Chapter 13 homework

The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following? A. either anaphase I or II B. mitosis in her ovary C. telophase II of one meiotic event D. telophase I of one meiotic event E. metaphase I of one meiotic event

A

How are sister chromatids and homologous chromosomes different from each other? A. They are not different. Homologous chromosomes and sister chromatids are both identical copies of each other. B. Sister chromatids are only formed during mitosis. Homologous chromosomes are formed during meiosis. C. Homologous chromosomes are identical copies of each other. One sister chromatid comes from the father, and one comes from the mother. D. Homologous chromosomes are closely associated with each other in both mitosis and meiosis. Sister chromatids are only associated with each other during mitosis. E. 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.

E

Human gametes are produced by _____. A. fertilization B. the cell cycle C. asexual reproduction D. mitosis E. meiosis

E

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

E

Which of the following best describes a karyotype? A. a pictorial representation of all the genes for a species B. the combination of all the maternal and paternal chromosomes of a species C. the collection of all the chromosomes in an individual organism D. a photograph of all the cells with missing or extra chromosomes E. a display of each of the chromosomes of a single cell

E

Which of the following occurs in meiosis but not in mitosis? A. chromosome replication B. production of daughter cells C. alignment of chromosomes at the equator D. condensation of chromatin E. synapsis of chromosomes

E

Animal life cycle:

Meiosis creates gametes (eggs and sperm) with only a single chromosome set (haploid or n) from parental cells with two chromosome sets (diploid or 2n). During fertilization, the haploid sperm (n) and egg (n) fuse, producing a diploid zygote (2n). The cells of the zygote then divide by mitosis (which does not change the ploidy level) to produce an adult organism (still 2n) of the next generation. In sexual life cycles, meiosis and fertilization keep the number of chromosomes constant from generation to generation.

What cells are haploids?

After meiosis 1 and before meiosis 2

A cell divides to produce two daughter cells that are genetically different. A. The statement is true for meiosis II only. B. The statement is true for meiosis I and meiosis II. C. The statement is true for mitosis and meiosis II. D. The statement is true for meiosis I only. E. The statement is true for mitosis and meiosis I.

B

What number and types of chromosomes are found in a human somatic cell? A. 22 autosomes and 1 sex chromosome B. 44 autosomes and 2 sex chromosomes C. n chromosomes D. 21 autosomes and 2 sex chromosomes E. 45 autosomes and 1 sex chromosome

B

Which of these statements is false? A. In humans, each of the 22 maternal autosomes has a homologous paternal chromosome. B. At sexual maturity, ovaries and testes produce diploid gametes by meiosis. C. Sexual life cycles differ with respect to the relative timing of meiosis and fertilization. D. Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization, forming a diploid (2n), single-celled zygote. E. In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY).

B

What is in both heredity and genetic variation?

DNA replication fertilization crossing over metaphase 1 to anaphase 1 metaphase 2 to anaphase 2

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A. It must be an animal. B. It must be sexually reproducing. C. It must be a primate. D. It must be human. E. Its gametes must have 23 chromosomes.

E

Assume that an organism exists in which crossing over does not occur, but that all other processes associated with meiosis occur normally. Consider how the absence of crossing over would affect the outcome of meiosis. If crossing over did not occur, which of the following statements about meiosis would be true? Select all that apply. A. Independent assortment of chromosomes would not occur. B. There would be less genetic variation among gametes. C. The daughter cells of meiosis I would be diploid, but the daughter cells of meiosis II would be haploid. D. The two sister chromatids of each replicated chromosome would no longer be identical. E. The two daughter cells produced in meiosis I would be identical. F. The four daughter cells produced in meiosis II would all be different.

B

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

B

A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes. A. 64 B. 32 C. 16 D. 30 E. 8

C

Meiosis terminology:

chromatin in its condensed form is called chromosomes. chromosomes are past to the next generation in gametes. genes are organized on chromosomes. chromosomes together constitute the cell's nuclear genome. chromosomes are located in the nucleus. genes are made of DNA. Genes encode heritable characteristics called traits. genes each have a locus. Locus that specifies its position on chromosomes.

Which of the following happens at the conclusion of meiosis I? A. Sister chromatids are separated. B. The chromosome number per cell is conserved. C. Homologous chromosomes of a pair are separated from each other. D. Four daughter cells are formed. E. Cohesins are cleaved at the centromeres.

C

The parent cell that enters meiosis is diploid, whereas the four daughter cells that result are haploid. Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II? A. DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II. B. DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II. C. DNA content is halved only in meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II. D. DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid only in meiosis II. E. DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid only in meiosis II.

A

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

A

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

A

If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents? A. It has half the chromosomes but twice the DNA of the originating cell. B. It has one-fourth the DNA and one-half the chromosomes as the originating cell. C. It has half the amount of DNA as the cell that began meiosis. D. It has the same number of chromosomes but each of them has different alleles than another cell from the same meiosis. E. It is identical in content to another cell from the same meiosis.

C

If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, and has both number 19 chromosomes with short genes, she will produce which of the following egg types? A. three-fourths blue long and one-fourth orange short gene eggs B. only orange short gene eggs C. one-half blue short and one-half orange short gene eggs D. only blue short gene eggs E. three-fourths blue short and one-fourth orange short gene eggs

C

Normal human gametes carry _____ chromosomes. A. 46 pairs of B. 46 C. 23 D. 5 E. 23 pairs of

C

The somatic cells of a privet shrub 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? A. Genes on a particular privet chromosome, such as the X, must be on a different human chromosome, such as number 18. B. Privet shrubs must be metabolically more like animals than like other shrubs. C. Genes of privet chromosomes are significantly different than those in humans. D. Privet cells cannot reproduce sexually. E. Privet sex cells have chromosomes that can synapse with human chromosomes in the laboratory.

C

This chromosome has two chromatids, joined at the centromere. What process led to the formation of the two chromatids? The two chromatids were formed by fertilization, bringing together maternal and paternal chromatids. The two chromatids were formed by synapsis and the formation of a synaptonemal complex. The two chromatids were formed by duplication of a chromosome.

C

Which of the following defines a genome? A. representation of a complete set of a cell's polypeptides B. a karyotype C. the complete set of an organism's genes D. the complete set of an organism's polypeptides E. the complete set of a species' polypeptides

C

To view and analyze human chromosomes in a dividing cell, which of the following is/are required? A. radioactive staining B. a scanning electron microscope C. fluorescent staining and a transmission electron microscope D. DNA staining and a light microscope E. a stain particular to human cells

D