Deck 11: Gene Expression and Epigenetics

Question 1

The main limitation of a drug that treats disease by altering chromatin remodeling is that

A) the changes would be passed on to daughter cells.
B) it would change the number of copies of a gene people inherit.
C) the changes would be epigenetic.
D) it would change the expression of many other genes.
E) it would cause mutations.

Answer 1

D

Question 2

Hemoglobin in the embryo consists of

A) two alpha chains and two beta chains.
B) two epsilon chains and two zeta chains.
C) two gamma chains and two alpha chains.
D) two gamma chains and two beta chains.
E) one alpha chain, one beta chain, one epsilon chain, and one gamma chain.

Answer 2

B

Question 3

Development of the pancreas in an embryo into a dual gland that has both exocrine and endocrine functions begins when

A) insulin is produced and bathes stem cells.
B) a transcription factor stimulates progenitor cells to give rise to exocrine or endocrine cells.
C) a globin gene duplicates and gives rise to alpha and beta globin genes.
D) progenitor cells become stem cells.
E) the primordial pancreas splits into two parts, one exocrine and one endocrine.

Answer 3

B

Question 4

An example of the utility of gene expression profiling in a clinical situation is

A) finding that a child has inherited a certain genotype.
B) identifying genes with aberrant expression levels in cancers likely to spread.
C) the ability to inject a gene to compensate for a defective or missing gene.
D) to determine whether a medical condition is inherited or not.
E) replacing a gene bearing a mutation with a wild type version in the affected tissue.

Question 5

Blood plasma contains about ____ different types of proteins,but only ___ types account for 90 percent of the total number of proteins.

A) 40,000; 10
B) 20,000; 20
C) 1,000; 100
D) 500; 35
E) 20; 10

Question 6

Modifiers of gene expression include

A)isolated amino acids and tRNAs.
B)specific classes of proteins and RNA molecules.
C)specific classes of lipids and carbohydrates.
D)nicotine and alcohol.
E)A,T,C,and G.

Question 7

Fetal hemoglobin carries _______ percent more oxygen than adult hemoglobin.

A) 5-10
B) 20-30
C) 50-60
D) 80-90
E) 0

Question 8

Globin chain switching replaces gamma chains with _____ chains in adult hemoglobin.

A) epsilon
B) zeta
C) beta
D) alpha
E) phi beta kappa

Question 9

A treatment for some forms of anemia is to take a drug that turns on transcription of fetal hemoglobin.This would increase the proportion of _____ globin chains.

A) alpha
B) beta
C) gamma
D) delta
E) epsilon

Question 10

Understanding the signals that activate pancreatic stem cells to differentiate as beta cells could be used to treat

A) acne.
B) restless legs syndrome.
C) male infertility.
D) endometriosis.
E) diabetes mellitus.

Question 11

A promoter of a gene is the sequence at the _____ end of a gene where RNA polymerase and transcription factors bind,marking the _________.

A) 3'; end point of transcription
B) 3'; start point of transcription.
C) 3'; end point of translation.
D) 3'; start point of translation.
E) 5'; start point of transcription.

Question 12

The reason for fetal globin chain switching is that

A) a fetus does not need oxygen but a newborn does.
B) a fetus has four alpha globin chains and a newborn has four beta globin chains.
C) a fetus' blood is clear until the sixth month, and then globin chains turn it red.
D) the newborn needs more iron than the fetus or embryo.
E) the embryo and fetus receive different concentrations of oxygen compared to after birth.

Question 13

In the adult pancreas,the beta,alpha,gamma,and F cells are

A) stem cells.
B) progenitor cells.
C) differentiated cells.
D) blood cells.
E) connective tissue cells.

Question 14

The term _______ refers to genes that encode proteins that control lipid synthesis.

A) genome
B) lipidome
C) proteome
D) glycome
E) biodome

Question 15

"Epigenetic" means

A) "inside the gene."
B) "inside the protein."
C) "outside the gene."
D) "outside the protein."
E) "unwind the DNA."

Question 16

Gene expression profiles differ from classic gene maps in that

A) gene expression profiles depict the relative locations of genes on chromosomes, and classic gene maps show the increase and decrease of transcription with time or in different tissues.
B) gene expression profiles depict the increase and decrease of transcription with time or in different tissues, and classic gene maps show the relative locations of genes on chromosomes.
C) gene expression profiles measure DNA and classic gene maps size-order the chromosomes.
D) gene expression profiles sequence genomes whereas classic gene maps do not actually sequence the DNA.
E) gene expression profiles have not yet been done in humans but classic gene maps have.

Question 17

Transcription factors account for a greater proportion of the proteome in a fetus compared to a 20-year-old because

A) many cells have already died in a 20-year-old.
B) a fetus does not yet need many of its proteins.
C) cells are actively differentiating and many structures are forming in a fetus.
D) an adult can carry out more activities than can a fetus.
E) the 20-year-old can consciously activate his or her transcription factors.

Question 18

Chromatin remodeling can block ________ and microRNA binding can block _______.

A) transcription; translation
B) translation; transcription
C) synthesis of tRNAs; synthesis of rRNAs
D) DNA replication; DNA repair
E) acetylation; phosphorylation

Question 19

A mutation in a promotor causes a disorder in which the blood clots too readily by

A) deleting a gene for a clotting factor.
B) blocking transcription of a clotting factor.
C) increasing susceptibility to a specific viral infection.
D) increasing the transcription rate of a particular clotting factor gene.
E) affecting how watery the blood is.

Question 20

Epigenetic changes

A) pass from one cell generation to the next but do not alter the DNA sequence.
B) do not pass from one cell generation to the next but do alter the DNA sequence.
C) irreversibly alter the DNA sequence and are only passed to the next cell generation if they add an advantage.
D) only occur in males.
E) alter the RNA codon - amino acid assignments of the genetic code.

Question 21

About __ percent of human genes are alternately spliced.

A) 10
B) 20
C) 40
D) 75
E) 90

Question 22

The most important chemical group that determines how tightly histones bind DNA is

A) acetyl.
B) methyl.
C) ethyl.
D) phosphate.
E) glucose.

Question 23

The most abundant type of DNA repeat sequence is called a

A) genome.
B) lipidome.
C) proteome.
D) transposon.
E) transcriptome.

Question 24

About ___ percent of the human genome actually encodes proteins.

A) 0.5
B) 1.5
C) 5.0
D) 10
E) 100

Question 25

A microRNA is ____ bases long.

A) 2-4
B) 12-13
C) 21-22
D) 100-110
E) 400-440

Question 26

MicroRNAs bind to

A) the 3' ends of specific mRNAs.
B) the 5' ends of specific mRNAs.
C) the 3' ends of specific tRNAs.
D) the 3' ends of specific macroRNAs.
E) the 4' ends of specific mRNAs.

Question 27

Multiple proteins can be produced from a single gene by

A) intron shuffling.
B) alternate splicing.
C) chain switching.
D) production of pseudogenes.
E) chromatin remodeling.

Question 28

Rett syndrome results from

A) a microRNA that binds the wrong set of mRNA targets.
B) failure to remove acetyls from histones on a gene expressed in the brain.
C) fetal hemoglobin that is reactivated in a child.
D) abnormal methylation of a gene expressed in the brain.
E) eating too much mercury-tainted fish.

Question 29

In chromatin remodeling,acetyl groups bind

A) mRNA.
B) the DNA sense strand.
C) lysines that are part of histones.
D) microRNAs.
E) globin genes.

Question 30

The human genome encodes about 21,000 genes,which encode about _____ mRNAs,which are translated in pieces and arranged to encode about _____ different proteins.

A) 1 million; 100,000
B) 100,000; 1 million
C) 21,000; 21,000
D) 21,000; 63,000
E) 63,000; 21,000

Question 31

Noncoding RNAs include all types of RNA molecules except

A) tRNAs.
B) rRNAs.
C) HERVs.
D) mRNAs.
E) microRNAs.

Question 32

Isoforms are

A) technologies that sequence DNA at very low temperatures.
B) different types of RNA molecules.
C) different versions of proteins that reflect different exon combinations.
D) the patterns of acetyls, phosphates, and methyl groups that bind to a particular gene.
E) the patterns of microRNAs that bind to a particular mRNA molecule.

Question 33

Which metaphors correctly compare chromatin remodeling and microRNA function?

A) a hammer and a nail
B) an on/off switch and a dimmer switch
C) an elevator and a submarine.
D) an activator and a repressor.
E) a stimulator and an inhibitor.

Question 34

Histone proteins

A) are male sex hormones.
B) are inert spool-like structural supports around which DNA winds.
C) control gene expression through chemical interactions that expose parts of the DNA to transcription factors, while shielding other parts.
D) bind to mRNAs, preventing their translation into protein.
E) are built of methyl groups.

Question 35

The complexity of microRNA function is that

A) microRNAs can be rRNA, mRNA, or tRNA.
B) they range in size from 10 to 10,000 bases.
C) a microRNA type can bind several mRNAs, and an mRNA can bind several microRNAs.
D) it can bind DNA, RNA, or protein.
E) it can be acetylated, phosphorylated, or methylated.

Question 36

Pseudogenes are

A) not transcribed.
B) transcribed but not translated.
C) transcribed and translated.
D) rare in the human genome.
E) double strand RNA loops.

Question 37

About __ of the human genome encodes tRNA.

A) 0.001
B) 0.01
C) 0.1
D) 1
E) 10

Question 38

The form of RNA that cuts rRNA molecules is

A) tRNAs.
B) pseudogenes.
C) snoRNAs.
D) microRNAs.
E) macroRNAs.

Question 39

About __ of the human genome sequence comes from retroviruses.

A) 4
B) 8
C) 12
D) 21
E) 35

Question 40

A typical human cell contains

A) one copy of each of 100 different microRNAs.
B) one copy of each of 3.2 billion different microRNAs.
C) one copy of each of about 20,000 different microRNAs.
D) from 1,000 to 200,000 microRNAs of about 1,000 types.
E) no microRNA unless the person develops cancer.