Lecture 4

Question 1

what does MRSA stand for?

Answer 1

methicillin-resistant staphylococcus aureus

Question 2

chromosome is ____ to fit into cell

Answer 2

supercoiled

Question 3

how many genes on bacteria chrom?

Answer 3

3000-4000

Question 4

how many chrom per cell?

Answer 4

just 1

Question 5

is DNA in circle or linear?

Answer 5

circle

Question 6

supercoiling controlled by these 2 enzymes:

Answer 6

DNA gyrase (create) and topoisomerase 1 (remove)

Question 7

second form of DNA carried by some bacteria

Answer 7

plasmid

Question 8

how different than chromosome?

Answer 8

smaller, multiple copies possible in cell, carry accessory genes (adaptation)

Question 9

accessory gene functions:

Answer 9

metabolic, pathogen, resistance

Question 10

minimum # genes required be free living?

Answer 10

between 200-500ish

Question 11

how is transcription/translation diff in procaryotes?

Answer 11

no export so process coupled, no introns need to be removed before translate

Question 12

procaryotes have ___S and ___S ribosomes

Answer 12

30 ; 50

Question 13

rate of growth is ___ in procaryotes cuz:

Answer 13

faster; high SA/V ratio, couple T and T, faster rate protein synth

Question 14

what gene mechanisms used generate diversity?

Answer 14

mutation, exchange

Question 15

a physical change in DNA sequence giving rise to change in mRNA and thus change in protein

Answer 15

mutation

Question 16

mutations either:

Answer 16

spontaneous (random errors), induced (external agents distort)

Question 17

random mutation is ___

Answer 17

slow

Question 18

enviro provides ____ which determines if mutation persist

Answer 18

selective pressure

Question 19

how to isolate bacteria with desired mutation?

Answer 19

1) treat with mutagenic agent 2) create enviro where only mutant grow (direct selection–>industrial setting)

Question 20

Biological assay that uses bacteria to assess mutagenic potential of new chem/drugs

Answer 20

Ames Test (prescreen before animal testing)

Question 21

bacteria exchange DNA by these 3 mechanisms:

Answer 21

transformation, transduction, conjugation

Question 22

what is transformation?

Answer 22

dead cell break open and spill fragments of DNA into enviro, bacteria with special surface proteins can take up

Question 23

what is transduction?

Answer 23

DNA transfer via bacteriophage: phage attach and inject its nucleic acid, bacterial chromosome breaks down and phage genes replicate. Cell burst and new phage released

Question 24

how does phage life cycle lead to transfer gene info between bacteria?

Answer 24

cuz transducing phage mistakenly gets packed with bacterial DNA

Question 25

why can’t have phage as anti-bacterial agents easily?

Answer 25

not broad spectrum, must be purified

Question 26

example of using purified phage components?

Answer 26

phage lysin to degrade PG

Question 27

phages can be used to control:

Answer 27

food borne organisms

Question 28

what is conjugation?

Answer 28

transfer of plasmids by direct cell to cell contact via sex pili