HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Haryana State Board HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life Important Questions and Answers.

Haryana Board 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Very Short-Answer Type Questions

Question 1.
Who discovered first cell and when ?
Answer:
A scientist named Robert Hooke discovered cell in 1665.

Question 2.
What was discovered by Leeuwenhoek?
Answer:
Leeuwenhoek discovered bacteria cell in 1674 with the help of a microscope.

Question 3.
Which scientist gave the name protoplasm to the living material inside the cell?
Answer:
J.E. Purkinje in 1939.

Question 4.
Which scientists proposed cell theory?
Answer:
M.Schleiden (1838) and T. Schwann (1839).

Question 5.
What is a cell ?
Answer:
The cell is the structural and functional unit of living organisms.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 6.
Which scientist expanded cell theory?
Answer:
Virchow (1855).

Question 7.
When was the electron microscope discovered?
Answer:
In 1940.

Question 8.
What is a unicellular organism?
Answer:
When a single cell of the organism performs all the life functions, it is called a unicellular organism.

Question 9.
What is a multicellular organism?
Answer:
When more than one cell group together to form an organism, it is called a multicellular organism.

Question 10.
Give some examples of unicellular organisms.
Answer:
Amoeba, Euglena, Entamoeba, Paramoecium.

Question 11.
Name one multicellular organism.
Answer:
Man.

Question 12.
Name the longest cell.
Answer:
Nerve cell.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 13.
Name the smallest cell.
Answer:
Mycoplasma galisepticum.

Question 14.
Which is the largest cell?
Answer:
Ostrich egg.

Question 15.
Name the smallest cell found in the human body.
Answer:
Lymphocyte.

Question 16.
Name the largest plant cell.
Answer:
Acetabularia.

Question 17.
Which cell organelle is responsible for protein synthesis?
Answer:
Ribosome.

Question 18.
In which organism is a division of labour found?
Answer:
In multicellular organisms.

Question 19.
What are cell organelles?
Answer:
In every cell, some specific components perform specific functions. They are called as cell organelles.

Question 20.
Cell organelles group together to form which unit?
Answer:
Cell.

Question 21.
Name the main functional zones oLa cell.
Answer:
The plasma membrane, nucleus cytoplasm.

Question 22.
Name one special feature of plasma membrane.
Answer:
Selective permeability.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 23.
What is osmosis?
Answer:
The movement of water or some other liquid substance from a region of high concentration to a region of low concentration through a semi-permeable membrane is called osmosis.

Question 24.
Give one example of osmosis.
Answer:
Absorption of water by plant roots.

Question 25.
Why does kishmish (dried raisin) get swollen in kheer?
Answer:
As the protoplasm of the kishmish is more concentrated than the kheer, internal osmosis takes place due to which it gets swollen.

Question 26.
What is diffusion?
Answer:
The movement of a substance from a region of high concentration to a medium of low concentration is called diffusion.

Question 27.
What happens when a cell is kept in a hypertonic solution?
Answer:
The cell will lose water by osmosis.

Question 28.
What is the membrane called which allows only specific substances to pass through it?
Answer:
Semi-permeable membrane.

Question 29.
What is plant cell wall made of?
Answer:
Cellulose.

Question 30.
Which cell organelle controls the activities of the cell?
Answer:
Nucleus.

Question 31.
Write the full form of RNA.
Answer:
Ribonucleic acid.

Question 32.
Write the full form of DNA.
Answer:
Deoxyribonucleic acid.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 33.
What is a gene?
Answer:
The functional unit of a chromosome is called a gene.

Question 34.
Which is the carrier of hereditary characters ?
Answer:
Chromosome.

Question 35.
How many chromosomes are found in man ?
Answer:
23 pairs or 46 chromosomes.

Question 36.
Name two cell organelles.
Answer:
Mitochondria, Golgi apparatus.

Question 37.
Which cell organelle is knows as suicide bag?
Answer:
Lysosome.

Question 38.
Name one secretive organelle of cell.
Answer:
Golgi apparatus.

Question 39.
Name the powerhouse of cell.
Answer:
Mitochondria.

Question 40.
What is ATP?
Answer:
ATP is the energy of the cell.

Question 41.
Name an organelle which is found only in plant tissue.
Answer:
Plastids.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 42.
Name the organelle which is helpful in cell division.
Answer:
Centrosome.

Question 43.
What are prokaryotic cells ?
Answer:
The cells which are small, have no cell organelle and have only one chromosome, are called prokaryotic cells.

Question 44.
What are eukaryotic cells ?
Answer:
Cells which are large in size, have cell organelle and more than one chromosome are called eukaryotic cells.

Question 45.
What is the green colour of plants due to ?
Answer:
Due to green pigment.

Question 46.
Name a prokaryotic cell.
Answer:
Bacteria.

Question 47.
Name a eukaryotic cell.
Answer:
Animal or plant cell.

Question 48.
What is cytoplasm ?
Answer:
The substance enclosed by the plasma membrane is called cytoplasm.

Question 49.
What is protoplasm ?
Answer:
Cytoplasm and nucleus together constitute protoplasm.

Question 50.
How many types of endoplasmic reticulum are there ?
Answer:
Two types:
(i) Rough Endoplasmic Reticulum (RER),
(ii) Smooth Endoplasmic Reticulum (SER).

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 51.
What is the main function of SER ?
Answer:
To Synthesis lipid molecules.

Question 52.
What does ER denote ?
Answer:
Endoplasmic Reticulum.

Question 53.
Which organelle detoxifies toxic substances and drugs in the liver cells ?
Answer:
SER.

Question 54.
Name coloured plastids.
Answer:
Chromoplast.

Question 55.
Name a white and colourless plastid.
Answer:
Leucoplast.

Question 56.
Which plastid contains chlorophyll ?
Answer:
Chloroplast.

Question 57.
Are the vacuoles present in plants smaller or larger (in size)?
Answer:
Larger.

Short-Answer Type Questions

Question 1.
What is a cell ?
Answer:
Just as a house is made up of small bricks, living organisms are formed of small units called cells. Cell is the structural and functional unit of each living organism cell has its own organisation.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 2.
Write a note on the size of the cell.
Answer:
The size of the cell is so small that it is difficult to see it. It can be seen under a microscope, but to see and measure its structural organisation, a special unit called micron (p) on a micrometre is used. A micron is the l/000th part of a millimetre. Generally cells are around 30 microns in size. The smallest cell is mycoplasmas galisepticum and the largest cell is the egg of ostrich which is 170 x 135 mm in size. The size of pleuropneumonia is 0.1 pm. The size of the cell depends on the function it performs.

Question 3.
What is cell theory (principal) ?
Answer:
Cell is the basic unit of life. This is the cell theory. According to this theory, all living organisms are made up of cells. Cell is the functional and structural unit of life. Cell is a body containing protoplasm. Cell theory was proposed by M. Schleiden (1838) and T. Schwann (1839) after studying plant and animal cells. Afterwards, in 1855, Virchow expanded the cell theory by saying, ‘The new cells are formed from division of pre-existing cell.’ This is the cell theory.

Question 4.
What are unicellular and multicellular organisms ?
Answer:
1. Unicellular organisms:
The organisms which are formed of single cell are called unicellular organisms; e.g. amoeba, fungi, chlamydomonas, paramoecium, euglena etc.
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 1

2. Multicellular organisms:
The organisms which are formed of many cells grouped together are called multicellular organisms; e.g. hydra, whale, sponge, ferm, man, tagetus, fish, etc.

Question 5.
Draw a labelled diagram of the cells of onion peel as seen under a microscope.
Answer:
Cells of onion peel:
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 2

Question 6.
Draw a labelled diagram of various cells found in human body.
Answer:
Different cells of human body
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 3
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 4

Question 7.
What are the major differences between the cells of unicellular and multicellular organisms ?
Answer:
The main differences between the cells of unicellular and multicellular organisms are :
(1) The cell of a unicellular organism is generally circular or oval, while the cells of multicellular organisms are cylindrical.

(2) As a unicellular organism is made up of a single cell, all the life activities are performed by this single cell. On the other hand in multicellular organisms, all cells perform certain specific functions.

(3) As all the life activities are performed by a single cell in unicellular organisms, these activities are not performed efficiently. But division of labour is found in the cells multicellular organisms. Different cells perform specific functions, which they do efficiently.

(4) Amoeba, Paramoecium, etc. are unicellular organisms while dog, frog, man, etc. are multicellular organisms.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 8.
What are the advantages of multicellularity ?
Answer:
Multicellularity has a lot of advantages. Because of multicellularity, division of labour is found in higher animals. Because of difference in the types of cells, various cells perform specific functions in these organisms. All the cells co ordinate with each other. Thus, all the activities relating to growth and development depend upon the co ordination between all the cells.

Question 9.
What are the differences between plasma membrane and cell wall ? Give their functions also.
Answer:
Differentiate between Plasma Membrane and cell wall are as follows :
Plasma Membrane:
1. It is living.
2. It is formed of proteins, and lipid peptides.
3. It is smooth and flexible.
4. It is semi-permeable.

Cell Wall:
1. It is non-living.
2. It is formed of cellulose, lignin and pectin.
3. It is hard.
4. It is permeable.

Functions:
Plasma Membrane: Only molecules of definite size can pass through it. It is semi-permeable. It is a protective covering of the cell.

Cell Wall: It provides shape, size and protection to the cell.

Question 10.
What happens when we put an animal cell or a plant cell into a sugar solution ?
Answer:
The following can happen if we put a living cell in sugar solutions having different concentration:
(1) When put in a hypotonic solution, water will enter the cell by osmosis.
(2) When put in an isotonic solution,there will be no net movement of water through the cell membrane.
(3) When put in a hypertonic solution, the water will come out of the cell through osmosis.

Question 11.
How is diffusion important for a cell ?
Answer:
Diffusion plays an important role for the entry and exit of water and gases in and out of the cell. It helps the cell to get nutrition from the outside environment. The entry and exit of various molecules and in and out of the cell takes place by diffusion only.

Question 12.
What is cell wall ?
Answer:
Cell Wall: Cell wall is found only in plant cells. Some bacteria also possess cell wall. As the cell wall is made up of cellulose, it is permeable to water. Because of hardening of cellulose, it is non-living.

Question 13.
Write the advantages and disadvantages of cell wall.
Answer:

Advantages:
(1) It provides a definite shape to the cell.
(2) The cell remains structurally strong and protected.
(3) The plasma membrane remains protected.
(4) Because of its permeability, the cell wall maintains balance of different materials inside the cell.
(5) It prevents the cell from the attack of disease causing molecules.
(6) It provides a definite structure to the cell.

Disadvantages:
(1) The pace of cell division gets slowed down because of cell wall.
(2) It reduce the expanding power of cell.

Question 14.
Write a note on protoplasm shrinkage.
Answer:
If a plant cell is kept in a hypertonic solution, then exosmosis starts, i.e. water starts coming out of cytoplasm, due to which the cell wall loosens. If the hypertonic solution is highly concentrated, then the shrinkage of protoplasm continues. This process is called protoplasm shrinkage.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 15.
What are the main functional zones of a cell ?
Answer:
The main functional zones of a cell are plasma membrane, cysoplasm and nucleus which perform the following functions : ‘
1. Plasma membrane: It is the outer covering of every cell. It is made of lipids and proteins. It protects the cell and controls the movement of molecules inside and outside the cell.

2. Cytoplasm: Apart from the nucleus it constitutes the remaining part of the cell. It has various cell organelles like Golgibodies, mitochondria, endoplasmic, reticulum, ribosomes, lysosomes and cnloroplasts which perform various functions.

3. Nucleus: It is the main part of the cell, circular of oval-shaped. It controls all the activities of the cell. It contains nucleoplasm, nucleolus and chromosomes. Nucleus is covered by nuclear membrane.

Question 16.
Name the main cell organelles.
Answer:
The main cell organelles are:
(1) Endoplasmic Reticulum
(2) Ribosomes
(3) Lysosomes
(4) Mitochondria
(5) Nucleus
(6) Golgibodies
(7) Cilia and Plagella
(8) Vacuoles
(9) Plastids
(10) Centrosomes
(11) Perotisomes.

Question 17.
Write a note on nucleus.
Answer:
Nucleus is circular and the largest cell organelle found in the centre of cytoplasm. It controls and co ordinates all the activities of a cell. Nucleus is surrounded by nuclear membrane which is filled by nucleoplasm. Nucleolus and chromosomes are present in the nucleoplasm. There are some cells which possess many nuclei. These are called coenocytes.

Question 18.
Give four functions of nucleus.
Answer:
Functions of nucleus :
(1) It controls all the activities of the cell.
(2) It controls cell division.
(3) It takes part in reproduction.
(4) It maintains the functional ability of the cell.

Question 19.
Name both the nucleic acids present in the cell. What functions do they perform ?
Answer:
(1) DNA (Deoxyribose nucleic acid),
(2) RNA (Ribose nucleic acid).

(i) Functions of DNA: It contains genes. DNA stores the hereditary characters and passes these characters to the next generation. So, it is the hereditary material.
(ii) Functions of RNA: It synthesises proteins. In many types of viruses, RNA also acts as the hereditaiy material.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 20.
Write a note on Gene.
Answer:
Small granular structures present on the chromosomes are called genes. Genes are always found in pail’s on the chromosomes. One pair of genes controls one character. For example, our height is decided by a pair of two genes present in our body. Similarly, other characters/features of our body, like skin colour, colour of the eyes, etc. develop from a pair of genes each.

Question 21.
What are genes ? What is their function ?
Answer:
Gene:
Gene is a part of deoxyribonucleic acid (DNA). They are present on the chromosome, one above the other, in a specific order. Gene is the hereditary unit of life. In living organisms one character is controlled by one pair of genes. Genes hold the chloroplasts together.

Question 22.
Describe prokaryotic and eukaryotic cells.
Answer:
Prokaryotic and eukaryotic ceils are of following types:
1. Prokaryotic ceils: Pro means primitive (primary) and karyon means nucleus. These cells do not possess nuclear membrane. Only one chromosome is found in these ceils. The cell organelles are not enclosed by a membrane in these cells, like blue-green algae, bacterial cell.

2. Eukaryotic cells: Eu means continuous and karyon means nucleus. These cells have a well-defined nucleus which is enclosed by a nuclear membrane. More than one chromosomes are present in these cells, like plant and animal cells.

Question 23.
Define the following :
Protoplasm, cytoplasm, nucleoplasm.
Answer:
(i) Protoplasm : All the substances present inside the cell membrane constitute protoplasm. Protoplasm is the very basis of life. It performs all the activities of life.
It has two parts:
(a) Nucleus
(b) Cytoplasm.

(ii) Cytoplasm : Apart from the nucleus, the remaining part of the protoplasm is called cytoplasm. It contains living as well as non-living material. Many cell organelles are present in the cytoplasm i.e. Mitochondria, ribosomes, Golgibodies, lysosomes, vacuoler, endoplasmic reticulum etc.

(iii) Nucleoplasm : It is found inside the nucleus in which proteins, nucleolus, enzymes and chromosomes are present.

Question 24.
Write a note on Endoplasmic Reticulum (E.R.) Or White down the functions of Endoplasmic Reticulum (E.R.).
Answer:
Near the nucleus, a large network of membrane-bound tubes is found, which is called endoplasmic reticulum. These look like long tubules or round or oblong bags (vesicles). ER is of two types:
(i) Rough Endoplasmic Reticulum (RER),
(ii) Smooth Endoplasmic Reticulum (SER).
ER helps in intracellular transport of materials. It also acts as a cytoskeleton for some bio-chemical reactions. In the liver cells of vertebrates it plays a crucial role in detoxifying many poisons and drugs.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 25.
Differentiate RER and SER.
Answer:
Differences between RER and SER as below:
RER (Rough Endoplasmic Reticulum)
1. They are present on the surface of the ribosomes.
2. They, lie near the nucleus.
3. They help in photosynthesis.

SER (Smooth Endoplasmic Reticulum):
1. They don’t have any ribosomes.
2. They are present near the plasma membrane.
3. They help in lipid synthesis and in the formation of plasma membrane.

Question 26.
Write a note on Golgibodies.
Answer:
Golgibodies were first described by Camillo Golgi. The substance secreted by Golgibodies is accumulated in the vacuoles. Golgibodies form the cell wall. They are made up of vesicles, vacuoles and tubules. They are called golgi complex or golgi apparatus. It packages the materials produced by the ER and despatches it outside the cell.

Question 27.
Which cell organelle is called digestive bag and why ?
Answer:
Lysosome functions as a digestive bag in the cell.
Lysosomes occur in all the cells. These are spherical structures enclosed by a green coloured membrane. These contain many membrane bound small vesicles which are filled with catabolic substances lenzymes, also which are called as digestive bags which contain enzymes. These vesicles digest organic substances in the cell. These work as intercellular digestive system.

Lysosomes also function in digestion of food particles as well as worn-out cell organisms as a result of which old cells die. Therefore, they are also called ‘suicidal bags’ because during disturbances in cellular metabolism, when the cell gets damaged, lysosomes burst and the enzymes digest their own cell. RER make the digestive enzymes of the lysosomes.
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 5

Question 28.
Write a note on lysosomes.
Answer:
Lysosomes: Lysosomes are sac like structures which are also called as suicidal bags. They are found in all cells. In each cells, there are over one hundred lysosomes. They were discovered by D. Dueve, a scientist, in 1955. Their function is the elimination of some disturbances in the cell as well as destruction of foreign particles. Many digestive enzymes are found in them due to which they are also called digestive enzymes.

Question 29.
What is a centrosome ?
Answer:
Centrosome: Centrosome is a spherical structure found near the nucleus. It is found only in animal cells and is totally absent in plant cells. It contains one or two centrioles. In plant cells, polar caps are present instead of centrosomes. Centrosome play an important role in cell division.

Question 30.
Write a note on ribosomes.
Answer:
They are made up of RNA and proteins. These extremely small bodies are either scattered freely in the cytoplasm or are attached on the outer surface membrane of the rough endoplasmic reticulum. In the cell, ribosomes systhesise proteins with the help of amino acids.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 31.
Write a note on mitochondria.
Answer:
Mitochondria is a spherical or rod-shaped important organelle of the cell bounded by two membranes. The outer membrane is smooth but the inner layer contains folds. These folds are called cristae. In between the two membranes, a fluid called matrix is present. Mitochondria produces respiratory enzymes. It also oxidises food to produce energy, so it is also called as energy house or power house of the cell.
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 6

Question 32.
Differentiate the structural organisation of lysosomes and mitochondria.
Answer:
Differences between the structural organisation of lysosomes and mitochondria are as follows :
Lysosomes:
1. These are sac like structures
2. These are enclosed by a single membrane.
3. They do not bear any folds on the inner surface.
4. They contain digestive enzymes, which digest the food material.
5. They do not contain DNA.

Mitochondria:
1. These are spherical or rod-shaped organelles.
2. These are enclosed by a double membrane.
3. They bear folds on the inner surface, which are called cristae.
4. They contain some specific enzymes, which help in respiration.
5. They contain DNA.

Question 33.
Give differences between the functions of lysosomes and mitochondria.
Answer:
Differences between the functions of lysosomes and mitochondria as follows :
Lysosomes
1. They produce energy by digesting stored food in the times of emergency.
2. They do not contain ATP.
3. The destroy viruses and bacteria.
4. They function to destroy old and damaged cell organelles.
5. Through destructive process, they destroy the unwanted materials and are also called as suicidal bags.

Mitochondria
1. They produce energy through respiration.
2. They store energy in ATP and release it according to the requirement.
3. They do not do so.
4. They are not capable to perform such functions.
5. They do not perform any protective functions.

Question 34.
Write any five differences between ribosomes and centrosomes.
Answer:
Differences between ribosomes and centrosomes are as follows:
Ribosomes:
1. These are granular and spherical structure.
2. These are found both in plant and animal cells.
3. They synthesise proteins from the amino acids.
4. They do not take part in cell division.
5. They are found either scattered freely in the cytoplasm or attached to the Rough Endoplasmic Reticulum.

Centrosomes:
1. These are small star-like structure present outside the nuclear Wall.
2. These are found only in the animal cells.
3. They do not take part in protein synthesise.
4. They form Aster Rays at the time of cell division.
5. They occur in pairs near the nucleus.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 35.
Write a brief note on chloroplasts.
Answer:
Chloroplast is found in all green-coloured plants. It a double membrane cell organelle on the inner membrane of which are found flat structures, thylakoids, the number of which is innumerable in a chloroplast. Thylakoids are held together in a granum. Chloroplast plays an important role in photosynthesis. Green coloured pigment called chlorophyll found in chloroplast. Its ground matter is called stroma.
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 7

Question 36.
Write a note on plastids.
Answer:
Plastids are present only in plant cells. They are of two types:
(1) Chromoplast (coloured plastid).
(2) Leucoplast (white and colourless plastid).
The plastid having green pigment is called chloroplast. It is essential for photosynthesis. Yellow and purple coloured pigments are also found in chloroplasts. Plastids also contain their own DNA and ribosomes.

Question 37.
Why does papaya look yellow, spinach look green and watermelon look red from inside ?
Answer:
Different pigments present in plants impart different colours in them. The pigment named carotene gives yellow colour to papaya, green pigment chlorophyll in spinach gives it green colour; xanthomycin pigment gives red colour to the inside of the watermelon. So, different colours found in plants are due to different pigments.

Question 38.
Write a note on vacuoles.
Answer:
Vacuoles are the storage sacs for solid or liquid materials. Vacuoles are small in size in animal cells whereas plant cells have larger vacuoles. In plant cell, vacuoles provide turgidity and rigidity to the cells. They play an important role in the disposal of waste products from the body.

Essay Type Questions

Question 1.
Explain the microscopic structure of an animal cell.
Answer:
Microscopic structure of an animal cell: The basic unit of life in living organism is called a cell. It is a small sized structure filled with protoplasm. The body of every animals is formed by grouping together of many cells. The shape ofthe cell varies and their number also varies (from organism to organism). Cell has two main parts:
(a) Cell membrane,
(b) Protoplasm.

(a) Cell membrane:
A cell is enclosed by a thin membrane which is made up of plasma. It is very thin, soft and smooth. Cell membrane is semi-permeable. It gives shape to the cell and protects the protoplasm in it. It controls the movement of material inside and outside the cell.

(b) Protoplasm:
All the material present inside the cell membrane constitutes protoplasm. In fact, protoplasm is the basis of life. All life activities are completed in the protoplasm. Protoplasm has two main parts:
(1) Nucleus,
(2) Cytoplasm.
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 8

1. Nucleus:
Every cell has a spherical structure in its centre known as nucleus. Nucleus controls all the activities of the cell. Nucleus has four main parts nuclear membrane, nucleoplasm, chromatin reticulum, nucleolus. Nucleus is enclosed by a double membrane which is attached to endoplasmic reticulum. Nucleus contains DNA, RNA and substance chromatin which is made up of proteins. Chromosomes are found on the thread-like structures which constitute chromatin. Chromosomes are composed of DNA and protein. Chromosomes carry the hereditary traits from parents to offspring through genes. In the centre of the nucleus is present a dense, dark straining organelle called nucleolus. It stores RNA in it and helps in cell division.

2. Cytoplasm: Protoplasmic material of the cell other than nucleus is called cytoplasm. It contains living as well as non-living particles.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Following cell organelles are present in the cytoplasm:

(i) Mitochondria: These are double membraned spherical or rod-shaped structures. Mitochondria contains DNA, RNA and respirator)’ enzymes. These are helpful in respiration. Mitochondria are also called energy houses or powerhouses of the cell.

(ii) Ribosomes: These are spherical structures composed of RNA and protein. They are found scattered freely throughout the cell cytoplasm in prokaryots. However, in eukaryotic cells they are found either in free state in the cytoplasm or attached on the outer surface membrane of RER.

(iii) Endoplasmic Reticulum:
It is a large network of membrane-bound tubules. ER communicates both with plasma-membrane as well as nuclear membrane. Ribosomes are found on its outer surface membrane (in case of RER). It is a network formed of proteins and lipids. It helps in the transport of materials within the cell. It establishes contact between cytoplasm and nucleus.

(iv) Golgibodies:
These are membrane-bound structures found near the nucleus. Its function is not so clear or distint, but it helps in the formation of cell wall and despatches the material synthesised in ER outside the cell.

(v) Centrosome:
It is a small spherical structure found near the nucleus. It contains one or two granules, the centrioles. It helps in cell division.

(vi) Lysosomes:
These are spherical or oval structures present inside the cell. They contain digestive enzymes. Lysosomes help in digestive activity and destruction of damaged cell organelles.

(vii) Vacuoles:
These are a few spherical or egg shaped regions in the cell where there is very little cytoplasm. These are called vacuoles. Vacuoles help in the disposal of poisonous material from the cell as well as in the storage of food particles. In some unicellular organisms, specialised vacuoles also help in expelling excess water outside the cell.

(viii) Cilia and Flagella:
These are some thin, hair-like structures which help in movement of the organism in a fluid medium. Cilia are more in number but smaller in size whereas flagella are one or two in number. Their length is comparatively more.

Question 2.
What is a nucleus ? Write its functions.
Answer:
Every cell has a nucleus present in the centre. It is spherical or oval-shaped. The cell which have more than one nucleus is called coenocyte.

Following are the main parts of a nucleus :
1. Nuclear membrane: It is a thin and elastic membrane which keeps the nucleus separate from the cytoplasm.
2. Nucleoplasm: The fluid present inside the nucleus is called nucleoplasm.
3. Nucleolus: It is present inside the nucleus and controls the synthesis of protein.
4. Chromosomes: Every nucleus contains thin and long structures called chromosomes. Chromosomes are composed of a substance called nucleoprotein. This substance is formed by the joining of nucleic acids and proteins. The number of chromosomes for one type‘of organisms is fixed.

Functions of Nucleus: Following are the functions of a nucleus:
(i) The main function of the nucleus is to control and coordinate the activities of the cell.
(ii) A cell cannot remain alive without a nucleus.
(iii) It controls the hereditary characters with the help of genes.

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

Question 3.
What are the main functions of:
(a) Plasma membrane
(b) Mitochondria
(c) Chromosomes
(d) Nucleolus
(e) Lysosomes
(f) Cell wall
(g) Ribosome
(h) Golgi apparatus
(j) Peroxisomes ?
Answer:
The main functions of each cell constituent are as follows :
(a) Plasma membrane: Being semi-permeable, it controls the movement of materials inside and outside the cell.
(b) Mitochondria: It is the powerhouse of the cell. It oxidises carbohydrates to produce energy.
(c) Chromosomes: They are the carriers of hereditary traits and DNA is present in them.
(d) Nucleolus: It synthesises ribosomes.
(e) Lysosomes: It functions as a digestive sac,/bag because it plays the role of intercellular digestion.
(f) Cell wall: It protects the internal contents of the cell.
(g) Ribosomes: These help in protein synthesis.
(h) Chloroplast: Its green pigment produces food during photosynthesis.
(i) Golgi apparatus: It forms lysosomes and peroxisomes.
(j) Peroxisomes: They are helpful in the oxidation reactions.

Practical Work

Experiment 1:
To observe osmosis with dried raisin.

Procedure:
(1) Take 3-4 dried raisins and put them in water. After 30 minutes observe them. Raisins swell because water enters them by osmosis.
(2) Place the swollen raisins in concentrated sugar solution and observe after half an hour. Raisins shrink because water in them moves to the solution because of osmosis.
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 9

Experiment 2:
To prepare a temporary slide of onion peel.

Procedure:
(1) Take onion peel from its concave side and place it in the watch glass containing water.
(2) Put a drop of water on a glass slide and with the help of a brush transfer the onion peel from the watch glass to the slide (on the drop of water) and put a drop of iodine and place a cover slip on it. Take care that there is no air bubble beneath the coverslip.
(3) Observe this under a compound microscope and make a diagram of the cells as per your observation.
HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life - 10

Quick Review of the Chapter

1. Who coined the term ‘cell’?
(A) Robert Brown
(B) Robert Hooke
(C) M. Schielden
(D) Virchow
Answer:
(B) Robert Hooke

2. Which substance ¡s used by Robert Hooke in discovery of cell?
(A) membrane of an onion
(B) cork
(C) a leaf
(D) Toot of a plant
Answer:
(B) cork

3. Which scientist discovered living cells first of all?
(A) Robert Hooke
(B) Leeuwenhoek
(C) Virchow
(D) Robert Brown
Answer:
(B) Leeuwenhoek

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

4. Who discovered the nucleus of a cell?
(A) Purkinje
(B) Virchow
(C) Robert Brown
(D) Robert Hooke
Answer:
(C) Robert Brown

5. Who gave the name protoplasm to the living material inside the cell?
(A) Purkinje
(B) Robert Brown
(C) M. Schleiden
(D) Virchow
Answer:
(A) Purkinje

6. Who proposed ‘Cell Theory’?
(A) M. Schleiden
(B) T. Schwann
(C) Virchow
(D) both (A) and (B)
Answer:
(D) both (A) and (B)

7. …………… is not a unicellular organism.
(A) Amoeba
(B) Euglena
(C) Ferns
(D) Paramoecium
Answer:
(C) Ferns

8. When was electron microscope discovered?
(A) in 1936
(B) in 1940
(C) in 1942
(D) in 1944
Ans.
(B) in 1940

9. Which organelle is not found in all organisms?
(A) plasma membrane
(B) cell wall
(C) nucleus
(D) cytoplasm
Answer:
(B) cell wall

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

10. Which organelle allows in and out of materials and stops them?
(A) plasma membrane
(B) cytoplasm
(C) nuclei’s
(D) centrosome
Answer:
(A) plasma membrane

11. The process of osmosis is related to:
(A) plasma membrane
(B) cell wall
(C) selective permeable membrane
(D) nucleus membrane
Answer:
(C) selective permeable membrane

12. The use of osmosis process ¡s carried out in the plants as:
(A) absorption of water by roots
(B) exchange of gases in leaves
(C) intake of nutrition from outside environment
(D) all of the above
Answer:
(D) all of the above

13. Which is not a feature of plasma membrane?
(A) flexible
(B) formed of lipid, protein
(C) study possible under simple microscope
(D) absence of selective permeable feature
Answer:
(D) absence of selective permeable feature

14. Plant cell wall is composed of which substance?
(A) minerals
(B) fats
(C) cellulose
(D) glucose
Answer:
(C) cellulose

15. The longest cell of human body is:
(A) RBC
(B) WBC
(C) neuron cell
(D) skin cell
Answer:
(C) neuron cell

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

16. Which is non-living?
(A) plasma membrane
(B) cell wall
(C) golgibodies
(D) ribosome
Answer:
(B) cell wall

17. Which waste require to be excreted out by the cell?
(A) CO2
(B) O
(C) water
(D) all of the above
Answer:
(A) CO2

18. controls all functions of a cell.
(A) centrosome
(B) golgi apparatus
(C) nucleus
(D) chromosome
Answer:
(C) nucleus

19. Where are chromosomes found?
(A) in nucleus
(B) in nucleolus
(C) in protoplasm
(D) in cytoplasm
Answer:
(A) in nucleus

20. Hereditary characters are found in
(A) nucleus
(B) chromosome
(C) nucleolus
(D) mitochondria
Answer:
(B) chromosome

21. Which substance forms chromosome?
(A) DNA
(B) Protein
(C) fat
(D) both (A) and (B)
Answer:
(D) both (A) and (B)

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

22. The functional unit of a chromosome is called
(A) chioroplast
(B) chromosome
(C) gene
(D) lamella
Answer:
(C) gene

23. The feature of prokaryotic is not:
(A) small size
(B) nucleus present
(C) only one chromosome
(D) nucleus is not surrounded by nucleus membrane
Answer:
(B) nucleus present

24. The feature of eukaryotic ¡s not:
(A) small size
(B) nucleus region fully developed
(C) nucleus is found
(D) more than one chromosome
Answer:
(A) smaLl size

25. Ribosomes synthesise ………..
(A) fats
(B) proteins
(C) carbohydrates
(D) all three
Answer:
(B) proteins

26. What is formed by endoplasmic reticulum (ER)?
(A) respiratory system
(B) food synthesis system
(C) reticulum system
(D) all three
Answer:
(C) reticulum system

27. Which organelle detoxifies toxic substances and drugs in the liver cells?
(A) ER
(B) goigi apparatus
(C) lysosome
(D) vacuoles
Answer:
(A) ER

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

28. Which scientist told about Golgi apparatus first of all?
(A) Virchow
(B) Purkinje
(C) Camino
(D) T. Schwann
Answer:
(C) Camillo

29. Lysosome is formed by
(A) ER
(B) golgi apparatus
(C) vacuole
(D) mitochondria
Answer:
(B) Golgi apparatus

30. Which is not an organ of an animal cell? ‘
(A) plasma membrane
(B) cytoplasm
(C) vacuole
(D) cell wall
Answer:
(D) cell wall

31. How many m are there in ijtm?
(A) 106
(B)
(C) l0
(D) 106
Answer:
(A) l06

32. What is the name of system of disposal of waste of a cell?
(A) golgi apparatus
(B) vacuoles
(C) lysosome
(D) centrioles
Answer:
(C) lysosome

33. ………. is called a suicidal bag.
(A) golgi apparatus
(B) lysosome
(C) ER
(D) plastid
Answer:
(B) lysosome

HBSE 9th Class Science Important Questions Chapter 5 The Fundamental Unit of Life

34. ………….. is called powerhouse of a cell.
(A) centriole
(B) Golgi bodies
(C) mitochondria
(D) plastid
Answer:
(C) mitochondria

35. plays an important role in photosynthesis.
(A) m mitochondria
(B) ch chloroplast
(C) vacuole
(D) Golgi bodies
Answer:
(B) chloroplast

36. pigments are found in the chloroplast.
(A) green
(B) yellow
(C) pink
(D) all above mentioned
Answer:
(A) green

37. are storage sacs of solid or liquid substances.
(A) lysosome
(B) golgi apparatus
(C) vacuoles
(D) ER
Answer:
(C) vacuoles

38. In which ‚ear cell was discovered?
(A) 1565
(8) 1605
(C) 1600
(D) 1665
Answer:
(D) 1665

39. The fundamental organizational unit of life is:
(A) Chromoplasts
(B) Cell
(C) Leucoplasts
(D) Plasma
Answer:
(B) Cell

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