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Introduction to cell Dr. Ajith Sominanda (MBBS,MPhil,PhD)

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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

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