Organization of body of living beings

Explore the levels of organization of body of living beings.

In 1665A.D. Robert Hooke has observed a section of a cork bark by a microscope. He has seen the bark was build up of number of capsules and named them as cells. In 1839 A.D. Matthias Schleiden and Theodore Schwan according to their cell theory said that cells are the stuctural and functional units of living organisms.

You can reveal the structure of plant and animal cells using the microscopic observations.

You can observe several parts of a cell (Eg: nucleus, cell wall,chloroplasts, vacuole, cytoplasm) through a light microscope. Some organelles cannot be observed through a light microscope clearly.( Eg: nucleus, mitochondria, golgi bodies,endoplasmic reticulum etc.) An electron microscope is necessary to observe these organelles.

Main diferences between plant cells and animal cells

Plant cell

* Cell wall is present

* Large vacuoles present

* Chloroplasts are present

Animal cell

* Cell wall is absent

* Large vacuoles not present

* Chloroplasts are not present

MAIN PARTS OF A CELL

NUCLEUS

* Control all cellular activities.

* Surrounded by the nuclear membrane

* Chromosomes and nucleolus present inside nucleus.

* Chromosomes consists of genes which are transmit the

hereditary characters to the next generation.

MITOCHONDRIA

* Oval shaped organelle, bound by two membranes.

* Release energy through aerobic respiration.

* This energy is used for all metabolic activities that

take place inside a cell.

GOLGI BODIES

* Tubular organelle.

* Works as a system of internal processing and transporting.

* Produce secreations for cellular activities and stored them for

temporary in vasicles. (Eg: Proteins,Hormones and Enzimes)

ENDOPLASMIC RETICULUM

* Tubular system connected with outer nucleur membrane.

* Main function is synthesis and transport of lipids and steroids.

CHLOROPLASTS

* Photosynthesis takes place.

* A green pigment - chlorophyll is present.

CELL MEMBRANE

* Semipermeable.

* Controls entering and outgoing of substances from the cell.