BMSC 210 Midterm 1 Review | 100% Correct Answers | Verified | Latest 2024 Version

BMSC 210 Midterm 1 Review | 100% Correct Answers | Verified | Latest 2024 Version Describe Koch's postulates and the significance of his experiment - Koch's postulates: with the use of anthrax provided a basis for Germ Theory. the experiment: extract blood from diseased individual grow culture put culture into healthy individual, develop disease extract this blood, culture it to show same results Describe the importance of Louis Pasteur and the significance of his swan-neck flask experiment - Disproved spontaneous generation (miasma) the swan-neck made contamination- and growth- visible Why are viruses not considered living? - they do not perform metabolism and they are parasitic (cannot grow on own), also missing cytoplasm How do light microscopes work? What light microscopes did we learn about? - Use of light to make observation, can see live specimen Brightfield: absorb and scatter light, use gram staining (due to lack of pigment), can observe motility Darkfield: specimen deflect and scatter light Phase-Contrast: very detailed, high contrast Differential Interference Contrast: #D w/ use of 2 light beams Fluorescence: use of fluorochromes, UV light, and excitation (confocal: 3D fluorescence) How do electron microscopes work? What types have we learned about? - Use of electrons and magnets, higher mag/res, but specimen must be dead TEM: go through specimen, can see inside SEM: electrons bounce off explain how gram staining works? - 1) stain with crystal violet (cells purple) 2) add iodine (cells purple) 3) de-colorize with alcohol (G- lose colour) 4) counter-stain with safranin (G- stay purple, G+ pink) What is the cell envelope? What is it composed of? - Cell envelope: layers around the cytoplasm -Cytoplasmic membrane: selectively permeable barrier -Cell Wall: prevent osmotic lysis and maintain shape Bacteria: made of peptidoglycan (lysozyme-sensitive) G+: thick, presence of techoic and lipotechoic acid, interbridge G-: thin so presence of outer membrane, presence of lipopolysaccharide (LPS) -S-Layer: outermost layer, protein mesh Bacteria: protection/adhesion archaea: act as cell wall (keep shape, prevent osmotic lysis) -Capsule & Slime Layer: sticky polysaccharide coat capsule: tight, strong attachment slime layer: loose what is the difference between Bacteria and Archaea cell walls? - cell walls of bacteria are made of peptidoglycan which is lysozyme-sensitive; archaea are lysozyme insensitive what are acid fast bacteria? - G+ w/ wax coat differentiate between G+ and G- bacteria - G+: have thick peptidoglycan wall and interbridge presence of techoic and lipotechoic acid G-: have outer membrane presence of LPS Compare and Contrast capsule and slime layer - both are outermost layers of the cell envelope made of sticky polysaccharides capsule: tight slime layer: loose Explain how the ABC transporter system works. What does ABC stand for? - ATP Binding Cassette uses ATP to transport molecules across a membrane