Ch. 1 The Cell Flashcards

Question

episomes

Answer 1

plasmids that can integrate into the genome of bacterium

Answer 2

* integrate foreign genetic material into host genome * originate from lysed bacteria * common in gram neg bacilli

Answer 3

* transfer of plasmid between bacteria * form conjugation bridge using sex pili * sex factors are required to have a sex pili * most common is F factor * transfer antibiotic resistance and virulence factors

Answer 4

* Hfr * bacterial conjugation and sex factor under goes transformation into the genome * donor cell attempts to transfer entire genome into recipient * if successful than cells are considered Hfr

Answer 5

* requires a vector - virus carries genetic info * bacteriophages - viruses that care the genetic info of other bacteria * phage infects bacteria and transfers genetics * genetics integrated into host genome * transposons - genetic elements capable of inserting and removing themselves from the genome. In pro and euk

Answer 6

* lag phase - adapting to conditions * exponential (log) phase - growth increases * stationary phase - resources and space reduced * death phase - environment depleted

Answer 7

protein coat on virus

Answer 8

* genetic info - circular or linear, single or double stranded, RNA or DNA * some have an envelope - phospholipids and proteins * surrounds capsid * easily denatured by heat and not resistant to sterilization * obligate intracelluar parasites * must express and replicate genetics in a host cell * make virions that are progeny

Answer 9

* inject genetic material * tail sheath as syringe * tail fibers determine which host cell * perform transduction

Answer 10

* when ssRNA * positive sense - genome directly translated to proteins by host ribosome * negative sense - must synthesize complementary RNA to strand before translation * requires RNA replicase * retrovirus - enveloped, ssRNA * usually 2 identical RNA molecules * reverse transciptase - synthesize DNA from ssRNA * DNA integrated into host and infected indefinitely * Ex. HIV

Answer 11

* envelope on virus binds to CD4 and CCR5 on the cell surface * fuse with cell to release contents * reverse transcriptase makes viral RNA into dsDNA * integrase inserts copy into host DNA * cell machinry transcirbe viral genome back into RNA and its used to translate proteins * viral RNA and proteins bud off as an immature virus * HIV protease matures the virus so it can infect again

Answer 12

* enveloped viruses fuse with the plasma membrane * must bind to specific receptors on host cell * phages use tail fibers to anchor themselves and inject genetic material * may have enzymatic activity that penetrates cell membrane and forms pores

Answer 13

* most DNA viruses got to nucleus to make mRNA * positive sense RNA - directly translated by host ribosome * negative sense RNA - RNA replicase synthesizes a complementary RNA strand that is used for translation * retroviruses - reverse transcription to make DNA that goes to nucleus and integrates into host genome * viral genome must be in original form to be packaged into the capsid

Answer 14

* initiate host cell death * lyse host cell * extusion - bud off of host cell membrane * productive cycle - host cell remains alive, can be continually used

Answer 15

* virulent bacteria * lytic cycle - phage injects, use host machinary to replicate viral genome, assemble progeny, lysis of host cell * lytogenic cycle - provirus or prophage are viruses that integrate into the host genome * virus is reproduced as host cell replicates * less vulnerable to superinfection - simultaneous infection with another phage * may re-enter the regular lytic cycle * when progeny leaves genome it can take some bacterial geneome and trasnfer it to another cell (specialized transduction)

Answer 16

* infectious proteins * trigger misfolding of proteins * may convert alpha helix to beta pleated sheet * protein aggregates form * cell funtion reduced

Answer 17

* small pathogens * short circular ssRNA that infects plants * silences genes * prevent synthesis * human example - hepatitis D virus which silences function of hepatocytes when hep B virus is present

Ch. 1 The Cell Flashcards

(41 cards)