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Cell & Cell organelles. pptx

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Shivaputra patil.
Shivaputra patil.

The human cell is the body’s fundamental building block, functioning as the smallest unit of life. It is equipped with specialized structures called organelles, each of which performs specific tasks that keep the cell alive and functional. Collectively, these organelles enable processes like energy production, waste removal, growth, and reproduction.

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Cell structure and functions Shivaputra Patil Medical Biochemistry
CONTENTS Cell structure Cell types Subcellular organelles Functions
Cell • Cell = Plasma membrane + cytoplasm • Cytoplasm = Cytosol + Subcellular organelles • All subcellular organelles, except ribosomes and cytoskeleton, are compartments within the cell, surrounded by cell membrane and containing their own aqueous fluid.
Cells- Structure INTRODUCTION • The cell is the Basic Structural and Functional Unit of all Living Organisms. • It is the basic unit of biological activity. • Therefore, the Evolution of cells is a crucial milestone in the evolution of life.
The cells of biological systems are divided into two categories. A. Prokaryotes B. Eukaryotes A. Prokaryotes ( Pro - before, karyon – Nucleus). • Lack a well-defined nucleus and possess a relatively simple structure. • Lower organism - bacteria. B. Eukaryotes ( Eu – true/good, karyon – Nucleus) • Have a membrane-enclosed nucleus encapsulating their DNA. • Higher organisms - Plants and animals. Cell types:
Differences Between Eukaryotic and Prokaryotic Cell
Cell & Cell organelles. pptx
Cell Organelles can be Separated by Ultracentrifugation.
Sub Cellular Organelles Nucleus Endoplasmic Reticulum Golgi apparatus Mitochondria Lysosomes Peroxisomes
Nucleus • Structure: Enclosed by a double membrane called the nuclear envelope, which has pores allowing the transport of molecules between the nucleus and cytoplasm. • Function: Acts as the control center of the cell, housing the cell’s DNA and coordinating activities like growth, metabolism, protein synthesis, and reproduction (cell division).
Nucleus • Contains DNA→ condensed with protein →chromatin → chromosomes (23 pairs) • Controls structure and function through genes. • Nucleolus: RNA processing and ribosome synthesis. • Functions: DNA synthesis
Endoplasmic reticulum • Network of interconnected membranes (railway track appearance) • Continuation of the outer nuclear membrane • Two types • Rough endoplasmic reticulum (ribosomes)(RER) • Smooth endoplasmic reticulum (SER)
Functions of Endoplasmic reticulum
Mitochondria • Power house of cell • Spherical, oval – 0.5μm diameter,7μm length. • 2 membranes – • inner – enzymes of ETC • Outer – phospholipase A2,MAO • Soluble matrix: enzymes of the citric acid cycle and urea cycle. • It contains its own specific DNA.
• Spherical, oval or rod-like bodies • Size: 0.2- 0.8 μm • The number of mitochondria in a cell varies. Erythrocytes no mitochondrion Liver cell 800-2500 Mitochondria
• Bilayer OMM – Smooth IMM – convolutes into folds - Cristae 2 Compartments – Intermembrane space – Matrix – Mitochondria are the ‘Power House’ of the Cell. IMM contains the ETC • Matrix- Enzymes of the TCA cycle, Beta Oxidation of FA, etc. Mitochondria
Mitochondria Supply Most of the Cell’s Need for ATP • Production of ATP • Cellular respiration • Oxidation of Carbohydrates and lipids • Urea and heme synthesis.
Clinical Significance • Luft’s disease – Defective energy transduction • Mt. Myopathies – OXPHOS diseases Due to mutation in Mt DNA • Parkinson’s, Cardiomyopathies – age-related degenerative diseases. • Antibiotics inhibiting bacterial protein synthesis do not affect cellular processes but inhibit mitochondrial protein synthesis. • Mitochondria are considered ‘parasites’ that enter the cell during the course of evolution!
Golgi apparatus • Network of flattened smooth membranes and vesicles Functions • Sorting, packing, and secretion of proteins. • It is composed of Cis, Medial and Trans cisternae. • Glycoproteins transported from ER to Cis, then to medial Golgi and finally trans Golgi for temporary storage. • Vesicle traffic in cell.
Lysosomes • Suicidal bag • Contain digestive enzymes (alpha-glucosidase, collagenase, ribonuclease, phospholipases) • Fuse with phagosomes → secondary lysosomes → foreign particles are progressively digested • Clinical significance: lysosomal storage disorder
Cell & Cell organelles. pptx
Clinical application • 1. In gout, urate crystals are deposited around the knee joint. • When it is phagocytosed, it causes damage to the lysosome, causing the release of enzymes, inflammation and arthritis results. • 2. Postmortem autolysis: following cell death, the lysosomes rupture, releasing the hydrolytic enzymes that bring the above changes. • 3. Cathepsins and proteases: involved in the tumor metastasis.
• 4. silicosis: Inhalation of silica into the lungs is engulfed by phagocytes, which leads to the rupture of the lysosomal membrane, leading to the release of enzymes. This stimulates fibrosis and decreases the elasticity of the lung. • 5. Inclusion cell disease: a rare condition in which lysosomes lack the enzymes but are seen in blood. It is a type of protein-targeting defect. The mannose-6-P deficient enzymes cannot reach their destination. Continue…
Peroxisomes • They have granular matrix. • Contain peroxidases, catalase • Platelets, leukocytes • Destroy unwanted peroxides & free radicals.
Cell & Cell organelles. pptx
• Clinical note: deficiency of peroxisomal matrix proteins can lead to adrenoleukodystrophy (ALD) (Brown-children’s disease), Zellweger syndrome and primary hyperoxaluria. • Adrenoleukodystrophy is rare autosomal recessive with progressive degeneration of the brain, liver, and kidney, and it is characterized by the defect of insufficient oxidation of long-chain fatty acids (VLCFA). • Zellweger syndrome: proteins are not transported to the peroxisomes, leading to the formation of empty peroxisomes or ghosts inside the cells.
Cell & Cell organelles. pptx

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Cell & Cell organelles. pptx

  • 1. Cell structure and functions Shivaputra Patil Medical Biochemistry
  • 3. Cell • Cell = Plasma membrane + cytoplasm • Cytoplasm = Cytosol + Subcellular organelles • All subcellular organelles, except ribosomes and cytoskeleton, are compartments within the cell, surrounded by cell membrane and containing their own aqueous fluid.
  • 4. Cells- Structure INTRODUCTION • The cell is the Basic Structural and Functional Unit of all Living Organisms. • It is the basic unit of biological activity. • Therefore, the Evolution of cells is a crucial milestone in the evolution of life.
  • 5. The cells of biological systems are divided into two categories. A. Prokaryotes B. Eukaryotes A. Prokaryotes ( Pro - before, karyon – Nucleus). • Lack a well-defined nucleus and possess a relatively simple structure. • Lower organism - bacteria. B. Eukaryotes ( Eu – true/good, karyon – Nucleus) • Have a membrane-enclosed nucleus encapsulating their DNA. • Higher organisms - Plants and animals. Cell types:
  • 6. Differences Between Eukaryotic and Prokaryotic Cell
  • 8. Cell Organelles can be Separated by Ultracentrifugation.
  • 9. Sub Cellular Organelles Nucleus Endoplasmic Reticulum Golgi apparatus Mitochondria Lysosomes Peroxisomes
  • 10. Nucleus • Structure: Enclosed by a double membrane called the nuclear envelope, which has pores allowing the transport of molecules between the nucleus and cytoplasm. • Function: Acts as the control center of the cell, housing the cell’s DNA and coordinating activities like growth, metabolism, protein synthesis, and reproduction (cell division).
  • 11. Nucleus • Contains DNA→ condensed with protein →chromatin → chromosomes (23 pairs) • Controls structure and function through genes. • Nucleolus: RNA processing and ribosome synthesis. • Functions: DNA synthesis
  • 12. Endoplasmic reticulum • Network of interconnected membranes (railway track appearance) • Continuation of the outer nuclear membrane • Two types • Rough endoplasmic reticulum (ribosomes)(RER) • Smooth endoplasmic reticulum (SER)
  • 14. Mitochondria • Power house of cell • Spherical, oval – 0.5μm diameter,7μm length. • 2 membranes – • inner – enzymes of ETC • Outer – phospholipase A2,MAO • Soluble matrix: enzymes of the citric acid cycle and urea cycle. • It contains its own specific DNA.
  • 15. • Spherical, oval or rod-like bodies • Size: 0.2- 0.8 μm • The number of mitochondria in a cell varies. Erythrocytes no mitochondrion Liver cell 800-2500 Mitochondria
  • 16. • Bilayer OMM – Smooth IMM – convolutes into folds - Cristae 2 Compartments – Intermembrane space – Matrix – Mitochondria are the ‘Power House’ of the Cell. IMM contains the ETC • Matrix- Enzymes of the TCA cycle, Beta Oxidation of FA, etc. Mitochondria
  • 17. Mitochondria Supply Most of the Cell’s Need for ATP • Production of ATP • Cellular respiration • Oxidation of Carbohydrates and lipids • Urea and heme synthesis.
  • 18. Clinical Significance • Luft’s disease – Defective energy transduction • Mt. Myopathies – OXPHOS diseases Due to mutation in Mt DNA • Parkinson’s, Cardiomyopathies – age-related degenerative diseases. • Antibiotics inhibiting bacterial protein synthesis do not affect cellular processes but inhibit mitochondrial protein synthesis. • Mitochondria are considered ‘parasites’ that enter the cell during the course of evolution!
  • 19. Golgi apparatus • Network of flattened smooth membranes and vesicles Functions • Sorting, packing, and secretion of proteins. • It is composed of Cis, Medial and Trans cisternae. • Glycoproteins transported from ER to Cis, then to medial Golgi and finally trans Golgi for temporary storage. • Vesicle traffic in cell.
  • 20. Lysosomes • Suicidal bag • Contain digestive enzymes (alpha-glucosidase, collagenase, ribonuclease, phospholipases) • Fuse with phagosomes → secondary lysosomes → foreign particles are progressively digested • Clinical significance: lysosomal storage disorder
  • 22. Clinical application • 1. In gout, urate crystals are deposited around the knee joint. • When it is phagocytosed, it causes damage to the lysosome, causing the release of enzymes, inflammation and arthritis results. • 2. Postmortem autolysis: following cell death, the lysosomes rupture, releasing the hydrolytic enzymes that bring the above changes. • 3. Cathepsins and proteases: involved in the tumor metastasis.
  • 23. • 4. silicosis: Inhalation of silica into the lungs is engulfed by phagocytes, which leads to the rupture of the lysosomal membrane, leading to the release of enzymes. This stimulates fibrosis and decreases the elasticity of the lung. • 5. Inclusion cell disease: a rare condition in which lysosomes lack the enzymes but are seen in blood. It is a type of protein-targeting defect. The mannose-6-P deficient enzymes cannot reach their destination. Continue…
  • 24. Peroxisomes • They have granular matrix. • Contain peroxidases, catalase • Platelets, leukocytes • Destroy unwanted peroxides & free radicals.
  • 26. • Clinical note: deficiency of peroxisomal matrix proteins can lead to adrenoleukodystrophy (ALD) (Brown-children’s disease), Zellweger syndrome and primary hyperoxaluria. • Adrenoleukodystrophy is rare autosomal recessive with progressive degeneration of the brain, liver, and kidney, and it is characterized by the defect of insufficient oxidation of long-chain fatty acids (VLCFA). • Zellweger syndrome: proteins are not transported to the peroxisomes, leading to the formation of empty peroxisomes or ghosts inside the cells.

Editor's Notes

  1. Mitochondrial DNA