AIMC

1. Cell Structure
& Function

2. Cell Theory
• All living things are made up of cells.Cells
are building blocks of our body (as bricks
are building blocks of a house).
• Cells are the smallest working units of all
living things.
• All cells come from pre-existing cells
through cell division.
• All living things have 3 common features:
Reproduction,Locomotion n Digestion

3. Definition of Cell
 A Cell is the structural and
functional unit of all living
organism.
 The cell is the smallest unit that is
capable of performing life
functions as
reproduction,locomotion and
digestion.

4. DISCOVARY
• By Robert Hook in 1665
• He observed boxes in bark of tree(cork)
under microscope.He named these boxes
Cells
• After staining with Eosine/Hematoxyline
cytoplasm looks pink and nucleus blue.

5. Examples of Cells
Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria

6. CELLS VARY IN
• No. of cells;
• Unicellular(Amoeba,bacteria)
• Multicellular(Animals-trillions-elepphant)
• Size of cells;
• 0.1-0.5µm(bacteria) to170x130mm(ostrich)
• Shape of cells;
• Round(RBC’s),spherical(WBC,s),elongate
d(Epithelial),Spindle(muscle),branched(ner
ve)

7. Two Types of Cells
•Prokaryotic
•Eukaryotic

8. 1
2
Prokaryotes
Cell membrane
Cytoplasm

9. Types of Cells
• Eukaryots;Cells having true
nucleus(Eu=true,karyo=nucleus
• Prokaryots;comprise bacteria which are
considered by scientists to have evolved
before eukaryotes
(pro=before,karyo=nucleus)

10. Prokaryotic-Bacteria
• Oldest form of life on earth
• Outermost capsule-cell wall-cell memb.
• Cytoplasm contain free single circular
DNA (nucleoid/plasmid) without
welldefined nucleous for reproduction.
• Ribosomes consist of rRNA n proteins.
• External structures-flagella,pili etc

11. Prokaryotic Cells

12. are the most complex form of life.
They have nucleus
Contain organelles surrounded by membranes
They are multicellular organisms (composed of
many cells).
Most living organisms
Examples: animals and plants.
Eukaryotic

13. Eukaryotic
Plant Animal

14. Common Characteristics
• All cells are surrounded by a barrier called
the cell membrane
• They contain the molecule that carries
biological information-DNA

15. Isolation of cell components
• The cellular compt. are obtained by
differential centrifugation of cells,after they
have been gently broken by one of the
following methods;
• Grinding,In Hypotonic soln.,Alternative
freezing thawing,Ultrasonification,Enzymic
treatment.
• The homogenized cells can be
fractionated by differential centrifugation at
various forces of gravity(1000-150,000g
for 10min-3hrs).

16. Differential Centrifugation

17. Eukaryotic cell

18. Cell-Tissue-Organ-System

19. Cell-Tissue-Organ-System-Organism

20. Cell Parts
Cell membrane
Cytoplasm- Organeles
Nucleous
CELL STRUCTURE AND FUNCTION

21. “Typical” Animal Cell

22. Cell Structures
• The Plasma Membrane—A Cell's Protective Coat
• The Cytoskeleton—A Cell's Scaffold
• The Cytoplasm—A Cell's Inner Space
• Genetic Material
Cell Organelles include
• The Nucleus—A Cell's Center
• The Endoplasmic Reticulum and the Golgi Apparatus
Macromolecule Manager
• The Ribosome—The Protein Production Machine
• Mitochondria and Chloroplasts—The Power Generators
• Lysosomes and Peroxisomes—The Cellular Digestive
System

23. Cytoplasm and Organelles
• Cytoplasm lies between the cell
membrane and nucleus and contains the
organelles.
• Cytosol is a gelatin like aqueous fluid that
contains salts, minerals and organic
molecules

24. ORGANELLES

25. Nucleus

26. Nucleus
• Most prominent structure
• Maintains its shape with a protein skeleton called the
nuclear matrix
• Double membrane – nuclear envelope
• Inside the envelope – chromatin (DNA & protein)
• When the cell is about to divide it forms the
chromosomes-made of DNA.
• Stores heriditary information in its DNA-transfer by
replication.
• RNA is copied from DNA-transcription- forming mRNA
• m-RNA travels from nucleus to the cytosol through small
holes in the envelope – nuclear pores
• Contains the nucleolus – the site where ribosomes are
synthesized

27. Nucleolus
• Inside nucleus
• Contains RNA to build
proteins
• Site where ribosome
are synthesized

28. Endoplasmic Reticulum

29. Endoplasmic Reticulum
• System of membranous tubules and sacs
• Intracellular Highway – molecules move from one
part of the cell to another
• 2 types – rough and smooth
• Rough ER-studded with ribosomes –synthesis of
proteins with posttranslational modifications- to be
used by the cell organelles, membrane or secreted
from the cell
• Smooth ER - no ribosomes-has enzymes for:
Synthesis of TAG & Phospholipids in enterocytes
Synthesis of steroids in gland cells
Has cyto.P450 for detoxification in liver
Regulation of calcium in muscle cells

30. Ribosomes

31. Ribosomes
• Most numerous
• Not surrounded by a membrane
• Synthesized in nucleolus in the nucleous.
• Made up of proteins and RNA
• RNA is packaged into the ribosomes then transported to
the cytosol
• Some ribosomes are free
• Some are attached to the endoplasmic reticulum
• Protein is synthesized in the ribosomes
• Proteins to be used in the cytosol – free ribosomes
• Proteins to be exported or inserted in the cell membrane
– ribosomes on the ER

32. Golgi Apparatus
• System of membranes
• Series of flattened sacs
with convex shape
• Works with the ER to
modify proteins
Processing, packaging
distributing proteins to
lysosomes,secretory
vesicles and pl.memb.

33. CYTOSKELETON
• .

34. CYTOSKELETON
• Network of long flexible fibrous protein strands,maintains
the shape and size of cell
• Microtubules – largest strands are hollow cyllindrical
tubes begin in nu n extend to pl memb. made up of
tubulin protein
– Help the cell divide by forming spindle
- Responsible for positioning of organelles
- Participates in the movement of vesicles
• Microfilaments – threads made of actin (protein) –
smallest strands-control the shape of cell n movement of
cell surface to move, divide n engulf.
• Intermediate filaments- are composed of fibrous
protein polymers-provide structural support to memb n
other cellular components.

35. Mitochondria
They are called the
“POWER HOUSE”
of the cell

36. Mitochondria
• Sites of chemical reactions that transfer energy from organic
compounds to ATP
• ATP- main energy source for cells
• Size 1-2 µ,1-1000 in number
• Cells with high energy requirements have more mito.
e.g.CNS,muscle,liver
• Have 2 membranes
• Smooth outer membrane serves as a boundary between the
mitochondria and the cytosol
• Inner membrane has many folds called Cristae – they enlarge the
surface area for more chemical reactions
• Have their own DNA n RNA(maternal)
• Mito has 120 proteins(13 encoded by mito.DNA. Mito can replicate.
• Mutations cause muscle n nerve,renal diseases e.g. LHON &
MERRF

37. LYSOSOMES

38. LYSOSOMES
• Small spherical organelles of digestion.
• Enclose hydrolytic enzymes, within single
membranes with ATPase to keep ph 5.5
• Digest proteins, carbohydrates, lipids, DNA and
RNA(Endocytosis)
• Eliminating unwanted material- old
organelles,misfold proteins
bacterias,viruses,tissue remodeling after injury
• Destroyed compt. are recycled
• L.Enz Defficiency leads to storage dis, L-cell
disease(T.sachs,Gaucher,Pompaei diseases)

40. PEROXYSOMES
• Spherical with single emb.,similar to
lysosomes in size,involved in oxidative
reactions using molecular O2,producing
H2O2 degraded by catalase.
• Function in oxidation of long chain FA &
synth of bile acids from cholestrol
• Can replicate by division like mito.

41. Label the parts of the cell
http://www.phschool.com/atschool/phbio/activities/cbd-3072/simbase.htm
http://www.harcourtschool.com/activity/cell/cell.htm