Ch8

B

A pair of sex chromosomes found in a human male is most like A) a pair of blue jeans. B) a bride and groom. C) a knife, fork, and spoon. D) identical twins

A

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? A) First view: G1; second view: G2; third view: telophase B) First view: G1; second view: metaphase; third view: cytokinesis C) First view: S; second view: prophase; third view: cytokinesis D) First view: G0; second view: G2; third view: telophase

B

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 A) density-independent inhibition. B) density-dependent inhibition. C) anchorage independence. D) growth factor inhibition.

B

Asexual reproduction requires ________ individual(s), whereas sexual reproduction requires _______ individual(s). A) 1; 1 B) 1; 2 C) 2; 1 D) 2; 2

A

At a chiasma, two ________ are attached to each other. A) homologous or nonsister chromatids B) homologous or sister chromatids C) nonhomologous chromosomes D) daughter cells

A

At the start of mitotic anaphase, A) the centromeres of each chromosome come apart. B) the chromatid DNA replicates. C) nuclear envelopes begin to form around the chromosomes. D) equivalent and complete collections of chromosomes have reached the two poles

B

Both mitosis and meiosis are preceded by A) prometaphase. B) interphase. C) prophase. D) telophase.

A

Cancer is not usually inherited because A) the chromosomal changes in cancer are usually confined to somatic cells. B) people with cancer usually die before reproducing. C) the causes of cancer are not usually genetic. D) the cancerous cells usually interfere with the ability to produce gametes

B

During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles? A) prophase B) metaphase C) anaphase D) telophase

D

During which phase of mitosis does the nuclear envelope re-form? A) anaphase B) metaphase C) prophase D) telophase

B

During which stage of meiosis do synapsis and crossing over occur? A) interphase I B) prophase I C) prophase II D) metaphase I

A

Eukaryotic cells spend most of their cell cycle in which phase? A) interphase B) prophase C) metaphase D) telophase

D

Eukaryotic chromosomes differ from prokaryotic chromosomes in that they A) are simpler. B) are circular in structure. C) include fewer proteins. D) are housed in a membrane-enclosed nucleus.

A

How many generations does it take to develop a new plant species by polyploidy? A) 1 B) 2 C) 10 D) about 20

B

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) A) deletion. B) inversion. C) translocation. D) reciprocal translocation

A

Independent orientation of chromosomes at metaphase I and random fertilization are most like A) shuffling cards and dealing out hands of poker. B) cutting up a pie into eight even-sized slices. C) alphabetizing files in a filing cabinet. D) pairing up similar socks after washing your clothes.

C

Independent orientation of chromosomes at metaphase I results in an increase in the number of A) gametes. B) homologous chromosomes. C) possible combinations of characteristics. D) sex chromosomes.

B

Karyotyping A) shows chromosomes as they appear in metaphase of meiosis II. B) can reveal alterations in chromosome number. C) examines points of crossing over. D) reveals the presence of cancerous genes

A

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 A) undergoing cytokinesis. B) in the S phase of interphase. C) in the G1 phase of interphase. D) about to undergo mitosis

C

Mature human nerve cells and muscle cells A) become cancerous more easily than other cell types. B) continue to divide throughout their lifetime. C) are permanently in a state of nondivision. D) cease dividing after a predetermined number of cell generations

C

Nondisjunction occurs when A) a portion of a chromosome breaks off and is lost. B) two chromosomes fuse into one. C) members of a chromosome pair fail to separate. D) an entire pair of chromosomes is lost during meiosis I.

D

Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called A) chromatin. B) sister chromosomes. C) nucleoli. D) sister chromatids

B

Sister chromatids are A) found right after a cell divides. B) joined together at a centromere. C) made only of DNA. D) unique to prokaryotes.

C

Strictly speaking, the phrase "like begets like" refers to A) all forms of reproduction. B) sexual reproduction only. C) asexual reproduction only. D) production of gametes from a premeiotic cell.

A

The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called A) asexual reproduction. B) sexual reproduction. C) regeneration. D) spontaneous generation.

C

The genetic material is duplicated during A) the mitotic phase. B) G1. C) the S phase. D) G2.

B

The phase of mitosis during which the mitotic spindle begins to form is A) interphase. B) prophase. C) metaphase. D) anaphase.

B

The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called A) mitosis. B) cytokinesis. C) binary fission. D) telophase.

A

Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are A) homologous chromosomes. B) heterologous chromosomes. C) complementary chromosomes. D) parallel chromosomes.

B

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 A) cell constraint. B) density-dependent inhibition. C) cell division repression. D) growth factor desensitization.

C

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

B

Which of the following helps maintain the structure of chromosomes and control the activity of genes? A) the nuclear membrane B) proteins C) centromeres D) ribosomes

A

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

D

Which of the following is probably the main factor responsible for the phenomenon of density-dependent inhibition? A) a local accumulation of growth-inhibiting factors B) cells' innate ability to "sense" when the organ of which they are a part has no need for additional cells C) a local deficiency of nutrients D) physical contact of cell-surface proteins between adjacent cells

B

Which of the following must occur for a plant or animal to grow and develop normally? A) The organism must receive a supply of the appropriate hormones from its parents. B) The organism must be able to control the timing and rate of cell division in different parts of its body. C) Sufficient light must be available to stimulate cell division. D) Sufficient oxygen must be available to stimulate cell division.

C

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

B

Which of the following shows the greatest promise as a cancer chemotherapy agent? A) a drug that interferes with cellular respiration B) a drug that prevents mitotic spindle from forming C) a drug that prevents crossing over D) a drug that prevents tetrad formation

B

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

Which of the following statements correctly describes the behavior of a tetrad during anaphase I of meiosis? A) It goes intact to one pole of the dividing cell. B) It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell. C) It splits into two pairs of homologous, nonsister chromatids, and one pair goes to each pole of the dividing cell. D) It splits into four chromosomes, which distribute in random pairs to the two poles of the dividing cell.

C

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.

D

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

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

C

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

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.

B

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.

A

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

D

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

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

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.

B

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.

C

Which of the following types of organisms commonly demonstrates polyploidy? A) mammals B) reptiles C) flowering plants D) fish

A

Which of the following variations of the sentence "Where is the cat?" is most like a chromosomal deletion? A) Where is cat? B) Where is the the cat? C) Where the is cat? D) Where is cat the the cat?

D

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) identical chromosomes but different genes. B) identical genes but different chromosomes. C) the same combination of traits but different genes. D) a similar but not identical combination of genes.

D

Without crossing over, A) cells could not complete meiosis. B) meiosis could not produce haploid gametes. C) only a small number of unique gametes could be produced by a single individual. D) genetic recombination could not occur

B

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? A) The chromosomes are circular in structure. B) The chromosomes are housed in a membrane-enclosed nucleus. C) The chromosomes contain very few proteins. D) The chromosomes are very simple in structure.

A

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) a cancerous tumor. B) skin from a human. C) a liver from a cow. D) the sperm-producing tissue of the testis.

C

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. What likely happened overnight? A) The single cell divided once to form four new cells via asexual reproduction. B) The single cell divided once to form four new cells via sexual reproduction. C) 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. D) The single cell divided to form two new cells, and the two new cells each divided to form four total cells, all by sexual reproduction.

C

A benign tumor differs from a malignant tumor in that a benign tumor A) is cancerous. B) spreads from the original site. C) does not metastasize. D) never causes health problems

D

A cell is initially diploid, but it has a unique cell cycle in that this cell goes through two S phases instead of one. What would the remainder of its cell cycle consist of if this cell is to produce four identical diploid daughter cells at the end of its cell cycle? A) two rounds of mitosis and one round of cytokinesis B) one round of mitosis and one round of cytokinesis C) one round of mitosis and two rounds of cytokinesis D) two rounds of mitosis and two rounds of cytokinesis

C

A karyotype is most like A) a map showing the hidden location of buried treasure. B) a movie showing the stages of the reproductive cycle of a beetle. C) photographs of every couple at a high school prom. D) the answer key to a multiple-choice exam.