1. The document discusses cells, including their history, structure, and function. It describes Leeuwenhoek's discovery of cells under the microscope and the formulation of the cell theory by Schleiden, Schwann, and Virchow.
2. The key components of cells are described, including the cell membrane, cell wall, cytoplasm, nucleus, and organelles. The functions of cells in support, growth, transport, energy production, and reproduction are outlined.
3. The document distinguishes between prokaryotic and eukaryotic cells. Prokaryotic cells lack a nucleus and organelles, while eukaryotic cells have a nucleus and membrane-bound organelles. Examples
2. Anton Von Leeuwenhoek first saw and described a
live cell. Robert Brown later discovered the nucleus.
Fundamental structural and functional unit of all
living organisms.
Unicellular organisms; multicellular organisms
3. CELL THEORY
Matthias Schleiden-plants
Theodore Schwann- animals-plasma membrane; plants-cell wall
Schwann proposed the hypothesis that the bodies of animals and plants are composed of
cells and products of cells. Schleiden and Schwann together formulated the cell theory.
Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-
existing cells (Omnis cellula-e cellula). He modified the hypothesis of Schleiden and Schwann
to give the cell theory a final shape.
Cell theory as understood today is: (i) all living organisms are composed of cells and products
of cells. (ii) all cells arise from pre-existing cells.
4. Structure of a cell-cell wall,cytoplasm,nuclear membrane,nucleus etc.
Shape-
6. Functions of Cell
Provides Support and Structure
Facilitate Growth Mitosis
Allows Transport of Substances
Energy Production
Aids in Reproduction
10. Prokaryotic Cell
Prokaryotic cells have no nucleus. Instead, some prokaryotes such as bacteria have a region
within the cell where the genetic material is freely suspended. This region is called the nucleoid.
They all are single-celled microorganisms. Examples include archaea, bacteria, and
cyanobacteria.
The cell size ranges from 0.1 to 0.5 µm in diameter.
The hereditary material can either be DNA or RNA.
Prokaryotes generally reproduce by binary fission, a form of asexual reproduction. They are also
known to use conjugation – which is often seen as the prokaryotic equivalent to sexual
reproduction (however, it is NOT sexual reproduction).
11. No organelles, like the ones in eukaryotes, are found in prokaryotic cells except for ribosomes.
Prokaryotes have something unique in the form of inclusions. A specialized differentiated form of
cell membrane called mesosome is the characteristic of prokaryotes. They are essentially
infoldings of cell membrane.
Ribosomes are the site of protein synthesis. Several ribosomes may attach to a single mRNA and
form a chain called polyribosomes or polysome. The ribosomes of a polysome translate themRNA
into proteins.
Inclusion bodies: Reserve material in prokaryotic cells are stored in the cytoplasm in the form of
inclusion bodies.
12. Eukaryotic Cell
Eukaryotic cells are characterised by a true nucleus.
The size of the cells ranges between 10–100 µm in diameter.
This broad category involves plants, fungi, protozoans, and animals.
The plasma membrane is responsible for monitoring the transport of nutrients and electrolytes in
and out of the cells. It is also responsible for cell to cell communication.
They reproduce sexually as well as asexually.
There are some contrasting features between plant and animal cells. For eg., the plant
cell contains chloroplast, central vacuoles, and other plastids, whereas the animal cells do not.
