Download ppt - University of Kentucky

The Cell
Basics of cell biology
[Presentation for t.A. screen test]
Mohati Desai
Dept of biology
University of kentucky
The Cell
• Cell- basic structural,
functional unit of all
living organisms
• All living organisms
are made up of cells
• Cells perform the
various functions
needed by the
organism to survive
Unicellular and Multicellular Organisms
• Unicellular organisms:
only a single cell that
performs all the functions
E.g. Bacteria
• Multicellular organisms:
more than one cell and in
many cases more than one
type of cells; collectively
perform all the functions
of the organism.
E.g. Higher plants and
animals
Prokaryotic and Eukaryotic cells
• Cells are divded into two categories depending on their
complexities: Prokaryotic cells and Eukaryotic cells.
• Prokaryotic cells: Simpler, smaller, have no membrane
bound nucleus or organelles. Have outer cell wall
enclosing a fluid cytoplasm. E.g. bacteria (E. coli).
• Eukaryotic cells: Have a nucleus and various cell
organelles; larger. E.g. plant cells, animal cells.
• The organelles help in compartmentalization and
allow specialized functions to be sequestered and
carried out in different locations.
Components and Organelles of Cells
Cell membrane/ Plasma membrane: Outermost
covering that confers structure, shape and
protection.
• It is made up of lipids embedded with proteins.
Cytoplasm: Everything between the cell
membrane and the nucleus.
• Primarily composed of water and includes salts,
dissolved gases, enzymes, nutrients, proteins and
all the cell organelles except the nucleus.
Nucleus: It is a dense spherical body in the
cytoplasm which regulates all cell activity.
• It contains the genetic material (DNA) of cell.
• It is enclosed by a membrane known as the nuclear
membrane.
Mitochondria: Known as the power house of the
cell
• Site of aerobic respiration and energy
production.
Endoplasmic Reticulum: A folded system of
membranes spread throughout the cell that loop
back and forth giving it a very large surface area
for cell reactions.
• Site for protein and lipid production.
Ribosomes: Small organelles found either attached
to the surface of the ER or free in the cytoplasm.
• Involved in protein synthesis
Golgi Bodies: Structure similar to the ER though
not so large and wide spread.
• Responsible for processing and packaging
proteins for the cell.
• Proteins are squeezed off into the little blebs which
drift off into the cytoplasm
Others: Chloroplast, lysosomes, centrioles,
vacuoles, cell wall, plastids, cilia, flagella
Flagella
Cilia