MICRO 401 Exam 2 Questions with Correct Answers Latest Update

MICRO 401 Exam 2 Questions with Correct Answers Latest Update Typical eucarya cell - Answers -nucleated -usually multiple chromosomes -ER host ribosomes -mitochondria Typical prokaryote - Answers -small and less complex that eukaryotic cells -no nucleus -no mitochondria -no membrane bound organelles -DNA usually in one circular chromosome -2-8 microns long Bacteria cell wall - Answers contains peptidoglycan Archea cell wall - Answers cell membrane covered by S-layer (wall) of glycoproteins or polysacchrides Fungi cell wall - Answers often contains chitin Plant cell wall - Answers usually contains cellulose What common bacteria shares name with rod shape? - Answers bacillus is a genus name of bacteria which are common in marine sendiments -bacillus is the name for rod shaped bacteria Outside cell wall - Answers outside cell wall: slime layer capsule, or extracellular polysaccharide (EPS) slime layer-loose, unstructured fluid capsule- attached to cell many hinder phagocytosis EPS- allows attachment to surfaces. provides physically barrier to antibiotics and bleach taxis - Answers Movement toward or away from a stimulus. Cell wall - Answers surrounds cytoplasmic membrane in all known marine prokaryotes, but not all prokaryotes -rigid, determines cell shape and anchors flagella Bacterial cell wall - Answers Exploit in two ways: 1. classification: Gram+ or gram- based on wall composition 2. control: enzyme in tears, saliva, egg white, breaks down bacteria cell walls Gram-negative bacteria - Answers 1. thinner than gram+ cell wall: ~20% peptidoglycan (aka murein) ie alternating molecules of N-acetylglucosamine and N-acetylmuramic acid 2. outer membrane contains lipopolysacchride (LPS) also known as endo toxin. unique to this bacteria Gram-positive bacteria - Answers ~90% peptidoglycan and teichoic acid, which links to muramic acid to join peptidoglycans -rare among pelagic marine bacteria, more common in sediments Bacteria and archea cytoplasmic membrane - Answers Plasma membrane -fluid mosaic model: phospholipids arrange hydrophilic heads out -allow passage of small molecules -membrane bound transporters allow passage of ions and other large molecules Archea membrane - Answers isoprenoids linked to L-glycerol by ether linkages -biomarkers for archea Bacteria cell membrane - Answers fatty acids linked to D-glycerol by ester linkages -contain hopanoids(five rings) Eucarya cell membrane - Answers fatty acids linked to D-glycerol by ester linkages -contain sterols (4 rings) What varies between bacterial/euk cell membranes and archea? - Answers -Bacteria/eucarya: have ester linkages and D-glycerol -archea: have ether linkages and contain L-glycerol Endospores - Answers -some cells sporulate in poor conditions Prokaryote genomes - Answers circular chromosome of 0.11 to ~ 13 mln nt, -usually contain 1 but may have 2/3 Oligotroph - Answers heterotrophs growing on media with low organic substrate Starvation-survival - Answers microbes in the ocean survive long periods in oligotrophic conditions and thrive when nutrients are right -rapid growth when right energy sources are available no growth otherwise -other responses to starvation -- levels of DNA, RNA some protein decline