromosomes

what chromosomes does this description fit: -same length -same staining pattern -genes for the same characteristics are located in the same location -each member of the pair originates from a different parent

homologous chromosomes

Chromatids are

identical copies of each other if they are part of the same chromosome

Eukaryotic cells spend most of their cell cycle in which phase?

interphase

Sister chromatids are

joined together at a centromere

In some organisms such as certain fungi and algae, cells undergo mitosis repeatedly without subsequently undergoing cytokinesis. What would be the consequence of this?

large cells containing many nuclei

Which of the following is a correct representation of an event that occurs in mitosis? A. prometaphase—there is movement of the chromosomes to the poles. B. anaphase—the nuclear envelope disappears. C. prophase—chromosomes uncoil. D. metaphase—chromosomes line up on the equatorial plane.

metaphase

which stage of mitosis is this: -mitotic spindle is fully developed -centrosomes are at opposite poles of the cell -chromosomes are lined up at the metaphase plate - each sister chromatid is attached to a spindle fiber originating from opposite poles

metaphase

what is the final stage for the cell cycle?

Cytokinesis

Which of the following statements correctly describes the timing of DNA synthesis? A. DNA is synthesized in G2 of interphase immediately preceding mitosis. B. DNA is synthesized continuously throughout the cell cycle C. DNA is synthesized only during mitosis. D. DNA is synthesized in the S phase of interphase.

DNA is synthesized in the S phase of interphase.

what are the genes called that code for normal cell cycle?

Proto-oncogenes

The genetic material is duplicated during

S phase

DNA replication occurs in _____.

S phase of interphase

Which of the following statements regarding the cell cycle control system is false? A. The cell cycle control system triggers and controls major events in the cell cycle. B. The cell cycle control system includes three key checkpoints to complete a cell cycle. C. The cell cycle control system operates independently of the growth factors. D. The cell cycle control system receives messages from outside the cell that influence cell division.

The cell cycle control system operates independently of the growth factors.

You and your lab partner are observing a cell under a microscope, but you do not know whether it is a eukaryote or a prokaryote. Which of the following observations regarding the chromosomes would you use to immediately conclude that the cell is a eukaryote?

The chromosomes are housed in a membrane-enclosed nucleus.

You are observing a single cell under a microscope. You go home for the night, and the next day you see four cells. The four cells look similar, and when you stain them with a dye that binds to DNA they all appear to contain the same amount of DNA as the original cell. What likely happened overnight?

The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by asexual reproduction.

Which of the following occurs during mitosis? A. Organelles replicate. B. Two genetically different daughter cells result. C. Two daughter nuclei, one at each pole of the cell, are generated. D. Chromosomes replicate.

Two daughter nuclei, one at each pole of the cell, are generated

genome

a cell's complete complement of DNA

DNA replication is ___directional

bi-

what is prokaryote cell division called?

binary fission

G0 (Subzero) phase

cells not actively dividing (temporary or permanent)

A benign and a malignant tumor differ in that _____.

cells of a benign tumor remain within the tumor, whereas cells of a malignant tumor can spread to other body tissues

After fertilization, the resulting zygote begins to divide by __________.

mitosis

what are the genes called that can cause cells to become cancerous?

oncogenes

the genomic DNA in prokaryotes characteristics

one, double-stranded DNA molecule which is circular

what is the name of the starting point of DNA replication?

origin

A cell that has a cell wall is undergoing cell division, and the following events are observed: the formation of a cell plate and the division of the cell into two daughter cells. What type of cell is being observed and what process(es) is it going through?

plant cell; telophase and cytokinesis of mitosis

asexual reproduction

produces offspring genetically identical to the parent

The term binary fission is best applied to _____.

prokaryotes

which stage of mitosis is this: -chromosomes continue to condense -kinetochores appear at the centromeres -mitotic spindle microtubules attach to kinetochores -centrosomes move toward opposite poles

prometaphase

In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____.

prophase

The phase of mitosis during which the mitotic spindle begins to form is

prophase

which stage of mitosis is this: - chromosomes condenses and become visible -spindle fibers emerge from the centrosomes -nuclear envelope breaks down -nucleolus disappears

prophase

mitosis in the correct chronological order

prophase prometaphase metaphase anaphase telophase

the structure around cell wall once formed

septum

Prior to mitosis and after S phase, each chromosome of a eukaryotic cell consists of a pair of identical structures called

sister chromatids