SCI 115 Week 6 Lab Quiz

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QUESTION 1

1. Most scientists who use DNA microarrays obtain them

 

from   companies that mass produce them

 

from   the government

 

by   making them in their labs

 

by   exploiting ambitious graduate students

QUESTION 2

1. “In this study, cancerous and normal skin tissue samples were excised with a scalpel. Each skin sample was then placed into a sample tube along with solvent, shaken on a vortex and centrifuged. When the sample tubes came out of the centrifuge, there was a top layer and a bottom layer. For our purposes, we went on to use ______________ for further processing.”

 

only   the top layer

 

only   the bottom layer

 

a   mixture of top and bottom layers

 

none   of the options listed

QUESTION 3

1. The purpose of the vortex instrument is to

 

vigorously   shake the tissue sample in the solvent so that it dissolves.

 

spin   the tissue/solvent mixture around to separate the solids

 

cause   the mRNA to bind to the pellets

 

dispose   of biohazardous waste safely

QUESTION 4

1. “Once the RNA is isolated from the DNA, proteins and other materials, the solvent/RNA mixture is run through a column of all beads. Each bead has several short strands of polyT RNA sticking out of it. In this step:”

 

“mRNA   sticks to the beads, while rRNA and tRNA run right through the column”

 

“tRNA   sticks to the beads, while mRNA and rRNA run right through the column”

 

“rRNA   and tRNA stick to the beads, while mRNA runs right through the column”

 

none   of the options listed

QUESTION 5

1. “Once the mRNA is isolated, you make a DNA copy of it using by adding polyT primers, labeled DNA nucleotides, and an enzyme known as:”

 

reverse   transcriptase

 

tyrosine   hydroxylase

 

alcohol   dehydrogenase

 

ATP   kinase

QUESTION 6

1. A DNA copy of a mRNA transcript is known as

 

complementary   DNA (abbreviated cDNA)

 

copied   DNA (abbreviated cDNA)

 

mitochondrial   DNA (abbreviated mtDNA)

 

recombinant   DNA (abbreviated rDNA)

QUESTION 7

1. Each spot on the DNA microarray in embedded with

 

copies   of DNA from one particular gene

 

copies   of DNA from several different genes with similar functions

 

copies   of DNA from several different genes with different functions

 

copies   of mRNA from one or more genes

QUESTION 8

1. “When we say that the cDNA derived from our sample has hybridized to a particular spot on the array, we mean that: ”

 

The   cDNA from the sample has stuck to the DNA on the microarray at that point.

 

The   cDNA from the sample is jumbled and cannot be trusted.

 

The   cDNA has been used to make an mRNA copy

 

You   need to buy microarrays from different manufacturers and triangulate the   results

QUESTION 9

1. “In this particular experiment, we used red-labeled DNA to process the sample from _____________ tissue and the green-labeled DNA to process the sample from ___________. ”

 

cancerous;   normal

 

normal;   cancerous

 

normal;   normal

 

cancerous;   cancerous

QUESTION 10

1. “After scanning the green labeled areas and the red labeled areas, when we combine the two images, the spots that show up as yellow correspond to ”

 

genes   expressed by both normal or cancerous skin cells.

 

genes   that were not expressed at all in either normal or cancerous skin cells

 

“genes   expressed by cancerous, but not normal skin cells”

 

“genes   expressed by normal, but not cancer skin cells. ”

QUESTION 11

1. “In interpreting the results of this study, spots on the microarray that are red correspond to:”

 

genes   that are turned up by cancer

 

genes   that are turned down by cancer

 

genes   that are unaffected by cancer

 

genes   that aren t expressed in normal or cancerous cells

QUESTION 12

1. “In interpreting the results of this study, spots on the the microarray that are green correspond to genes that are ”

 

genes   that are turned down by cancer

 

genes   that are turned up by cancer

 

genes   that are unaffected by cancer

 

genes   that aren t expressed in normal or cancerous cells

QUESTION 13

1. “When the DNA microarray study tells us that a large number of genes have been turned up (or turned down) by a disorder, the most likely explanation is that ”

 

the   turned up genes are likely controlled by a gene that has gone bad

 

all   of these genes are genes that have gone bad themselves

 

even   just one mutation in any of these affected genes would have been sufficient   to cause the disorder

 

the   cytoplasm has too many free radicals in it

QUESTION 14

1. A gene shown by the microarray to be expressed is :

 

“probably   making protein, but a protein expression analysis would be needed to know for   sure”

 

definitely   making protein

 

definitely   not making protein

 

probably   making protein but there’s no way to know for sure

QUESTION 15

1. “In the application of this technique to skin cancer, a gene that has gone bad ”

 

“may   or may not be identified at all, but the overall pattern of results can give   important clues”

 

can   almost always be identified via DNA microarray

 
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