CBSE Class 9 Biology Fundamental Unit Of Life Worksheet Set A

CBSE Class 9 Biology Worksheet - Fundamental Unit Of Life

Worksheets have become an integral part of the education system. Worksheets are very critical for every student to practice his/ her concepts. Students, teachers and parents can download all CBSE educational material and extremely well prepared worksheets from this website. All revision worksheets, Sample papers, Question banks and easy to learn study notes for all classes and subjects have been prepared based on the latest guidelines sent by CBSE. All CBSE educational material is developed by our panel of teachers, have also been submitted by thousands of teachers and students. The study material has been carefully compiled by the best teachers in India. Worksheets have been submitted by teachers of various CBSE schools and also have been carefully developed keeping into consideration the latest CBSE syllabus.

Q1. Explain the history of discovery of cell .

Q2. Describe cell on the basis of its complexity i,e prokaryotic and eukaryotic .

Q3. Describe the structure and functions of nucleus.

Q4. How is mitochondria important for a cell ?

Q5.Describe the structure and functions of the two types of endoplasmic reticulum.

Q6.Why are lysosomes called as suicide bags ?

Q7. Plastids are present only in plants . comment .

Q8. Differentiate between a plant cell and an animal cell .

Q9. Write a short note on vacuoles.

Q10 Describe the chemical composition of cell wall.

Q11.(a) What is DNA? Where is it found?

(b) Name the functional segment of DNA.

Q12. List two similarities between mitochondria and plastids.

Q13. Name the organelle that is referred to as the ‘powerhouse of the

cell’.Why is it called so?

Q14. Mention any two functions of the endoplasmic reticulum.

Q15. Give the functions of the following organelles in a cell.

a)Chloroplast b)Nucleus c) Leucoplast d)Chromoplast

Q16. Write the names of two cell organelles that have their own DNA and ribosomes.

Q17. What is endocytosis? Name an organism that feeds by this method.

Q18.Give technical term for a medium which has exactly the same concentration as

the cell? Why does the size of the cell remain the same when placed in such a

solution ?

Q19. (a) What would happen to the life of a cell if there was no Golgi apparatus?

(b) Which cell organelle detoxifies poisons and drugs in liver of vertebrates?

Q20. State cell theory. Name the scientists who presented it.
 

Exam Questions NCERT Class 9 Science Chapter 5 The Fundamental Unit of Life

Question. Who gave the cell theory? What does it state? Which organism is an exception of cell theory?
Answer : Two biologists; “Schleiden and Schwann” gave the “Cell theory” which expanded by “Rudolf Virchow”.Cell theory states that :
(i) All plants and animals are composed of cells.
(ii) Cell is the basic unit of life.
(iii) All cells arise from pre-existing cells. Viruses are the exceptions of cell theory.

Question. Do vacuoles store material? If so, name them.
Answer :Yes, vacuoles store some important substances required in life of the plant cell. These are amino acids, sugars, various organic acids and also some proteins.
Example : Amoeba, vacuoles also store food.

Question. How do substances like CO2 and water move in and out of the cell?
Answer : The substances like CO2 move in and out of a cell by diffusion from the region of high concentration to low concentration. Water also obey the law of diffusion.
The movement of water molecule through such a selective permeable membrane is called osmosis.

Question. How does fungi and bacteria can withstand much greater changes in the surrounding medium than animal cells?
Answer : The cell wall present in fungi and bacteria permits these cells to resist very dilute external medium without bursting. Water is taken up by osmosis.
Hence, cells swell and build the pressure against the cell wall. The wall exerts an equal pressure against the swollen cell. It is because of the cell wall, such cells can resist much greater changes in the surrounding medium than animal cells.

Question. Give difference between diffusion and osmosis.
Answer : Diffusion :
1. Diffusion can occur in any medium.
2. The diffusing molecules may be solids, liquids or gases.
3. Semipermeable membrane is not required.
4. An equilibrium in the free energy of diffusion molecules is achieved in the system.
Osmosis :
1. It occurs only in liquid medium.
2. It involves movement of solvent molecules only.
3. Semipermeable membrane is required.
4. Equilibrium in the free energy of solvent molecules is never achieved.

Question. What are the function of endoplasmic reticulum and lysosome.
Answer : (a) Functions of endoplasmic reticulum :
(i) It forms supporting skeletal framework of the cell.
(ii) ER provides a pathway for the distribution of nuclear material from one cell to the other.
(b) Functions of lysosomes :
(i) Lysosomes serve as intracellular digestive system. They destroy any foreign material which enters the cells such as bacteria and virus.
(ii) Lysosomes also remove the worn out and poorly working cellular organelles by digesting them to make way for their new replacements.

Question. Explain the functions of various cell organelles.
Answer : Functions of cell organelles :
(i) Endoplasmic Reticulum : It forms the supporting skeletal framework of the cell.
(ii) Ribosomes : It synthesises proteins.
(iii) Golgi Apparatus : It produces vacuoles which contain cellular secretion.
(iv) Lysosomes : It serves as intracellular digestive system as it digest the foreign materials which enter the cell.
(v) Mitochondria : These are the sites of cellular respirations.
(vi) Plastids : These are present only in plants and trap solar energy to manufacture food for plants.
(vii) Vacuoles : They help to maintain the osmotic pressure in a cell.
(viii) Peroxisomes : They carry-out some oxidative reactions.
(ix) Centrosome : It helps in cell division in the animal cell.

Question. Which cell organelle is known as the ‘suicidal bags’ of a cell? Why?
Answer :Lysosomes are known as suicidal bag of cell. During the disturbance in cellular metabolism, lysosome may burst and the enzymes digest their own cell. Hence, lysosome are called ‘suicide bags’ of a cell.

Question. What is nucleoid?
Answer : The nuclear region in some cells are poorly defined due to the absence of a nuclear membrane, it contains only nucleic acid. This undefined nuclear region with nucleic acid in it is called nucleoid.

Question. (i) Name the largest animal cell.
(ii) Name the smallest cell.
Answer : (i) An ostrich egg.
(ii) Pleuro pneumonia bacterium.

Question. What is osmosis?
Answer : The movement of water molecules through a selectively permeable membrane is called osmosis. This takes place from higher water concentration to lower water concentration.

Please click the below link to access CBSE Class 9 Biology Worksheet - Fundamental Unit Of Life