Bacteria Flashcards
What is a bacteria?
Prokaryotic cell; can act as a pathogen.
What are the components of a bacterial cell?
Cell wall, cytoplasm, chromosome, ribosome, penicillin binding proteins, peptidoglycan, lipopolysaccharide, capsule, flagella, fimbriae, plasmid, bacteriophage, spores
What is the function of the capsule?
Can protect against engulfment by eukaryotic cells, thus enhancing the ability of bacteria to cause disease (virulence factor).
What is the function of the fimbriae?
Used by bacteria to provide adherence to one another/animal cells and inanimate objects.
What are spores?
Highly resistant, dormant structures (no metabolic activity) which help in the survival of organisms during adverse environmental conditions.
What is the function of the plasmid?
Small, circular double stranded DNA molecule which can carry genes to enhance bacterial survival or can carry genes needed for DNA replication.
What are the two types of bacteria?
Gram-positive and gram-negative
How are gram-positive and gram-negative bacteria identified in testing?
Grams test:
Gram-positive = Purple
Gram-negative = Red/Pink
What distinguishes gram-positive bacteria?
Gram positive bacteria have cell walls composed mostly of a substance unique to bacteria known as peptidoglycan, or murein. These bacteria stain purple after Gram staining.
What distinguishes gram-negative bacteria?
Gram negative bacteria have cell walls with only a thin layer of peptidoglycan and an outer membrane with a lipopolysaccharide component not found in Gram positive bacteria. Gram negative bacteria stain red after Gram staining.
What shape is cocci?
Spherical
What shape is bacilli?
Rod-shaped
How do bacteria replicate?
Binary fusion- identical progeny
How do bacteria develop genetic variation?
Spontaneous mutation
Transfer of DNA (horizontal)
What are bacteriophages?
Bacteriophages are viruses that infect bacteria but are harmless to humans. To reproduce, they get into a bacterium, where they multiply, and finally they break the bacterial cell open to release the new viruses. Therefore, bacteriophages kill bacteria.
