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22 Cards in this Set
- Front
- Back
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What is different in the way eukaryotes and prokaryotes transcribe gene?
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Eukaryotes: each gene transcribed individually
Prokaryotes: multiple genes may be transcribed together, almost no introns/splicing |
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What are inverted repeats and what is their function
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repeated sequence arranged in inverse orientation, site of recognition by proteins
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What is function of DNA gyrase?
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introduces supercoils into bacterial and archaea DNA
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What are plasmids?
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genetic elements that replicate independently of host, non-essential(like antibiotic resistance)
How many plasmids/cell varies |
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What are bacteriocins?
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proteins produced by bacteria that inhibit/kill closely related species or different strains of same species
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Give examples of bacteriocins
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Colicin, nisin
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How do some pathogenic bacteria encode for virulence characteristics?
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plasmid genes
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What are virulence factors?
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enables pathogen to colonize and/or cause host damage
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What are some examples of pathogens that cause host damage?
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hemolysin
enterotoxin |
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How do RNA polymerases recognize the promoter to start transcription?
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sigma factors recognize -10 and -35 region upstream transcription start site
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How many Hydrogen bonds does A-T have? What about G-C?
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A-T = 2 H bonds
C-G = 3 H bonds |
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What are stem loops?
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Short double helical regions caused by nearby inverted repeats.
Only in RNA |
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What are examples of pyrimidine bases?
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C, U, T
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What is a pribnow box?
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-10 region ( 10 bases before start of transcription)
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What are intrinsic terminators?
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Transcription is terminated without any additional factors
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What is Rho-dependent termination?
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Rho protein recognizes specific DNA sequences and causes termination.
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What is a unit of transcription?
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A gene.
Unit of chromosome bounded by sites where transcription is initiated and terminated |
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What is polycistronic mRNA?
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An mRNA encoding a group of cotranscribed genes
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What is an operon?
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A group of related genes cotranscribed on a polycistronic mRNA
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What is the function of an operon?
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Allows coordinated expression of multiple genes
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Why do antibiolotics inhibit translation only in bacteria an not humans?
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Antibiotics inhibit translation by interacting with 70S bacterial ribosomes. Humans have 80S ribosomes
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What are signal sequences?
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sequences found on proteins requiring transport out of cell
Signal the cell's secretory system (Sec system) |
