cell the unit of life

1. NaveenaGirish
ZMCTE

3. *
Reductionist Biology?’

4. *Concepts and Techniques of Physics and
Chemistry applied to understand Biology.
Reductionist Biology

5. *
Presence of basic unit of life - cell

6. *A cell is the functional and structural unit of
life/ living organisms
*Any thing else less than cell can’t be
considered as basic unit since it doesn’t
perform independent living
*Unicellular organism has
Independent existence Independent functioning

7. Hey, I have a
story to say

8. *Study about structural and functional organisation of
cell is called cell biology / cytology.

9. *Robert Hooke – Father of cytology
*Observed cork tissue and named cavities inside
it as cell
*Cellula – little rooms(latin)

10. *Anton Von Leeuwenhoek first saw and
described a live cell

11. Cell
Theory
Mathhias Schleiden
1838
German botanist
Theodore Schwann
1839
British Zoologist
Rudolf Virchow
1855

12. Schleiden
• – All plants are composed of cells
Schwann
• – cell has an outer layer today know as
plasma membarane , plant cell has cell
wall. Bodies of plants and animals
composed of cells and its products
Cell Theory

13. *Rudolf Virchow showed all cells divide and
form new cells formed from preexisting cell.

14. *
*All living organisms are composed of cells and
products of cells
*All cells arise from pre-existing cell.
It can be applied to prokaryotes as well as eukaryotes
It is the basis of cytology
But can’t be applied to viruses

15. Human cheek
cells
Onion peel cells
Cell wall present only in plant cells

16. *Cell which has membrane bound nucleus and
membrane bound orgenelles is called eukaryotes
*Cell which has no membrane bound nucleus is called
prokaryote
*Prokaryotes lack membrane bound orgenelles like
ER, mitochondria ,lysosome, golgi
*Cell has protoplasm which contains cytoplasm and
nucleoplasm
*Cytoplasm is semi fluid matrix in which cell
organelles present and various chemical reactions
takes place.

17. *Ribosomes are non membrane bound orgenelles
present in cytoplasm, mitochondria, rough ER,
chloroplast etc.
*Animal cell has centriole non membrane bound
organelle which help in cell division.

18. *Cell differ in size, shape and activities
*Smallest cell – Mycoplasma -0.3µm
*Largest single cell- egg of ostrich
*Longest cell- nerve cell

19. *

21. *

22. *

23. *

24. *

25. **
* bacteria
PPLO
Blue green algae

26. *

28. *
Small circular DNA outside genomic DNA
Give resistance to antibiotics
As a vector in gene transfer technology

29. *
Glycocalyx
Slime layer
(Loose sheath)
Capsule
(Thick and Tough)
Plasma membrane is semi permeable and just like eukaryotic membrane

30. *Bacteria can be motile and non motile
*Motile ones has flagella
*It has filament, hook, basal body
*Filament is the longest portion and extends
from cell surface to outside

31. *Pili is elongated tubular structure on bacterial
surface
*Fimbriae are small
bristle like fibers
it help to attach rock
and host tissue

32. *Ribosomes are sites of protein synthesis
*Several ribosomes attach to single mRNA and
form polysomes.
*Ribosomes on mRNA translates mRNA to protein

36. * The cytoplam is in constant motion called
cytoplasmic streaming and the this movement
around vacoule is called cyclosis
cytoplasm is the physical basis of cell

37. *

38. Membrane bound organelles
Organised nucleus with an envelope
80s ribosome
Genetic material organised
as chromosome
present
Non membrane bound orgenelles
Nucleoid with out envelope
70s ribosome
Circular DNA and plasmids
Histones and cytoplasmic streaming absent

39. Plasma membrane/ plasmalemma
It separates cellular cytoplasm with environment

40. *
Al living beings have the unit membrane model – so called unit membrane due to
unity

41. *
*Most accepted one
*Peripheral protein on surface of membrane and integral
protein partially or completely buried inside membrane
*Proposed by Singer and Nicolson
*Proteins are free to move ice berges floating in sea
*So the name fluid mosaic model

42. *Functions
*Completely envelopes cytoplasm
*Gives shape to cell
*Exchange of materials in and out of cell
*Allows free movement of water
*Certain cell organelles develop from plasma
membrane

43. Engulfing
Solid particles
Engulfing
liquid particles
Cell vomiting
Eliminating secretory products
from outside cytoplasm

44. *
According to
expenditure of
energy
Membrane
transport
Passive
transport
Osmosis
Diffusion
Active transport
Using energy
and carrier
proteins
No energy needed Energy needed
Active transport works against concentration gradient as in Na+ K+ pumb

47. *
*Rigid protective layer
*Protects from damage
*Can see in Fungi and Plants only
It gives rigidity
Maintains osmotic balance
Protects from turgor pressure and
damage

48. *

49. *Algal cell wall contains…
Cellulose
Galactans
Mannans
Calcium carbonate

50. Structure
Middle lamella made up of calcium pectate.lamella act as a glue
for adjusant cells to stick together

51. *
*Golgi
*Endoplasmic Reticulum
*Lysosome
*Vacuole
* mitochondria
*Chloroplast
*peroxisomes

53. * Network of membrane bound cavities,tubules, vesicles through
out ctoplasm
* Term coined by porter
* Cisternae- it is long
Flattened parellel bundle
vesicles- ovoid structures
Tubules- highly branched
and smoothwalled
ER divides intracellular space
In to two distinct compartment
Luminal{inside ER}
Extra luminal {cytoplasm}
ER in muscle cells is called
sarcoplasmic reticulum

55. *
*Cellular circulatory system
*Rough ER produce protein with the help of
ribosome
*Smooth ER produce lipids , steroid hormones,
cholestrol
*It help in secretion

56. Cisternae has cis forming face
and trans phase maturing face

57. *Lysosomes
Suicidal bags/ Digestive tracts of cell
/ hydrolytic enzymes active at acidic
ph

58. *It digest food material
*It digest foreighn material
*Egg membrane during fertilisation dissolves by
action of lysosome

60. vacuole
Identify the difference?
In plants 90% volume of cell is vacuole
Only some animal cells has vacuole
Membrane bound space which
has water sap excretory products
Not useful for cell

61. *Its lipoprotenaceous membrane is called
tonoplat

62. *In amoeba contractile vacuole are important
for excretion

63. *
*They serve as storage bag
*They are involved in material transport in
cytoplasm
*They maintain internal pressure and turgidity
of cell