Biology- Chapter 8 The Cellular Basis of Reproduction and Inheritance

TRUE OR FALSE (OF CELL DIVISION): Cell division can reproduce an entire organism.

True

TRUE OR FALSE (OF CELL DIVISION): Cell division is necessary for development to occur.

True

TRUE OR FALSE (OF CELL DIVISION): Cell division is the basis of both sexual and asexual reproduction.

True

TRUE OR FALSE: A zygote is a fertilized egg.

True

TRUE OR FALSE: Gametes are haploid cells.

True

TRUE OR FALSE: Two haploid cells fuse during fertilization.

True

In comparing a frog cell in metaphase of mitosis with one in metaphase I of meiosis, how would tell you which was which?

Unlike mitosis, in meiosis each chromosome would be opposite its homolog.

What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells?

all of the above are differences between prokaryotic and eukaryotic DNA. which is > - the amount of DNA present - whether the DNA is housed in a nucleus or not - whether the DNA is linear or circular

Crossing over is important because it __________.

allows the exchange of different versions of genes between homologous chromosomes

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

anaphase

Homologous chromosomes migrate to opposite poles during _____.

anaphase I

During _____ sister chromatids separate.

anaphase II

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

Mature human neuron (nerve) cells and muscle cells

are permanently in a state of nondivision

A cell replicates its entire chromosomal DNA only __________.

before it is about to divide

Bacteria divide by

binary fission

During _____ chromosomes align single file along the equator of a haploid cell.

metaphase II

During _____ a spindle forms in a haploid cell.

prophase II

The exchange of parts between nonhomologous chromosomes is called _____.

reciprocal translocation

One version of a gene may encode __________, whereas a different version of the same gene may encode __________.

red eyes; white eyes

In meiosis II, _____.

sister chromatids are separated

Crossing over of chromosomes during meiosis shuffles parental chromosomes, resulting in a genetically unique child.

- During prophase I of meiosis I, homologous paternal and maternal chromosomes pair up and undergo crossing over. - During meiosis II, sister chromatids separate into four different gametes. - A hybrid chromosome that has crossed over will contain pieces of both the maternal and paternal chromosomes

Which processes lead to most genetic variation in sexually reproducing organisms?

- crossing over - independent orientation of chromosomes in meiosis -random fertilization

Which of the following events have not yet occurred?

- separation of sister chromatids into distinct cells - production of four haploid gametes

Places the events of meiosis in the proper order. Rank from the first event to the last event left to right.

1. homologous chromosomes pair up 2. nonsister chromatids form chiasmata 3. crossing over occurs 4. homologous chromosomes separate 5. sister chromatids separate 6. four haploid gametes are produced

Asexual reproduction requires ________ individual(s), whereas sexual reproduction requires _______ individual(s).

1;2

How many pairs of autosomes do humans have?

22

A human somatic cell contains __________ chromosomes.

46

In a cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing __________ chromosomes.

5

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

The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?

Anaphase

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

Anaphase

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

Asexual reproduction

During meiosis I, homologous chromosomes form a tetrad and crossing over occurs. What is the outcome of crossing over?

Crossing over creates new combinations of genes present on a single chromosome.

At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.

Cytokinesis (Cytokinesis is the division of the cytoplasm that occurs in conjunction with telophase, the last phase in mitosis)

Which of the following statements correctly describes the timing of DNA synthesis?

DNA is synthesized in the S phase of interphase.

The first step of bacterial replication is _____.

DNA replication

Which of these phases encompasses all of the stages of mitosis?

E

TRUE OR FALSE (OF CELL DIVISION): Cell division is common in eukaryotes but rare in prokaryotes.

False

TRUE OR FALSE: An X chromosome is an autosome

False

Immune system cells enter a resting phase after undergoing mitosis. When activated—for example, by an infection—they can reenter the sequence of events in the cell cycle that leads to cell division. What would be the correct cell cycle sequence of events for these reactivated cells?

G1, S, G2, M (After reactivation, these cells move into G1. Here they grow in preparation for DNA replication (S phase). Once complete, the cells move into G2 and make the final preparations for mitosis.)

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

Interphase

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.

The chromosomes line up in the center of the cell during which phase of mitosis?

Metaphase

Which of the following statements regarding the function of mitosis is false? -Mitosis promotes genetic diversity -Mitosis is necessary for asexual reproduction in eukaryotes -Mitosis promotes repair tissues -Mitosis allows organisms to grow.

Mitosis promotes genetic diversity.

Many cancer drugs known as "antimitotics" target microtubules. What is the first stage of mitosis at which these drugs are likely to have an effect?

Prophase

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?

Prophase

Synapsis occurs during _____.

Prophase I

Which of the following statements regarding mitosis and meiosis is true?

Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis.

The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?

Telophase

What must happen before a cell can begin mitosis?

The chromosomes must be duplicated (Before mitosis can begin, the chromosomes, or genetic material, must be copied, which occurs during interphase)

What would be the immediate consequence of destroying a cell's centrosomes?

The mitotic spindle would not form.

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. (Except for the occurrence of rare mutations, this is always the case. Both sister chromatids come from replication of a single DNA molecule, which is present in the one chromatid before replication.)

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 represents a chromosomally normal human female?

XX

Meiosis differs from mitosis in that _____ only occurs in meiosis.

crossing over

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.

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.

The diploid phase of the human life cycle begins with _____

fertilization

Which of the following types of organisms commonly demonstrates polyploidy?

flowering plants

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

formation of a cell plate

Meiosis II typically produces _____ cells, each of which is _____.

four ... haploid

The function of meiosis is to make __________.

four cells with a haploid number of chromosomes

What is the typical result when a diploid cell undergoes meiosis?

four haploid cells

At the conclusion of meiosis I, the daughter cells are _____.

haploid and the sister chromatids are joined

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

homologous chromosomes

Synapsis occurs during _____.

prophase I

In anaphase I, __________.

homologous chromosomes move toward opposite poles

During anaphase I, __________.

homologous chromosomes separate and migrate toward opposite poles

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

interphase

Nucleoli are present during _____.

interphase

Both mitosis and meiosis are preceded by

interphase.

A fragment of chromosome 21 reattaches to chromosome 21, but in the reverse direction. What is the name given to this change?

inversion

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.

When we say that an organism is haploid, we mean that _____

its cells each have one set of chromosomes

Sister chromatids are

joined together at a centromere.

Which of the following is a correct representation of an event that occurs in mitosis?

metaphase—chromosomes line up on the equatorial plane.

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

mitosis

If the four cells shown resulted from cell division of a single cell with diploid chromosome number 2n = 4, what best describes what just occurred?

nondisjunction

Spindle fibers attach to kinetochores during _____.

prometaphase

Chromosomes become visible during _____.

prophase

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

prophase (During prophase we observe the formation of the spindle, the condensation of chromatin, and the disappearance of the nucleolus, which are the opposite events to those occurring during telophase.)

During anaphase II, __________.

sister chromatids separate and migrate toward opposite poles

The kinetochores are __________.

sites at which microtubules attach to chromosomes

An example of a cell that is 2n is a __________.

somatic cell (Somatic is a word used to refer to the "body." These body cells are diploid and have two homologous copies of each chromosome.)

Cytokinesis often, but not always, accompanies _____.

telophase

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

telophase

At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.

telophase I

At the end of _____ and cytokinesis there are four haploid cells.

telophase II

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

the mitotic phase

During mitosis, the chromosomes move because _____.

they attach to a dynamic, precisely regulated mitotic spindle

Meiosis I produces _____ cells, each of which is _____.

two ... haploid

During prophase a homologous pair of chromosomes consists of _____.

two chromosomes and four chromatids

Mitosis and cytokinesis result in the formation of __________; meiosis and cytokinesis result in the formation of __________.

two diploid cells : four haploid cells

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! You realize that this cell is

undergoing cytokinesis.

Homologous chromosomes possess the same genes arranged in the same order but may possess different __________ of some of these genes.

versions