CELL AND IT'S COMPONENTS
● First discovered by Robert Hooke in 1665 in cork cells
● First living cell discovered by Anton van Leeuwenhoek.
● Cell is the basic structural and functional unit of all living organisms.
CELL THEORY
● Given by schleiden and Schwann.
● Described that all animals and plants are made of cells and their
products.
● Rudolf Virchow added by stating that all cells arise from pre-existing
cells (Omanis cellula e cellula)
● This theory is accepted widely with some exceptions like viruses, prions,
viroids etc.
FACT: the smallest living organism is PPLO or mycoplasma measuring
only 0.1micrometeres
CELL MEMBRANE
● It is the outermost layer in the animal cell and present inner to the cell
wall in bacteria, fungi, and plant cells.
● It is a living structure and absent in dead cells components of cell
membrane
a) Lipid-present in the form of phospholipid bilayer with a hydrophobic tail
and hydrophilic head b) Protein-can be fully embedded in the membrane or
peripheral.
c) Glycoprotein
d) Glycolipid
● The most widely accepted model of cell membrane is the fluid mosaic
model by Singer and Nicholson. It describes cell membrane as a quasi fluid
with an ocean of lipid and protein as icebergs.
, ● Transport across the membrane occurs through diffusion, active
transport or facilitated transport
● Active transport uses energy and protein channels to transport
substances from lower concentration to higher concentration.
● Facilitated transport occurs with the help of proteins but transport
substances from higher concentration to lower concentration.
CELL WALL
● Present in plant cell and fungi
● It is a dead structure
● It gives shape, rigidity, and protection from the environment
● The matrix of cell wall of bacteria is made up of galactan,
mannan and calcium carbonate.
● Cell wall is further divided into
a) Primary cell wall : made up of cellulose, hemicellulose,
pectin, and protein.
b) Secondary cell wall: present between plasma membrane
and primary cell wall. Made up of cellulose, pectin, and
lignin or subrein.
c) Middle lamellae: present between primary cell wall and
neighboring cell. Made up of calcium or magnesium
pectate.
ENDOMEMBRANE SYSTEM
● Consist of organelles with membrane that work in co-ordination
● Includes endoplasmic reticulum, Golgi bodies, vacuoles, and
lysosomes.
● First discovered by Robert Hooke in 1665 in cork cells
● First living cell discovered by Anton van Leeuwenhoek.
● Cell is the basic structural and functional unit of all living organisms.
CELL THEORY
● Given by schleiden and Schwann.
● Described that all animals and plants are made of cells and their
products.
● Rudolf Virchow added by stating that all cells arise from pre-existing
cells (Omanis cellula e cellula)
● This theory is accepted widely with some exceptions like viruses, prions,
viroids etc.
FACT: the smallest living organism is PPLO or mycoplasma measuring
only 0.1micrometeres
CELL MEMBRANE
● It is the outermost layer in the animal cell and present inner to the cell
wall in bacteria, fungi, and plant cells.
● It is a living structure and absent in dead cells components of cell
membrane
a) Lipid-present in the form of phospholipid bilayer with a hydrophobic tail
and hydrophilic head b) Protein-can be fully embedded in the membrane or
peripheral.
c) Glycoprotein
d) Glycolipid
● The most widely accepted model of cell membrane is the fluid mosaic
model by Singer and Nicholson. It describes cell membrane as a quasi fluid
with an ocean of lipid and protein as icebergs.
, ● Transport across the membrane occurs through diffusion, active
transport or facilitated transport
● Active transport uses energy and protein channels to transport
substances from lower concentration to higher concentration.
● Facilitated transport occurs with the help of proteins but transport
substances from higher concentration to lower concentration.
CELL WALL
● Present in plant cell and fungi
● It is a dead structure
● It gives shape, rigidity, and protection from the environment
● The matrix of cell wall of bacteria is made up of galactan,
mannan and calcium carbonate.
● Cell wall is further divided into
a) Primary cell wall : made up of cellulose, hemicellulose,
pectin, and protein.
b) Secondary cell wall: present between plasma membrane
and primary cell wall. Made up of cellulose, pectin, and
lignin or subrein.
c) Middle lamellae: present between primary cell wall and
neighboring cell. Made up of calcium or magnesium
pectate.
ENDOMEMBRANE SYSTEM
● Consist of organelles with membrane that work in co-ordination
● Includes endoplasmic reticulum, Golgi bodies, vacuoles, and
lysosomes.
