Bacteriophage

Question 1

Complex Bacteriophage Structure

sheath

Answer 1

helical capsid (also called tail) which contracts and delivers the tail tube through the bacterial cell wall

Question 1

Complex Bacteriophage Structure

icosahedral capsid head

Answer 1

houses phage nucleic acids

Question 2

Complex Bacteriophage Structure

tail fibers

Answer 2

associate with host cell receptors

Question 3

Complex Bacteriophage Structure

tail pins

Answer 3

associate with the cell wall to hold tail close to pentration site

Question 4

Complex Bacteriophage Structure

baseplate

Answer 4

multiprotein molecular machine that mediates attachment, sheath contraction, and phage DNA ejection

Question 5

Types of Phage Infection

Virulent phage

Answer 5

lytic cycle leads to phage replication and lysis of cell

Question 6

Types of Phage Infection

temperature phage

Answer 6

can reproduce using lytic or lysogenic cycles

Question 7

Temperature Phage

lytic cycle

Answer 7

proceeds similar to virulent phage; ends with phage replication and cell lysis

Question 8

Temperature Phage

lysogenic cycle

Answer 8

results in lysogeny where the phage DNA is integrated forming a prophage

Question 9

Temperature Phage

phage/lysogeny conversion

Answer 9

phage DNA can introduce new characteristics in the host bacterium

Question 10

Temperature Phage

‘immunity’

Answer 10

host cannot be reinfected with the same phage

Question 11

Temperature Phage

induction

Answer 11

change in condition can end the lysogenic phase and the cell enters the lytic cycle

Question 12

synthesis: early proteins

Answer 12

enzymes for phage DNA replication and modification of host ezymes for viral replication

Question 13

synthesis: middle and late proteins

Answer 13

head and tail proteins and enzymes required for host cell lysis

Question 14

Temperature Phage

prophage

Answer 14

phage genome that has been integrated into the bacterial host chromosome
- mediated by recombinase/integrase which are typically phage encoded

Question 15

Temperature Phage: Role in Transduction

generalized transduction

Answer 15

any gene in the bacterial genome is packaged in the virion

Question 16

Temperature Phage: Role in Transduction

specialized transduction

Answer 16

genes near the insertion site are repeatedly packaged along with the phage DNA at low frequencies

Question 17

Bacterial Defense Against Phage

Nonspecific

Answer 17

analogous to innate immunity

Question 18

Bacterial Defenses Against Phage

specific

Answer 18

analogous to adaptive immunity

Question 19

Non-specific Bacterial Defenses Against Phage: Restriction Endonuclease

MTase

Answer 19

enzyme that methylates bacterial DNA

Question 20

Nonspecific Bacterial Defenses Against Phage: Restriction Endonuclease

restriction endonuclease

Answer 20

cleaves unmethylated DNA at specific nucleotide sequences

Question 21

Nonspecific Bacterial Defense Against Phage: Toxin-antitoxin systems

abortive infection

Answer 21

phage DNA can induce cell suicide through inactivation of the antitoxin, allowing the toxin to induce cell death

Question 22

Specific Defense Against Phage: CRISPR

protospacer

Answer 22

a specific sequence of DNA within a bacterial genome that matches a sequence found in a foreign genetic element (PAMs)

Question 23

Specific Defense Against Phage: CRISPR

cas protiens

Answer 23

cleave near PAM on viral DNA, inserts short DNA into the chromsome resulting in immuniza

Question 24

Detecting Phage

plaque forming assay

Answer 24

used in lab to enumerate phage in lab

Question 25

Indicators of fecal contamination

fecal indicators

Answer 25

used to detect fecal contamination in food, water, treated wastewater