Recitation 11: Cancer Genetics

Question 1

DNA microarrays are clarifying the … of health and disease and speeding … discovery. They could also hasten the day when customer tailored treatment plans replace a one-size-fits-all approach to health care

Answer 1

molecular roots; drug

Question 2

cancer discussed is called

Answer 2

diffuse large B cell lymphoma

Question 3

large B cell lymphoma comes in different forms caused by

Answer 3

distinct molecular abnormalities

Question 4

DNA microarray is also known as

Answer 4

DNA chip

Question 5

DNA microarray enabled researchers to distinguish between long- and short- term survivors based on differences in the overall pattern of activity exhibited by hundreds of … in their …. at the time of diagnosis

Answer 5

genes; malignant cells

Question 6

DNA microarray should lead to a … able to identify the patients in greatest danger

Answer 6

diagnostic test

Question 7

Microarrays are beginning to revolutionize how scientists explore the operation of … in the body and the … that underlie medical disorders

Answer 7

normal cells; molecular aberrations

Question 8

Microarrays will pave the way for …, more … diagnoses of many conditions and to help doctors personalize medical care–that is, tailor therapies to the exact … of disease in each person and select the drugs likely to work best, with the mildest side effects, in those individuals

Answer 8

faster; accurate

Question 9

Arrays all assess the …. of genetic material in a tissue sample, and consist of a lawn of … DNA molecules (probes) that are tethered to a wafer often no bigger than a thumbprint.

Answer 9

composition; single-stranded;

Question 10

Arrays also capitalize on

Answer 10

complementary base pairing

Question 11

DNA microarrays can track tens of thousands of complementary base pair reactions in … on a … This is possible because each kind of probe sits at an assigned spot within a chekerboardlike grid on the chip and the DNA/RNA molecules that get poured over the array carry a … or other label that can be detected by a scanner, which converts the raw data into a color coded readout

Answer 11

parallel; single chip; fluorescent tag

Question 12

The DNA on a chip is compared with DNA in a tissue sample to determine …. or to decipher the order of … in as yet … strings of DNA

Answer 12

which genes are in the sample; code letters; unsequenced

Question 13

Arrays can be used not only to assess the presence/sequence of genes in a sample but the …, or …, of those genes

Answer 13

expression; activity level

Question 14

The genotype approach has been used to … in different organisms to find clues to … and to compare the genes in … with those in … to uncover subtle differences in composition/number

Answer 14

compare the genes; evolutionary history; tumors; normal tissues;

Question 15

the chips can be designed to detect specific … or to measure … in tissue samples

Answer 15

genes; gene activity

Question 16

…, which have great promise as diagnostic devices and as aids to biological research, are being developed as well.

Answer 16

protein arrays

Question 17

another major use of arrays

Answer 17

expression profiling

Question 18

expression profiles are produced by measuring the amounts of different … Generally, the more copies of this a cell makes, the more copies of … it will make, so these quantities can indirectly indicate the … and … present

Answer 18

mRNAs in a tissue sample; proteins; types; amounts of proteins

Question 19

By using the genome as a sensor pad
to detect activity changes in a cell’s various
genes, scientists can gain exquisitely
detailed “snapshots” of how a cell’s functions
have been

Answer 19

altered by drugs or disease

states

Question 20

Cell biologists
like it because knowledge of the proteins
that predominate after a tissue is exposed
to different conditions can provide insight
into how the tissue normally ….and what goes wrong
when …

Answer 20

compensates

for disruptions; diseases develop

Question 21

Expression arrays can also be used to learn the … of genes that have recently been discovered

Answer 21

functoins

Question 22

guilt-by-association method: method using arrays based on idea that no gene is an

Answer 22

island

Question 23

pharmaceuticals use expression profiling to pick out and eliminate drug candidates that are likely to produce

Answer 23

unacceptable side effects

Question 24

experiment is using expression profiles to determine if a protease inhibitor (used for HIV), …., produced some of its side effects by acting on the …

Answer 24

ritonavir; liver

Question 25

they produced expression profiles of … exposed to an assortment of compounds that can be toxic to the liver, then grouped the compounds according to similarities of expression signatures. They delivered ritonavir to rat livers and compared the resulting expression profiles with those developed earleir

Answer 25

rat liver tissue

Question 26

they found that ritonavir raises … levels in the liver by elevating the liver’s … and inhibiting its breakdown of …

Answer 26

lipid; synthesis of lipids; lipid-containing proteins

Question 27

proto-oncogenes produce proteins that are involved in … the cell cycle. mutations in these genes tend to cause either an … of protein (…) or a protein to be … (pushing the cell cycle forward even in the absence of a signal to divide, e.g. growth factor)

Answer 27

promoting; over-production; over-expression; constitutively active

Question 28

tumor suppressor genes: put the … on the cell cycle, usually at key checkpoints. Mutations in tumor suppressor genes that contribute to carcinogenesis can cause either abnormally … levels of protein or no … (…) at all. A mutation like this could allow a damaged or rogue cell to divide when it shouldnt

Answer 28

low; functional protein; under-expression

Question 29

genome-maintenance genes include the … gene (which helps extend the life of a chromosome, and, consequently, the number of … that it can undergo) and DNA … genes (which keep the level of … in all genes low)

Answer 29

telomerase; cell division cycles; repair; mutations