Cell The unit of life

Basic unit of all living organisms

The cell

Unicellular organisms are capable of

1. Independent existence

2. Performing the essential functions of life

What is the fundamental structural and functional unit of all living organisms

CELL

Who first described live cell ?

Anton Von Leeuwenhook

Who discovered nucleus?

Robert Brown

Modified cell theory is given by

Rudolf virchow

What is cell theory ?

1. All living organisms are composed of cells and products of cells

2. All cells arise from pre existing cells

1. Membrane bound nucleus

2. Non membrane bound nucleus

1. Eukaryotic

2. Prokaryotic

What is cytoplasm & its function

Occupies the vloume of the cell & main arena of cellular activities

Membrane bound organelles are present in

Eukaryotic

ribosomes are

Non membrane bound organelles found in all cells

Ribosomes are found in ywo organelles

1. chloroplast (in plants)

2. Mitochondria & rough endoplasmic reticulum

Animal cells have another non membrane bound organelle

Centrosome which help in cell division

The smallest cells

Mycoplasma only ,0.3 in length

Bacteria size

3-5

The largest isolated single cell

Egg of an ostrich q

Diameter of red blood cells

7.0, in diameter

Shape of the cells

1. Red blood cells

2. White blood cells

3. Columnar epithelial cells

4. Nerve cell

5. A tracheids

6. Mesophyll cells

1. Biconcave & round

2. Amoeboid

3. Long & narrow

4. Branched & long

5. Elongated

6. Round & oval

Prokaryotic cells are represented by

Bacteria blue green algae mycoplasma and pplo

4 basic shapes of bacteria are

Bacillus ( rod like )

Coccus ( spherical )

Vibrio ( comma shape )

Spirillum ( spiral )

In addition to Genomic DNA , many bacteria have small circular DNA outside the genomic which is called as

Plasma DNA

Specialised differentiated form of cell membrane called mesosome is the characteristic of prokaryotes which are essentially

In foldings of cell membrane

The cell envelope consists of a tightly bound 3 laid structure

Outermost a glycocalix followed by the cell wall and plasma membrane

Although each layer of the envelope performs a distinct function they together act as a

Single protective unit

Glycocalix differs and composition and thickness among different bacteria

1. It could be a loose sheet called

2. It maybe thick and tough called

1. Slime layer

2. Capsule

Extensions of the mesosome are

1. Vesicles

2. Tubules

3. Lamellae

Extensions of mesosome helps in

1. Cell wall formation

2. DNA replication & distribution to daughter cells

3. Respiration secretion process to increase the surface area of the plasma membrane and enzymetic content

Incyanobacteria the membraneous extensions are called

Chromatophores which contain pigments

Bacteria is motive they have thin filamentous extensions from their cell wall called

Flagella

The parts of bacterial flagellum is

1. Filament

2. Hook

3. Basal body

Which is the longest proportion and extends from the cell surface to the outside

Filament

What are the surface structures of bacteria but do not play a role in motility

1. Pili

2. Fimbriae

Sub units of 70s prokaryotic ribosomes

50S and 30S

Z several ribosomes mein attach to a single mrna and form a chain called

Poly ribosomes or polysomes

Reserve materials in prokaryotic cells are stored in the cytoplasm in the form of

Inclusion bodies

These are not bound by any membrane systems and lie free in the cytoplasm

In cell membrane the major lipid are

Phospholipids which are arranged in bilayer

In human beings the mebrain of the erythrocytes approximately

52% protein and 40% lipids

An improved model of the structure of cell membrane was proposed by

Singer and Nicholson 1974

The fluid nature of the membrane is also important from the point of view of functions like

1. Cell growth

2. Formation of intercellular junction

3. Secretion endocytosis cell formation

Movement of water by diffusion is called

Osmosis

Algae have cell wall made up of

Cellulose , galactans , mannans and calcium carbonate

Plant cell walls are made up of

Cellulose hemicellulose pectins and proteins

The layer mainly of calcium pettate which holds or glues the different neighbouring cells together

Middle lamellae

Rough endoplasmic reticulum are involved in

Protein synthesis and secretion

Smooth endoplasmic reticulum is the major site for

Synthesis of lipid

Golgi Apparatus principally performes the functions of

Packaging materials to delivered either to intra cellular targets or secreted outside the cell

Golgi Apparatus is the important site of formation of

Glycoprotein & glycolipid

Isolated lysosomal vesicles have been found to be very rich in almost all types of

Hydrolytic enzymes

The vacuel is bound by single membrane called

Tonoplast

Vakils can occupy up to ____ percent of the volume of the cell

90%

In amoeba the contractile vacuole important for

Osmoregulation and excretion

( Food vakils are formed by engulfing food particles )

That diameter and the length of mitochondria

Diameter is 0.2-1

Length is 1-4.1

Mitochondria produce cellular energy in the form of ATP hence they are called

Powerhouse of the cell

Mitochondria contains

Single circular DNA ,nfew RNA molecules , ribosome (70s) and the components required for the synthesis of proteins

The chloroplast contains

Chlorophyll and carotonoid pigments which are responsible for trapping light energy during photosynthesis

The chromoplast are

Fat soluble character knight pigments like carrot in Xanthophylls and others are present.

This gives the part of the plant a yellow orange or red colour

The leucoplast are

Colourless plastics of varied shapes and size store nutrients

1. Amyloplast stores

2. Elaioplast Stores

3. Alueroplast Stores

1. Carbohydrates starch example potato

2. Oil and fats

3. Proteins

Chloroplast contains

Double standard circular DNA and the ribosomes