Introduction to cell
Dr. Ajith Sominanda (MBBS,MPhil,PhD)Senior LecturerDepartment of AnatomyFaculty of MedicinePeradeniya
Outline of the lecture
1.Origin of the life2.Characteristic features of living things3.The unit of the life: the cell4.Components of the cell and their
functions5.Beyond the cell
1. Origin of the life
Origin of the universe occurred
15 billion years ago
Prebiotic chemistry and origin of the life
‘’Life could have arisen through chemistry’’
-Charlse Darwin (probably)
Miller-Urey’s experiments on pre-biotic chemistry in 1953
Change of organic chemicals into ‘life’ substance
Chemically reducing conditions can form amino acids
Pre-biotic earth was low in oxygen (reducing atmosphere) and therefore amino acids could have formed with lightning or in the sea bed hydrothermal vents etc.
Archean chemistry of prebiotic era
Life could have come from outside rather than the chemical evolution on earth
Murchison meteorite, which fell in Australia. Amino acids found in the meteorite were apparently present in it when it fell.
The earlier most evidence of life on earth
3.5 billion years back
Fossilized imprints of micro-organisms which resemble modern blue-green algae (cynobacteria)
The scientific definition
An organized thing or a system capable of self 1.Growth2.Synthesis and degradation of materials by utilizing or releasing energy-Metabolism3.Keep a balance of the activities and conditions - Homeostasis4.Response to the environmental stimuli5.Reproduction
Antony van Leeuwenhoek (1632-1723) and the micro world
The visibility & the expansion of our understanding
Electron microscope & Ultra structure
Hydrogen atom 0.1nm = 1Å
The unit of the life: Cell
Differences between pro and eu Karyotic cells
?
Components of the eukaryotic cell
Cell membrane Cytoplasm Nucleus Endoplasmic
reticulum Golgi apparatus Mitochondria Endosomes &
Lysosomes Cytoskeleton
Cell membrane; the wall of the life
Nucleus - The control center of life
Nucleus contains the genetic materials that control the cell growth, development & transfer informations to the next generation.
A nerve cell
Eukaryotic nucleus is membrane bound and contains organized nucleic acid (chromosomes)associated with nuclear proteins
Organelles
Membrane bound structures unique to eukaryotic cells
Endoplasmic reticulum (Rough & Smooth)
Mitochondria Golgi Endosomes and lysosomes
Endoplasmic reticulum (ER), Golgi apparatus & vescicles - The factory of life
FunctionsTransfer of information from nucleus to cytoplasm to synthesize molecules needed for cellular functions
Gene mRNA protein function
Origin of nucleus & ER
Mitochondrium – The Energy for living -
Origin of mitochondria
Endosomes & lysosomes – The (‘toilet’) recycler of life
the scavengers or recycling system Endo-lysosomal system
Ingestion of materials
Enclosed by parts of plasma membrane (Endosomes)
Degradation by lysosomes
expulsion
The support to the cell - Cytoskeleton
Cytoskeleton
Cell and its immediate environment, the extracellular matrix is in constant communication through receptors / mollecules
Cells and beyond
Cells
Tissues
Organs
systems
Terminology
1. Archaebacteria2. Prebiotic era3. Prokaryotes 4. Eukaryotes5. Symbiosis6. Cell membrane7. Cytoplasm
8. Nucleus9. Endoplasmic
reticulum10.Golgi apparatus11.Mitochondria12.Endosomes &
Lysosomes13.Cytoskeleton
Home work
Find a text book in histology, i.e. Basic Histology by Carlos Junqueira
Read the first chapters on cytoplasm and nucleus and then list the structural features and functions of components of the cell
The END
Thank you