Structure and functions of cell
Introduction
All living things are composed of cells. A single cell is the smallest
unit that has all the characteristics of life.
A cell is defined as the structural and functional unit of the living
body.
General characteristics of cells
Each cell in the body:
1. Needs nutrition and oxygen.
2. Produces its own energy necessary for growth, repair, and other
activities.
3. Eliminates carbon dioxide and other metabolic wastes.
4. Maintains the environment for its survival.
5. Shows immediate response to the entry of bacteria or toxic
substances into the body.
6. Reproduces by division. (There are exceptions like neurons, which
do not reproduce.)
STRUCTURE AND FUNCTIONS OF CELLS
Organelles and their functions
,S. No. Organelles Functions
Rough
Synthesis of proteins.
1. endoplasmic
Degradation of worn-out organelles.
reticulum
Synthesis of lipids and steroids.
Smooth Role in cellular metabolism.
2. endoplasmic Storage and metabolism of calcium.
reticulum Catabolism and detoxification of toxic
substances.
Processing, packaging, labeling, and
3. Golgi apparatus
delivery of proteins and lipids.
Degradation of macromolecules.
Degradation of worn-out organelles.
4. Lysosomes Removal of excess secretory products.
Secretion of perforin, granzymes,
melanin, and serotonin.
Breakdown of excess fatty acids.
Detoxification of hydrogen peroxide and
other metabolic products.
5. Peroxisomes Oxygen utilization. Acceleration of
gluconeogenesis.
Degradation of purine to uric acid.
Role in myelin and bile acid formation.
, S. No. Organelles Functions
Movement of chromosomes during cell
6. Centrosome
division.
Production of energy.
7. Mitochondria Synthesis of ATP
Initiation of apoptosis.
8. Ribosomes Synthesis of proteins.
Determination of cell shape.
9. Cytoskeleton Stability of cell shape.
Cellular movements.
Control of all activities of the cell.
Synthesis of RNA
Sending genetic instructions to the
10. Nucleus cytoplasm for protein synthesis.
Formation of subunits of ribosomes.
Control of cell division. Storage of
hereditary information in genes.
TRANSPORT ACROSS CELL MEMBRANE
Introduction
All living things are composed of cells. A single cell is the smallest
unit that has all the characteristics of life.
A cell is defined as the structural and functional unit of the living
body.
General characteristics of cells
Each cell in the body:
1. Needs nutrition and oxygen.
2. Produces its own energy necessary for growth, repair, and other
activities.
3. Eliminates carbon dioxide and other metabolic wastes.
4. Maintains the environment for its survival.
5. Shows immediate response to the entry of bacteria or toxic
substances into the body.
6. Reproduces by division. (There are exceptions like neurons, which
do not reproduce.)
STRUCTURE AND FUNCTIONS OF CELLS
Organelles and their functions
,S. No. Organelles Functions
Rough
Synthesis of proteins.
1. endoplasmic
Degradation of worn-out organelles.
reticulum
Synthesis of lipids and steroids.
Smooth Role in cellular metabolism.
2. endoplasmic Storage and metabolism of calcium.
reticulum Catabolism and detoxification of toxic
substances.
Processing, packaging, labeling, and
3. Golgi apparatus
delivery of proteins and lipids.
Degradation of macromolecules.
Degradation of worn-out organelles.
4. Lysosomes Removal of excess secretory products.
Secretion of perforin, granzymes,
melanin, and serotonin.
Breakdown of excess fatty acids.
Detoxification of hydrogen peroxide and
other metabolic products.
5. Peroxisomes Oxygen utilization. Acceleration of
gluconeogenesis.
Degradation of purine to uric acid.
Role in myelin and bile acid formation.
, S. No. Organelles Functions
Movement of chromosomes during cell
6. Centrosome
division.
Production of energy.
7. Mitochondria Synthesis of ATP
Initiation of apoptosis.
8. Ribosomes Synthesis of proteins.
Determination of cell shape.
9. Cytoskeleton Stability of cell shape.
Cellular movements.
Control of all activities of the cell.
Synthesis of RNA
Sending genetic instructions to the
10. Nucleus cytoplasm for protein synthesis.
Formation of subunits of ribosomes.
Control of cell division. Storage of
hereditary information in genes.
TRANSPORT ACROSS CELL MEMBRANE
