Cells

Question 1

Definition of a cell

Answer 1

Cells are the fundamental, structural and functional units of living organisms. The cell is the basic structural and functional unit of living organisms. Multicellular and unicellular cells are the 2 types of cells.

Question 2

Characteristics of Eukaryotic Cells

Answer 2

1. The size of a cell is generally large.
2. Nucleus is present
3. Contains many chromosomes
4. Nucleolus is present
5. All membrane bound cell organelles are present
6. Cell division occurs by mitotic or meiotic - in mitotic the chromosomes replicate (spread rapidly).

Question 3

Characteristics of Prokaryotic Cells

Answer 3

1. The size of a cell is generally small
2. Nucleus is absent : the nuclear region (nucleoid) is not surrounded by a nuclear membrane.
3. Contains single chromosome
4. Nucleolus is absent
5. Membrane bound cell organelles are absent
6. Cell division takes place by fission or through budding.

Question 4

Unicellular Organism

Answer 4

A unicellular organism is represented by a single cell. All activities of organisms are performed by a single cell. There is no division of labor as the single cell performs all the life activities. Reproduction consumes a single cell. The lifespan of an individual is short. Protozoa, yeast, amoeba, bacteria.

Question 5

Multicellular Organisms

Answer 5

A multicellular organism consists of large no. of cells. A single cell performs one or few activities of the organism. Cells are specialized to perform different functions of the body, so there is a division of labor within cells. Only some cells of the body called germ cells take part in reproduction, other cells remain intact. Lifespan of an individual is long.