Ch 27 Flashcards
(53 cards)
What are the masters of adaptation?
Prokaryotes are the masters of evolution
Which two domains include prokaryotes?
Bacteria and Archaea
Prokaryotes: are they multicellular or unicellular?
unicellular
Prokaryotes: compare their size relative to eukaryotic cells.
much smaller than eukaryotes
Prokaryotes: what three shapes are most common?
Spherical (cocci), Rod shaped (Bacilli), Spiral Shaped (Spirallis)
Prokaryotes: what is the composition of the typical bacterial cell wall?
Peptidoglycan
A key feature of prokaryotic cells is the cell wall. What three functions does it provide for the cell?
Structure, protection, and allows it to bind to other cells
What material comprises the cell wall of plants? of fungi?
Plants: Cellulose
Fungi: Chitin
How are Archaea’s cell walls different?
They lack peptidoglycan and have polysaccharides and proteins instead.
Explain the difference between Gram-positive and Gram-negative bacteria.
Gram-positive: simpler cell walls with more peptidoglycan
Gram-negative: have less peptidoglycan and a more complex outer structure because it has lipopolysaccharides (carbs bonded to lipids)
What is a bacterial capsule? What functions may it serve?
A bacterial capsule is a sticky layer of polysaccharide or protein that enables prokaryotes to adhere to substrate or other individuals in a colony. Functions besides adherence include protection from dehydration and defending against host’s immune system (pathogenic prokaryotes)
Many prokaryotes are capable of directional movement. What is this called? What bacterial feature makes this possible?
This directional movement is called motility. An appendage called the flagella
Under ideal conditions, how quickly can E. coli divide? What conditions check prokaryotic
reproduction?
An E. Coli can divide as often as every 20 minutes. Poisons from waste, a limited nutrient supply, endocytosis by other organisms, and/or competition causes a check on reproduction.
What three key features allow prokaryotic populations to consist of trillions of individuals?
Small, reproduce via binary fission, short generation times.
What are the small, circular, self-replicating pieces of DNA found in bacteria called?
Plasmids
When conditions for survival are difficult, some species produce endospores. What are these? Can you name any species that form endospores? As a hint, consider what causes botulism or tetanus.
Endospores are resistant cells that can develop when a particular nucleus is lacking.
Define transformation. This idea was first described by Frederick Griffith.
Genotype and Phenotype can be affected by uptake of foreign DNA from its surrounding.
Ex: Griffith’s experiments with Streptococcus Pneumoniae that is harmless can cause pneumonia when placed into a medium with dead cells of the pathogenic strain.
What is transduction? What is the vector for this process?
Bacteriophages are the vector, and in transduction they carry bacterial genes from one host cell to another host cell.
What is a sex pilus? What is the F factor? And how are the two related?
A sex pilus is what attaches donor cells to recipient cells for transfer of DNA. The F Factor is a particular piece of DNA that allows for formation of the sex pili.
What occurs in bacterial conjugation?
Genetic material is transferred between bacterial cells that are temporarily joined together by sex pili.
What is the bacterial
cell called: when the F factor is in plasmid form?
F+
What is the bacterial
cell called: when it lacks an F plasmid?
F-
What is the baterial cell called: when it is integrated within the chromosome?
Hfr cell
When a mating bridge forms between an F+ cell and an F– cell and the F plasmid is replicatedand transferred, what is the status of the F– cell afterward?
F+
