CBSE Class 9 Biology Fundamental Unit Of Life Worksheet Set D

Question: Why does the skin of your finger shrink when you wash clothes for a long time?
Answer:  Soap solution is very concentrated – Hypertonic solution, so water moves out of your finger cells by osmosis.

Question: We eat food composed of all the nutrients like carbohydrates, proteins, fats, vitamins, minerals and water. After digestion, these are absorbed in the form of glucose, aminoacids, fatty acids, glycerol etc. What mechanisms are involved in absorption of digested food and water?
Answer:  Diffusion and osmosis respectively

Question: Why are lysosomes known as ‘suicide-bags’ of a cell?
Answer:  Lysosomes are known as ‘suicide-bags’ because when cell gets damaged during the disturbance in cellular metabolism, lysosomes may burst and the digestive enzymes thus released digest their own cell.

Question: A person takes concentrated solution of salt, after sometime, he starts vomiting. What is the phenomenon responsible for such situation? Explain.
Answer:  Swallowing a concentration solution of salt results in exosmosis from cells of the alimentary canal. Due to this, dehydration occurs in the person. As a result, the person starts vomiting.

Question: If you are provided with some vegetables to cook. You generally add salt into the vegetables during cooking process. After adding salt, vegetables release water. What mechanism is responsible for this?
Answer:  Exosmosis

Question: Why is endocytosis found in animals only?
Answer:  Cell wall is absent in animals. Due to this, movement of substances inside the cells is easier in animals than in plants. Due to this, endocytosis is found in animals only.

Question: Do you agree that “A cell is a building unit of an organism”. If yes, explain why?
Answer:  I agree with the statement that “A cell is a building block of an organism”. This is true because all living beings are made up of cells and cell is the smallest independent unit of living beings.

Question: Bacteria do not have chloroplast but some bacteria are photoautorophic in nature and perform photosynthesis. Which part of bacterial cell performs this?
Answer:  Small vesicles which are associated with plasma membrane are present in such bacteria. These vesicles contain pigments which can trap solar energy to produce food.

Question: If cells of onion peel and RBC are separately kept in hypotonic solution, what among the following will take place? Explain the reason for your Answer:
(a) Both the cells will swell.
(b) RBC will burst easily while cells of onion peel will resist the bursting to some extent.
(c) a and b both are correct.
(d) RBC and onion peel cells will behave similarly.
Answer:  (c) a and b both are correct. When surrounding medium is hypotonic, water moves into the cells. This will result in swelling of cells. RBCs do not have cell wall and hence they will easily burst. Presence of cell wall in the cells of onion peel will prevent their bursting.

Question: Match the following A and B
Answer: a—(iv); b—(v); c—(iii); d—(i); e—(ii).

Question: How is a bacterial cell different from an onion peel cell?
Answer:

Question: How do substances like carbon dioxide (CO₂) and water (H₂O) move in and out of the cell?
Answer:  Carbon dioxide moves through diffusion, while water moves through osmosis.

Question: Draw a plant cell and label the parts which
(a) determines the function and development of the cell
(b) packages materials coming from the endoplasmic reticulum
(c) provides resistance to microbes to withstand hypotonic external media without bursting
(d) is site for many biochemical reactions necessary to sustain life.
(e) is a fluid contained inside the nucleus
Answer:  (a) Nucleus
(b) Golgi apparatus
(c) Cell wall
(d) Cytoplasm
(e) Nucleoplasm.

Question: Name the two organelles in a plant cell that contain their own genetic material and ribosomes.
Answer:  Mitochondria and plastids

Question: Write the name of different plant parts in which chromoplast, chloroplast and leucoplast are present.
Answer:  Flower and Fruit— Chromoplast
Leaves of the plant— Chloroplast
Root of the plant— Leucoplast

Question: How does amoeba obtain its food?
Answer:  Amoeba makes pseudopodia to surround a food particle. It then ingest the food particles; along with a drop of water and then forms food vacuole. This process of obtaining food by Amoeba is called endocytosis.

Question: Why are lysosomes also known as “scavengers of the cells”?
Answer:  Lysosomes contain enzymes which are used for destroying worn out parts of the cell. Lysosomes also destroys waste materials. Due to this, lysosomes are also known as ‘scavengers of the cells’.

Question: Why do plant cells possess large sized vacuole?
Answer:  Vacuoles not only store many important substances, they also contain cell sap that give turgidity to cell.

Question: How are chromatin, chromatid and chromosomes related to each other?
Answer:  Chromosomes are made up of chromatids and chromatids are made up of chromatin.

Question: Which cell organelle controls most of the activities of the cell?
Answer:  Nucleus

Question: What are the consequences of the following conditions?
(a) A cell containing higher water concentration than the surrounding medium
(b) A cell having low water concentration than the surrounding medium.
(c) A cell having equal water concentration to its surrounding medium.
Answer:  (A) Exosmosis
(B) (Endosmosis
(C) No effect

Question: Draw a neat diagram of plant cell and label any three parts which differentiate it from animal cell.
Answer:

Question: Illustrate only a plant cell as seen under electron microscope. How is it different from animal cell?Answer:

Question: Which kind of plastid is more common in
(a) roots of the plant
(b) leaves of the plant
(c) flowers and fruits
Answer:  (A) Leucoplast
(B) Chloroplast
(C) Chromoplast

Question: Draw a well labelled diagram of an eukaryotic nucleus. How is it different from nucleoid?
Answer:

Question: Differentiate between rough and smooth endoplasmic reticulum. How is endoplasmic reticulum important for membrane biogenesis?
Answer:  The ribosomes, which are present in all active cells, are the sites of protein synthesis. Endoplasmic reticulum helps in transporting these proteins to various places. The smooth endoplasmic reticulum help in manufacture of fat and lipids which along with proteins help in building the cell membrane.

Question: Draw a neat labelled diagram of an animal cell.
Answer: