NEET Biology Class 9 Chapter 1 The Fundamental Unit of Life Short Question And Answers

The Fundamental Unit of Life Short Answer Questions

Question 1. Explain why it is not enough just to say that a Answer: is “hypertonic.”
Answer:

Hypertonic and hypotonic are relative terms: A Answer: that is hypertonic to tap water could be hypotonic to seawater. In using these terms, you must provide a comparison, as in “The Answer: is hypertonic to the cell.

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Question 2. As a cell increases in size, its surface-to-volume ratio decreases which causes the cell to function less effiiently. Discuss ways in which variations in cell structure can help overcome this problem.
Answer:

Cells with spines or extensions help to overcome the surface area-to-volume ratio problem by increasing their surface area. Elongated or non-spherical cells also have a more favourable ratio.

Question 3. Why is the presence of organelles within eukaryotes signifiant? In otherwords, why are eukaryotes so complex and diverse as compared with prokaryotes?
Answer:

Eukaryotes have organelles that each contain different enzymes, so the enzymes do not mix and interact within the cytoplasm of the cell. This arrangement allows for greater diversity in types of enzymes and reactions and greater diversity in eukaryotes. Prokaryotes do not have such organelles.

Question 4. Distinguish between rough endoplasmic reticulum and smooth endoplasmic reticulum, both structurally and functionally.
Answer:

Rough ER consists of cisternae with numerous polysomes on their outer surface, whereas smooth ER lacks ribosomes and is mostly tubular. Rough ER is involved in protein synthesis, but smooth ER is involved in the synthesis of lipids.

Question 5. How is osmosis a special type of diffusion?
Answer:

Osmosis is a special type of diffusion because both involve movement of molecules of substance from the region of its higher concentration to the region of its lower concentration. In osmosis water moves across a semi-permeable membrane.

NEET Biology The Fundamental Unit of Life short questions and answers

Question 6. What are the functions of vacuoles in plant cells and unicellular organisms?
Answer:

In plant cells vacuoles:

1. Provide rigidity to the cell.
2. Store waste products, and useful substances like amino acids, sugars, organic acids, proteins, minerals and pigments.

In unicellular organisms like Amoeba:

1. Food material is enclosed in vacuoles, called the food vacuole.
2. Contractile vacuoles expel water and waste products from the cell.

Question 7. Proteins embedded in the plasma membrane have several important functions in the life of the cell. Describe two of these functions. Explain why they are important to the cell?
Answer:

One function of proteins embedded in the plasma membrane is to form gateways that allow selective passage of ions and molecules in and out of the cell. This allows wastes to be removed and needed substances to enter. Another function is to recognize changes in the outside environment and to communicate with other cells for the quick response to change occurred.

Question 8. Organelles are the functional subunits of the cell. Each organelle has a specifi function which makes it easier to master the names, structure, and function of each component. In the following table, indicate the functions associated with each structure.

Organelles:

1. Nucleus
Answer:

Control centre of cell ; houses DNA

2. Rough Endoplasmic Reticulum
Answer:

Site of protein synthesis.

Important short questions from The Fundamental Unit of Life for NEET

3. Smooth Endoplasmic Reticulum
Answer:

Lipid Synthesis

4. Golgi body
Answer:

Center For Packaging And Secretion

5. Lysosomes
Answer:

Degrade Debris, Recycle Cell Contents

6. Mitochondrion
Answer:

Organelle In Which Energy Transformation Occur.

7. Chloroplast
Answer:

Site Of Photosynthesis

8. Peroxisomes
Answer:

Contain enzymes that help the cell use oxygen

The Fundamental Unit of Life Class 9 short answer questions with solutions

Question 9. Why do plant cells have more in number and big sized vacuoles as compared to the animal cell?
Answer:

Plant cells attain turgidity and rigidity due to the more number of vacoules as well as large sized vacuoles help the plant cells to withstand the wear and tear, external environment conditions. They also help in the storage of essential material required by plants for their growth like amino acids, sugar and various organic substances.

Question 10. 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:

Water is absorbed by osmosis; fatty acids and glycerol are absorbed by diffusion (passive transport) and glucose, amino acids and some ions are absorbed by active transport.

Question 11. Write the name of different plant parts in which chromoplast, chloroplast and leucoplast are present.
Answer:

• Chromoplasts – Flowers and fruits.
• Chloroplasts – Green leaves and green parts of young stems.
• Leucoplasts – Root and underground stem

Question 12. Give two major differences between prokaryotes and eukaryotes.
Answer:

Structure and function of cell organelles short answer questions NEET

Question 13. What is the main function of each of the following cell organelles?

1. Ribosome
Answer:

Ribosomes are the sites of protein synthesis.

2. Cell wall
Answer:

The cell wall provides shape, rigidity and protection to the cell.

Difference between plant and animal cells short questions NEET

Question 14. State two types of plastids. Write one function of each.
Answer:

Two types of plastids in plant cells are:

• Leucoplasts (colourless plastids). These store carbohydrates, proteins and lipids in the cells.
• Chromoplasts (coloured plastids). Green plastids e.g. chloroplasts synthesize food in the presence of sunlight by the process called photosynthesis.

Question 15. What are chromosomes? List their two functions.
Answer:

Chromosomes are thread-like structures usually present in the nucleus and become visible only during cell division.

They are composed of DNA and proteins:

• Chromosomes contain hereditary information of the cell.
• DNA of chromosomes also controls all the activities of the cell

Question 16. Name the nucleic acids that are present in an animal cell.
Answer:

Deoxyribonucleic acid (DNA). Ribonucleic acid (RNA)

Question 17. Cell wall is composed of which chief material. How many molecules of glucose contributes o prepare cellulose?
Answer:

Cellulose (carbohydrate). A cellulose molecule is a long, unbranched chain of about 6000 glucose molecules.

Plasma membrane and its functions short answer questions NEET

Question 18.

1. Is the cell wall in a plant cell living or non-living?
Answer:

The plant cell wall is non-living.

2. Is the cell wall in a plant cell permeable or selectively permeable?
Answer:

It is permeable.

Question 3. What is its chemical composition?
Answer:

Plant cell wall is chiefl composed ofinsoluble fibous polysaccharide, cellulose (carbohydrate). Certain other compounds (hemicellulose, pectins and proteins) also occur in the cell wall.

Question 19.

1. Who coined the term ‘cell’?
Answer:

Robert Hooke coined the term cell

NCERT-based short answer questions on The Fundamental Unit of Life

2. Name three major differences between light microscope and electron microscope.
Answer:

Question 20.

1. Name any two cell organelles which are bounded by double membranes.
Answer:

Mitochondria and chloroplast.

2. Why are mitochondria called semiautonomous organelles?
Answer:

Mitochondria are capable of self duplication. They are also able to synthesize some of their own proteins. Hence, they are regarded as semiautonomous organelles

3. Where one would fid green chlorophyll pigment in a plant cell?
Answer:

Chlorophyll pigments are found in thylakoids of chloroplasts in a plant cell.

Osmosis and diffusion short answer questions NEET

Question 21.

1. Name any two cell organelles that are bounded by double membranes.
Answer:

Nuclear envelope, nuclear sap, chromatin material, nucleolus and nuclear matrix.

2. What are chromosomes? Give their chemical composition.
Answer:

Chromosomes are thread-like structures usually present in the nucleus and become visible only during cell division. Each chromosome is made up of DNA and proteins.

3. List the type of chromosome if it has the following position of the centromere.

1. In the middle.
Answer:

Metacentric chromosome

2. At the tip of chromosome.
Answer:

Telocentric chromosome.

Question 22. What is a nucleoid?
Answer:

The nuclear region in some cells are poorly defied 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.