The number of chromatids in a chromosome at anaphase is

2 in mitosis and 1 in meiosis
1 in mitosis and 2 in meiosis
2 each in mitosis and meiosis
2 in mitosis and 4 in meiosis

If you are provided with root-tips of onion in your class and are asked to count the chromosomes, which of the following stages can you most conveniently look into –

Telophase
Anaphase
Prophase
Metaphase

Kinetin (Cytokinin) increase the rate of mitosis by reducing the duration of –

Interphase
Metaphase
Anaphase
Telophase

The process of mitosis is divided into 4 phases. Identify the correct order in which these phases appear in mitosis

Anaphase, metaphase, telophase and prophase
Telophase, anaphase, metaphase and prophase
Metaphase, prophase, anaphase and telophase
Prophase, metaphase, anaphase and telophase

Mitosis is the process by which eukaryotic cells

Expose the genes for protein synthesis
Become specialized in structure and function
Multiply
Grow

In telophase of mitosis, the mitotic spindle breaks down and nuclear membranes form. This is essentially the opposite of what happens in

prophase
interphase
metaphase
S phase

Solution

The mitotic spindle forms and the nuclear membrane disperses during prophase.

Which of the following is true of the mitotic spindle?

It is composed of actin and myosin micro filaments.
It is composed of kinetochores at the metaphase plate.
It is composed of microtubules, which help separate the chromosomes to opposite poles of the cell.
It originates only at the centrioles in the centrosomes.

Solution

The mitotic spindle is composed of microtubules, not actin and myosin filaments. The spindle originates from the centrosome, which may or may not have centrioles.

A cell in prophase of mitosis can be distinguished from a cell in prohase-I of meiosis by

The presence of only half as many chromosomes in themeiotic cell
The formation of tetrads in the meiotic cell
The presence of twice as many chromosomes in themeiotic cell
None of the above

The absence of centrioles from higher plant cells means that during somatic cell nuclear division there is :

no apparent organiser of mitotic spindles.
no equatorial arrangement of chromosomes at metaphase.
no new cell wall laid down at telophase.
no spindle formed.

Solution

Although no centrioles are visible, there is spindle formation and the chromosomes do exhibit equatorial arrangement. Spindle formation is probably by another organelle, unknown as yet.

Meiosis takes place in –

Apical meristem
Intercalary meristem
Reproductive cells
Vegetative cells

Solution

Meiosis takes place in reproductive cells.

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