Introduction

Question 1

What is a cell?

Answer 1

Cell is the fundamental, structural and functional unit of all living organisms.

Question 2

Who is (i) Robert Hooke, (ii) Anton Von Leeuwenhoek, (iii) Robert Brown?

Answer 2

(i) He studied and discovered the cell from a cork (dead cell).
(ii) He first observed living cells (bacteria, protozoa, spermatozoa, RBCs).
(iii) He discovered the nucleus of a cell.

Question 3

Who formulated the cell theory?

Answer 3

• Matthias Schleiden (German Botanist)- All organisms are composed of cells which form the tissue of the plant.
• Theodore Schwann (British Zoologist)- discovered cell membrane, cell wall, concluded that all living organisms are made of cells and products of cells.

Question 4

Who modified the cell theory?

Answer 4

Rudolf Virchow explained how all cells arise from pre-existing cells in his theory Omnis cellula-e-cellula.

Question 5

What is cell theory?

Answer 5

1. All living organisms are composed of cells and products of cells.
2. All cells arise from pre-existing cells.
3. Activities of an organism are the outcome of the sum total of activities and interactions of its constituent cells.

Question 6

The nucleus contains chromosomes which in turn contain DNA (genentic material). On the basis of presence of nuclear material, there are two types of cells.

Answer 6

1. Eukaryotic
2. Prokaryotic

Question 7

What is cytoplasm?

Answer 7

• It is the semi fluid matrix which occupies the volume of the cell.
• It is the main area of cellular activities.

Question 8

Eukaryotic cells have membrane bound organelles while prokaryotic cells do not. What are these organelles?

Answer 8

Endoplasmic Reticulum, Golgi Apparatus, Lysosomes, Mitochondria, Microbodies, Vacuoles.

Question 9

What are Ribosomes?

Answer 9

• They are non-membrane bound organelles.
• They are found in all cells
• Found in the cytoplasm and in chloroplasts (plant cells) and mitochondria (animal cells) and on RER.

Question 10

What is a Centriole?

Answer 10

• It is present in animal cell.
• Non membrane bound.
• helps in cell division.

Question 11

What is the (i)Smallest cell, (ii) Largest isolated single cell, (iii) Longest cell, (iv) Size of human RBCs?

Answer 11

(i) Mycoplasma (o.3mim)
(ii) Ostrich egg
(iii) Nerve cell
(iv) 7mim