Homework 4

Question 1

Chemical signals used by microorganisms as they communicate via quorum sensing

Answer 1

autoinducers

Question 2

T or F: the arginine operon repressor is made active and only inactivated in the presence of the amino acid arginine

Answer 2

False

Question 3

restriction enzyme

Answer 3

cuts DNA at precise sequence

Question 4

PCR primers

Answer 4

short sequences of DNA that binds to end of a target sequence

Question 5

DNA ligase

Answer 5

enzyme that “glues” DNA together

Question 6

recombinant DNA

Answer 6

DNA from one source that has been introduced into another host or cell

Question 7

deepest region of a lake, including the bottom soil, and includes many anaerobic microorganisms and methanogens

Answer 7

benthic zone

Question 8

this type of mutation changes the original DNA nucleotide sequence but the resulting amino acid remains the same as the original version

Answer 8

silent

Question 9

Frederick Griffith showed that certain bacteria can uptake DNA from the environment in a process now known as

Answer 9

transformation

Question 10

T or F: during gel electrophoresis, the negatively charged DNA will migrate down towards the positively charged bottom of the gel

Answer 10

true

Question 11

lokiarcheota

Answer 11

archaea that is most closely related to eukaryotes

Question 12

dinoflagellates

Answer 12

algae that produce neurotoxins that can infect animals via shellfish

Question 13

cyanobacteria

Answer 13

group of bacteria that “invented” oxygenic photosynthesis

Question 14

methanogens

Answer 14

archaea that produce methane

Question 15

operator

Answer 15

site on DNA where repressor binds

Question 16

repressor

Answer 16

protein that can turn an operon off

Question 17

promoter

Answer 17

region of DNA where RNA polymerase will bind

Question 18

gene

Answer 18

protein-coding region of DNA

Question 19

You attempt to clone a fragment of DNA cut with a restriction enzyme into a plasmid that contains both an antibiotic resistance gene and a toxin gene (which contains a site recognized by your restriction enzyme). If your DNA fragment fails to insert into the plasmid, and that plasmid is taken up by E. coli, what do you expect to occur?

Answer 19

the bacteria will be killed by the plasmid toxin

Question 20

process used by certain microorganisms that converts atmospheric nitrogen (N2) into ammonium ions

Answer 20

nitrogen fixation

Question 21

T or F: during excision repair, the damaged or incorrect DNA is removed and the gap is repaired by DNA polymerase III and ligase

Answer 21

False

Question 22

name given to bacteria growing as a community on a surface

Answer 22

biofilm

Question 23

T or F: If lactose is present, and glucose is absent, allolactose (the inducer) will inactivate the lac repressor protein and the lac operon will be transcribed by RNA polymerase.

Answer 23

true

Question 24

Photosynthetic organisms such as phytoplankton are most abundant in this freshwater zone

Answer 24

photic

Question 25

asbestos is an example of what type of mutagen

Answer 25

chemical

Question 26

T or F: the codon AUG is the start codon of the genetic code and encodes for the amino acid methionine

Answer 26

True