Biology Test
7th December
9th std.
Answer the following questions
Q1 Define Mitosis, Plasmolysis (1×2=2)
Q2 Give reasons (1×4=4)
a) Mitochondria is called power house of a cell.
b) Plastids are strange organelles like mitochondria.
c) Grapes if kept in concentrated salt solution get wrinkled after some time.
d) Plant cells have definite shape.
Q3 Differentiate between prokaryotes and Eukaryotes. (2)
Q4 Why Lysosomes are called suicidal bags of a cell? (2)
Answers
Answer:
1. mitosis is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which the total number of chromosomes is maintained. Therefore, mitosis is also known as equational division.
Plasmolysis is a typical response of plant cells exposed to hyperosmotic stress. The loss of turgor causes the violent detachment of the living protoplast from the cell wall. The plasmolytic process is mainly driven by the vacuole. Plasmolysis is reversible (deplasmolysis) and characteristic to living plant cells.
2. (a). mitochondria produce the energy necessary for the cell's survival and functioning. Through a series of chemical reactions, mitochondria break down glucose into an energy molecule known as adenosine triphosphate (ATP), which is used to fuel various other cellular processes.