Properties and functions of the cell

Properties and functions of the cell
Subtopic: Growth
In our previous lessons, we had discussed nutrition, movement, respiration and excretion are some of the properties and functions of the cell. Properties and functions of the cell are the characteristics features shown by living things. The cell is also a living thing
This week lesson will be focused on growth which is also one of the property and function of the cell
Growth in living things can be defined as the irreversible increase in size and mass due to the utilization of food to make additional protoplasm
Cell theory states that new cells are formed from the preexisting ones
All multicellular organisms begin life as a single fertilised cell. This cell divides into two,then four and so on.

Therefore, cell division brings about an increase in the number of cells.
After cell division, the daughter cells increase in mass and size I.e enlarge. After enlargement, each cell may develop into a special type of cell by changing its shape and structure to carry out a particular function.
The kind of cell it becomes depend on its position in the body of the organism. If the cell is in the brain it develops in to nerve cell, sperm cell if it is in the testes or a ciliated cell,if it is the trachea (wind pipe). This process is known as cell differentiation.
CELL DIVISION (MITOSIS)
Mitosis is a cell division that occurs

1. During growth and development of an organism,
2. During asexual reproduction
3. It takes place in the somatic cells I.e body cells that are not involved in the production of gametes.
   The somatic cell of a particular organism has a certain number of chromosomes in its nucleus. These chromosomes are always in pairs I.e there are two sets of chromosomes, members of each pair are called homologous chromosomes, for example, each human somatic cells has 46 chromosomes. These are present as 23 pairs of homologous chromosomes.
   The number of chromosomes in each somatic cell of an organism is known as diploid number (2n).

EVALUATION

1. Define growth
2. Explain the following
   a. Mitosis
   b. Cell differentiation
   c. Diploid cell
   d. Chromosome
3. State the importance of cell division in multicellular organisms.