Cell ultrastructure and cell organelles

2. Dev Hingra
Dept of GPB.
RCA, MPUAT, Udaipur
Mail Id- mail2devhingra@gmail.com

3. Cell ultrastructure
and
cell organelles

4. Cell is a structural and functional unit of all living
organisms, except viruses.
Described by Robert C. Hooke in January 01, 1653

5. Cell ultra structure:-

6. The various structures seen in cells are:-
•Cell membrane
•Golgi complex
•Endoplasmic reticulum
•Mitochondria
•Chloroplast
•Ribosomes
•Lysosomes
•Vacuoles
•Nucleus

7. .
Parts
•Middle lamella
•Primary cell wall
•Secondary cell wall.
Function
plant cell are surrounded by a non living coat called cell
wall.
Provide mechanical support, shape and strength to tissues
and organs.
Cell wall:-

8. Plasma lemma:-
Is composed of lipids and protein.

9. The plasma membrane (cell membrane) is made of two
layers of phospholipids. The membrane has many
proteins embedded in it.
The plasma membrane regulates what enters and leaves
the cell. Many molecules cross the cell membrane by
diffusion and osmosis.

10. Endoplasmic reticulum:-

11. The endoplasmic reticulum is a network
of tubules and flattened sacs that serve a
variety of functions in the cell. There are
two regions of the ER that differ in both
structure and function. One region is
called rough ER because it has ribosomes
attached to the cytoplasmic side of the
membrane. The other region is called
smooth ER because it lacks attached
ribosomes

12. Mitochondria :-
(1µm in diameter and 7µm in length)
Dis. by Rudolf Albrecht von Kölliker.
Term given by Benda.
Mostly protein, but also contains some lipid, DNA and RNA
Power house of the cell
Energy is stored in high energy phosphate bonds of ATP
Mitochondria convert energy from the breakdown of glucose
into adenosine triphosphate (ATP)
Responsible for aerobic respiration.

13.  Metabolic activity of a cell is related to the number of
cristae (larger surface area) and mitochondria
 Cells with a high metabolic activity have many well
developed mitochondria

15. Chloroplast:-

16. Chloroplasts are specialized organelles found in all
higher plant cells. These organelles contain the
plant cell's chlorophyll responsible for the plant's
green colour and the ability to absorb energy from
sunlight. This energy is used to convert water plus
atmospheric carbon dioxide into metabolizable
sugars by the biochemical process of
photosynthesis. Chloroplasts have a double outer
membrane. Within the stroma are other
membrane structures - the thylakoids. Thylakoids
appear in stacks called "grana" (singular =
granum).

17. •Vacuoles:-

18. A vacuole is a membrane-bound sac that plays roles
in intracellular digestion and the release of cellular
waste products. In animal cells, vacuoles are
generally small.
Vacuoles tend to be large in plant cells and play a
role in turgor pressure. When a plant is well-
watered, water collects in cell vacuoles producing
rigidity in the plant. Without sufficient water,
pressure in the vacuole is reduced and the plant
wilts.

19. Lysosomes:-
• Christian de Duve (1917).
stomach of the cell

20.  Performs intracellular digestion - more numerous in cells
performing phagocytosis.
 Limiting membrane keeps digestive enzymes separate from
the cytoplasm.
 Lysosomal enzymes digest particles
o They function optimally at pH 5 and are mostly inactive
at cytosolic pH
o Lysosomal enzymes are synthesized on rough ER
o Transferred to the Golgi apparatus for modification and
packaging

21. Ribosome :-

22. Assembly of protein chains.
The ribosome accomplishes the reading of the
messenger RNAs and the binding of amino
acids to the transfer RNAs to build up the
protein structures.
This process is called translation, a word that
seems appropriate since it translates the four-
character alphabet of the bases used in the
genetic code to proteins built in the twenty-
character alphabet of amino acids.

23. Nucleus :-

24. • Surrounded by a double membrane.
•nucleus regulates all cell activity.
• It communicates with the surrounding
cytosol via numerous nuclear pores.
• Dic. by Robert brown

25. Golgi complex :-

26. •discovered in 1898 by Italian physician Camillo
Golgi
•The processing of proteins generated in
endoplasmic reticulum
•They condense the proteins synthesized in the
ribosomes.
•They help in the formation of cell plate during
cell division