Exam One Study Guide - Microbio.docx

Cell membrane 44 what are phospholipids are made of

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Cell membrane 44. What are phospholipids are made of? What is the important feature of these molecules? Phospholipids are made up of two fatty acids attached to a glycerol backbone. Important feature: the tails are hydrophobic and the heads are hydrophilic 45. Compare the prokaryotes/eukaryotes for the composition/presence of cell wall/cell membrane Cell wall:
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o Prokaryotes have a cell wall. Composed of peptidoglycan o Eukaryotes do not have a cell wall. But if present, includes chitin and cellulose Cell membrane: o Prokaryotes: carbohydrates and lacks sterols. o Eukaryotes: carbohydrates and sterols that act as receptors. 46. Briefly explain chemiosmotic mechanism of ATP production. Page 126 Chemiosmosis: ATP synthesis using the ETC. involved oxidative phosphorylation. Steps for chemiosmosis: o Proton pumps in the chain pump actively transport protons across the membrane as electrons from NADH pass down the ETC. o This pumping is one-directional, which establishes a proton gradient. This results in an electrochemical gradient that has potential energy called the proton motive force. o The protons on the side with higher concentration can only diffuse across the membrane through special protein channels that contain ATP synthase. Once this flow happens, energy is released and used by the enzyme to synthesize ATP from ADP and i ¿ P ¿ . 47. What is the difference between obligate aerobes, and facultative anaerobes. Obligate aerobes: require oxygen for growth Facultative anaerobes: can grow both with or without oxygen, but when oxygen is present growth is greater 48. What Bacteria are capable of doing if they possess: Plasmid: passing along genetic information such as antibiotic resistant genes or the production of toxins. Capsule: important in contributing to the degree to which a pathogen causes disease and protect pathogenic bacteria from phagocytosis Pili: provide motility and DNA transfer 49. What is biofilm? What is its significance? Biofilm: a microbial community that usually forms as a slimy layer on a surface. Positive significance: o Protect your mucous membranes from harmful microbes o In lakes, they provide food for aquatic animals Negative significance: o Can clog water pipes o On medical implants, they can cause infections such as endocarditis (inflammation of the heart.) 50. Describe what occurs during the lag phase of bacterial growth. Page 167
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Lag phase: intense activity preparing for microbial growth but no increase in population. Log phase: exponential increase in population (we use this phase to determine generation time because it is at a constant minimum) Stationary: equilibrium is reached due to bacteria approaching their carrying capacity Death phase: population decreases at a logarithmic rate. 51. Define sporulation, germination and vegetative stage of life. Importance of endospores? Sporulation: the formation of nearly dormant forms of bacteria Germination: the development of a plant from a seed or spore after a period of dormancy Vegetative stage of life: bacterial cells that are metabolizing and undergoing binary fission Endospores form to keep the bacteria alive in extreme conditions or environmental stress 52. List and compare four major polymers with respect to their: Carbohydrates: o Building blocks: glucose (sugar) o Example: peptidoglycan o Function: energy source o Location in cell: cell wall Lipids: o
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