Bacteria and Archaea Lesson PDF

ARCHAEBACTERIA AND EUBACTERIA 🞆 Why did the bacteria cross the microscope? 🞆 TO GET TO THE OTHER SLIDE 🞆 What do you remember about prokaryotic cells? BACTERIA: PROKARYOTIC CELLS 🞆 Single celled organisms that are capable of independent life. 🞆 much smaller, measured in microm...

ARCHAEBACTERIA AND EUBACTERIA 🞆 Why did the bacteria cross the microscope? 🞆 TO GET TO THE OTHER SLIDE 🞆 What do you remember about prokaryotic cells? BACTERIA: PROKARYOTIC CELLS 🞆 Single celled organisms that are capable of independent life. 🞆 much smaller, measured in micrometers (um) and more simple than eukaryotes. 🞆 prokaryotes are molecules surrounded by a membrane and cell wall. 🞆 they lack a true nucleus and don’t have complex organelles like mitochondria, etc. 🞆 large surface-to-volume ratio: nutrients can easily and rapidly reach any part of the cells interior ANATOMY OF A BACTERIA CELL ANATOMY OF A BACTERIA CELL 🞆 Outer layer – two components: 1. Rigid cell wall (contains peptidoglycan) 2. Cytoplasmic (Cell/ Plasma) membrane – present beneath cell wall 🞆 Cytoplasm – has cytoplasmic inclusions, ribosomes, nucleoid region (contains DNA) 🞆 Additional structures – plasmid (extra circular DNA), slime layer, capsule (protection), flagella (movement), fimbriae/pili (attachment to other bacteria) 🞆 Bacteria are of immense importance because of their rapid growth, reproduction, and mutation rates, as well as, their ability to exist under adverse conditions. 🞆 The oldest fossils known, nearly 3.5 billion years old, are fossils of bacteria- like organisms. ARCHAEBACTERIA Methanogens These Archaebacteria are anaerobes. They make methane (natural gas) as a waste product. They are found in swamp sediments, sewage, and in buried landfills. Halophiles 🞆 Salt-loving Archaebacteria that grow in places like the Great Salt Lake of Utah or salt ponds on the edge of San Francisco Bay. Large numbers of certain halophiles can turn these waters a dark pink. 🞆 Use a pigment, called bacteriorhodopsin for a type of photosynthesis that does not produce oxygen. Thermophiles 🞆 Archaebacteria from hot springs and other high temperature environments. Some can grow above the boiling temperature of water EUBACTERIA Cyanobacteria This is a group of bacteria that includes some that are single cells and some that are chains of cells. You may have seen them as "green slime" in your aquarium or in a pond. Cyanobacteria can do "modern photosynthesis", which is the kind that makes oxygen from water. All plants do this kind of photosynthesis and inherited the ability from the cyanobacteria. 🞆 Other Bacteria live symbiotically in the guts of animals or elsewhere in their bodies (in balanced numbers) 🞆 For example, bacteria (E.Coli ) in your gut produce vitamin K which is essential to blood clot formation. 🞆 Still other Bacteria live on the roots of certain plants, converting nitrogen into a usable form. 🞆 Bacteria put the tang in yogurt and the sour in sourdough bread. 🞆 Saprobes help to break down dead organic matter. 🞆 Bacteria make up the base of the food web in many environments. Streptococcus thermophilus in yogurt BACTERIAL CLASSIFICATION Bacteria can be classified according to: 🞆 Shape 🞆 Cell wall Structure (gram + vs gram -) 🞆 Metabolism (autotroph vs heterotroph) 🞆 Endospore formation SHAPES OF BACTERIA CELL WALL STRUCTURE: GRAM STAINING 🞆 The Gram stain, which divides most clinically significant bacteria into two main groups, is the first step in bacterial identification. 🞆 Bacteria stained purple are Gram + - their cell walls have thick peptidoglycan layer. 🞆 Bacteria stained pink are Gram – their cell walls have a thin peptidoglycan layer. In Gram-positive bacteria, the purple crystal violet stain is trapped by the layer of peptidoglycan which forms the outer layer of the cell. In Gram-negative bacteria, the outer membrane of lipopolysaccharides prevents the stain from reaching the peptidoglycan layer. The outer membrane is then permeabilized by acetone treatment, and the pink safranin METABOLISM There are many ways bacteria obtain energy: autotrophic (make food) and heterotrophic 1. Photoautotrophic bacteria – cyanobacteria use photosynthesis to obtain energy. 2. Chemoautrophic bacteria - use chemical reactions instead of light to convert carbon dioxide into sugar eg. Thermophiles, halophiles (archae) 3. Heterotrophic bacteria – get energy from either consuming dead plants and animals METABOLISM 🞆 Depending on the species, bacteria can be aerobic which means they require oxygen to live or anaerobic which means oxygen is deadly to them.. 🞆 Obligate aerobe – must have oxygen to survive. 🞆 Obligate anaerobe – must live in the absence of oxygen. Eg. Methane producing archaebacteria (live in digestive tracts of cattle, landfill sites, swamps) 🞆 Facultative anaerobes, like E. Coli can survive and grow with or without oxygen 🞆 Bacteria reproduce by means of asexual reproduction through binary fission. 🞆 What are plasmids? 🞆 Sexual reproduction is not common, however bacteria can exchange genetic material through a special process called conjugation. 🞆 Two bacteria cells hook up through a conjugation bridge or sex pilus. Plasmids containing genes for antibiotic resistance can be transferred. ENDOSPORE 🞆 Bacteria can go into a dormant (inactive) state during unfavorable conditions by producing an endospore. 🞆 Resistant to heat, acidic, basic, and other extreme conditions. 🞆 Will germinate and become active bacteria when conditions are optimal 🞆 Bacteria are prokaryotic and unicellular. 🞆 Bacteria have cell walls. 🞆 Bacteria have circular DNA called plasmids 🞆 Bacteria can be anaerobes or aerobes. 🞆 Bacteria are heterotrophs or autotrophs. 🞆 Bacteria reproduce asexually through binary fission.