Chapter 2.2, Problem 3TPSQ

(a)

Summary Introduction

To determine:

The number of chromosomes and DNA molecules at prophase of mitosis, if the cell has 8 chromosomes in metaphase II of meiosis.

Introduction:

Chromosome includes a thread like arrangement of nucleic acid and protein present in the nucleus of the living cell. Chromosome carries genetic codes in the form of genes. The cell cycle is the set of events that happens in a cell, which leads to the division and duplication of its DNA to form two daughter nuclei. DNA contains all the hereditary information that regulates the protein synthesis. Chromosome and DNA are more likely to be similar. When the DNA is condensed and uncoiled they form a more intact and organized structure called a chromosome that is less complex.

Explanation of Solution

(a) Prophase of mitosis.

Mitosis represent a type of cell division in which two daughter cells are formed each having the same number and same type of chromosome as the original cell has. It mainly includes the duplication of somatic cells and the cells in this stage are diploid and contain homologous chromosome.

According to the question the cell has 8 chromosomes in metaphase II of meiosis. The cell originally will have 16 chromosomes before the beginning of meiosis I because the number of chromosomes already has been halved during meiosis I.

In prophase of mitosis the cell will hold 16 chromosomes because the DNA condenses and uncoils to form chromosomes to become visible as separate chromosomal structures.

(b)

Summary Introduction

To determine:

The number of chromosomes and DNA molecules at metaphase I of meiosis, if the cell has 8 chromosomes in metaphase II of meiosis.

Introduction:

Chromosome includes a thread like arrangement of nucleic acid and protein present in the nucleus of the living cell. Chromosome carries genetic codes in the form of genes. The cell cycle is the set of events that happens in a cell, which leads to the division and duplication of its DNA to form two daughter nuclei. DNA contains all the hereditary information that regulates the protein synthesis. Chromosome and DNA are more likely to be similar. When the DNA is condensed and uncoiled they form a more intact and organized structure called a chromosome that is less complex.

Explanation of Solution

(b) Metaphase I of meiosis

Meiosis represent a type of cell division in which a single cell divides two times to produce four daughter cells. These daughter cells contain half the original amount of genetic information of the parent cell. Meiosis includes two cell divisions: meiosis I and meiosis II

According to the question the cell has 8 chromosomes in metaphase II of meiosis. The cell originally will have 16 chromosomes before the beginning of meiosis I because the number of chromosomes already has been halved during meiosis I.

In metaphase I of meiosis, the homologous pair of chromosomes aligns themselves along the metaphase plate to perform reduction division. Hence, the number of chromosomes will remain same in this stage. There will be 8 chromosomes in metaphase I of meiosis.

(c)

Summary Introduction

To determine:

The number of chromosomes and DNA molecules at anaphase of mitosis, if the cell has 8 chromosomes in metaphase II of meiosis.

Introduction:

Chromosome includes a thread like arrangement of nucleic acid and protein present in the nucleus of the living cell. Chromosome carries genetic codes in the form of genes. The cell cycle is the set of events that happens in a cell, which leads to the division and duplication of its DNA to form two daughter nuclei. DNA contains all the hereditary information that regulates the protein synthesis. Chromosome and DNA are more likely to be similar. When the DNA is condensed and uncoiled they form a more intact and organized structure called a chromosome that is less complex.

Explanation of Solution

(c) Anaphase of mitosis

Mitosis represent a type of cell division in which two daughter cells are formed each having the same number and same type of chromosome as the original cell has. It mainly includes the duplication of somatic cells and the cells in this stage are diploid and contain homologous chromosome

According to the question the cell has 8 chromosomes in metaphase II of meiosis. The cell originally will have 16 chromosomes before the beginning of meiosis I because the number of chromosomes already has been halved during meiosis I.

Anaphase of mitosis will include the disconnection of sister chromatids and their movement towards the poles. Therefore, the chromosomes will not divide and the cells will have 16 chromosomes as the nuclear division is not complete and no reduction division occurs.

(d)

Summary Introduction

To determine:

The number of chromosomes and DNA molecules at anaphase II of meiosis, if the cell has 8 chromosomes in metaphase II of meiosis.

Introduction:

Chromosome includes a thread like arrangement of nucleic acid and protein present in the nucleus of the living cell. Chromosome carries genetic codes in the form of genes. The cell cycle is the set of events that happens in a cell, which leads to the division and duplication of its DNA to form two daughter nuclei. DNA contains all the hereditary information that regulates the protein synthesis. Chromosome and DNA are more likely to be similar. When the DNA is condensed and uncoiled they form a more intact and organized structure called a chromosome that is less complex.

Explanation of Solution

(d) Anaphase II of meiosis

Meiosis represent a type of cell division in which a single cell divides two times to produce four daughter cells. These daughter cells contain half the original amount of genetic information of the parent cell. Meiosis includes two cell divisions: meiosis I and meiosis II

According to the question the cell has 8 chromosomes in metaphase II of meiosis. The cell originally will have 16 chromosomes before the beginning of meiosis I because the number of chromosomes already has been halved during meiosis I.

Anaphase II of meiosis also includes the separation of sisters chromatids same as mitosis. But before this stage, the cell performed reduction division and so it will contain 8 chromosomes in each of the daughter cells, which is haploid.\

(e)

Summary Introduction

To determine:

The number of chromosomes and DNA molecules at anaphase I of meiosis, if the cell has 8 chromosomes in metaphase II of meiosis.

Introduction:

Chromosome includes a thread like arrangement of nucleic acid and protein present in the nucleus of the living cell. Chromosome carries genetic codes in the form of genes. The cell cycle is the set of events that happens in a cell, which leads to the division and duplication of its DNA to form two daughter nuclei. DNA contains all the hereditary information that regulates the protein synthesis. Chromosome and DNA are more likely to be similar. When the DNA is condensed and uncoiled they form a more intact and organized structure called a chromosome that is less complex.

Explanation of Solution

(e) Anaphase I of meiosis

Meiosis represent a type of cell division in which a single cell divides two times to produce four daughter cells. These daughter cells contain half the original amount of genetic information of the parent cell. Meiosis includes two cell divisions: meiosis I and meiosis II

According to the question the cell has 8 chromosomes in metaphase II of meiosis. The cell originally will have 16 chromosomes before the beginning of meiosis I because the number of chromosomes already has been halved during meiosis I.

Anaphase I of meiosis includes the alignment of sister chromatids along the spindle poles for segregation. The reduction division is just about to complete by the termination of this phase of meiotic cycle, the number of chromosome will remain 16 in the cells.

(f)

Summary Introduction

To determine:

The number of chromosomes and DNA molecules after cytokinesis that follow mitosis, if the cell has 8 chromosomes in metaphase II of meiosis.

Introduction:

Chromosome includes a thread like arrangement of nucleic acid and protein present in the nucleus of the living cell. Chromosome carries genetic codes in the form of genes. The cell cycle is the set of events that happens in a cell, which leads to the division and duplication of its DNA to form two daughter nuclei. DNA contains all the hereditary information that regulates the protein synthesis. Chromosome and DNA are more likely to be similar. When the DNA is condensed and uncoiled they form a more intact and organized structure called a chromosome that is less complex.

Explanation of Solution

(f) After cytokinesis that follow mitosis

Mitosis represent a type of cell division in which two daughter cells are formed each having the same number and same type of chromosome as the original cell has. It mainly includes the duplication of somatic cells and the cells in this stage are diploid and contain homologous chromosome

According to the question the cell has 8 chromosomes in metaphase II of meiosis. The cell originally will have 16 chromosomes before the beginning of meiosis I because the number of chromosomes already has been halved during meiosis I.

After cytokinesis, the number of chromosomes undergone mitosis would have completed nuclear division and segregated into two daughter cells. Therefore, the number of chromosomes will be 8.

(g)

Summary Introduction

To determine:

The number of chromosomes and DNA molecules after cytokinesis that follow meiosis II, if the cell has 8 chromosomes in metaphase II of meiosis.

Introduction:

Chromosome includes a thread like arrangement of nucleic acid and protein present in the nucleus of the living cell. Chromosome carries genetic codes in the form of genes. The cell cycle is the set of events that happens in a cell, which leads to the division and duplication of its DNA to form two daughter nuclei. DNA contains all the hereditary information that regulates the protein synthesis. Chromosome and DNA are more likely to be similar. When the DNA is condensed and uncoiled they form a more intact and organized structure called a chromosome that is less complex.

Explanation of Solution

(g) After cytokinesis that follow meiosis II

Meiosis represent a type of cell division in which a single cell divides two times to produce four daughter cells. These daughter cells contain half the original amount of genetic information of the parent cell. Meiosis includes two cell divisions: meiosis I and meiosis II

According to the question the cell has 8 chromosomes in metaphase II of meiosis. The cell originally will have 16 chromosomes before the beginning of meiosis I because the number of chromosome already has been halved during meiosis I.

After cytokinesis the cells which follow meiosis II, the number of chromosome will be half in each daughter cells because by the end of meiosis the daughter cells formed will be haploid. Therefore, the number of chromosomes will be 4.