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