What is the significance of meiosis? | Class 11 Biology Chapter Cell cycle and Cell Division, Cell cycle and Cell Division NCERT Solutions

Name the pathological condition when uncontrolled cell division occurs.
 

Mitosis results in producing two cells which are similar to each other. What would be the consequence if each of the following irregularities
occur during mitosis?
a. Nuclear membrane fails to disintegrate
b. Duplication of DNA does not occur
c. Centromeres do not divide
d. Cytokinesis does not occur.

The diagram shows a bivalent at prophase-I of meiosis. Which of the four chromatids can cross over?

Name a cell that is found arrested in diplotene stage for months and years. Comment in 2-3 lines how it completes cell cycle?
 

Given that the average duplication time of E.coli is 20 minutes, how much time will two E.coli cells take to become 32 cells?
 

Name a stain commonly used to colour chromosomes.
 

Define a taxon. Give some examples of taxa at different hierarchical levels.

What are the steps involved in formation of a root nodule?

Aquatic animals generally are ammonotelic in nature where as terrestual forms are not. Comment.
 

Name the cells/tissues in human body which
a. exhibit ameboid movement
b. exhibit ciliary movement

How do you distinguish between a skeletal muscle and a cardiac muscle?

Why earthworm is called the friend of farmer?
 

Which of the following is correct:
(a) Cells of all living organisms have a nucleus.
(b) Both animal and plant cells have a well defined cell wall.
(c) In prokaryotes, there are no membrane bound organelles.
(d) Cells are formed de novo from abiotic materials.

Label the different components of actin filament in the diagram given below.

Rhizome of ginger is like the roots of other plants that grows underground. Despite this fact ginger is a stem and not a root. Justify.