Chapter 4, Problem 1P

Choose the best matching phrase in the right column for each of the terms in the left column.

a. meiosis	1. X and Y
b. gametes	2. chromosomes that do not differ between the sexes
c. karyotype	3. one of the two identical halves of a replicated chromosome
d. mitosis	4. microtubule organizing centers at the spindle poles
e. interphase	5. cells in the testes that undergo meiosis
f. syncytium	6. division of the cytoplasm
g. synapsis	7. haploid germ cells that unite at fertilization
h. sex chromosomes	8. an animal cell containing more than one nucleus
i. cytokinesis	9. pairing of homologous chromosomes
j. anaphase	10. one diploid cell gives rise to two diploid cells
k. chromatid	11. the array of chromosomes in a given cell
l. autosomes	12. the part of the cell cycle during which the chromosomes are not visible
m. centromere	13. one diploid cell gives rise to four haploid cells
n. centrosomes	14. cell produced by meiosis that does not become a gamete
o. polar body	15. the time during mitosis when sister chromatids separate
p. spermatocytes	16. site of the closest connection between sister chromatids

Summary Introduction

a.

To determine:

The phrase that describes “meiosis” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule-organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Meiosis is a reductional type of cell division in the living organisms.

Answer to Problem 1P

Correct answer:

Meiosis: one diploid cell gives rise to four haploid cells

Explanation of Solution

The cell division in which the number of chromosomes is reduced to half of the parent cell and give rise to four gametes is called meiosis.

Summary Introduction

b.

To determine:

The phrase that describes “gametes” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Gametes are haploid and their fusion leads to the production of diploid zygote. These are the sex cells of organisms.

Answer to Problem 1P

Correct answer:

Gametes: haploid germ cells that unite at fertilization

Explanation of Solution

A haploid cell that fuses with another haploid cell of opposite sex at the time of fertilization. This fusion results in the formation of a zygote.

Summary Introduction

c.

To determine:

The phrase that describes “karyotype” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Karyotype can be defined as the entire set of the chromosomes that is particularly present in the cell.

Answer to Problem 1P

Correct answer:

Karyotype: the array of chromosomes in a given cell

Explanation of Solution

The complete set of chromosomes that is present in a cell is termed as karyotype. It exhibits the number and appearance of chromosomes in the nucleus.

Summary Introduction

d.

To determine:

The phrase that describes “mitosis” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Mitosis is a type of equational cell division that occurs in the somatic cell of the organisms.

Answer to Problem 1P

Correct answer:

Mitosis: one diploid cell gives rise to two diploid cells

Explanation of Solution

The cell division in which parental cell replicates and divides into two genetically identical daughter cells is called mitosis.

Summary Introduction

e.

To determine:

The phrase that describes “interphase” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Interphase is the phase of the cell cycle during which nucleus does not undergo the division process.

Answer to Problem 1P

Correct answer:

Interphase: the part of the cell cycle during which the chromosomes are not visible

Explanation of Solution

The stage between two consecutive mitotic divisions when nucleus is not dividing is termed as interphase.

Summary Introduction

f.

To determine:

The phrase that describes “syncytium” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Animal cells may contain one or more than one nuclei in number. Presence of more than one nuclei leads to the syncytium condition.

Answer to Problem 1P

Correct answer:

Syncytium: an animal cell containing more than one nucleus

Explanation of Solution

A syncytium is also known as symplasm. It is a single cell that contains more than one nucleus due to fusion of multiple cells or nuclear division.

Summary Introduction

g.

To determine:

The phrase that describes “synapsis” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

At the chiasmata of chromosomes, the process of pairing of homologous chromosomes occurs.

Answer to Problem 1P

Correct answer:

Synapsis: pairing of homologous chromosomes

Explanation of Solution

The pairing of chromosomes pairs during meiosis is known as synapsis. It occurs during prophase I stage of meiosis.

Summary Introduction

h.

To determine:

The phrase that describes “sex chromosomes” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Sex chromosomes determines the sex of an organism at the time of fertilization.

Answer to Problem 1P

Correct answer:

Sex chromosomes: X and Y

Explanation of Solution

The sex chromosomes are the chromosomes that are responsible for the determination of sex of an organism. There are 23 pairs of chromosomes in humans. Out of which, one pair of chromosomes contains sex chromosomes. Females have XX chromosomes and males have XY chromosomes.

Summary Introduction

i.

To determine:

The phrase that describes “cytokinesis” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Division of cytoplasm is referred to as cutokinesis.

Answer to Problem 1P

Correct answer:

Cytokinesis: division of the cytoplasm

Explanation of Solution

The process during which the cytoplasm of a parental cell divides into two daughter cells is called cytokinesis.

Summary Introduction

j.

To determine:

The phrase that describes “anaphase” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Anapahse is one of the phases of the cell cycle at which sepration of sister chromatids occurs.

Answer to Problem 1P

Correct answer:

Anaphase: the time during mitosis when sister chromatids separate.

Explanation of Solution

The replicated chromosome separates and the sister chromatids are moved towards the opposite poles of the cell during anaphase of the cell cycle.

Summary Introduction

k.

To determine:

The phrase that describes “chromatid” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Chromatid can be defined as the one of the two exactly similar halves of a specific chromosome during the process of replication.

Answer to Problem 1P

Correct answer:

Chromatid: one of the two identical halves of a replicated chromosome

Explanation of Solution

A replicated chromosome has two identical thread like stands. Each strand is termed as chromatid.

Summary Introduction

l.

To determine:

The phrase that describes “autosomes” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Autosomes are the chromosomes that are not at all involved in the determination of sex of the organisms.

Answer to Problem 1P

Correct answer:

Autosomes: chromosomes that do not differ between the sexes

Explanation of Solution

Autosomes are a type of chromosomes which have genes but do not differ in different sexes. They have no role in sex determination.

Summary Introduction

m.

To determine:

The phrase that describes “centromere” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Centromere is the specifc point on the chromosomes at which attachment of spindle fibers occurs.

Answer to Problem 1P

Correct answer:

Centromere: site of the closest connection between sister chromatids

Explanation of Solution

The region of chromosome that connects the microtubules of the spindle during cell division is called centromere.

Summary Introduction

n.

To determine:

The phrase that describes “centrosomes” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Centrosomes are the specialized centers that help in the organization of the microtubules at the poles of spindle fibers.

Answer to Problem 1P

Correct answer:

Centrosomes: microtubule organizing centers at the spindle poles

Explanation of Solution

The cell microtubules are organized by the centrosome of the cell. The microtubule interacts with the chromosomes to form the mitotic spindle.

Summary Introduction

o.

To determine:

The phrase that describes “polar body” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Polar body is the result of meosis process. This polar body cannot take part in the process of fertilization.

Answer to Problem 1P

Correct answer:

Polar body: cell produced by meiosis that does not become a gamete

Explanation of Solution

A haploid cell that is formed as an egg cell and cannot take place in fertilization is called a polar body.

Summary Introduction

p.

To determine:

The phrase that describes “spermatocytes” among the options given below.

1. X and Y

2. chromosomes that do not differ between the sexes

3. one of the two identical halves of a replicated chromosome

4. microtubule organizing centers at the spindle poles

5. cells in the testes that undergo meiosis

6. division of the cytoplasm

7. haploid germ cells that unite at fertilization

8. an animal cell containing more than one nucleus

9. pairing of homologous chromosomes

10. one diploid cell gives rise to two diploid cells

11. the array of chromosomes in a given cell

12. the part of the cell cycle during which the chromosomes are not visible

13. one diploid cell gives rise to four haploid cells

14. cell produced by meiosis that does not become a gamete

15. the time during mitosis when sister chromatids separate

16. site of the closest connection between sister chromatids

Introduction:

Spermatocytes are the immature cells that are present in the testes of males. These cells develop in sperms on maturation.

Answer to Problem 1P

Correct answer:

Spermatocytes: cells in the testes that undergo meiosis

Explanation of Solution

The male gametocytes or sperm cells that are found at early childhood in testes are called spermatocytes. They come from immature germ cells called spermatogonia. They undergo meiosis to produce cells with half the number of chromosomes.