Deck 16: Gene Regulation in Eukaryotes

Question 1

Results from RNAi studies are most likely to vary due to

A) varying amount of cellular uptake of dsDNA.
B) its low heritability.
C) different levels of starting mRNA.
D) issues related to fertilization.
E) differences in translation.

Answer 1

A

Question 2

What is the most common cause of rare spontaneous ectopic gene expression?

A) insertion mutation
B) deletion mutation
C) a mutation that moves the gene next to a new regulatory element
D) point mutation
E) substitution mutation

Answer 2

C

Question 3

What technique is most efficiently used to produce a phenocopy?

A) RNAi
B) transgene
C) isolation of mutations
D) QTL mapping analysis
E) phosphorylation

Answer 3

A

Question 4

Which of the following is not a type of loss-of-function mutation?

A) conditional
B) hypomorphic
C) null
D) dominant-negative
E) ectopic

Question 5

A partial loss-of-function mutation is

A) null.
B) hypomorphic.
C) conditional.
D) dominant-negative.
E) hypermorphic.

Question 6

What is the most significant advantage of using RNAi to study development?

A) Geneticists have only been able to identify a subset of the genes involved in development.
B) Genetic studies on a single gene can be completed without the creation or isolation of new mutant organisms.
C) RNA is easy to isolate.
D) RNAi causes phenotypes not typical of in vivo development.
E) RNAi always completely silences a single gene.

Question 7

A ligand secreted from a cell to a nearby cell that signals developmental differentiation is called

A) juxtacrine factor.
B) paracrine factor.
C) endocrine factor.
D) exocrine factor.
E) autonomous factor.

Question 8

Mutations that disrupt the earliest stages of human development almost always cause

A) no effect.
B) polydactyly.
C) spontaneous abortion.
D) disruption of the segmented body plan.
E) immunodeficiency.

Question 9

A loss-of-function mutation that depends on special circumstances is called

A) null.
B) hypomorphic.
C) conditional.
D) dominant-negative.
E) codominant.

Question 10

Gain-of-function alleles are usually

A) null.
B) conditional.
C) recessive.
D) dominant.
E) hypervariable.

Question 11

What type of mutation is particularly useful to researchers who wish to study a gene's effect on development when a natural loss-of function mutation has not yet been isolated?

A) haploinsufficient
B) hypomorphic
C) conditional
D) dominant-negative
E) recessive

Question 12

Which of the following is not a taboo on the use of humans in genetics studies?

A) phenotypic analysis
B) experimental manipulation of affected individuals
C) forced matings
D) deliberate production of mutants
E) controlled environments

Question 13

An unusual loss-of-function mutation that is not recessive is

A) null.
B) hypomorphic.
C) conditional.
D) dominant-negative.
E) epistatic.

Question 14

Which of the following is not true of RNAi?

A) it depletes the protein products of genes.
B) it depends on dsRNA to trigger the degradation of mRNA.
C) it can be used to create a functional knock-out.
D) it always produces the same results in replicated experiments.
E) it is used in model organisms.

Question 15

Which of the following is most likely to cause a gain-of-function mutation?

A) deletion of a promoter region
B) constitutive activation of an enzyme
C) a synonymous mutation
D) a null mutation
E) RNAi

Question 16

Mutations that result in a new phenotype for a gene through the production of too much protein are best described by the term

A) conditional.
B) permissive.
C) hypomorphic.
D) gain of function.
E) null.

Question 17

Signaling factors that complete cell-to-cell communication in the form of direct contact are called

A) juxtacrine factors.
B) paracrine factors.
C) endocrine factors.
D) exocrine factors.
E) autocrine factors.

Question 18

The expression of a gene at an abnormal place or time is called

A) epistasis.
B) ectopic.
C) epigenetic.
D) expressivity.
E) erratic.

Question 19

Ligands that circulate throughout the body and signal developmental differentiation are called

A) juxtacrine factors.
B) paracrine factors.
C) endocrine factors.
D) exocrine factors.
E) autonomous factors.

Question 20

The Aniridia gene in humans is involved in eye formation.Although eye development is very different in flies,this gene is highly conserved.What is its homolog in Drosophila?

A) eyeless (ey)
B) Pax6
C) noeye (ne)
D) ommatidia (om)
E) Hox9

Question 21

A cloned organism will always be genotypically and phenotypically identical to the individual from which it was cloned.

Question 22

What technique would you use to best determine when and in what cells of a given tissue a specific gene is expressed?

A) Northern analysis
B) In situ hybridization
C) RT-PCR
D) Southern analysis
E) PCR

Question 23

How would you best follow the developmental timing of a given protein in vivo?

A) in situ hybridization
B) western blotting
C) using a GFP-fusion protein transgenic organism
D) microarray analysis
E) PCR

Question 24

Developmental regulation occurs mostly at the level of mRNA stability.

Question 25

The presence of a homeodomain in a protein suggests what about its function?

A) It has kinase activity.
B) It is a membrane bound receptor.
C) It is a secreted protein.
D) It is a transcription factor.
E) It has phosphorylase activity.

Question 26

Which of the following is a zygotic gap gene in Drosophila?

A) knirps (kni)
B) even-skipped (eve)
C) caudal (cad)
D) hedgehog (hh)
E) agamous (ag)

Question 27

A molecule whose concentration determines the developmental fate of a cell is called

A) monomorphic.
B) a juxtacrine protein.
C) a signaling molecule.
D) a morphogen.
E) a paracrine molecule.

Question 28

In Drosophila,two maternal transcripts that are distributed evenly throughout the oocyte prior to fertilization are:

A) caudal and knirps
B) bicoid and nanos
C) caudal and hunchback
D) agamous and hunchback
E) caudal and agamous

Question 29

Which of the choices gives the correct sequence of early embryonic development in Drosophila?

A) zygote,syncytial blastoderm,multinucleate syncytium,cellular blastoderm
B) zygote,cellular blastoderm,syncytial blastoderm,multinucleate syncytium
C) zygote,multinucleate syncytium,syncytial blastoderm,cellular blastoderm
D) zygote,syncytial blastoderm,cellular blastoderm,multinucleate syncytium
E) cellular blastoderm,multinucleate syncytium,zygote,syncytial blastoderm

Question 30

In Drosophila embryos,segment polarity genes operate prior to pair-rule genes.

Question 31

Screening for maternal-effect mutations would involve looking for which of the following?

A) unusual phenotypes in female progeny
B) embryos that are all obviously developmentally arrested
C) asymmetric mutations
D) eggs that can not be fertilized
E) dominant negative phenotypes

Question 32

Maternal and zygotic genes affect early development.

Question 33

Development requires progressive changes in gene expression.

Question 34

What does a homeodomain do?

A) acts as a receptor
B) has kinase activity
C) binds to specific DNA sequences
D) causes transposition
E) induces cell division

Question 35

Cells that provide large amounts of mRNA and proteins for deposition into the egg are called

A) doctor cells.
B) nurse cells.
C) helper cells.
D) bicoid cells.
E) pump cells.

Question 36

Bicoid is a maternal-effect mutation that results in larvae with two heads.

Question 37

Although stem cells can continue dividing indefinitely,half of the cells they give rise to can differentiate into a variety of different cell types.

Question 38

The green fluorescent protein gene is often joined to genes of interest thus producing a fusion protein that is easily followed in vivo.

Question 39

An example of ectopic gene expression is shown by

A) achondroplastic dwarfism.
B) lack of eye development.
C) abnormal vulvar shape.
D) legs instead of antennae.
E) stem cells.

Question 40

A nurse cell produces large amounts of mRNA and proteins for deposit into the Drosophila egg.

Question 41

You recover Drosophila embryos in which,instead of having a head region and tail region,have two tail regions in mirror-image arrangement.Describe a maternal mutation that could cause this condition.

Question 42

Due to ethical considerations,development is studied in model organisms.How do you use genetic information gained from other species to isolate the human genes involved in development?

Question 43

The homeodomain is a common DNA-binding domain in many transcription factors that regulate development.

Question 44

What properties of C.elegans is a transparent round worm with an invariant number of cells in the adult.The female is a hermaphrodite.C.elegans make it the most useful model organism?

Question 45

How can hypomorphic mutations help "tease" out pleiotropic effects in development?

Question 46

The maternal Nanos (nos)RNA transcript is the primary anterior morphogen in Drosophila zygote development.

Question 47

Bicoid is a maternal protein deposited in the anterior region of the egg in Drosophila.

Question 48

One action of the Bicoid protein is to repress the translation of the caudal (cdl)transcripts.

Question 49

The sequence of early embryonic development in Drosophila is zygote,multinucleate syncytium,syncytial blastoderm,and cellular blastoderm.

Question 50

How do cells which all contain identical genetic information differentiate into myriad cell types and ultimately undergo the "miracle" of development from an embryo into a child?

Question 51

What is the molecular basis of haploinsufficiency?

Question 52

What gene controls eye development and to what degree is it evolutionarily conserved?

Question 53

What kind of mutation would be most helpful to test a hypothesis regarding the timing of developmental stages?

Question 54

What three characteristics of value to geneticists do model organisms share?

Question 55

You are a very lucky scientist.You observe that an interesting mutant phenotype has arisen in your cell culture.A clonal kidney cell line has what appears to be a patch of muscle cells growing in it.(This suggests that the cell began from a single mutant cell. )You wish to test the hypothesis that gene expression changes result in a change in morphology.How would you test your hypothesis?

Question 56

Maternal mRNA transcripts of the bicoid (bcd)gene are deposited in the anterior portion of the egg in Drosophila.

Question 57

What is a dominant-negative mutation?

Question 58

What advantages,in particular,do yeast cells provide with respect to the study of eukaryotes?

Question 59

Model organisms are useful for the study of developmental genetics because significant ethical limitations restrict studies in humans.Discuss some taboos to research in humans.

Question 60

Describe the hierarchy of expression of zygotic genes in determining segmentation in Drosophila embryos.