Topic 10 Flashcards
How do prokaryotic cells differ from eukaryotes?
i) Small and unicellular
ii) High rates of metabolism
iii) Variety of cell shapes
iv) Circular genome not surrounded by a nuclear membrane
v) No membrane-bound organelles
What are the five structural and functional adaptations that contribute to prokaryotic success?
i) Cell-surface structures
ii) Endospores
iii) Motility
iv) Internal organization and DNA
v) Reproduction
How do cell-surface structures contribute to prokaryotic success?
Cell walls, gram stains, capsules and fimbriae contribute to their success
What is the structure that surrounds prokaryotes with a sticky polysaccharide or protein layer?
Capsule
What are prokaryotic fimbriae?
Hair-like appendages that help cells adhere to a substrate or other individuals in a colony
What are bacterial cell walls composed of?
Peptidoglycan
What do cell walls do?
i) Maintain cell shape
ii) Protect the cell
iii) Prevents bursting
What are Gram-positive bacteria?
They have one membrane with a large amount of peptidoglycan
What are Gram-negative bacteria?
They have an outer lipopolysaccharide membrane, a middle layer of peptidoglycan and an inner membrane
What form of bacteria are metabolically inactive and can remain viable in harsh conditions?
Endospores
How are prokaryotes motile?
They have flagella
How do prokaryotes reproduce?
They reproduce quickly by binary fission
What are the three factors that contribute to prokaryotic genetic variation?
i) Rapid reproduction
ii) Mutation
iii) Genetic recombination
What is the movement of genes among individuals from different species?
Horizontal gene transfer
What are the three ways genetic recombination occurs in prokaryotes?
i) Transformation
ii) Transduction
iii) Conjugation
What process involves the uptake and incorporation of foreign DNA from the surrounding environment?
Transformation
What process is the movement of genes between bacteria by a bacteriophage?
Transduction
What process is where genetic material is transferred between prokaryotic cells?
Conjugation
How does conjugation occur?
i) Donor transfers DNA to recipient
ii) Donor attaches to recipient by a pilus to pull it closer
iii) Transfer of DNA unidirectionally
What is metabolism?
The chemical pathways used by living organisms to build up molecules (anabolism) or to break down molecules (catabolism)
What are phototrophs?
They obtain energy from light
What are chemotrophs?
They obtain energy from chemicals
What are autotrophs?
They use inorganic molecules as a carbon source
What are heterotrophs?
They use organic substances to obtain carbon
What organisms require O2 for cellular respiration?
Obligate aerobes
What organisms use fermentation or anaerobic respiration?
Obligate anaerobes
What element can prokaryotes metabolize?
Nitrogen
What group of bacteria is large and metabolically diverse?
Proteobacteria
What type of proteobacteria includes pathogens?
Gamma and epsilon proteobacteria
What group of bacteria are parasites that live within animal cells?
Chlamydias
Also: have no peptidoglycan
What prokaryotes are the only ones that produce O2 through photoautotropy?
Cyanobacteria
What bacterial group are the only ones that stain Gram-positive?
Gram-positive bacteria
What group of bacteria includes important decomposers and dangerous pathogens?
Gram-positive bacteria
What domain shares traits with both bacteria and eukaryotes?
Domain Archaea
What type of organism prefers living in extreme environments characterized by low pH, high salt, etc.? Give an example
Extremophiles
Ex. Archaea
Methanogens that produce methane live in:
Anoxic (low O2) habitats such as swamps/marshes
Extreme halophiles live in:
High saline environments
Extreme thermophiles thrive in:
Very hot environments
What do chemoheterotropic prokaryotes do?
Decompose waste
What is an ecological relationship in which two species live in close contact with a host and symbiont?
Symbiosis
What relationship has both symbiotic organisms benefitting?
Mutualism
What is commensalism?
One organism benefits while neither harming nor helping others
What relationship is when an organism harms but does not kill its host?
Parasitism
