Meiosis

Quaking aspen can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?

38

How many double-helical DNA molecules will be present in the sperm and egg cells of dogs that are diploid animals that contain 78 replicated chromosomes in each cell that enters meiosis?

39

Which statement about the difference between homologous chromosomes and sister chromatids is correct? a. Homologous chromosomes contain the same genes but often different alleles. Sister chromatids contain the same genes and the same alleles. b. Neither homologous chromosomes nor sister chromatids contain the same alleles. c. Sister chromatids contain the same genes but different alleles. Homologous chromosomes contain the same genes and the same alleles. e. Homologous chromosomes and sister chromatids contain the same genes and the same alleles.

A, Sister chromatids are produced by the process of DNA replication, whereas homologous chromosomes are inherited from the mother and father.

Which of the following happens at the conclusion of meiosis I? a. Four daughter cells are formed. b. Cohesins are cleaved at the centromeres. c. Sister chromatids are separated. d. Homologous chromosomes of a pair are separated from each other. e. The chromosome number per cell remains the same.

D

An advantage of asexual reproduction is that it _____.

enables the species to rapidly colonize habitats that are favorable to that species

What makes sexually reproduced offspring genetically different from their parents?

genetic recombination during meiosis

How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I? They have _____.

half the number of chromosomes and one fourth the amount of DNA.

After telophase I of meiosis, the chromosomal makeup of each daughter cell is _____.

haploid, and the chromosomes are each composed of two chromatids

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

two, haploid.

What is the ploidy of organisms that have two sets of chromosomes?

2n

What proportion of chromosomes in a man's skin cell are maternal chromosomes?

1/2

If a cell has 24 chromosomes, how many chromosomes would each of its four daughter cells have after meiosis?

12. Meiosis is a reduction division that reduces the number of chromosomes passed on to daughter cells by one-half.

Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?

2

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

4, haploid.

The chromosome number of hexaploid wheat, Triticum aestivum, can be represented as _____.

6n

The egg of a fruit fly has 4 individual chromosomes. How many chromosomes are in a somatic (body) cell of a fruit fly?

8

Which of the following statements about the meiosis are correct? a. Non-sister chromatids are found on two different homologs. b. Crossing over occurs between sister chromatids. c. Sister chromatids are homologous chromosomes. d. A chiasma forms between two of the four molecules of double-stranded DNA on duplicated homologous chromosomes.

A and D

Which of he following Statements about meiosis and mitosis is true? A. Meiosis II is similar to mitosis in that sister chromatids of each chromosome separate. B. In meiosis II and mitosis, a diploid cell divides. C. In mitosis and meiosis I, homologous chromosomes move independently of each other. D. Each daughter cell produced during meiosis and mitosis is genetically identical to the parent cell.

A. Both meiosis II and mitosis are cell divisions involving the separation of sister chromatids.

Homologous chromosomes migrate to opposite poles during ____.

Anaphase I

If you followed a woman's cells through meiosis, at what stage of meiosis would the amount of DNA in one of these cells be equal to the amount of DNA in one of her G1 phase (before DNA replication) kidney cells?

At the end of meiosis I

A key difference between mitosis and meiosis is a. Meiosis I is most like Mitosis, while Meiosis II is different b. The chromosomes condense in mitosis but not in meiosis. c. Homologs pair up and crossing over happens during meiosis I but does not happen in mitosis d. Sister chromatids exist in mitosis but not in meiosis

C, In prophase I of meiosis, homologous chromosomes pair and exchange sequences in a process called crossing over, and are linked by chiasmata.

What are homologous chromosomes?

Chromosomes that are similar in their size, shape, and gene content.

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? 1. 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. 2. DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II. 3. DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid only in meiosis II. 4. DNA content is halved only in meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II. 5.DNA content is halved only in meiosis I. Ploidy level changes from diploid to haploid only in meiosis II.

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.

True or false? A haploid organism has one pair of homologous chromosomes.

False. A haploid organism only has one set of chromosomes, so it has no homologous chromosomes.

The somatic cells of a privet shrub each contain 46 chromosomes. How do privet chromosomes differ from the chromosomes of humans, who also have 46?

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

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

Metaphase II

What is the composition of a tetrad at the beginning of prophase I?

One pair of homologous chromosomes.

Synapsis occurs during _____.

Prophase I

During ___ a spindle forms in a haploid cell.

Prophase II

What is a major difference between mitosis and meiosis I in a diploid organism?

Sister chromatids separate in mitosis; homologous pairs of chromosomes separate in meiosis I.

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

What information cannot be obtained from and individual's karyotype?

The sequence of bases of a particular gene.

In meiosis, homologous chromosomes are separated during ________.

anaphase I

Centromeres split and sister chromatids migrate to opposite poles in ________ of meiosis.

anaphase II

During _____ sister chromatids separate.

anaphase II

Which of the following stages of meiosis is correctly matched to chromosome composition at that stage? a. Anaphase II−−two sister chromatids b. Prophase II−−a single chromatid c. Anaphase I−−two sister chromatids d. Prophase I−−a single chromatid

c

Which structure is directly correlated with the production of genetic variability in the daughter cells produced during meiosis? a. Tetrad b. Synapsis c. Chiasma d. Centromere

c. The chiasma is an X-shaped structure formed from the crossing over of homologous chromosomes, which can then exchange segments at the crossover sites.

Homologous chromosomes _____.

carry information for the same traits

For the duration of meiosis I, each chromosome _____.

consists of two sister chromatids joined by a centromere

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 do the two chromosomes of the pair have in common?

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

Crossing over normally takes place during which of the following processes?

meiosis I

Independent assortment of chromosomes occurs during _____.

meiosis I only

Homologous pairs of chromosomes align opposite to each other at the equator of a cell during ________.

metaphase I of meiosis

Sister chromatids separate from each other during _____.

mitosis and meiosis II

When does DNA replication take place regarding meiosis? DNA replication _____.

occurs before meiosis I begins

When we first see chiasmata under a microscope, we know that _____.

prophase I is occurring

Which of the following occurs in meiosis but not in mitosis?

synapsis of chromosomes.

What information can not be obtained from an individual's karyotype?

the sequence of bases of a particular gene