Exam I Vocabulary C

Question 1

Gel Electrophoresis

Answer 1

separates molecules by size using a gel and a positive charge to attract negative charges

Question 2

Coomassie Stain

Answer 2

stains all of the proteins in a gel

Question 3

Western Blots

Answer 3

after gel electrophoresis product is transferred to filter paper, use an antibody to bind to a specific protein, or through fluorescent or luminescent detection

Question 4

SDS-PAGE

Answer 4

sodium dodecyl sulfate polyacrimide gel electrophoresis; separates proteins by size using a polyacrimide gel and certain agents to make the proteins more suitable for the test

Question 5

SDS

Answer 5

strong ionic detergent denatures proteins and coats proteins with a uniform negative charge

Question 6

BME

Answer 6

reducing agent removes disulfide bonds

Question 7

Immunoprecipitation

Answer 7

express a tagged protein in a cell, precipitate tagged protein using a specific antibody, and then separate the precipitate

Question 8

DNA Polymerase

Answer 8

replicative polymerase that catalyzes DNA replication in a 5’-3’ direction

Question 9

Helicase

Answer 9

unwinds/unzips DNA, advancing the replication fork

Question 10

Topoisomerase

Answer 10

prevents DNA from supercoiling in front of the replication fork

Question 11

Primase

Answer 11

synthesizes RNA primers in DNA for the beginning of the leading strand and throughout the lagging strand

Question 12

Ligase

Answer 12

seals remaining nicks in the DNA

Question 13

Replication Fork

Answer 13

the place where DNA is separated into single strands for replication

Question 14

Replication Bubble

Answer 14

consists of the unwound and separated area of DNA where replication is commencing in both directions

Question 15

ORI

Answer 15

a location on the DNA where DNA replication is initiated and the double strand is unwound; prokaryotes typically have one where eukaryotes have many

Question 16

Continuous DNA Synthesis

Answer 16

occurs on the leading strand, DNA is continuously synthesized in the 5’-3’ direction with just one primer used

Question 17

Telomere

Answer 17

protects the end of the chromosome where it is located, consists of a unique DNA sequence which is repeated several times, but doesn’t actually code for necessary proteins; maintained by telomerase

Question 18

Telomerase

Answer 18

composed of RNA and protein and adds repeats to the ends of telomeres (sequence varies between different organisms) and is a type of reverse transriptase that has an RNA tempate associated with it

Question 19

Meselson and Stahl Experiment

Answer 19

to determine semiconservative method occurs in DNA replication; DNA first replicated in heavy (15) Nitrogen then in light (14) Nitrogen; determined by gel electrophoresis

Question 20

Heavy DNA

Answer 20

DNA made with Nitrogen-15

Question 21

Light DNA

Answer 21

DNA made with Nitrogen-14

Question 22

DNA Polymerase

Answer 22

replicative polymerase that catalyzes DNA replication in a 5’-3’ direction

Question 23

Primer

Answer 23

made of RNA, used to being DNA replication

Question 24

Beta Sliding Clamp

Answer 24

helps make DNA replication fast and efficient

Question 25

Clamp Loader

Answer 25

opens and closes clamps around DNA, and specifically targets clamps to sites where DNA synthesis is initiated and orients them correctly for replication

Question 26

Discontinuous DNA Synthesis

Answer 26

occurs on the lagging strand, DNA discontinuously synthesized in the 5’-3’ direction, resulting in an overall 3’-5’ direction with multiple primers used and ligase sealing the nicks left over

Question 27

Leading Strand

Answer 27

synthesized continuously in the 5’-3’ direction

Question 28

Lagging Strand

Answer 28

synthesized discontinuously with short fragments synthesized in the 5’->3’ direction using primers but overall replication continues in the 3’->5’ direction

Question 29

Pulse-Chase Experiment

Answer 29

pulse treatment with radio labelled compound; chase time, then measure the labelled compound concentration in molecule of interest at different time intervals

Question 30

Okazaki Fragments

Answer 30

created on the lagging strand because of replication in 5’->3’ direction

Question 31

Reverse Transcriptase

Answer 31

an enzyme that produces DNA from an RNA template

Question 32

FISH

Answer 32

(fluorescent in situ hybridization) used to detect specific sequences in the context of the cell or tissue; used to visualize genes in a cell

Question 33

Autoradiogram

Answer 33

image produced by the pattern of decay emissions (ex. beta particles or gamma rays) from a radioactive antibody

Question 34

Probe

Answer 34

small singe stranded piece of DNA, complementary to region of DNA you want to analyze; fluorescent multiple colors detected by microscopy, radioactive detected by exposure of film

Question 35

Co-Immunoprecipitation

Answer 35

if protein of interest binds other proteins or functions within a complex of proteins, you will also immunoprecipitate the complex

Question 36

Southern Blot

Answer 36

run a nucleic acid sample of fragmented pieces through an agarose gel, with DNA stained by EtBr, transfer to nitrocellulose membrane, hybridize with nucleic acid probe, use autoradiogram to reveal fragments annealed with probe

Question 37

Northern Blot

Answer 37

method to measure and analyze specific RNA molecules (similar to Southern blot); probe used typically made of DNA (more stable)

Question 38

Protein Tag

Answer 38

peptide sequences genetically grafted onto a recombinant protein, often removable by chemical agents or enzymatic means; used to various purposes such as affinity or chromatography or immunoprecipitation

Question 39

Conservative Replication

Answer 39

a hypothetic form of replication in which double stranded DNA produces two daughter double stranded DNAs, one of which consists of the two original strands, the other of the two newly synthesized strands

Question 40

Semiconservative Replication

Answer 40

generally accepted method of DNA replication, in which the two strands of DNA helix separate and the nucleotides pair with the exposed bases on the single chains to form two new DNA molecules

Question 41

Dispersive Replication

Answer 41

disproved model of DNA synthesis suggesting more-or less random interspersion of parental and new segments in daughter DNA molecules

Question 42

CsCl Gradient

Answer 42

DNA mixed with CsCl and centrifuged to produce gradient with lightest density at the top and heaviest density at the bottom; used to separate DNA based on density