BIO 101 Ch 8

The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called

asexual reproduction.

Which of the following statements regarding sexual and asexual reproduction is true?
A) Cell division only occurs after sexual reproduction.
B) Only offspring from asexual reproduction inherit traits from two parents.
C) Sexual reproduction typically includes the development of unfertilized eggs.
D) Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.

D.) Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.

Strictly speaking, the phrase "like begets like" refers to

asexual reproduction only.

Asexual reproduction requires ________ individual(s).

1

With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have

a similar but not identical combination of genes.

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

D) Cell division is common in eukaryotes but rare in prokaryotes.

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

A) Prokaryotic chromosomes are more complex than those of eukaryotes.

Eukaryotic chromosomes differ from prokaryotic chromosomes in that they

are housed in a membrane-enclosed nucleus.

Which of the following helps maintain the structure of chromosomes and control the activity of genes?

proteins

Sister chromatids are

joined together at a centromere.

Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called

sister chromatids.

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

interphase

Which of the following occurs during interphase?

cell growth and duplication of the chromosomes

The genetic material is duplicated during

the S phase.

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

cytokinesis

Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! Then you realize that this cell is

undergoing cytokinesis.

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

prophase.

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

metaphase

At the start of mitotic anaphase,

the centromeres of each chromosome come apart.

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

telophase

Which of the following is a feature of plant cell division that distinguishes it from animal cell division?

formation of a cell plate

Which of the following features likely accounts for the difference between plant and animal cell cytokinesis?

Plant cells have cell walls.

Which of the following must occur for a plant or animal to grow and develop normally?

The organism must be able to control the timing and rate of cell division in different parts of its body

When animal cells are grown in a petri dish, they typically stop dividing once they have formed a single, unbroken layer on the bottom of the dish. This arrest of division is an example of

density-dependent inhibition.

As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of

density-dependent inhibition.

Which of the following is probably the main factor responsible for the phenomenon of density-dependent inhibition?

physical contact of cell-surface proteins between adjacent cells.

Mature human nerve cells and muscle cells

are permanently in a state of nondivision.

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

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

You are asked to culture an unidentified sample of animal tissue. You notice that the cells seem to fail to exhibit density-dependent inhibition. The source of this tissue sample is most likely

a cancer

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

does not metastasize.

Which of the following shows the greatest promise as a cancer chemotherapy agent?

a drug that prevents mitotic spindle from forming

Which of the following statements regarding the function of mitosis is false?
A) Mitosis allows organisms to grow.
B) Mitosis allows organisms to generate genetic diversity.
C) Mitosis allows organisms to reproduce asexually.
D) Mitosis allows organisms to repair tissues.

Mitosis allows organisms to generate genetic diversity.

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

homologous chromosomes.

A pair of sex chromosomes found in a human male is most like

a bride and groom.

Which of the following statements regarding mitosis and meiosis is false?
A) Meiosis only occurs in the ovaries and testes.
B) All sexual life cycles involve an alternation of diploid and haploid stages.
C) Mitosis produces daughter cells with half the number of chromosomes as the parent cell.
D) A normal human zygote has 46 chromosomes.

C) Mitosis produces daughter cells with half the number of chromosomes as the parent cell.

Which of the following statements is false?
A) Gametes are haploid cells.
B) Two haploid cells fuse during fertilization.
C) An X chromosome is an autosome.
D) A zygote is a fertilized egg.

C) An X chromosome is an autosome.

During which stage of meiosis do synapsis and crossing over occur?

prophase I

Which of the following options correctly describes the behavior of a tetrad during anaphase I of meiosis?

It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell.

Which of the following statements regarding the differences between mitosis and meiosis is false?
A) In meiosis four daughter cells are produced, whereas in mitosis two daughter cells are produced.
B) Cells produced by mitosis are diploid, whereas cells produced by meiosis are haploid.
C) In mitosis cytokinesis occurs once, whereas in meiosis cytokinesis occurs twice.
D) Crossing over is a phenomenon that creates genetic diversity during mitosis.

D) Crossing over is a phenomenon that creates genetic diversity during mitosis.

Which of the following statements regarding mitosis and meiosis is false?
A) Mitosis provides for growth and tissue repair.
B) Meiosis provides for asexual reproduction.
C) In mitosis, the chromosomes replicate only once in the preceding interphase.
D) All the events unique to meiosis occur during meiosis I.

B) Meiosis provides for asexual reproduction.

Both mitosis and meiosis are preceded by

interphase.

Independent orientation of chromosomes at metaphase I and random fertilization are most like

shuffling cards and dealing out hands of poker.

Independent orientation of chromosomes at metaphase I results in an increase in the number of

possible combinations of characteristics.

Which of the following statements regarding genetic diversity is false?
A) Genetic diversity is enhanced by random fertilization.
B) Genetic diversity is enhanced by independent orientation of chromosomes at metaphase I.
C) Genetic diversity is enhanced by mitosis.
D) Genetic diversity is enhanced by crossing over during meiosis.

C) Genetic diversity is enhanced by mitosis.

At a chiasma, two ________ are attached to each other.

homologous or non-sister chromatids

Without crossing over

genetic recombination could not occur.

Karyotyping

can reveal alterations in chromosome number.

A karyotype is most like

photographs of every couple at a high school prom.

Which of the following statements regarding Down syndrome is false?
A) Trisomy 21 is the cause of Down syndrome.
B) Down syndrome is the most common serious birth defect in the United States.
C) People with Down syndrome usually have a shorter life span than normal.
D) Down syndrome is least likely to be seen in the infants of mothers over 40.

D) Down syndrome is least likely to be seen in the infants of mothers over 40.

Nondisjunction occurs when

members of a chromosome pair fail to separate.

Which of the following statements about nondisjunction is false?
A) Nondisjunction in meiosis can affect autosomes and sex chromosomes.
B) In mammals, extra copies of the Y chromosome are typically inactivated.
C) In general, a single Y chromosome is enough to produce "maleness."
D) Women with a single X chromosome have Turner syndrome and are sterile.

B) In mammals, extra copies of the Y chromosome are typically inactivated.

Which of the following types of organisms commonly demonstrates polyploidy?

flowering plants

How many generations does it take to develop a new plant species by polyploidy?

one

Which of the following variations of the sentence "Where is the cat" is most like a chromosomal deletion?

Where is cat?

If a chromosome fragment breaks off and then reattaches to the original chromosome, but in the reverse direction, the resulting chromosomal abnormality is called a(n)

inversion.

Cancer is not usually inherited because

the chromosomal changes in cancer are usually confined to somatic cells.