Which of the following is found in a animal cell , but not in a plant cell?
a-nuclei
b-centrioles
c-mitochodria
d-central vacuole

The centrosome is present outside the nucleus in an animal cell. It is the structure that contains centrioles. These are the structures that are essential during cell division. The plant cells lack centrioles and are able to divide in their absence.

Further Explanation:

The centrioles are present particularly in animal cells and are located within the centrosome which is present near the nucleus. The centrosome is a granular mass that acts as a center for microtubules. The centrioles are two in numbers and are positioned at the right angle with respect to each other. Each centriole is composed of microtubules forming nine bundles that are arranged in a ring formation.

In an animal cell during interphase, the components of the centrosome along with the centrioles are doubled. Initially, the duplicated pairs of centrioles remain close to each other but with the initiation of mitosis, the pairs tend to separate and get located in the newly formed microtubule-organizing centers. The microtubules are radiated through these centers in the star-shaped clusters called asters. With the movement of asters towards the opposite poles, the microtubules span the cell attaining a spindle-shaped formation. The spindle fibers help in the alignment of chromosomes during their separation at the time of cell division.

In animal cells, centrioles are important for mitosis to take place whereas reproduction in plant cells can occur even without centrioles. The presence of centrioles in animal cells has made mitosis an efficient and error-free process while its absence results in divisional errors and also delays the mitotic process.

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Answer Details:

Grade: High School

Chapter: The Cell

Subject: Biology

Keywords:

Cell, centrosome, centriole, granular mass, microtubules, interphase, duplication, cell division, mitosis, spindle formation, asters, microtubule organizing center, chromosomes, reproduction, animal cell, plant cell.