1. Introduction to cell Dr. Ajith Sominanda (MBBS,MPhil,PhD)
Senior Lecturer
Department of Anatomy
Faculty of Medicine
Peradeniya

2. Characteristic features of living things
Outline of the lecture
Origin of the life
Characteristic features of living things
The unit of the life: the cell
Components of the cell and their functions
Beyond the cell
modern evolutionary movement, which is now thought to have occurred in six phases: (1) Cosmic Evolution (the origin of space, time, matter and energy from nothing); (2) Chemical Evolution (the development of the higher elements from hydrogen); (3) Stellar and Planetary Evolution (the origin of stars and planets); (4) Organic Evolution (the origin of organic life from a rock); (5) Macro Evolution (the origin of major kinds); and (6) Micro Evolution (the variation within the kinds).

3. Origin of the life

4. Origin of the universe occurred 15 billion years ago

5. Prebiotic chemistry and origin of the life
‘’Life could have arisen through chemistry’’
-Charlse Darwin (probably)

6. Miller-Urey’s experiments on pre-biotic chemistry in 1953

8. 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.

9. Archean chemistry of prebiotic era

10. 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.

11. 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)

12. The scientific definition
An organized thing or a system capable of self
Growth
Synthesis and degradation of materials by utilizing or releasing energy-Metabolism
Keep a balance of the activities and conditions - Homeostasis
Response to the environmental stimuli
Reproduction

13. Antony van Leeuwenhoek (1632-1723) and the micro world

14. The visibility & the expansion of our understanding

15. Electron microscope & Ultra structure
Hydrogen atom 0.1nm = 1Å

16. The unit of the life: Cell

17. Differences between pro and eu Karyotic cells?

18. Components of the eukaryotic cell
Cell membrane
Cytoplasm
Nucleus
Endoplasmic reticulum
Golgi apparatus
Mitochondria
Endosomes & Lysosomes
Cytoskeleton

19. Cell membrane; the wall of the life

20. Nucleus - The control center of life
A nerve cell
Nucleus contains the genetic materials that control the cell growth, development & transfer informations to the next generation.

21. Eukaryotic nucleus is membrane bound and contains organized nucleic acid (chromosomes)associated with nuclear proteins

22. Organelles Membrane bound structures unique to eukaryotic cells
Endoplasmic reticulum (Rough & Smooth)
Mitochondria
Golgi
Endosomes and lysosomes

23. Endoplasmic reticulum (ER), Golgi apparatus & vescicles - The factory of life

24. Functions Transfer of information from nucleus to cytoplasm to synthesize molecules needed for cellular functions
Gene mRNA protein function

25. Origin of nucleus & ER

26. Mitochondrium – The Energy for living -

27. Origin of mitochondria

28. Endosomes & lysosomes – The (‘toilet’) recycler of life

29. the scavengers or recycling system Endo-lysosomal system
Ingestion of materials
Enclosed by parts of
plasma membrane (Endosomes)
Degradation by lysosomes
expulsion

30. The support to the cell - Cytoskeleton

31. Cytoskeleton

32. Cell and its immediate environment, the extracellular matrix is in constant communication through receptors / mollecules

33. Cells and beyond
Cells
Tissues
Organs
systems

34. Terminology Archaebacteria Nucleus Prebiotic era Endoplasmic reticulum
Prokaryotes
Eukaryotes
Symbiosis
Cell membrane
Cytoplasm
Nucleus
Endoplasmic reticulum
Golgi apparatus
Mitochondria
Endosomes & Lysosomes
Cytoskeleton

35. 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

36. The END
Thank you