Tag: the origin of cells and cell division

Questions Related to the origin of cells and cell division

Cell division is tightly regulated, which of the following is true regarding mitosis or meiosis.
I. Mitosis shows no homologous pairing.
II. There is no S phase between meiosis I and II.
III. Meiosis centromeres do not divide at anaphase I.

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. I and III only

  2. I and II only

  3. II only

  4. I, II and III

Show answer
Correct Option: D
Explanation:

Homologous pairing occurs in meiosis when homologous chromosomes come closer and synapsis occur leading to homologous pairing.

S phase occurs between G1 and G2 phase not between meiosis1 and meiosis2.
At anaphase I, sister chromatids remain attached to their centromeres, so they do not divide at this stage.
So the correct option is 'I, II and III'

Which of the following can not be used to differentiate meiosis with mitosis?

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. Replication of chromosome before division

  2. Exchange of genetic material

  3. Formation of tetrad

  4. $2$ & $3$ both

Show answer
Correct Option: A
Explanation:

Answer is A. Replication of chromosome some before division

can not be used to differentiate meiosis with mitosis because it is the process which is done in interphase. And interphase are same in both meiosis and mitosis. 

A cell in mitotic prophase can be distinguished from a cell in meiotic prophase by?

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. Formation of tetrad in a meiotic cell

  2. The terminalisation of chiasmata in late prophase of mitosis

  3. Zipping in early prophase of mitosis

  4. Presence of only half as many chromosomes in the meiotic cell

Show answer
Correct Option: A
Explanation:

The formation of tetrad is a special characteristic of Prophase 1 of meiosis 1.

The homologous pair aligns with each other and gets ready for crossing over.
So, the correct option is 'Formation of tetrad in a meiotic cell'.

The basic difference between mitosis and meiosis is that

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. Homologous chromosomes form tetrads in mitosis but not in meiosis

  2. Homologous chromosomes form tetrads in meiosis but not in mitosis

  3. The nuclear membrane disappears in mitosis but not in meiosis

  4. A spindle forms in mitosis but not in meiosis

  5. A spindle forms in meiosis but not in mitosis

Show answer
Correct Option: B
Explanation:
  • The pairing of homologous chromosomes during the zygotene of prophase I and formation of tetrads are characteristic of meiosis; not mitosis. 
  • Both mitosis and meiotic divisions exhibit the disappearance of the nuclear membrane and spindle formation.

  •  So, the correct answer is B. 

Which of the following is unique to mitosis and not a part of meiosis? 

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. Homologous chromosomes behave independently

  2. Chromatids are separated during anaphase

  3. Homologous chromosomes pair and form bivalents

  4. Homologous chromosomes crossover

Show answer
Correct Option: A
Explanation:

Mitosis and meiosis are the two types of cell division which occur in a living cell. The meiosis is characterized by the pairing of homologous chromosomes, crossing over and separation of homologous chromosomes. Because the homologous chromosomes separate, the chromosome number is reduced to one-half during meiosis. In mitosis, the homologous chromosomes do not pair or exchange segments. There is no separation of homologous chromosomes consequently the chromosome number is not reduced. The homologous chromosomes remain separate or independent throughout mitosis.

So, the correct answer is option A.

Meiosis I is reduction division. Meiosis II is equational division due to 

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. Separation of chromatids

  2. Crossing over

  3. Pairing of homologous chromosomes

  4. Disjunction of homologous chromosomes

Show answer
Correct Option: A
Explanation:

Meiosis is a reduction division because the end result of this special type of cell division is four haploid cells. The first meiotic division occurs which results in two cells, each with 46 chromosomes. Then, the second round of meiotic division occurs and each of these two cells divides resulting in four haploid cells. 

In meiosis II, the two chromatids of each chromosome separate from each other and go to separate daughter cells. As a result, the number of chromosomes remains the same as produced by meiosis I. Therefore, meiosis II is also called as homotypic or equational division.  
So, the correct answer is option A.

Which of the following is a correct comparison between mitosis and meiosis?

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. Meiosis II resembles mitosis when sister chromatids split

  2. Both prophase of mitosis and meiosis include pairing up of homologous chromosomes

  3. In mitosis, aligning of maternal and paternal chromosomes can be random whereas, in meiosis, the alignment is fixed

  4. Replication of chromosomes occurs at the start of mitosis and meiosis during prophase

Show answer
Correct Option: A
Explanation:

Meiosis II is similar to Mitosis as sister chromatids of the haploid set of chromosomes split during Anaphase II of Meiosis II. 

So, the correct answer is 'Meiosis II resembles mitosis when sister chromatids split'

Meiosis not occurs in 

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. Ovule

  2. Anther

  3. Microsporangia

  4. Shoot tip

Show answer
Correct Option: D
Explanation:

Cell division or mitotic division is active in developing embryos and in the shoot tips and roots tips of plants. 

Meiosis is a process that occurs only in specialized tissues of an organism. The end results of the process are the production of gametes (egg and sperm) or spores having half as many chromosomes as the beginning cell. Meiosis divides the chromosome number to half for each gamete. Meiosis occurs in ovules, anther, and microsporangia.
So, the correct answer is option D.

As compared to mitosis, meiosis has

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. No telophase

  2. Exchange of chromatid segments

  3. Duplication of chromosomes during anaphase

  4. Daughter cells similar to parent cells

Show answer
Correct Option: B
Explanation:

 Mitosis occurs in all somatic cells. It is responsible for the growth of that organism and no exchange of genetic material takes place between the two chromosomes. In meiosis the number of chromosomes in the parent cell is reduced by half and produces four gamete cells, hence also called reductional division. In meiosis crossing over of chromosomes takes place during prophase 1 that results in an exchange of genetic material between the two chromosomes. This crossover is called synapsis and is responsible for genetic variation in the offspring. Thus the correct answer is option B.

Pick the correct statements. 
A. Synapsis of homologous chromosomes takes place during prophase I of meiosis.
B. Division of centromeres takes place during anaphase I of meiosis.
C. Spindle fibres disappear completely in telophase of mitosis.
D. Nucleoli reappear at telophase I of meiosis.

botany division for growth and reproduction difference between meiosis and mitosis meiosis the origin of cells and cell division

  1. A only

  2. C only

  3. A and B only

  4. A, C and D only

  5. A and C only

Show answer
Correct Option: D
Explanation:

The complete knowledge of cell division, that is, mitosis and meiosis make us identify that synapsis of homologous chromosomes takes place during prophase I of meiosis where the exchange of segments takes place between the homologous chromosome which is the main cause of variation. The spindle fibers disappear completely in the telophase of mitosis as the nuclear membrane is reformed to separate the two daughter cell. Nucleoli reappear at telophase I of meiosis.

So, the correct answer is option D.