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Cytology

Cytology. The study of cells. Cell Types. 1) Procaryotic 2) Eucaryotic. Procaryotic Cells. Cells lack a true nucleus Cells have only non-membrane bound organelles Bacteria and some algae. Eucaryotic Cells. Cells have a true nuclues Cells have membrane bound organelles

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Cytology

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  1. Cytology The study of cells

  2. Cell Types 1) Procaryotic 2) Eucaryotic

  3. Procaryotic Cells Cells lack a true nucleus Cells have only non-membrane bound organelles Bacteria and some algae

  4. Eucaryotic Cells Cells have a true nuclues Cells have membrane bound organelles Most protists All fungi, plants, animals, and humans

  5. Cellular Structures 1) Boundary 2) Cytoplasm 3) Nucleus

  6. Cellular Boundaries • Plasma membrane • Cell wall • Middle lamella • Capsule / sheath / slime coat

  7. Plasma membrane • The outermost boundary of all cells • Semi-permeable • Phospholipid bilayer • Proteins are embedded within • transportation • cell recognition • cell adhesion

  8. Plasma membrane

  9. Laminin video clip by louiegiglio

  10. Cell wall • Rigid structure surrounding some cells • all procaryotes • plants, algae, fungi, and protozoans • Porous • Composed of cellulose or chitin

  11. Middle lamella • Layer between two adjacent cell walls • Acts as a lubricant

  12. Capsule / Sheath / Slime coat • A cellular secretion of polysaccharides • Surrounds unicellular or colonial organisms • Protective • Attackers must first dissolve the capsule or penetrate it

  13. Cytoplasmic matrix Ribosomes Endoplasmic reticulum Mitochondria Plastids Golgi body Lysosomes Vacuoles Centrioles Flagellum Cilia Cytoplasmic Organelles

  14. Cytoplasmic Matrix(aka: the cytoplasm) • Located in all types of cells • A semi-solid watery substance in which all other organelles are suspended • Think “jello salad” • Provides structure to the cell thanks to its cytoskeleton • Cytoplasmic streaming – contents are always moving

  15. Ribosome • Located in all types of cells • Mass of proteins and RNA • Function: protein synthesis

  16. Endoplasmic Reticulum • Seen only in eukaryotic cells • Folds of cellular membranes • Continuous with both the plasma membrane and the nuclear membrane • Functions: • Provide flexible but structural shape • Synthesis of proteins, lipids, & polysaccharides • Movement of substances throughout the cell

  17. Types of ER’s

  18. Mitochondria • Seen only in eukaryotic cells • A double-membrane bound bean shape structure • Inner membrane is folded to form cristae • Function: cellular respiration • Quantity is dependent on the activity level of the cell

  19. Mitochondria

  20. Plastids • Seen only in plants and algae • A double-membrane bound structure • Function: synthesis and storage of polysaccharides

  21. Types of Plastids • Chromoplasts • Contains the pigments used in synthesizing polysaccharides • Given specific names based on the type of pigment in the chromoplast • Most important chromoplast: the chloroplast (green pigment)

  22. Chloroplast • Inner membrane is folded to form the thylakoid • Stack of thylakoids is called a grana • Fluid within the chloroplast is called stroma

  23. Types of Plastids • Leucoplasts • Colorless structure • Function: a storehouse of starch • Most numerous in the fleshy, storage areas of plants

  24. Golgi body • Seen only in eukaryotic cells • A flat, curved, membrane structure • Function: • Synthesizing polysaccharides • Final modifications of proteins & lipids for their final destination

  25. Lysosome • Seen only in eukaryotic cells • Small, membrane bound spherical structure • Contains digestive enzymes • Function: • digestion of old, used organelles • digestion of invading cells

  26. Vacuoles • Seen only in eukaryotic cells • Function: storage • 4 types of vacuoles • Phagocytic • Pinocytic • Waste • Contractile

  27. Types of Vacuoles • Phagocytic • Storage of food • Formed by phagocytosis • Pinocytic • Storage of water • Formed by pinocytosis • Waste • Storage of nondigestible material • Fuses with the plasma membrane to release material

  28. Types of Vacuoles • Contractile vacuole • Found in unicellular organisms that live in a freshwater environment • Collects excess water and pushes the water back out of the cell

  29. Centriole • Seen only in eukaryotic cells, except plants • 2 cylinders occurring at right angles to each other • Always located near the nucleus • Function: cell division

  30. Flagellum • Located in all types of cells • Long, tubular extension of the cytoskeleton within the cytoplasm • Small quantity: usually have 1 – 4 flagella on a cell • Function: locomotion of the cell

  31. Cilia • Located in all types of cells • Short extensions of the cytoskeleton • Usually covers the entire cell or a large section of a cell • Function: locomotion of the cell or movement of substances within an organism

  32. Internal Structure of Cilia & Flagella • Both have the same internal structures • Both structures have been used to disprove evolution • Irreducibly complex

  33. Nucleus(the control center of the cell) • Nuclear envelope • Chromatin material • Nucleolus

  34. Nuclear Envelope • Seen only in eukaryotic cells • Porous • Phospholipid bilayer • Continuous with the endoplasmic reticulum

  35. Chromatin Material • Seen in all types of cells • Long, thin strands consisting of DNA and proteins • Function: codes for the information needed for protein synthesis • DNA permits activity of a cell, but it does not decide what the cell is capable of doing • DNA was programmed by God at creation

  36. Nucleolus • An area with a large concentration of RNA (a substance similar to DNA)

  37. Review of Cellular Structures

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