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NCERT solutions Biology Textbook for Class 11 chapter 8 Cell: The Unit of Life

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Chapter 8 - Cell: The Unit of Life

Page 141

Which of the following is not correct?

(a) Robert Brown discovered the cell.

(b) Schleiden and Schwann formulated the cell theory.

(c) Virchow explained that cells are formed from pre-existing cells.

(d) A unicellular organism carries out its life activities within a single cell.

Q 1 | Page 141 | view solution

New cells generate from

(a) bacterial fermentation       

(b) regeneration of old cells

(c) pre-existing cells              

(d) abiotic materials

Q 2 | Page 141 | view solution

Match the following

  Column I   Column II
a Cristae 1 Flat membranous sacs in stroma
b Cisternae 2 Infoldings in mitochondria
c Thylakoids 3 Disc-shaped sacs in Golgi apparatus
Q 3 | Page 141 | view solution

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.

Q 4 | Page 141 | view solution

What is a mesosome in a prokaryotic cell? Mention the functions that it performs.

Q 5 | Page 141 | view solution

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?

Q 6 | Page 141 | view solution

Name two cell-organelles that are double membrane bound. What are the characteristics of these two organelles? State their functions and draw labelled diagrams of both?

Q 7 | Page 141 | view solution

Multicellular organisms have division of labour. Explain.

Q 9 | Page 141 | view solution

Cell is the basic unit of life. Discuss in brief.

Q 10 | Page 141 | view solution

What are nuclear pores? State their function.

Q 11 | Page 141 | view solution

Both lysosomes and vacuoles are endomembrane structures, yet they differ in terms of their functions. Comment.

Q 12 | Page 141 | view solution

Describe the structure of the following withthe help of labelled diagrams

Nucleus

Q 13.1 | Page 141 | view solution

Describe the structure of the following withthe help of labelled diagrams.

Centrosome

Q 13.2 | Page 141 | view solution

What is a centromere?

Q 14.1 | Page 141 | view solution

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.

Q 14.2 | Page 141 | view solution

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