Questions on Chapter = 5 ( THE FUNDAMENTAL UNIT OF LIFE)

These are Online Practice Questions on Chapter =  5 ( THE FUNDAMENTAL UNIT OF LIFE) 

VERY SHORT ANSWER TYPE QUESTIONS (1 Mark):

1. Name the largest cell of living world ?

2. Amoeba is a.............organism.

3. Who gave the fluid mosaic model of plasma membrane ?

4. Movement of solvent into the cell is called as................. .

5. Which cell organelle is called as the ‘Head quarter of cell’ ?

6. Which cell organelle is called as ‘Power house of cell’ ?

7. Which cell organelle contains enzymes for ATP production ?

8. In mitochondria, which portion contains specific proteins ?

9. Which cell organelle is called as ‘Digestive bag’ ?

10. Which organelle controls osomostic pressure in a cell ?

11. Plastids having coloured pigments are called as............... .

SHORT ANSWER TYPE QUESTIONS (2 Marks):

1. What is the composition of protoplasm ?

2. Define cell ?

3. What is the difference between diffusion and osmosis ?

4. Why plasma membrane is called as selectively permeable                 membrane ?

5. Define Cristae ?

6. State any two function of Golgi body ?

7. Name various type of plastids present in a plant cell ?

8. State the main function of lisosome ?

LONG ANSWER TYPE QUESTIONS (5 Marks):

1. Who gave the cell theory ? What does it state ? Which organism      is an exception of cell theory ?

2. Draw a neat and labelled diagram of nucleus. State its main              function.

3. Describe the types of endoplasmic reticulum and draw necessary      figure ? Give its main functions also?

4. Draw a neat and labelled diagram of mitochondria.

5. Differentiate between plant and animal cell with suitable figures.

Online Notes on Chapter = 5 ( THE FUNDAMENTAL UNIT OF LIFE) Part 4

This is Online Notes on Chapter =  5 ( THE FUNDAMENTAL UNIT OF LIFE)  Part 4 for preparation of CBSE BOARD Examination, NTSE etc.

Mitochondria:

It is a rod shaped structure found in cytoplasm of all eukaryotic cells except mammalian RBC’s.

• These are also absent in prokaryotes.

• It was first seen by Kolliker in insect cells.

• Maximum mitochondria are found in metabolically active cells.

• It is also called as ‘Power House of the Cell’ or the ‘Storage Battery’.

• It is double membranous structure where outer membrane has specific proteins while inner membrane is folded inside to form chambers called "Cristae".

Functions of Mitochondria :

(a) Its main function is to produce and store the energy in the form of ATP.

(b) It is the site of Kreb cycle of respiration

Ribosomes:

Ribosomes are the sites of protein synthesis.

All structural and functional proteins (enzymes) coded by the nuclear DNA are synthesized upon cytoplasmic ribosomes. The DNA codes are transcripted into messenger RNA (mRNA) molecules in the chromosomes of the nucleus.

Functions of Ribosomes :

(a) Ribosomes are the main site of protein synthesis. Synthesized

proteins is transported by endoplasmic reticulum.

Plastid:

• It is double membranous discoidal structure, found only in plant cells.

• Besides being discoidal of rhombic in plant cells, they occur in variable shapes like in algae. They can be ‘U’-shaped, spiral, coiled, ribbonshaped etc.

Depending upon the type of pigment present in them, they are of following three types :

(i) Leucoplast – White, found in underground parts

(ii) Chloroplast – Red, brown

(iii) Chloroplast – Green in colour, found in aerial parts of plants

These are found only in plant cell. It helps in the process of photosynthesis so it is called the ‘Kitchen of Plants’.

Chloroplast have following two parts :

(i) Grana : It constitutes the lamellar system. These are found layered on top of each other. These stacks are called Grana. Each granum of the chloroplast is formed by superimposed closed compartments called Thylakoids.

Function : They are the sites of light reaction of photosynthesis as they contain photosynthetic pigment chlorophyll. In each thylakoid,

Quantasomes are present which are called as Photosynthetic units.

(ii) Stroma : It is a granular transparent substance also called as

matrix. Grana are embedded in it. Besides Grana they also contain lipid droplets, starch grains, ribosomes etc.

Function : This is the site of dark reaction of photosynthesis. Also helps in protein synthesis due to presence of ribosomes.

Vacuoles:

• These are membrane bounded regions in the cytoplasm containing water and other substances.

• They are bounded by a single membrane called Tonoplast.

• In animal cells vacuoles are smaller in size and numerous while in plant cells a single large vacuole is found which occupies about 90% of the volume of cell.

Functions :

It helps in maintaining osmotic pressure in a cell & stores toxic metabolic products of plant cell.

Lysosome:

• They are tiny sac-like granules containing enzymes of intracellular digestion.

• They are bounded by a single membrane.

• They occur in animal cells and a few plant cells.

• They do not have a definite shape or size.

Functions :

(a) Their main function is phagy = digestion.

(b) They are kind of waste disposal system.

(c) They help in digesting foreign materials & cells.

Suicidal Bag : During disturbances in cellular metabolism i.e., in case of cell damage, lysosomes burst and their enzymes are released into the cytoplasm and they digest their own cell. So they are also called ‘Suicidal Bag’.

Online Notes on Chapter = 5 ( THE FUNDAMENTAL UNIT OF LIFE) Part 3

This is Online Notes on Chapter =  5 ( THE FUNDAMENTAL UNIT OF LIFE)  Part 3 for preparation of CBSE BOARD Examination, NTSE etc.

Cell Wall:

• It is the outermost covering of the plant cells.

• It is absent in animal cells.

• Cell wall is rigid, strong, thick, porous and non-living structure. It is made up of cellulose and hemicelluloses. Cell walls of two adjacent cells are joined by a layer called middle lamellae.

Functions of Cell Wall :

(a) It provides definite shape to the cell.

(b) It provides strength to the cell.

(c) It is permeable and allows entry of molecules of different sizes.

(d) It has the characteristics of repair and regeneration.

Nucleus:

•Nucleus is the most important cell organelle which directs and controls all its cellular activities.

• It is called as ‘Headquarter of the cell’.

• It was discovered by Robert Brown in 1831.

• In Eukaryotes, a well-defined nucleus is present while in Prokaryotes, a well-defined nucleus is absent.

• Prokaryotes contain a primitive nucleus.

• It has double layered covering called as nuclear membrane.

• Nuclear membrane has pores which regulate the movement of materials in & out of the cell.

• Besides nuclear membrane, nucleus also contains nucleolus and

chromatin material and the substance filled inside the nucleus is nucleolus.

• Chromosomes or chromatin material consists of DNA which stores and transmits hereditary information for the cell to function, grow and reproduce.

Functions of Nucleus :

(a) It controls all the metabolic activities of the cell and regulates the cell cycle.

(b) It helps in transmission of hereditary characters from parents to

off springs.

Cytoplasm:

• Cytoplasm was discovered by Kolliker in 1862.

• It is the site of both biosynthetic and catabolic pathways.

• It can be divided into two parts :

(i) Cytosol : Aqueous soluble part contains various fibrous proteins

forming cytoskeleton.

(ii) Cell organelles : Living part of the cells having definite shape,

structure and function bounded by plasma membrane.

Endoplasmic Reticulum:

• It is the network of membranes present in the cytoplasm.

• It was discovered by Porter, Claude and Fullam.

• These are present in all cells except prokaryotes and mammalian

erythrocytes.

Functions of ER :

(a) It is the only organelle which can move within a cell so it serves

as a channel for the transport of materials between various regions of cytoplasm and between cytoplasm and nucleus.

(b) It also functions as a cytoplasmic framework to provide space for some of the biochemical activities. It forms endoskeleton of cell.

(c) It helps in synthesis of fats, steroids, cholesterol etc.

(d) SER plays a crucial role in detoxification of drugs and poisonous by-products.

Golgi Apparatus:

Golgi apparatus consists of a system of membrane bounded vesicles arranged parallel to each other in stacks called Cisternae along with some large and spherical vacuoles. It was discovered by Camilo Golgi. In plants Golgi membrane is bounded. It is single membrane bounded. It is absent in prokaryotes, mammalian

RBC’s & sieve cells.

Functions of Golgi apparatus :

(a) It helps in formation of lipids.

(b) It helps in formation of middle lamellae.

(c) It is secretary in nature.

(d) It helps in melanin synthesis.

(e) Lipids and proteins synthesized in endoplasmic reticulum are

packed at Golgi complex. They provide the site for assembly of

new membrane material.

Online Notes on Chapter = 5 ( THE FUNDAMENTAL UNIT OF LIFE) Part 2

This is Online Notes on Chapter =  5 ( THE FUNDAMENTAL UNIT OF LIFE)  Part 2 for

preparation of CBSE BOARD Examination, NTSE etc.

Cell Shape : 

Cells are of variable shapes and sizes. Their shape is according to the function. Generally cells are spherical but they may be elongated (nerve  cell), branched (pigmented), discoidal (RBC), spindle-shaped (muscle cell) etc. 

Different kinds of cell found in the human body.

Cell Size : 

Size of cell is variable depending upon the type of organism.

Some are microscopic while some are visible with naked eyes. 

Their size may vary from 0.2 mm to 18 cm.

• Size of a typical cell in a multicellular organism ranges from 20-30 mm.

• The largest cell is ostrich egg (15 cm in diameter with shell & 8 cm in diameter without cell).

• The longest cell is nerve cell (upto 1 m or more).

• Smallest cells so far known are PPLOs e.g., mycoplasma (0.1 mm in diameter).

• Human egg is 0.1 mm in diameter.
Components of Cell

There is an occurrence of division of labour within a cell as they all got certain specific components called ‘Cell organelles’.

Each of them perform a specific function.

The three basic components of all the cells are :

(i) Plasma membrane
(ii) Nucleus

(iii) Cytoplasm

Cell Membrane :

(a) Cell membrane is also called as plasma membrane or plasma
lemma.

(b) It is the limiting boundary of each cell which separates the
cytoplasm from its surroundings.

(c) It is found in both plant as well as animal cells.

(d) It is the outermost covering of a cell in case of animals and lies
below the cell wall in case of plants.


(e) It is made up of proteins and lipids where proteins are sandwiched between bilayer of lipids.

(f) Plasma membrane is selectively permeable in nature. It allows or permits the entry and exit of some materials in and out of the cell.

(g) Singer and Nicholson gave the fluid mosaic model of plasma
membrane. According to them, it consists of a protein layer
sandwiched between two layers of lipids. It is in quasifluid state.
It is 75A thick.


(h) It is flexible and can be folded, broken and reunited.

Functions of Plasma Membrane :

(a) It regulates the movement of molecules inside and outside the

cell.
(b) It helps in maintaining the distinct composition of the cell.

(ii) Transportation of molecules across the Plasma Membrane :

This can be done by following ways :

• Diffusion : Movement of solutes or ions from higher concentration to lower concentration is called as diffusion. It does not require energy therefore, it is called as passive transport.

• Osmosis : The movement of solvent or water from higher concentration (solvent) to lower concentration (solvent) through a semipermeable membrane is called as "osmosis" Or the movement of solvent or water from lower concentration to higher concentration of solution through a semipermeable membrane is called as osmosis.

• Osmosis can also be called as ‘Diffusion of solvents’.

• Endomosis : Movement of solvent into the cell is called as Endomosis.

• Exosmosis : Movement of solvent outside the cell is called as Exomosis.

Types of Solutions on the Basis of Concentration:

(a) Isotonic Solution : When the concentration of the solution
outside the cell is equal to the concentration of cytoplasm of the
cell, it is called as isotonic solution.

(b) Hypertonic Solution : When the concentration of the solution
outside the cell is more than the inside the cell. Due to this, cell
looses water and becomes plasmolysed.

(c) Hypotonic Solution : When the concentration of the solution
outside the cell is lesser than that of cytoplasm of cell. Due to

this, cell swells up and bursts

Online Notes on Chapter = 5 ( THE FUNDAMENTAL UNIT OF LIFE) Part 1

This is Online Notes on Chapter =  5 ( THE FUNDAMENTAL UNIT OF LIFE)  Part 1 for

preparation of CBSE BOARD Examination, NTSE etc.

Study Key Points :

Discovery of Cell, Types of Cell & Organism, Unicellular & Multicellular,Prokaryotic & Eukaryotic, Plant Cell & Animal Cell, Cell Shape, Cell Size, Cell Membrane, Cell wall, Diffusion & Osmosis, Nucleus, Cytoplasm, Endoplasmic Reticulum, Golgi Apparatus, Mitochondria, Ribosomes, Plastid, Vacuoles, Lysosomes.

All living forms are composed of microscopic units called as ‘Cells’.

• A cell is the basic structural and functional unit of all life forms.

• Study of structure and composition of cell is called as ‘Cytology’.

• Cell was first observed by Robert Hooke in a dead cork slice in the year 1665.

• First living cell was discovered by A. V. Leeuwenhoek.

• Its consistency differs under different condition. It exists in sol gel states.

• Protoplasm is an aggregate of various chemicals such as water, ions, salts and other organic molecules like proteins, carbohydrates, fats, nucleic acids, vitamins etc.

Cell Theory :

Two biologists, Schleiden and Schwann gave the Cell theory which 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.

Types of Cell & Organism :

On the Basis of Type of Organization:

Online Practice Q_ANS on CHAPTER => 6 (life processes )

This is Online Practice Q_ANS on CHAPTER => 6 (life processes ) for
preparation of CBSE BOARD Examination, NTSE etc.

VERY SHORT QUESTIONS (1 Mark)

1. State one difference between autotrophic and hetrotrophic mode of nutrition.
2. Define peristaltic movement.
3. What is the role of saliva in the digestion of food ?

4. Name the tissue that transports water and minerals in plants.
5. What is the role of acid in our stomach ?
6. What is emulsification ?

7. Name the cell organelle in which photosynthesis occur.
8. Name the largest artery in the human body.

9. Define transpiration.
10. What is the structural and functional unit of kidney called ?

SHORT ANSWER TYPE QUESTIONS (2 Marks)

1. How is small intestine designed to absorb digested food ?
2. What are stomata ? Draw a labeled diagram of stomata.
3. Write the equation for the process of breakdown of glucose in a cell :
(a) in the presence of oxygen.
(b) in the absence of oxygen.

4. Write the differences between inhalation and exhalation.
5. List the three events which occur during photosynthesis.
6. How does transpiration help in upward transport of substances.

7. Write the functions of the components of blood.
8. Why is small intestine longer in herbivores than in carnivores ?
9. Explain the cause of cramps after excessive physical exercise.

10. Why is the rate of breathing in aquatic organisms much faster than that seen in terrestrial organisms.

SHORT ANSWER TYPE QUESTIONS (3 Marks)

1. Describe the process of double circulation in human beings.
2. What are the methods used by plants to get rid of their waste products ?

3. Give reason for the following :
(a) Arteries are thick walled blood vessels.
(b) Veins are thin walled blood vessels.
(c) Veins have valves in them.

LONG ANSWER TYPE QUESTIONS (5 Marks)

1. If you chew chapatti for long, after some time it taste sweet ? Why is this so ?
2. What is the benefit of residual volume of air in the respiratory process ?
3. Why is the energy needs in plants is very less as compared to animals ? Explain.

4. Draw a well-labelled diagram of Nephron. Explain the process of formation of urine in the human kidney.
5. Draw a diagram showing Human Respiratory System. Label the following parts :
(a) Alveolus (b) Trachea
(c) Bronchus (d) Lungs

Hints to Long Answer Type Questions

1. Chapati will taste sweet as saliva breaks down starch which is a complex molecule to give sugar.
2. The lungs always contain a residual volume of air so that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
3. Plant gets most of energy during photosynthesis.

4. See the given diagram.
5. See the given diagram.