Python Notes for mca i year students osmania university.docx
Tour of the Cell
1. A Tour of the Cell Tour Guide… Mrs. Erin Fortenberry
2. Question ? Can cells be seen with the naked eye? Yes, a few are large enough, but most require the use of a microscope.
3.
4. Microscope History 1590 - Janseen Brothers invent the compound microscope. 1665 - Robert Hooke “discovers” cells in cork. Early 1700’s - von Leeuwenhoek makes many observations of cells including bacteria.
5. Light Microscope - LM Uses visible light to illuminate the object. Relatively inexpensive type of microscope. Can examine live or dead objects.
6. Electron Microscopes Use beams of electrons instead of light. Invented in 1939, but not used much until after WWII.
11. History of Cells Robert Hooke - Observed cells in cork. Coined the term "cells” in 1665.
12. History of Cells 1833 - Robert Brown, discovered the nucleus. 1838 - M.J. Schleiden, all plants are made of cells. 1839 - T. Schwann, all animals are made of cells.
13. Cell Theory All living matter is composed of one or more cells. The cell is the structural and functional unit of life.
14. Types of Cells Prokaryotic - lack a nucleus and other membrane bounded structures. Eukaryotic - have a nucleus and other membrane bounded structures.
37. Endoplasmic Reticulum Often referred to as ER. Makes up to 1/2 of the total membrane in cells. Often continuous with the nuclear membrane.
38.
39. Structure of ER Folded sheets or tubes of membranes. Very “fluid” in structure with the membranes constantly changing size and shape.
40. Types of ER Smooth ER: no ribosomes. Used for lipid synthesis, carbohydrate storage, detoxification of poisons. Rough ER: with ribosomes. Makes secretory proteins.
41. Golgi Apparatus Structure: parallel array of flattened cisternae. (looks like a stack of Pita bread) 3 to 20 per cell. Likely an outgrowth of the ER system.
42.
43. Function of Golgi Bodies Processing - modification of ER products. Distribution - packaging of ER products for transport.
44. Golgi Vesicles Small sacs of membranes that bud off the Golgi Body. Transportation vehicle for the modified ER products.
50. Function Breakdown and degradation of cellular materials. Contains enzymes for fats, proteins, polysaccharides, and nucleic acids. Over 40 types known.
51.
52.
53. Lysosomes Important in cell death. Missing enzymes may cause various genetic enzyme diseases.
54. Vacuoles Structure - single membrane, usually larger than the Golgi vesicles. Function - depends on the organism.
55. Protists Contractile vacuoles - pump out excess water. Food vacuoles - store newly ingested food until the lysosomes can digest it.
56.
57. Plants Large single vacuole when mature making up to 90% of the cell's volume. Tonoplast - the name for the vacuole membrane.
58.
59. Function Water regulation. Storage of ions. Storage of hydrophilic pigments. (e.g. red and blues in flower petals).
60. Function: Plant vacuole Used to enlarge cells and create turgor pressure. Enzymes (various types). Store toxins. Coloration.
64. Mitochondria Structure: 2 membranes. The inner membrane has more surface area than the outer membrane. Matrix: inner space. Intermembrane space: area between the membranes.
65.
66. Inner Membrane Folded into cristae. Amount of folding depends on the level of cell activity. Contains many enzymes. ATP generated here.
67. Function Cell Respiration - the release of energy from food. Major location of ATP generation. “Powerhouse” of the cell.
68. Mitochondria Have ribosomes. Have their own DNA. Can reproduce themselves. May have been independent cells at one time.
69. Chloroplasts Structure - two outer membranes. Complex internal membrane. Fluid-like stroma is around the internal membranes.
70.
71. Inner or Thylakoid Membranes Arranged into flattened sacs called thylakoids. Some regions stacked into layers called grana. Contain the green pigment chlorophyll.
80. Microtubules Structure - small hollow tubes made of repeating units of a protein dimer. Size - 25 nm diameter with a 15 nm lumen. Can be 200 nm to 25 mm in length.
93. Functions Muscle contraction. Cytoplasmic streaming. Pseudopodia. Cleavage furrow formation. Maintenance and changes in cell shape.
94. Intermediate Filaments Fibrous proteins that are super coiled into thicker cables and filaments 8 - 12 nm in diameter. Made from several different types of protein.
97. Cytoskeleton Very dynamic; changing in composition and shape frequently. Cell is not just a "bag" of cytoplasm within a cell membrane.
98. Cell Wall Nonliving jacket that surrounds some cells. Found in: Plants Prokaryotes Fungi Some Protists
99. Plant Cell Walls All plant cells have a Primary Cell Wall. Some cells will develop a Secondary Cell Wall.
100.
101. Primary Wall Thin and flexible. Cellulose fibers placed at right angles to expansion. Placement of fibers guided by microtubules.
102. Secondary Wall Thick and rigid. Added between the cell membrane and the primary cell wall in laminated layers. May cover only part of the cell; giving spirals. Makes up "wood”.
103. Middle Lamella Thin layer rich in pectin found between adjacent plant cells. Glues cells together.
104. Cell Walls May be made of other types of polysaccharides and/or silica. Function as the cell's exoskeleton for support and protection.
105. Extracellular Matrix - ECM Fuzzy coat on animal cells. Helps glue cells together. Made of glycoproteins and collagen. Evidence suggests ECM is involved with cell behavior and cell communication.
108. Plasmodesmata Channels between cells through adjacent cell walls. Allows communication between cells. Also allows viruses to travel rapidly between cells.
112. Tight Junctions Very tight fusion of the membranes of adjacent cells. Seals off areas between the cells. Prevents movement of materials around cells.
113. Desmosomes Bundles of filaments which anchor junctions between cells. Does not close off the area between adjacent cells. Coordination of movement between groups of cells.
114. Gap Junctions Open channels between cells, similar to plasmodesmata. Allows “communication” between cells.
