Which of the following is not correct? | Class 11 Biology Chapter Cell: The Unit of Life, Cell: The Unit of Life NCERT Solutions

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.

Write the functions of the following
a. Centromere
b. Cell wall
c. Smooth ER
d. Golgi Apparatus
e. Centrioles
 

The genomic content of the nucleus is constant for a given species where as the extra chromosomal DNA is found to be variable among the
members of a population. Explain.

What are the characteristics of prokaryotic cells?

Describe the structure of the following with the help of labelled diagrams.
(i) Nucleus
(ii) Centrosome

Is extra genomic DNA present in prokaryotes and eukaryotes? If yes, indicate their location in both the types of organisms.
 

How do neutral solutes move across the plasma membrane? Can the polar molecules also move across it in the same way? If not, then how are these transported across the membrane?

What is a centromere? How does the position of centromere form the basis of classification of chromosomes. Support your answer with a diagram showing the position of centromere on different types of chromosomes.

What are nuclear pores? State their function.

New cells generate from (a) bacterial fermentation (b) regeneration of old cells (c) pre-existing cells (d) abiotic materials

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

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

Name the pathological condition when uncontrolled cell division occurs.
 

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?
 

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.