Question 1

Question 1:
Distinguish between prokaryotic and enkaryotic The Fundamental Unit of Lifes.

Accepted Answer

Answer:

Prokaryotic The Fundamental Unit of Life
Eukaryotic The Fundamental Unit of Life

Size of the The Fundamental Unit of Life is comparatively small (1–10 nm).
Size of the The Fundamental Unit of Life is larger (5–100 nm).

Nucleus is absent.
Nucleus is present.

The Fundamental Unit of Life division occurs by fission or budding (no mitosis).
The Fundamental Unit of Life division occurs by mitotic or meiotic The Fundamental Unit of Life division.

Membrane-bound The Fundamental Unit of Life organelles are absent.
Membrane-bound The Fundamental Unit of Life organelles are present.

Question 2

Question 2:
Write down differences between organ and organelle.

Accepted Answer

Answer:

Organs
Organelles

They are found in multiThe Fundamental Unit of Lifeular organisms.
They are found in uniThe Fundamental Unit of Lifeular and multiThe Fundamental Unit of Lifeular organisms.

They are formed by tissues.
They are formed by micromolecules and macromolecules.

They are macroscopic.
They are microscopic.

Different organs constitute organ systems.
Different organelles constitute The Fundamental Unit of Lifes.

Question 3

Question 3:
Write down differences between nucleus and nucleoid.

Accepted Answer

Answer:

Nucleus
Nucleoid

It is larger than nucleoid.
It is comparatively smaller than nucleus.

It has a covering of double membrane.
Covering membrane is absent.

Nucleolus is present.
Nucleolus is absent.

Its DNA is wrapped with histone proteins to form chromatin.
Histone proteins are absent and DNA of a nucleoid is often naked.

Question 4

Question 4:
Mention differences between light microscope and electron microscope.

Accepted Answer

Answer:

Light Microscope
Electron Microscope

Glass lenses are used.
Electromagnets are used.

It uses a beam of light to illuminate the object.
It uses a beam of electrons to illuminate the object.

Internal vacuum is not essential.
Internal vacuum is essential.

Question 5

Question 5:
Give a brief account of discovery of the The Fundamental Unit of Life.

Accepted Answer

Answer:
Discovery of The Fundamental Unit of Life:
The Fundamental Unit of Life was first discovered and named in 1665 by an English scientist Robert Hooke. He was examining a thin slice of cork and observed that the cork resembled the structure of honeycomb consisting of many little compartments. He called these compartments as The Fundamental Unit of Lifes (meaning 'little room' in Latin).
In 1838, Jakob Matthias Schleiden first proposed the idea that all plants consist of The Fundamental Unit of Lifes.
In 1839, Theodor Schwaan proposed that all animals and plants are made up of The Fundamental Unit of Lifes.

Question 6

Question 6:
Describe the proteins of plasma membrane.

Accepted Answer

Answer:
Plasma membrane consists of two types of proteins that floats in the fluid phospholipid layer:
(i) Intrinsic proteins: They completely cover the lipid bilayer.
(ii) Extrinsic proteins: They occur either on the outer surface or on the inner surface of the lipid membrane.

Question 7

Question 7:
Enumerate functions of plasma membrane.

Accepted Answer

Answer:
Plasma membrane serves as a barrier for the entry and exit of materials in the The Fundamental Unit of Lifes. It allows only certain selective materials to pass through it. Apart from this, it also performs certain physical and biological activities. These are as follows:
(i) Diffusion.
(ii) Osmosis.
(iii) Active transport.
(iv) Endocytosis.

Question 8

Question 8:
Give an example of diffusion across plasma membrane.

Accepted Answer

Answer:
Diffusion is the process of movement of molecules from a region of high concentration to a region of lower concentration until an equilibrium is reached.
When concentration of gases such as CO2 gets high in the The Fundamental Unit of Life as compared to the external environment, then CO2 moves out of the The Fundamental Unit of Life by the process of diffusion via plasma membrane. Similarly, O2 enters the The Fundamental Unit of Life by the process of diffusion when its concentration is reduced in the The Fundamental Unit of Life.

Question 9

Question 10:
Write down the differences between diffusion and osmosis.

Accepted Answer

Answer:

Diffusion
Osmosis

It can occur in any medium.
It occurs only in liquid medium.

Diffusing molecules may be solid, liquid, or gas.
Movement of only solvent molecules occur.

It does not require a semi-permeable membrane.
It requires semi-permeable membrane.

It achieves an equilibrium in the free energy of diffusing molecules.
It never achieves an equilibrium in the free energy of solvent molecules.

Question 10

Question 11:
Write a note on endocytosis.

Accepted Answer

Answer:
Endocytosis:
The ingestion of materials by the The Fundamental Unit of Lifes through the plasma membrane is called endocytosis. It includes three processes—that is,
(a) phagocytosis (The Fundamental Unit of Life eating),
(b) photocytosis (The Fundamental Unit of Life drinking), and
(c) receptor-mediated endocytosis.
 All of these processes require energy, so these may be considered as different forms of active transport.

Question 11

Question 12:
What would happen when eukaryotic The Fundamental Unit of Lifes are placed in hypotonic, hypertonic and isotomic solutions?

Accepted Answer

Answer:
When we place an eukaryotic The Fundamental Unit of Life in hypotonic solution, it swells up and ultimately bursts because of the large quantity of water entering the The Fundamental Unit of Life.
When we place an eukaryotic The Fundamental Unit of Life in isotonic solution, there is no change in its size, as the water concentrations in the external and internal media are the same.
When we place an eukaryotic The Fundamental Unit of Life in hypertonic solution, it gets plasmolysed because of the excess loss of water.

Question 12

Question 13:
Name the following :
(a) Smallest The Fundamental Unit of Life organelle

(b) Largest The Fundamental Unit of Life organelle;
(c) ER studded with ribosomes

(d) Functional segments of the DNA molecule.

Accepted Answer

Answer:
(a) Ribosome is the smallest The Fundamental Unit of Life organelle.
(b) Nucleus is the largest The Fundamental Unit of Life organelle.
(c) ER studded with ribosomes is referred to as rough endoplasmic reticulum (RER).
(d) Genes are the functional segments of the DNA molecule.

Question 13

Question 14:
Distinguish between the following
(a) Chromoplast and chloroplast

(b) Ribosome and centrosome.

Accepted Answer

Answer:
(a)

Chloroplast
Chromoplast

It is a green plastid.
It is a non-green plastid.

It contains chlorophyll and carotenoids.
It lacks chlorophyll. Only carotenoids and phycobilins are present.

(b)

Ribosomes
Centrosomes

They are present in both animal and plant The Fundamental Unit of Lifes.
They are present only in animal The Fundamental Unit of Lifes.

They aid in the synthesis of proteins.
They do not have any function in protein synthesis. They aid in The Fundamental Unit of Life division.

Question 14

Question 15:
Write main differences between plant and animal The Fundamental Unit of Lifes.

Accepted Answer

Answer:

Plant The Fundamental Unit of Life
Animal The Fundamental Unit of Life

It is larger in size than animal The Fundamental Unit of Life.
It is comparatively smaller in size.

It contains a The Fundamental Unit of Life wall.
It lacks a The Fundamental Unit of Life wall.

Plastids are present in plant The Fundamental Unit of Life.
Plastids are absent in animal The Fundamental Unit of Life.

It lacks centrosome and centriole.
It contains centrosome and centriole.

Question 15

Question 16:
What will happen in a The Fundamental Unit of Life if its nucleus is removed? Give reasons in support of your answer.

Accepted Answer

Answer:
If the nucleus of a The Fundamental Unit of Life is removed, then the The Fundamental Unit of Life will die. This is because the nucleus of a The Fundamental Unit of Life controls all the metabolic activities in a The Fundamental Unit of Life, and if it is not present, then the metabolic functioning of the The Fundamental Unit of Life will stop and its protoplasm will dry up ultimately, causing The Fundamental Unit of Life death.

Question 16

Question 17:
Explain why do spinach look green, papaya yellow and edible part of water melon red?

Accepted Answer

Answer:
Spinach looks green due to the presence of a green pigment called chlorophyll in them. Similarly, papaya looks yellow and edible part of watermelon looks red due to the presence of coloured plastids called chromoplasts in these fruits. Chromoplasts lack chlorophyll but contains carotenoid pigments that give different colours to these fruits.

Question 17

Question 18:
Write down two main functions of
(a) Endoplasmic reticulum

(b) Lysosome.

Accepted Answer

Answer:
(a) Functions of endoplasmic reticulum are as follows:
(i) It forms a supporting skeletal framework of the The Fundamental Unit of Life.
(ii) It provides a pathway for the distribution of nuclear material from one The Fundamental Unit of Life to the other.

(b) Functions of lysosomes are as follows:
(i) They remove the worn out or poorly working The Fundamental Unit of Lifeular organelles by digesting them to make way for new The Fundamental Unit of Lifes.
(ii) They destroy foreign materials such as bacteria and viruses that enter the The Fundamental Unit of Life.

Question 18

Question 19:
Name the following
(a) The The Fundamental Unit of Life organelle which synthesizes protein.

(b) The type of plastid which stores food.

Accepted Answer

Answer:
(a) Ribosome is the The Fundamental Unit of Life organelle that synthesises protein.
(b) Leucoplast is the type of plastid that stores food.

Question 19

Question 20:
"Lysosomes are known as suicide bags". Why?

Accepted Answer

Answer:
'Lysosomes are known as suicide bags' because the enzymes of lysosomes eat up their own The Fundamental Unit of Lifes if the The Fundamental Unit of Lifes get damaged. This is referred to as autolysis or self-digestion in which the The Fundamental Unit of Life is destroyed by the action of its own enzymes.

Question 20

Question 21:
Define the following terms :
(a) The Fundamental Unit of Life inclusions

(b) Cytosol
(c) Protoplasm

(d) Nucleoplasm.

Accepted Answer

Answer:
(a) The Fundamental Unit of Life inclusions: They are considered to be the non-living components of the The Fundamental Unit of Life that do not possess metabolic activity and are not bounded by membranes.
(b) Cytosol: It refers to the soluble part of cytoplasm that contains protein fibres and is located between the The Fundamental Unit of Life organelles.
(c) Protoplasm: It is the living content of the The Fundamental Unit of Life that is surrounded by the plasma membrane.
(d) Nucleoplasm: It is the ground substance of the nucleus enclosed by a nuclear envelope.

Chapter 2 : The Fundamental Unit of Life