Biology - Cell Division Flashcards
Cell Division
This type of cell division occurs in unicellular prokaryotic
organisms like Bacteria, Yeast etc. In this division, at first the nuclear materials are directly splitted into two portions and then the cell divides into two from the middle region. As a result, from one cell there’ develops two.
Amitosis
A type of cell division by which a eukaryotic cell divides into two by a special method. In this process, the nucleus and chromosome are divided once and the number, structure and properties of chromosome in the newly formed cell remain just alike the mother.
Mitosis
A type of cell division by which a Eukaryotic cell divides into four cells by a special method. In this process the nucleus divides twice but the chromosome divides once. The number of chromosome in the newly formed daughter cell reduces to the half the number of mother cell. As the number of chromosome reduces to half this process is also termed as reduction division.
Meiosis
It is termed as equational division. Normally this
division occurs in somatic cell. As a result of this division, the plant and animal increases in length and breadth. It occurs in all meristematic cells of plants.
Mitosis
At this stage, the nucleus swells up.
Chromosomes begin to be dehydrated. As a result, the chromosomes gradually become shorter and thicker. Then they are visible under microscopes. At the end of this stage nucleolus and nuclear membrane become disappear.
Prophase
At the beginning of this stage, the fibrous protein converse to form a bi-polar spindle apparatus. Each chromosome is then become attached to a fibre of the spindle apparatus by its centromere. The nuclear membrane breaks apart into numerous “membrane vesicles”.
Pro-Metaphase
Chromosomes are arranged at the equatorial plane of the spindle. The centromere of each chromosome remains at the equatorial plane and the two arms are placed towards two poles. At this stage, the chromosomes become maximum thick and short. Two chromatids of a chromosome become maximum thick and short. Two chromatids of a chromosome become clearly visible and the centromere is divided into two parts.
Metaphase
Two separate chromatids of a chromosome move towards the opposite pole of the spindle apparatus. Centromere goes ahead at the movement of the chromatids towards the pole and the arms follow them. When the daughter
chromosomes reaches near the poles the stage ends.
Anaphase
Daughter chromosomes take position at two opposite poles. Chromosomes gradually take water and become elongated, thin and long. Nuclear membrane develops encircling the chromosomes. Nucleolus reappears at the
secondary constriction of the Sat chromosome. Spindle apparatus disappears. At the end of this stage, gradually a cell wall develops at the equatorial region of the cell.
Telophase
In human beings
there are how many pairs of chromosome?
23 pairs
If the sex chromosome pair is XY, the child will be?
Male
If the sex chromosome pair is XX, the child will be?
Female
Numbered chromosomes that contain genes for anything that does not relate to sex determination.
Autosomes
The basic physical and functional unit of heredity
Gene
An organism’s reproductive cells. They are also referred to as sex cells. Female’s are called ova or egg cells, and male’s are called sperm. They are haploid cells, and each cell carries only one copy of each chromosome.
Gamete
