can some give me some idea on how to give seminar on the topic cell
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Introduction
In this project we will study about cells and its structure. A cell is a tiny mass of protoplasm which is limited by a membrane and capable of performing all Functions of life. A typical cell is formed of three parts :
(i) Plasma membrane or cell membrane
(ii) Nucleus
(iii) Cytoplasm.
It is called structural unit because the structure of human being is decided by the living cells present inside him and it is called functional unit because the functioning of organism is also dependent on these cells.
Discovery of the Cell
In 1665, Robert Hooke - an English scientist, saw cells for the first time in a thin slice of cork resembled the structure of honey combike structures and he named this as a cell.
Discovery of Living Cells :
A Van Leevwenhoek in 1674, studied the living cells as bacteria, protozoa, RBCs etc. for first time with the help of his improved microscope.
Shape & Size of Cells
The size and shape of cells very considerably but all of these are ultimately determine by the specific function of the cell. Cells can be polygonal, spherical, elliptical, spindle shaped, cuboidal.
Some cells can change their shape like, white blood cells while most of the plant cells and animal cells have almost fixed shapes. Human RBCs are biconcave disc shaped, nerve cells are elongated thread like. In a multi-cellular organisms the shape of a cell depends mainly on its functional adaptations and partly on the surface tension, viscocity of the protoplasm, mechanical action between adjoining cells and rigidity of the cell membrane.
Plasma Membrane or Cell Membrane :
Each cell is bound by an extremely delicate, thin, elastic membrane, called plasma membrane. It encloses nucleus and cytoplasm of the cell, which constitutes the 'protoplasma' and it is a selectively permeable membrane. It is a living membrane and it is made up of lipids and proteins.
Functions :
The following Functions are performed by plasma membrane:
• It gives definite shape to the cell.
• It provides mechanical barrier for the protection of the internal contents on the cell.
• It is selectively permeable membrane.
The plasma is a vehicle for the transport of the body’s important fuels such as glucose and basic fats. Other substances that are carried in the plasma include iron, which is essential for the formation of the oxygencarrying pigment haemoglobin, and a number of important hormones such as thyroid hormone. Plasma therefore consists of a water solution of minerals, foods and small amounts of essential compoun ds such as hormones plus one other essential component-the protein that makes up a major part of it.
Nucleus :
Nucleus is the largest cell structure. It is bounded by two membranes. It is a specialized protoplasmic body denser than the surrounding cytoplasm. It is oval or spherical in shape. It is the controlling centre of all cell activities.
Cytoplasm :
The protoplasmic mass of the cell excluding nucleus is called as cytoplasm. When the cell is young, the cytoplasm completely fills the space in between nucleus and plasma membrane. As it increases in size, a number of small cavities appear in the cytoplasma called as vacuoles.
Cytoplasm is a viscous, homogeneous and colloidal liquid that contains various molecules such as water, amino acids, carbohydrates, lipids proteins, etc. It is also contains various organelles. These organelles may be bounded by a membrane. These organisms are the actual sites for various metabolic Functions of the cells.
A cell has to perform several vital Functions of the body. These activities of the cell are performed by different cell organelles. These cell organelles are mostly enclosed by membranes. The different cell organelles are :
(a) Mitochondria : Mitochondria (singular mitochondrion) are organelles found in the cytoplasm of all eukaryotic cells. Mammalian RBCs are devoid of mitochondria. They are commonly known as ‘power house of the cell’ because they contain enzymes necessary for the total oxidation of food and for release of high amount of energy in the form of ATP (Adenosine triphosphate) molecules.
Mitochondria are rod shaped or filamentous organelles. Each mitochondria is bounded by two membranes. The outer membrane is smooth whereas the inner membrane is folded inwards to form cristae. Cristae increases the surface area for metabolic reactions to take place. The inner membrane encloses a matrix, which contains enzyme, which are required for the release of energy.
Function :
Mitochondria provide energy for vital activities of living cells, like synthesis of chemical compounds, their transport, and for mechanical work.
(b) Plastids :
Plastids are the largest cell organelle found only in plant cells. On basis of pigments present in
I hope this will helpful because it is more but I have shorten it.
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