bacteria and archaea. you must know… the key ways in which prokaryotes differ from eukaryotes with...
TRANSCRIPT
BACTERIA AND ARCHAEA
YOU MUST KNOW…• THE KEY WAYS IN WHICH
PROKARYOTES DIFFER FROM EUKARYOTES WITH RESPECT TO GENOME, MEMBRANE-BOUND ORGANELLES, SIZE, AND REPRODUCTION
CONCEPT 27.1• STRUCTURAL AND FUNCTIONAL
ADAPTATIONS CONTRIBUTE TO PROKARYOTIC SUCCESS
3 DOMAINS
• ARCHAEA• BACTERIA• EUKARYA• ARCHAEA AND BACTERIA ARE
PROKARYOTES
• PROKARYOTES - NO TRUE NUCLEI OR INTERNAL COMPARTMENTALIZATION
• DNA IS IN A NUCLEOID REGION• SMALL GENOMES, ONE MAJOR CHROMOSOME
AND SMALLER, CIRCULAR, INDEPENDENT PIECES OF DNA CALLED PLASMIDS
• CELL WALL CONTAINING PEPTIDOGLYCANS• GRAM-POSITIVE – CELL WALL WITH
PEPTIDOGLYCANS• GRAM-NEGATIVE – MORE COMPLEX CELL
WALLS• PILI – ADHERE TO SURFACES• MAY HAVE FLAGELLA – FOR MOVEMENT
CONCEPT 27.2• RAPID REPRODUCTION,
MUTATION, AND GENETIC RECOMBINATION PROMOTE GENETIC DIVERSITY IN PROKARYOTES
3 MECHANISMS OF GENETIC MATERIAL TRANSFER
• TRANSFORMATION – PROKARYOTE TAKES UP DNA FROM ITS ENVT
• CONJUGATION – GENES ARE DIRECTLY TRANFERRED FROM ONE PROKARYOTE TO ANOTHER
• TRANSDUCTION – VIRUSES TRANSFER GENES BETWEEN PROKARYOTES
• MUTATION – THE MAJOR SOURCE OF GENETIC VARIATION IN PROKARYOTES
CONCEPT 27.3• A GREAT DIVERSITY OF
NUTRITIONAL AND METABOLIC ADAPTATIONS HAS EVOLVED IN PROKARYOTES
4 GROUPS OF PROKARYOTES
• PLACED IN FOUR GROUPS ACCORDING TO HOW THEY TAKE IN CARBON AND HOW THEY OBTAIN ENERGY
• PHOTOAUTOTROPHS – PHOTOSYNTHETIC, USE POWER OF SUNLIGHT TO CONVERT CARBON DIOXIDE INTO ORGANIC COMPOUNDS
• CHEMOAUTOTROPHS – USE CARBON DIOXIDE AS THEIR SOURCE OF CARBON BUT THEY GET THEIR ENERGY FROM OXIDIZING INORGANIC SUBSTANCES
• PHOTOHETEROTROPHS – USE LIGHT TO MAKE ATP BUT MUST OBTAIN THEIR CARBON FROM AN OUTSIDE SOURCE ALREADY FIXED IN ORGANIC COMPOUNDS
• CHEMOHETEROTROPHS – GET BOTH CARBON AND ENERGY FROM ORGANIC COMPOUNDS
• OBLIGATE AEROBES – CANNOT GROW WITHOUT OXYGEN BECAUSE THEY NEED OXYGEN FOR CELLULAR RESPIRATION
• OBLIGATE ANAEROBES – POISONED BY OXYGEN, USE FERMENTATION
• FACULTATIVE ANAEROBES – USE OXYGEN IF AVAILABLE BUT CAN USE FERMENTATION IF NO OXYGEN
• SOME PROKARYOTES CAN USE NITROGEN AFTER NITROGEN FIXATION
CONCEPT 27.4• MOLECULAR SYSTEMATICS IS
ILLUMINATING PROKARYOTIC PHYLOGENY
EXTREMOPHILES• FIRST PROKARYOTES (ARCHAEA) • EXTREME HALOPHILES – LIVE IN
SALINE ENVTS• EXTREME THERMOHILES – LIVE IN VERY
HOT ENVTS• OTHER ARCHAEA DO NOT LIVE IN
EXTREMES• METHANOGENS USE CARBON DIOXIDE
TO OXIDIZE H2 AND PRODUCE METHANE AS A WASTE PRODUCT
CONCEPT 27.5• PROKARYOTES PLAY CRUCIAL
ROLES IN THE BIOSPHERE
• DECOMPOSERS – BREAKING DOWN DEAD CORPSES, VEGETATION, AND WASTE PRODUCTS
• SYMBIOTIC – FORM RELATIONSHIPS WITH OTHER SPECIES
• MUTUALISM – BOTH SYMBIOTIC ORGANISMS BENEFIT
• COMMENSALISM – ONE BENEFITS AND THE OTHER IS NEITHER HELPED OR HARMED
• PARASITISM – ONE ORGANISM BENEFITS AT THE EXPENSE OF THE OTHER
CONCEPT 27.6• PROKARYOTES HAVE BOTH
HARMFUL AND BENEFICIAL IMPACTS ON HUMANS
• SOME PROKARYOTES ARE PATHOGENIC AND CAUSE ILLNESS BY PRODUCING TOXINS
• ANTIBIOTICS – CHEMICALS THAT CAN KILL PROKARYOTES
USES OF PROKARYOTES• BIOREMEDIATION – REMOVING
POLLUTANTS FROM SOIL, AIR, OR WATER (TREATING SEWAGE, CLEANING UP OIL SPILLS)
• SYMBIONTS IN THE GUT (MAKE VITAMINS, DIGEST FOODS)
• GENE CLONING AND PRODUCING TRANSGENIC ORGANISMS
• PRODUCTION OF CHEESE AND YOGURT