Chapter 8 Review

asexual reproduction

asexual reproduction

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

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

Which statement regarding sexual and asexual reproduction is true?

asexual reproduction only.

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

1; 2

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

a similar but not identical combination of genes.

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

Cell division is common in eukaryotes but rare in prokaryotes.

Which statement regarding cell division is false?

are housed in a membrane-enclosed nucleus.

Eukaryotic chromosomes differ from prokaryotic chromosomes in that they

Prokaryotic chromosomes are more complex than those of eukaryotes.

Which statement regarding prokaryotes is false?

proteins

What helps maintain the structure of chromosomes and control the activity of genes?

joined together at a centromere.

Sister chromatids are

sister chromatids.

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

interphase

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

cell growth and duplication of the chromosomes

Which event occurs during interphase?

the S phase.

The genetic material is duplicated during

cytokinesis

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

undergoing 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! You realize that this cell is

prophase

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

metaphase

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

the centromeres of each chromosome come apart.

At the start of mitotic anaphase,

telophase

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

formation of a cell plate

Which feature of plant cell division distinguishes it from animal cell division?

Plant cells have cell walls.

Which feature likely accounts for the difference between plant and animal cell cytokinesis?

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

What must occur for a plant or animal to grow and develop normally?

density-dependent inhibition

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

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

physical contact of cell-surface proteins between adjacent cells

Mature human neuron (nerve) cells and muscle cells

are permanently in a state of nondivision.

Which statement regarding the cell cycle control system is false?

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

a cancerous tumor.

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

does not metastasize.

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

a drug that prevents mitotic spindle from forming

Which drug shows the greatest promise as a cancer chemotherapy agent?

Mitosis promotes genetic diversity.

Which statement regarding the function of mitosis is false?

homologous chromosomes.

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

a bride and groom.

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

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

Which statement regarding mitosis and meiosis is false?

Meiosis of the zygote generates somatic cells.

Which statement regarding the diploid life cycle is false?

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

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

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

Which statement regarding the differences between mitosis and meiosis is false?

Meiosis provides for asexual reproduction.

Which statement regarding mitosis and meiosis is false?

interphase

Both mitosis and meiosis are preceded by

possible combinations of characteristics.

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

homologous or nonsister chromatids

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

Karyotyping

can reveal alterations in chromosome number.

photographs of every couple at a high school prom.

A karyotype is most like

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

Which statement regarding Down syndrome is false?

members of a chromosome pair fail to separate.

Nondisjunction occurs when

flowering plants

Which type of organisms commonly demonstrates polyploidy?

1

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

Where the is cat?

Which variation of the sentence "Where is the cat?" is most like a chromosomal inversion?

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)

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

Cancer is not usually inherited because

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.

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 chromosomes are housed in a membrane-enclosed nucleus.

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 observation regarding the chromosomes would allow you to immediately conclude that the cell is a eukaryote?

First view: G₁; second view: G₂; third view: telophase

A skin cell of a red fox has 34 chromosomes. You look at the cell under a microscope and see that it has 34 chromosomes and one nucleus. Several hours later, you look at the same cell again and see that it has double the amount of DNA and one nucleus. A little while later, you see that it has 68 chromosomes and two nuclei. What stage of the cell cycle was this cell in when you viewed it at each time point?

plant cell; telophase and cytokinesis of mitosis

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?

The cells in flask B will have grown significantly, but the cells in flask A will have not grown at all.

You have two flasks (labeled A and B) that each contain an equal population of normal animal cells. You place flask A in a machine called a shaking incubator, which shakes the flask at 37°C and keeps the cells moving so as to prevent them from adhering to the bottom of the flask. Flask B is allowed to sit in an incubator (without shaking) at 37°C. If you let the cells in each flask grow for a week, which result are you most likely to observe?

40

When observing a bird skin cell in G₂ under a microscope, you count 160 total chromatids. How many chromosomes does a male chicken have in its sperm cells?

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

Which statement regarding mitosis and meiosis is true?

I: random fertilization; II: independent orientation; III: crossing over

Below are three statements. Classify them as examples of independent orientation, crossing over, or random fertilization.
I: The formation of a zygote from an egg and a sperm is an unpredictable event.
II: Random combinations of paternal and maternal chromosomes end up in gametes.
III: An allele on the paternal chromosome 18 ends up on the maternal chromosome 18.

Perform a karyotype using a person's white blood cells.

Jacobsen syndrome, which can cause heart defects, intellectual deficiencies, and bleeding disorders, is caused by a deletion of the terminal end of chromosome 11. What method could you use to determine whether an individual has Jacobsen syndrome?

Turner Syndrome

You are a medical student and are reviewing a case study about a past patient. The patient was 4 feet 8 inches tall at age 38, was unable to have children, and had cognitive impairments. The patient also had an irregular number of chromosomes. What diagnosis would you give the patient?

Add cells from the tissue sample to a cell culture dish and compare their growth against a sample of noncancerous cells from the patient.

Oncologists (medical doctors who treat cancer patients) routinely take biopsies (samples) of tissue from patients to determine whether the tissue is cancerous or not. What would be the best technique to use to determine whether cells from the tissue sample are cancerous?

Haploid cells must undergo mitosis to produce a multicellular haploid stage.

In some plants such as mosses and ferns, there is a multicellular stage in the life cycle that is haploid and a different stage that is diploid. What can you conclude from this?

muscle or nerve cells.

If scientists studying cancer could understand how to promote cell division in cells that do not ordinarily divide, this might help people who had injuries involving

failure of cytokinesis following mitosis

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

three chromosomes, each single-stranded (unduplicated)

You are studying chromosomal movement in a frog species whose haploid number is 3. What will you see in meiosis I prophase of this cell?

meiosis II prophase

What is the stage of cell division in a diploid organism if you see seven chromosomes, each consisting of a pair of sister chromatids?

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

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

prophase

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?

uncontrolled cell division.

Cancer is caused by

The cell will divide into two plant cells.

What event will immediately follow the event shown in the following image?

nondisjunction

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?

about 44 or 45

According to the graph, at what maternal age is the incidence of Down syndrome equal to five times the incidence at age 40?

Women in this study who were 45 years old had three times the incidence of babies with Down syndrome as did 40-year-old women.

Which conclusion can best be drawn from this study?

anaphase II

Mr. and Mrs. Smith have three sons in elementary school. Two of their children are progressing normally, but their youngest son, Charles, has been much slower than his siblings in developing speech and language skills. His parents are concerned that he has a learning disability and decide to investigate further. Since some learning disabilities can be genetically based, their pediatrician recommends a chromosomal analysis.

The results show that Charles has a trisomy of the sex chromosomes, diagnosed as XYY. A mistake during sperm formation resulted in an extra copy of the Y chromosome. The extra copy was passed on to Charles during fertilization. Most often, this chromosomal change causes no unusual physical features or medical problems, but those with trisomy of the sex chromosomes may have a higher-than-normal risk of delays in learning development.


During which stage of meiosis could this mistake have occurred?

nondisjunction involving a Y chromosome.

The problem that occurred during meiosis in sperm formation was

C

Which peak represents cells that contain the most DNA?

A: G₁; B: S; C: G₂

Which peak corresponds to cells in G₁? In S phase? In G₂?

G₁

In this sample of cells, what stage of the cell cycle are most of the cells in?

A only

If you used flow cytometry to sort a sample of cancerous cells that have been treated with a drug to prevent them from replicating their DNA, what peaks would you expect to see on the resulting flow cytometry data set?

Sample 2 is likely from tissue in the middle of the plant because fewer cells are in any mitotic stage.

What can you conclude from these data?

Metaphase lasts about twice as long as anaphase

From the data shown what can you conclude about the amount of time these plant cells spend in various stages of the cell cycle?