Chapter 10

In animals, fertilization is to zygote as meiosis is to which of the following? A. mitosis B. diploid C. chromosome D. replication E. gamete

E. gamete

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following statements describes the genetic or chromosomal contents of this cell? - It is identical in content to another cell from the same meiosis. - It has twice the number of chromosomes. - It has half the amount of DNA of the cell that began meiosis. - It has half the chromosomes but twice the DNA of the originating cell.

- It has half the amount of DNA of the cell that began meiosis.

A given organism has 46 chromosomes in its karyotype. Which of the following statements is correct regarding this organism? - It must be human. - It must be sexually reproducing. - Its gametes must have 23 chromosomes. - It must be an animal.

- Its gametes must have 23 chromosomes.

If a sexually reproducing organism has a diploid number of 36, how many individual chromosomes would any of its gametes have? - 72 chromosomes - 36 chromosomes - 18 chromosomes - 9 chromosomes

- 18 chromosomes

Which of the following statements correctly describes an organism's genome? - A genome is made up of the genes found in a gamete produced by the organism. - A genome is a representation of a single gene locus in an organism. - A genome is a representation of the complete set of polypeptides in any of the organism's cells. - A genome is a complete set of all of an organism's genes.

- A genome is a complete set of all of an organism's genes.

Why are cells arrested at metaphase in the preparation of a karyotype? - All of the chromosomes are at their least condensed state and are easy to visualize. - All of their chromosomes are highly condensed and easy to visualize. - The chromosomes have duplicated, making them easier to visualize. - All of the sister chromatids have separated into two new daughter cells.

- All of their chromosomes are highly condensed and easy to visualize.

If a horticulturist breeding plants known as gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following processes would be her most probable and efficient route to establishing a line of such plants with that particular set of traits? - Force the plant to self-pollinate to obtain an identical one. - Clone the plant asexually to produce an identical one. - Breed this plant with another plant with much weaker traits. - Go back through her previous experiments to obtain another plant with the same traits.

- Clone the plant asexually to produce an identical one.

Which of the following is true of an organism that has a chromosome number of 2n = 16? - During the S phase of the cell cycle, there will be 32 separate chromosomes. - The species has 16 sets of chromosomes per cell. - Each cell has eight homologous pairs of chromosomes. - A gamete from this species has four chromosomes.

- Each cell has eight homologous pairs of chromosomes.

The somatic cells of a type of shrub called a privet each contain 46 chromosomes. To be as different as they are from human cells, which have the same number of chromosomes, which of the following must be true? - Privet shrubs must be metabolically more like animals than like other shrubs. - Genes on a particular privet chromosome, such as the X, must be on a different human chromosome, such as number 18. - Privet cells cannot reproduce sexually. - Genes of privet chromosomes are significantly different from those in humans.

- Genes of privet chromosomes are significantly different from those in humans.

An individual with dark skin will be advised to take capsules with vitamin D if he moves to Northern Europe. This is because: - It is important to take multivitamins when you're adjusting to a new environment - Having more melanin in your skin blocks the sun which is in charge of fixing vitamin D in your bones - There is too much sunlight in his new environment so he better be protected.

- Having more melanin in your skin blocks the sun which is in charge of fixing vitamin D in your bones

How are sister chromatids and homologous chromosomes different from each other? - Sister chromatids are only formed during mitosis. Homologous chromosomes are formed during meiosis. - Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication. - Homologous chromosomes are closely associated with each other in both mitosis and meiosis. Sister chromatids are only associated with each other during mitosis. - They are not different. Homologous chromosomes and sister chromatids are both identical copies of each other. - Homologous chromosomes are identical copies of each other. One sister chromatid comes from the father, and one comes from the mother.

- Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication.

Which of the following processes happens during meiosis I? - The chromosome number per cell is conserved. - Homologous chromosomes of a pair are separated from each other. - Sister chromatids are separated. - Four daughter cells are formed.

- Homologous chromosomes of a pair are separated from each other.

When homologous chromosomes cross over, what is the result? - Two sister chromatids get tangled, resulting in one altering the sequence of its DNA. - Specific proteins break the two strands of nonsister chromatids and re-join them. - Each of the four DNA strands of a homologous pair is broken, and the pieces are mixed. - Two sister chromatids exchange identical pieces of DNA.

- Specific proteins break the two strands of nonsister chromatids and re-join them.

Which of the following occurs during meiosis but not during mitosis? - Chromosomes align at the metaphase plate. - Synapsis occurs. - A spindle apparatus forms. - Chromosomes migrate to opposite poles. - Chromosomes condense.

- Synapsis occurs.

How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? - They have half the number of chromosomes and half the amount of DNA. - They have the same number of chromosomes and half the amount of DNA. - They have half the amount of cytoplasm and twice the amount of DNA. - They have half the number of chromosomes and one-fourth the amount of DNA.

- They have half the number of chromosomes and one-fourth the amount of DNA.

During mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. Such molecules must have which of the following properties? - They must be intact for nuclear envelope re-formation. - They must be removed before meiosis can begin. - They must be removed before sister chromatids or homologous chromosomes can separate. - They must persist throughout the cell cycle.

- They must be removed before sister chromatids or homologous chromosomes can separate.

Which of the following types of cells would be produced by meiosis? - a diploid unicellular organism - a diploid animal cell - a diploid plant cell - a haploid animal cell

- a haploid animal cell

A human cell containing 22 autosomes and a Y chromosome is __________. - a sperm - a zygote - an egg - a somatic cell of a male

- a sperm

(figure shows: One diploid cell appears in the meiosis stage where the chromosomes are in the middle, attached to the mitotic spindle fibers, and moving toward the centrioles.) Which phase of meiosis is represented in the figure above? - prophase I - anaphase II - anaphase I telophase I

- anaphase I

In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following characteristics are most likely for the two chromosomes of the pair to have in common? - length, centromere position, staining pattern, and traits coded for by their genes - length, centromere position, and staining pattern only - length, centromere position, staining pattern, and DNA sequences - length and position of the centromere only

- length, centromere position, staining pattern, and traits coded for by their genes

(figure shows: A dividing cell contains three pairs of X-like structures paired with the same X-like structures of another color.) This cell must be undergoing ______ because ______ are associated with each other at the metaphase plate and chiasmata are present. - mitosis; homologous chromosomes - meiosis; homologous chromosomes - mitosis; individual chromatids - meiosis; individual chromatids

- meiosis; homologous chromosomes

Which process is currently going on in your hand? - mitosis - meiosis - gametogenesis - both mitosis and meiosis - none of the above

- mitosis

To visualize and identify meiotic cells at metaphase I with a microscope, what would you look for? - individual chromosomes all at the cell's center - an uninterrupted spindle array - sister chromatids of a replicated chromosome grouped at the poles - pairs of homologous chromosomes all aligned at the cell's center

- pairs of homologous chromosomes all aligned at the cell's center

If chiasmata can be seen in a cell under a microscope, which of the following meiotic processes must have occurred? - anaphase II - meiosis II - prophase I - anaphase I

- prophase I

Which of the following events occurs in meiosis but not in mitosis? - production of daughter cells - condensation of chromatin - synapsis of pairs of homologous chromosomes - chromosome replication

- synapsis of pairs of homologous chromosomes

What is crossing over? - the movement of genetic material from one chromosome to a nonhomologous chromosome - a direct consequence of the separation of sister chromatids - making an RNA copy of a DNA strand - also referred to as the "independent assortment of chromosomes" - the exchange of homologous portions of nonsister chromatids

- the exchange of homologous portions of nonsister chromatids

Independent assortment of chromosomes during meiosis is a result of - the relatively small degree of homology shared by the X and Y chromosomes. - the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. - the random distribution of the sister chromatids to the two daughter cells during anaphase II. - the random nature of the fertilization of ova by sperm.

- the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I.

In a typical animal, mitosis produces ___ while meiosis produces ___. - two diploid daughter cells ... four haploid daughter cells - four haploid daughter cells ... two diploid daughter cells - two diploid daughter cells ... two haploid daughter cells - four diploid daughter cells ... four haploid daughter cells - two diploid daughter cells ... two diploid daughter cells

- two diploid daughter cells ... four haploid daughter cells

As a male, I have 46 chromosomes and: 44 are autosomes and 2 are sexual chromosomes (X and Y) 44 are autosomes and 2 are sexual chromosomes (X and X) 46 autosomes 46 sexual chromosomes

44 are autosomes and 2 are sexual chromosomes (X and Y)

A haploid set of unreplicated chromosomes (n = 4) of the fruit fly Drosophila melanogaster has a mass of 0.14 p g. What is the mass of D N A in single Drosophila cell at the end of telophase II? A. 0.14 pg B. 0.28 pg C. 0.42 pg D. 0.56 pg

A. 0.14 pg

A haploid set of unreplicated chromosomes (n = 4) of the fruit fly Drosophila melanogaster has a mass of 0.14 p g. What is the mass of D N A in single Drosophila cell in prophase II? A. 0.14 p g B. 0.28 p g C. 0.42 p g D. 0.56 p g

B. 0.28 p g

Diploid cells may undergo either mitosis or meiosis. Can haploid cells? A. Haploid cells can undergo both mitosis and meiosis. B. Haploid cells can undergo mitosis but not meiosis. C. Haploid cells can undergo meiosis but not mitosis. D. Haploid cells can undergo neither mitosis nor meiosis.

B. Haploid cells can undergo mitosis but not meiosis.

Why is it more practical to prepare karyotypes by viewing somatic diploid cells rather than haploid gametes? A. Only diploid cells have condensed chromosomes. B. Only diploid cells have all the organism's chromosomes. C. Haploid cells are too small. D. Haploid cells are not easily available.

B. Only diploid cells have all the organism's chromosomes.

Prophase I of meiosis is generally the longest phase of meiosis. Why might this be? A. D N A replication B. synapsis and recombination C. independent assortment D. gamete formation

B. synapsis and recombination

Consider an organism of karyotype 2n = 4. Which diagram properly depicts metaphase I? A. a B. b C. c D. d

C. c

Consider an organism of karyotype 2n = 4. Which diagram properly depicts metaphase II? A. a B. b C. c D. d

C. c

In this cell, what phase is represented? A. mitotic metaphase B. meiosis I anaphase C. meiosis I metaphase D. meiosis II anaphase E. meiosis II metaphase

C. meiosis I metaphase

At what stage is the independent assortment of chromosomes determined? A. prophase I pairing of homologs B. anaphase II separation of homologs C. metaphase I alignment of paired homologs D. telophase I

C. metaphase I alignment of paired homologs

A haploid set of unreplicated chromosomes (n = 4) of the fruit fly Drosophila melanogaster has a mass of 0.14 p g. What is the mass of D N A in single Drosophila cell in prophase I? A. 0.14 p g B. 0.28 p g C. 0.42 p g D. 0.56 p g

D. 0.56 p g

What is the main advantage of sexual reproduction over asexual reproduction? A. It is more efficient at producing offspring. B. Two parents can invest resources in offspring. C. It allows for more competition. D. It increases genetic variation among offspring.

D. It increases genetic variation among offspring.

Privet shrubs and humans each have a diploid number of 46 chromosomes per cell. Why are the two species so dissimilar? A. Privet chromosomes undergo only mitosis. B. Privet chromosomes are shaped differently. C. Human chromosomes have genes grouped together differently. D. The two species have appreciably different genes. E. Privets do not have sex chromosomes.

D. The two species have appreciably different genes.

Which of the following are ways in which gametes from one individual diploid cell can be different from one another? A. mutation B. crossing over C. independent assortment D. all of the above

D. all of the above