Daily Practice Problems
Class 9 Science
The Fundamental Unit of Life
daily practice problem

Question 1:

Name the scientists who

(i) discovered cells

(ii) discovered the compound microscope

(iii) discovered the nucleus in the cell

(iv) coined the term ‘protoplasm’ for the fluid substance of the cell

(v) presented the Cell theory

(vi) who proposed that all cells arise from pre-existing cells.

(vii) who first described the Golgi apparatus

Question 2:

Justify the following statement “Every multicellular organism has come from a single cell.”

Question 3:

Differentiate between the following:

(i) unicellular and multicellular organisms

(ii) prokaryotic and eukaryotic organisms

(iii) rough endoplasmic reticulum and smooth endoplasmic reticulum

(iv) mitosis and meiosis

Question 4:

What is meant by plasma membrane? Why is it called ‘selectively permeable’?

Question 5:

What will happen if you place a living cell into a:

(i) hypertonic solution

(ii) hypotonic solution

(iii) isotonic solution

Question 6:

Why are plant cells rigid in comparison to the animal cells?

Question 7:

What do we call the rod-shaped structures of the nucleus that are visible only when the cell is about to divide? Why are they significant?

Question 8:

What do we call the components of the cell that together confers division of labour within the cells by performing special function? Give a few examples.

Question 9:

Name the type of cell organelle that forms a large network of membrane-bound tubes and sheets. Name its types.

Question 10:

Give any three functions performed by the Golgi apparatus.

Question 11:

Why are ‘lysosomes’ called the suicidal bags of the cell?

Question 12:

Name the two cell organelles that have their own DNA.

Question 13:

Name the cell organelles that are referred to as the powerhouse of the cell. Why are they called so?

Question 14:

Name the various types of plastids. Also mention their functions.

Question 15:

Briefly enlist any three uses of vacuoles in a cell.

Question 16:

What is meant by cell division? How many types of cell divisions are there? Name them.

Question 17:

Why don’t viruses show characteristics of life until they enter a living body?

Question 18:

Name the following:

(i) The structural and functional unit of life.

(ii) The free movement of substances from its region of higher concentration to the region of lower concentration.

(iii) The process which is enabled by the flexibility of the cell membrane  that allows the cell to engulf in food and other materials from its external surrounding.

(iv) The chemical substance which constitutes the genes.

(v) Organisms whose body is composed of many cells.

Question 19:

Match the columns A and B:

              Column A                                                  Column B

1. ATP                                                   i. Cellulose

2. Gene                                                ii. Energy currency of the cell

3. Osmosis                                          iii. Functional segments of DNA

4. Plant cell wall                                iv. Cell division

5. Mitosis                                            v. Semi-permeable membrane

Question 20:

State whether the following statements are true or false.

(i) All animal cells contain a cell wall.

(ii) Plant cells contain large vacuoles.

(iii) Genes are located in chromosomes.

(iv) The cell membrane is freely permeable.

(v) The activities of the cell are controlled by the nucleus.