Cell and cell organelles

For UG students

1. CELL & CELL ORGANELLES Binaya Tamang Lecturer UCMS-TH

2. Introduction The cell is the structural and functional unit of life. Types: TWO Prokaryotes lack of well defined nucleus Devoid of nuclear envelop. possess simple structure. e.g. bacteria, blue green algae, mycoplasma Eukaryotes: possess a well defined nucleus Have nuclear envelop more complex in their structure e.g. animals and plants.

3. Comparison

4. Cell Organelles

5. 1. Cell membrane Fluid and mosaic model ( Singer & Nicolson) phospholipid bilayer Protein  floating on it Cholesterol Small amount of carbohydrates Glycoprotein & glycolipid Function Separates cell from external environment Protects cell Insulating property Forms framework Has selective permeability Receptor site for signal

6. 2.Mitochondria : ATP mill / power house of cell Spherical ,oval or rod like bodies ( 0.5-1 µm X 7 µm) Double membrane 1-100 per cell Inner membrane fold into finger like projection: cristae Absent in RBC Functions Electron Transport Chain: ATP Krebs cycle β oxidation of fatty acid Gluconeogenesis

7. 3.Nucleus: Control center of cell Bcoz : Contain DNA  chemical basis of gene govern all function of cell. Largest & Spherical in shape Most prominent cell organelle Double membrane. Inner membrane has nuclear pores of 90 nm  free passage Outer membrane is continuous with endoplasmic reticulum In side it, nucleolus : RNA processing & ribosome synthesis Function DNA replication & RNA synthesis Home for chromosome nucleolus

8. 4.Ribosome ( Engine of cell) Smallest and highest in number Protein factory Ribonucleic protein ( RNA + protein) Structure some free in cytoplasm some attached to ER 70s(prokaryote) & 80s(eukaryote) Have two subunits (large & small) 70s : 50s + 30s , 80s : 60s + 40s Function Read instructions to build proteins from mRNA protein factories

9. 5.Endoplasmic Reticulum The network of membrane or tubules extended throughout cytoplasm. from nucleus to plasma membrane Types Rough ER Smooth ER

10. 6.Golgi bodies “ sorting sites” Cluster of membrane vesicles Appears like : Stacks of flattened sacs Function: Receive and modify protein made by rough ER protein packaging, modify protein & secretion glycosylation and sulfation of protein Vesicle fuses with plasma membrane protein is released by exocytosis E.g. pancreatic enzymes & insulin

11. Vesicle with modified protein

12. 7.Lysosome ( Suicidal bag) In Town, solid waste are decomposed in incinerators. Inside cell  lysosome Spherical vesicles , single membrane. Aka: Suicidal bag, scavengers of cell It contains Hydrolases enzymes ( glucosidase, cathepsin, lipase, ribonuclease) Acidic pH 4.6-5 Function Digest food [ used to make energy] Clean up & recycle [digest broken organelles]

13. Lysosomes small food particle vacuole digesting food lysosomes digesting broken organelles 13

14. 8.Peroxisomes Are single membrane and have granular matrix. Spherical and oval in shape Imp: TWO enzymes catalase peroxidase Function Protects the cell from free radicals and antioxidant. Also involved in oxidation of long chain fatty acids(>C18),

15. 9.Cytosol and cytoskeleton The cellular matrix is aqueous gel like medium  cytosol . Consist of several enzymes , metabolites and salts. Place for : glycolysis, protein synthesis, glycogen metabolism, HMP shunt pathway etc. Cytoskeleton Cytoplasm actually contains a complex of protein filaments. 3 types- microtubules, actin filaments intermediate filaments. Role in cell morphology, intracellular transport, cell motility, cell division ( centrioles)

16. cell membrane cell boundary controls movement of materials in & out  recognizes signals cytoplasm jelly-like material holding organelles in place mitochondria make ATP energy from sugar + O 2 nucleus protects DNA controls cell ribosomes builds proteins ER helps finish proteins makes membranes Golgi apparatus finishes, packages & ships proteins lysosome food digestion garbage disposal & recycling vacuole & vesicles transport inside cells storage centrioles cell division

17. 👍 Thank you😊