FINAL 2

Question 1

differnce between ionizing and nonionizing wavelengths

Answer 1

ionizing= <1nm (xrays, gammarays) create ions and hydroxyl radicals-> causes mutations in DNA
nonionizing=>1nm (UV light), creates thymine dimers

Question 2

bactericidal zone of radiation wavelengths

Answer 2

200-295nm

Question 3

most resistent to chemical biocides

least?

Answer 3

prions

viruses w lipid envelopes

Question 4

what is replication

Answer 4

DNA replicated, parent cells divide via binary fission

Question 5

steps in replication (leading strand)

Answer 5

1) parental double helix unwound by helicase
2) proteins stabilize unwound DNA strands so don’t stick or tangle each other
3) leading strand synth. by DNA polymerase

Question 6

steps in replication (lagging strand)

Answer 6

1) primase synthesizes a short RNA primer
2) DNA polymerase digests primer, replaces w DNA
3) disoncinuous fragments (okazaki fragments) joined by DNA ligase

Question 7

define transformation

Answer 7

bacteria able to pick genes up from environment, incorporate into genome

Question 8

define conjugation

Answer 8

recombination via pili (sex pilus) or mating bridges

Question 9

3 natural types of recombination

Answer 9

transformation, conjugation, transduction

Question 10

during conjugation the plasmid contained with in the F+ cell is also called

Answer 10

the F factor (what is given to F- cell)

Question 11

define transduction (steps)

Answer 11

bacteriophages land on surface of bacteria, inject DNA into cell, takes over machinery, breaks down host DNA, when new phages begin forming pieces of bacterial DNA packaged into phage capsids, released-> new hosts

Question 12

what are restriction enzymes

Answer 12

bacterias immune system has enzymes that make cuts to specific DNA sequences

Question 13

role of restriction enzymes in recombinant DNA tech

Answer 13

able to cut double stranded dna at particular sites, create sticky ends, DNA cut w same enzyme join together via base pairing, produces a molecule of recombinant DNA

Question 14

why primers are added to PCR

Answer 14

help start rxn, complementary to ends of target DNA, DNA polymerase recognizes

Question 15

roles of dna polymerase in PCR

Answer 15

copies the target DNA

Question 16

why we start a PCR by incubating a target DNA strand at 94C

Answer 16

separates the strands

Question 17

list evidence of theory of endosymbiosis

Answer 17

similarities between prokaryotic cells and euk organelles: circular DNA, formylenethionine= 1st amino acid in protein synth., 70S ribosomes, divide by binary fission, same size range, organelles double membraned (from being engulfed)

Question 18

describe a slide agglutination test

Answer 18

unknown bacterium placed in drop of saline on several slides, diff drops of known antiserums added, bacteria clump when mixed w antibodies related to that species of bacteria

Question 19

wolbachia is in what prokaryote group

Answer 19

alphaproteobacteria

Question 20

most common infectious bacteria, where is it found

Answer 20

wolbachia, found in 75% insects, transmitted thro eggs

Question 21

list the gammaproteobacteria and what diseases they cause

Answer 21

pseudomonas- common causal agent of infections due to burns
legionella- legionnaires disease (pneumonia)
Escheichia- hemmoragic diarrhea
Klebsiella- pnuemonia
Yersinia- (pestis) black death/bubonic plague (rats and fleas)

Question 22

diff between lytic and lysogenic cycle

Answer 22

after phage DNA is in host and circularizes…
Lytic- new phage DNA synthesizes, phage virions assembled
lysogenic- phage DNA integrates within bacterial chromosome

Question 23

what are prions

Answer 23

short segments of proteins which cause the misshaping of similar proteins

Question 24

diseases caused by prions

Answer 24

spongiform encephalopithies (scrapie, CJ disease, mad cow disease) bc poke holes in grey matter of brain