MODEL SUBJECTIVE QUESTION OF CELL DIVISION
abidaWrite on cell cycle Give mechanism of control of cell cycle. Write not on mitosis. Describe different step of meiosis. Discuss spermatogenesis and oogenesis.
DEFINITIONS AND KEY POINTS Of Cell Division
TERMS DEFINITIONS I Cell cycle I The period from the time a cell is produced until it completes mitosis is called cell cycle. Mitcjsis The type of…
Meiosis : The basis of sexual reproduction
Meiosis is a type of cell division in which number chromosome reduced to one half in the daughter cell. Sexual reproduction requires a genetic ontribution from two different sex cells.…
ETHYLENE
sanaSmoke was used for ripening of bananas in old time. Later it was found that smoke contain ethylene. It was found that this gas is also produced by the plant.…
NUCLEOLUS
rubabThe most visible structure within the non dividing nucleus is the nucleolus. The nucleolus is a 11011-membranous bound structure. The function of the nucleolus is to synthesize ribosomes. Sometimes, there…
Abscisic Acid (ABA) and its role in plant growth
P.F. Wareing in U.K. and F.T. Addicott in USA in 1961 discovered growth inhibiting hormone. It was named abscisic acid (ABA). Abscisic acid was discovered from the leaves of Acer…
CONTROL OF CELL CYCLE
Different cells have different duration of cell cycle. Some cell actively divides like liver cells. But some cell never divides again like nerve cell. GI phase is a key period…
CYTOKININS
Cytokinin stimulates the cell division in plants. It has following history of discovery: Earlier, it was believed that coconut milk contain cell division causing factors. The developing endosperm of maize…
MITOSIS
The type of cell division in which number of chromosomes remains constant in the daughter generations is called mitosis. Mitosis is divided intc four phases: prophase, metaphase, anaphase, and telophase.…
GIBBERELLINS
Gibberellin was discovered by Kurosawn in 1928. He observed that a rice. plant was infected by the fungus Gibberella. It showed excessive stein elongation. The symptom is called "Bakanae- disease.…