Cytology is the branch of science which deals the Study of cell structure only but cell biology include study of cell structure, function & Reproduction also so we can define both the terms like-
Cytology:- Study of cell structure.
Cell biology :-Study of cell structure,function & Reproduction.
Father of modern cytology – C.P. Swanson
Father of Indian cytology – A.K. Sharma
Institutes of Cell & Molecular Biology
- National centre for cell science, Pune.
- Institute of life sciences, Bhubaneshwar.
- National Institute of oceanography, Panjeem.(Goa)
- Advance center for cell & chromosome Research (Kolkata).
- National Institute of Immunology, New Delhi.
- National Brain Research center, Manesar, Gurgaon.
- Centre for cellular and molecular Biology, Hyderabad.
- Center for DNA finger printing and diagnostics Hyderabad (CDFD).
- Institute of genomics and integrative biology, New Delhi.
- International Centre for Genetic Engineering & Biotechnology (ICGEB) – New Delhi
- Robert Hook (1665) in his book “Micrographia“ coined the term “Cell”. He first observed cell in a piece of cork (dead cells) (Greek word cella = Small hollow space or Chamber)
- Malpighi (1671) & Grew (1682) first observed living cells in plants and called them “Bladders” and “Utricles” respectively.
- Leeuwenhoek (1674) first observed animal cells (Free animal cells) and called them “Animalcule”.
M.J. Schleiden (1838) – German Botanist
T.Schwann (1839) – German Zoologist
(1) Living organisms are made up of cells and substances produced by cells (Cell is structural units)
(2) All cells arises from the preexisting cells only (confirmed by Rudolph virchow (1855) by stating “Omnis cellulae cellula“. Virchow proposed “Cell Lineage theory”. [Karl Nageli showed that plant cells arise from the division of pre existing cells].
(3) All cells are basically similar in structure and metabolic function.
(4) Vital activities of an organism are due to the activities of its cells (Cell is functional units).
(5) Each cell has a unit of heredity.
Exception of cell theory : –
According to this theory all the living organism are made up of cells. Viruses are exception of this theory because virus lacks cell organization.
According to modern scientists all the acellular organism – monera and protista, Xanthophytes,(Vaucharia) Phycomycetes (Rhizopus) are exception of cell theory.
- Cell Principle
- First of all cell hypothesis was proposed by Schwann (1839).
- It was raised to the status of cell theory by Schleiden and Schwann.
- It was modified, when R.Virchow (1855), Put forward the theory of cell lineage or development of cells from preexisting cells. (“Omnis cellulae cellula”).
- As a result of these additions the cell theory has been as “cell principle or cell doctrine” the cell principle is better than cell theory as it applies almost to all the living things, plants, animals and microbes and it also incorporates nearly all the modern findings about a cell.Modern cell theory or cell principle states that :
- 1) The body of all living beings is made up of cells and their products.2) Cell is the unit of structure of body of all organisms.3) A cell is made up of a small mass of protoplasm having a nucleus, a number of organelles and covering membrane.
4) Each cell is capable of independent existence but a cell organelle can not survive independently.
5) All cells have fundamental similarity in structure, chemical composition and basic metabolic reactions.
6) Life exists only in cells because all activities of life are performed by cells.
7) New cells arise from pre-existing cells through division.
8) Each cell contains the whole complement of genetic information not for itself but for the whole organism (Totipotency)
9) Genetic information are stored and expressed within the cells.
10) Life transferred from one generation to the next only in the form of cells.
11) All cells of present day organisms have evolved from primitive cells of the remote past.
12) They have a common ancestry.
13) The cells of an individual get transformed structurally and functionally to perform specific function, loss of centriole in nerve cells. Lost of nucleus in mammalian RBCs & form of sperms.
14) Cells maintain homoeostasis and their internal environment.
15) No organism, organ, or tissue can have any activity that is absent in its cell.
16) All cells have a full genetic information coded in their DNA, but each cell type uses only a part of information, require for its special function or structure.
17) A cell has definite life span.
(a) Nucleus is absent in prokaryotes, mature RBCs.
(b) Prokaryotes lack a number of cell organelles present in eukaryotes.
(c) Virus do not obey theory of cell lineage.
(d) A number of nuclei present in coenocyte or syncytial