Week_2-_Microscopy_Cell_Structure.pdf

Cellular Structures and Functions Mary Quenie E. Velasco  CLO AND TLO CLO2. Understand the cell as the basic structural and functional unit of life TLO2. Describe the fundamental structure and function of the cell including its organelles  LEARNING...

Cellular Structures and Functions Mary Quenie E. Velasco  CLO AND TLO CLO2. Understand the cell as the basic structural and functional unit of life TLO2. Describe the fundamental structure and function of the cell including its organelles  LEARNING OBJECTIVES Identify the different organelles of the cell. Explain the functions of the different organelles of the cell.  A L B the Cell Theory I O 9 7 0 0 1665 - Robert Hooke discovered and described the fundamental / 2 unit of all living things (cells) by examining thin slices of cork 0 0 6 J K  A L B I O 9 1674 - The first man to witness a live cell under a microscope was 7 0 Anton Van Leeuwenhoek, describing the algae Spirogyra and named the 0 / 2 moving organisms animalcules, meaning "little animals" 0 0 6 J K 1838 – Matthias Schleiden suggested that all plants are made of cells 1839 – Theodor Schwann suggested the same for animals General cell theory emerged: “the basic unit structure and function of all living organisms is the cell” 1855 – Rudolph Virchow’s theory: “all cells arise from pre-existing cells by cell division”  CELL THEORY All living things are made up of cells. Cells are the smallest working unit of all living things. All cells come from pre- existing cells through cell division. Type of Cells  Prokaryotic Cells Prokaryotic (“before” “nucleus”) cells lack a membrane bound nucleus Prokaryotic cells are also much smaller than eukaryotic Domains Bacteria and Archaea are prokaryotic All cells contain – Cell membrane (plasma membrane) – Cytoplasm – Genetic material  Prokaryotic cells contain Prokaryotic Cells – Cell membrane Allows substances in and out – Cytoplasm Fluid that fills cell – Ribosomes Protein synthesis – Cell wall Holds cell shape – Pili Allows attachment to solid surfaces – Flagella (some cells) movement  Eukaryotic Cells Eukaryotic (“true” “nucleus”) cells have a membrane bound nucleus Domain Eukarya contains eukaryotic cells Larger than prokaryotic cells Less surface area to volume Contains organelles (“little organs”) that perform specific functions  Animal Cell Eukaryotic Cells Plant Cell – Notice the cell wall, chloroplasts, and large central vacuole  The Animal Cells Animal Cells  2. Nucleus Notable structure within the cell The genetic control centre of the cell -chromatin(network of dark-staining threads) Surrounded by nuclear envelope Function: directs cell division control protein synthesis and many of the metabolic activities of the cell  1.Nucleolus largest structure in the nucleus consists of nucleolar organizers, ribosomal RNA, and proteins Function: primarily serves as the site of ribosome synthesis and assembly..  3. Ribosome Tiny spherical structure Bodies in which the amino acids are bound together FUNCTION: Site of protein synthesis An electron micrograph of polysomes held together with mRNA. Image courtesy of Alexander Rich  4. Vesicle A vesicle is a small structure within a cell, consisting of fluid enclosed by a lipid bilayer. FUNCTION: move molecules, secrete substances, digest materials, or regulate the pressure in the cell.  5. Rough Endoplasmic Reticulum Endoplasmic Reticulum - A large interconnecting membrane of Tunnels. Continuous with the nuclear network of interconnected flattened envelope sacs- is studded with ribosomes Function: to make protein( secretory protein), to make more membrane channeling products both to the outside of the cell, via the membrane  8. Smooth Endoplasmic Reticulum network of interconnected tubules, lack of ribomes Function: Synthesizing and secreting of certain steroid hormones, enzymes of carbohydrate metabolism, and enzymes of lipid synthesis.  6. Golgi apparatus (or "Golgi body") Named from Camillo Golgi, an Italian biologist and physician A series of from 3 to 20 parallel flattened sacs closely stacked together, cisternae End of the sacs bud off various vesicles Function: receives and modifies and packages the substances manufactured by ER,  7. Cytoskeleton ▪ an intracellular matrix that supports cell shape and function ▪ The matrix is a dynamic structure composed of three main proteins ▪ Has three components: ▪ microfilaments ▪ microtubules ▪ intermediate filaments Actin filaments are in red, microtubules are in green,  Cytoskeleton  Microtubules- These are long hollow structures approx. 25nm in diameter. Determine shape of the cell, role in the contraction of the spindle and movement of chromosomes and centrioles as well as in ciliary and flagellar motion.  Microfilaments- They are long solid fibers 4-6 nm in diameter. They comprise the contractile protein actin and are responsible for the cell motion.  Intermediate Filaments- They are 8-14nm in diameter and are made up of various subunits. They form a flexible scaffolding or cell and help it resist external pressure.  In their absence cell ruptures more easily and when they are abnormal in human, blistering in common.  The proteins that makeup intermediate filament are cell types specific and are thus frequently used as cellular markers. Microtubules  9. Mitochondrion Are spherical to rod- shaped structures from 0.2 to 7µm; a doubled layer membrane Cristae( complex folding of inner membrane) Mobile structures, capable of changing their shapes “powerhouse of the cell” Function: produced energy in the form of ATP  10. Vacuole ▪ enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution Function: Digestion; storage of chemicals, cell enlargement; water balance  11. Cytosol & Cytoplasm Cytoplasm is the entire Cytosol is known as content within the cell the matrix of the membrane. Protoplasm that cytoplasm. surrounds the nucleus Protoplasm https://ph.images.search.yahoo.com/  12. Lysosome Produced by the rough ER and the Golgi apparatus. Two Greek words, “breakdown body” Are membrane bound, dense- appearing structures that contain enzymes( acid hydrolases) Function: acts as waste – disposal units, digesting and removing foreign material Lysosome diagram showcasing enzyme complexes within the “suicidal bag” single-walled membrane Sournce: https://byjus.com/biology/lysosomes/  Intracellular digestion Autophagy Autolysis during apoptosis Extracellular digestion  13. Centrosome Centriole—pair of small rod –like structure there are attached microtubules in the wall quite near the nucleus inside of it is the centriole Function: active in the process of cell division( mitosis)  14. Cell Membrane The border of the cell About 8 nm thick A semi-permeable membrane Composed of proteins and lipids Unit membrane Model-tripartite arrangement of the plasma membrane (protein-lipid-protein) Cell Membrane Cell Membrane: Fluid Mosaic Model  Membrane components Membrane LIPIDS 1. phospholipids 2. glycolipids 3. cholesterol Phospholipid bilayer  Functions of Integral Proteins Channel protein Carrier protein Cell recognition protein/ cell identity markers Receptor protein Enzymatic protein Cytoskeleton anchor protein https://ph.images.search.yahoo.com/ Cell Membrane Modifications 1. Microvilli Cell Membrane Modifications 2. glycocalyx Cell Membrane Modifications 3. Cell wall  Peroxisomes  Diameter- 0.5µm  A lipid bilayer membrane surrounds which regulates what enters or exits the peroxisomes. oxidation reactions and break down metabolic hydrogen peroxide. Structure is like that of the lysosomes but with a different chemical composition  Peroxisomes can be formed by the budding of ER, or by division  Parts of Animal Cell 1. Nucleus 2. Nucleolus 3. Ribosome 4. Vesicle 5. Rough endoplasmic reticulum 6. Golgi apparatus (or "Golgi body") 7. Cytoskeleton 8. Smooth endoplasmic reticulum 9. Mitochondrion 10. Vacuole 11. Cytosol & Cytoplasm 12. Lysosome 13. Centrosome 14. Cell membrane