THE FUNDAMENTAL UNIT OF LIFE. (BIO).

How Robert Hooke discovered Cell?

He saw that the cork resembled the honeycomb structure consisting of many small compartments. Cork is the substance which comes from the bark of the tree.

what is cell?

Cell is the basic structural and functional unit of life.

When did Robert Hooke discovered the cell?

He discovered the cell in 1665

Who discovered free living cell and in which year?

Antoine Van Leeuwenhoek discovered free living cell in 1674.

Who coined the term ‘Protoplasm’?

Purkinje coined the term Protoplasm for the fluid content of the cell. In 1839

The cell Theory:-

Matthias Schleiden in 1838 all plants are made of cell

Theodre Schwann in 1839 all animals are made of cell

Rudolf virchow in 1855 all cells comes from pre existing cell.

Who extended the cell Theory?

Rudolf virchow extended the cell Theory in 1855 by proposing that all cells comes from pre existing cell.

What are the types of organisms?

Unicellular Organisms

Multicellular Organisms.

Unicellular Organisms -

These organisms are single celled and they perform all their functions.

Multicellular Organisms -

They are made of group of different cells and to perform specific different functions of the body

Types of cells-

2 type of cells

Prokaryotic and Eukaryotic cell.

Prokaryotic cell -

The cells of this organism lacks nuclear membrane. They lacks neucleolus. They are unicellular organism. membranes bound cell organelles are absent. Centriole are absent. Reproduction is asexually only. Cell division is through Binary fission only. They have only single chromosomes.

Eg. Bacteria, Blue green Algae etc.

Eukaryotic cell -

The cells of this organism has neuclear membrane. They have neucleolus. They have single or multi chromosomes. Membrane bound cell organelles are present like Mitochondria. Centriole are present only in Animal cell. They can reproduce by both sexually or asexually. Cell division is through Mitosis or meiosis only. They are multicellular Organisms.

Eg. animal cell ,plant cell, Fungi

Difference between Prokaryotic and Eukaryotic cell?

Prokaryotic cell-

1. The cells of this organism lacks nuclear membrane.

2. The cells lack neucleolus.ry

3. They have single chromosomes.

4. They can reproduce asexually

5. Membranes bound cell organelles are absent.

6. They are unicellular organism.

7. The cell division is only through Binary fission.

8. Centrioles are absent

9. Eg. Bacteria, Blue Green Algae.

Eukaryotic cell -

1. The cells of this organism has neuclear membrane.

2. They have neucleolus.

3. The are multicellular Organisms.

4. They can reproduce by both sexually or asexually.

5. They have single or multi chromosomes.

6. The membrane bound cell organelles are present like Mitochondria.

7. Centrioles are present only in Animal cell

8. The cell division is through Mitosis or meiosis.

9. Eg. animal cell, Plant cell, Fungi etc.

Animal cell -

1. The cell walls are absent.

2. The plastids are absent.

3. The Centriole are present

4. The centrosome are present.

5. The golgi bodies are present.

6. The vacuole are absent Even if they are present they are every small in size.

Plant Cell-

1. The cell walls are present.

2. The plastids are present.

3. The Centriole are absent.

4. The centrosome are absent.

5. The golgi bodies are also called dictyosome.

6. The vacuole is present and they are very large in size.

Write the difference between plant cell and Animal cell.

Hypertonic Solution-

Outside medium has low concentration of water than in the cell.

Isotonic Solution -

Outside medium has same concentration of water than in the cell.

Hypotonic Solution -

Outside medium has high concentration of water than in the cell.

Plasma Membrane -

It is the selectively Permeable Membrane. It is made up of lipids and proteins. It allows or permits the entry or exit of some materials in and out of the cell.

Diffusion -

The spontaneous movement of (solid, liquid and gas) from the region of higher concentration to the region of low concentration.

Osmosis-

The movement of solvent or water from hig concentration to low concentration through selectively semi permeable membrane.

Osmosis is divided into _________

2 types, Endomosis and exosmosis.

What is endocytosis?

Plasma membrane is flexible, and it's flexibility allows the cell to engulf it's food and other materials from external medium .

Usually Amoeba aquire it's food through this process.

Cell wall-

It is the rigid outer covering of the cell. It is only found in Plant cell. Cell wall is mainly composed of Cellulose. The cellulose is the complex substance which provides structural strength to the plants.

Plasmolysis-

It only occurs in plant cell, when the living plant cell loses water through osmosis there is shrikage or contraction of the living cell contents away from the cell wall.

Neucleus-

It is the controlling or regulating part of the cell. It is the brain of the cell. It contains Chromosomes. It also consist of 🧬 genetic material for the transfer of hereditary characteristics from the parents to their offsprings.

Briefly describe the structure and functions of the Nucleus.

It is the controlling centre of the cell. It has 2 neuclear membrane or double layered membrane. It encloses with neucleolus, neuclear pore and neucleoplasm.

How are Chromosomes and chromosomes are different from each other?

Inside the Neucleoplasm, the scattered thread like structure present is called chromatin network and when the cell is about to divide the chromatin network changes into rod shaped bodies they are called chromosomes.

Endoplasmic Reticulum-

Endoplasmic Reticulum is of 2 types :-

1. Rough Endoplasmic Reticulum (RER).

2. Smooth Endoplasmic Reticulum (SER).

Smooth Endoplasmic Reticulum

SER helps in the manufacturing of lipids or fat.

Rough Endoplasmic Reticulum

Rough Endoplasmic Reticulum looks rough under microscopic vision because it has ribosomes attached to its surface, and the ribosomes helps in the manufacturing of Protein.

Lysosome-

Lysosome is the waste disposal system of our cell. During any disturbance in cellular metabolism like when the cell get damaged or any other bacteria or foreign material enters the cell the lysosome may burst itself and digest or destroy the damaged cell or any other foreign material.

Mitochondria -

Mitochondria is also known as the powerhouse of the cell. Mitochondria has 2 membrane or double layered membrane. The outer membrane is highly porous and the inner membrane is deeply folded to form cristae.

Full form of ATP?

Adenoisne Triphosphate.

Why mitochondria is known as the powerhouse of the cell?

Mitochondria is known as the powerhouse of the cell because it contains enzymes necessary for the total oxidation of the food, and for the release of high amount of energy in the form of ATP (Adenoisne Triphosphate).

Why the outer membrane of mitochondria is porous?

The outer membrane of mitochondria is porous because the energy molecules ATP comes out through the outer porous membrane of the mitochondria into the cytoplasm and other cell organelles.

Why Mitochondria is called semi autonomous cell organelle?

Mitochondria is also called semi autonomous cell organelle because it have it's own DNA, ribosomes, enzymes and proteins.

The inner membrane of mitochondria is highly folded. Give Reasons.

The inner membrane of the mitochondria is highly folded because it increases the surface area for ATP generating chemical reactions.

What are Plastids?

Plastids are only found in plant cell. They are of three types:-

1. Chromoplasts ( they are coloured plastids)

2. Chloroplasts( they contains the pigment chlorophyll)

3. Leucoplasts(they are the colourless or white coloured plastids).

Functions:-

• Chromoplasts plastids are found in flowers and fruits.

• Chloroplasts plastids helps in the photosynthesis of the plant.

• Leucoplasts are the organelles in which minerals such as oil, starch and protein granules are stored.

Vacuole -

Vacuoles are the storage sac which contains liquid and solid contents. Vacuoles are absent in Animal cell and even if they are present they are very small in size but in plants they are very large in size.