Deck 13: The Genetic Control of Development

Question 1

The class of genes required that act at a double-segment periodicity is the:

A)maternal-effect genes.
B)gap genes.
C)pair-rule genes.
D)segment polarity genes.
E)Hox genes.

Answer 1

C

Question 2

In Drosophila melanogaster,Hox genes are:

A)clustered into operons.
B)clustered in one large gene complex.
C)clustered together in two gene complexes.
D)clustered together in three gene complexes.
E)evenly distributed throughout the genome.

Answer 2

C

Question 3

The maternal-effect Bicoid gene codes for:

A)a signal protein.
B)a serine protease.
C)a DNA-binding transcription factor.
D)a cell-to-cell junction protein.
E)a transmembrane protein.

Answer 3

C

Question 4

The genes required for proper organization of the anteroposterior body axis of the fly embryo are grouped into how many classes?

A)1
B)2
C)3
D)4
E)5

Question 5

In the developing chick vertebral limb bud,the zone of polarizing activity (ZPA)organizes a pattern along the anteroposterior axis.Transplantation of the ZPA from a posterior to anterior position:

A)causes no change in development.
B)induces extra digits with reverse polarity.
C)induces extra digits with the same polarity.
D)induces extra limbs.
E)None of the answer options are correct.

Question 6

The class of genes that affect patterning within each segment is the:

A)maternal-effect genes.
B)gap genes.
C)pair-rule genes.
D)segment polarity genes.
E)Hox genes.

Question 7

Drosophila melanogaster development proceeds in which of the following stages?

A)egg-segmented embryo-pupa-larva-adult
B)segmented embryo-egg-pupa-larva -adult
C)egg-segmented embryo-larva-pupa-adult
D)egg-larva-segmented embryo -pupa-adult
E)segmented embryo-larva-egg-pupa-adult

Question 8

There are ______ Hox genes in Drosophila melanogaster.

A)12
B)8
C)10
D)25
E)39

Question 9

In homeotic mutants:

A)one body structure is missing.
B)one body structure has been changed into another.
C)one body structure has been duplicated.
D)one body structure has significantly increased in size.
E)the organism is infertile.

Question 10

The class of genes required for establishing the anteroposterior axis is the:

A)maternal-effect genes.
B)gap genes.
C)pair-rule genes.
D)segment polarity genes.
E)Hox genes.

Question 11

The homeodomain encodes:

A)a helix-turn-helix motif.
B)an ATP-binding domain.
C)a leucine zipper.
D)a zinc-finger.
E)a protease.

Question 12

A morphogen is a molecule that induces:

A)cells to undergo cellular division.
B)cells to increase in size.
C)various responses in surrounding tissue in a non-concentration-dependent manner.
D)various responses in surrounding tissue in a concentration-dependent manner.
E)None of the answer options are correct.

Question 13

Establishment of the dorsal-ventral axis of the Drosophila embryo:

A)involves the production of localized DL mRNA on the ventral side of the developing embryo.
B)occurs via at least two paracrine signals transmitted between the developing oocyte and the surrounding somatic follicle cells.
C)involves the zygotically expressed DL morphogen.
D)depends on the activity of anterior-posterior morphogens,such as BCD or HB-M.
E)None of the answer options are correct.

Question 14

The homeotic,gap,pair-rule,and segment polarity genes all control:

A)aspects of anterior-posterior pattern formation.
B)the number of segments.
C)the developmental fates (identities)of the individual segments.
D)dorsal-ventral pattern formation.
E)the production of the anterior-posterior morphogens.

Question 15

There are ______ Hox genes in the laboratory mouse.

A)12
B)8
C)10
D)25
E)39

Question 16

The class of genes required for establishing the formation of a contiguous block of segments is the:

A)maternal-effect genes.
B)gap genes.
C)pair-rule genes.
D)segment polarity genes.
E)Hox genes.

Question 17

In the developing Drosophila embryo,the Hox genes are expressed:

A)in temporally restricted domains.
B)uniformly throughout the embryo.
C)only in homeotic mutants.
D)in spatially restricted domains.
E)None of the answer options are correct.

Question 18

Genes with products provided by the female to the egg are called:

A)paternal-effect genes.
B)maternal-effect genes.
C)sex-linked genes.
D)embryo-specific genes.
E)egg-specific genes.

Question 19

All eight Drosophila Hox genes encode proteins containing a highly conserved 60-amino-acid domain called the:

A)hox box.
B)homeodomain.
C)hox domain.
D)heterodomain.
E)chromodomain.

Question 20

Homeosis is defined as the failure to:

A)form the correct number of segments.
B)correctly polarize a developing embryo.
C)develop antenna.
D)correctly establish segmental identity.
E)None of the answer options are correct.

Question 21

The doublesex (dsx)gene plays a central role in governing the sexual identity of somatic (non-germ-line)tissue.Null mutations in dsx cause:

A)males to develop as females.
B)females to develop as males.
C)females and males to develop as intermediate intersexes.
D)only females to develop as intermediate intersexes.
E)None of the answer options are correct.

Question 22

Shown below is a list of molecules that function in Drosophila development (a-g)and a list of possible distribution patterns (1-5).On the line following each distribution pattern,write the letter(s)of the molecule(s)showing that type of distribution pattern.
a)toll transmembrane receptor
b)hunchback protein
c)activated SPZ ligand
d)inactive DL protein
e)active DL protein
f)NOS protein
g)Bicoid protein
1)Highest gradient is in the anterior end of the embryo.__________
2)Highest gradient is in the posterior end of the embryo.__________
3)Highest gradient is at the ventral midpoint of the embryo.__________
4)This is distributed throughout the oocyte/embryo.__________
5)This is present uniformly in the oocyte plasma membrane.__________

Question 23

The products of the gene let-7 is a well-known:

A)transcription factor.
B)polarity protein.
C)trans-acting activator of pair-rule genes.
D)microRNA.
E)homeotic protein.

Question 24

Shown below is a list of gene classes that play a role in Drosophila development.
$\quad$$\quad$$\quad$$\quad$$\quad$ homeotic genes
$\quad$$\quad$$\quad$$\quad$$\quad$ gap genes
$\quad$$\quad$$\quad$$\quad$$\quad$ segment-polarity genes
$\quad$$\quad$$\quad$$\quad$$\quad$ maternal-effect genes
$\quad$$\quad$$\quad$$\quad$$\quad$ pair-rule genes

(i)Describe the role of each class of genes and the impact that a mutation in the class has on Drosophila development.
(ii)The different classes of genes function at different times during Drosophila development.Put the gene classes in order,from earliest to latest.

Question 25

A scientist working in a Drosophila lab locates a mutation in an organism that caused antenna to be transformed into legs.He determines that this is a homeotic transformation.Do you agree?

Question 26

In Drosophila,the vast majority of A-P axis genes that contribute to pattern formation encode:

A)transcription factors.
B)histones.
C)sugar-utilizing enzymes.
D)operons.
E)ligands.

Question 27

The early Drosophila embryo has multiple nuclei within a single cytoplasm and is considered a:

A)coenocyte.
B)hyphae.
C)syncytium.
D)chorion.
E)None of the answer options are correct.

Question 28

The pre-mRNA for Sex-lethal,transformer,and doublesex are:

A)identical in both sexes.
B)shorter in females.
C)shorter in males.
D)longer in females.
E)longer in males.

Question 29

In the nematode worm,C.elegans,embryonic development is controlled largely by controlling _______________.

A)Bicoid
B)transcription
C)post-transcription
D)protein processing
E)None of the answer options are correct.

Question 30

Why would animals as diverse as mice,humans,and Drosophila have maintained nearly identical Hox genes?

Question 31

A Drosophila researcher recently isolated a number of mutant fruit flies.The phenotype of each mutant is described below (i-iv).For each mutant,describe the type of gene (maternal-effect gene,gap gene,segment-polarity gene,or homeotic gene)that was most likely the cause of the altered phenotype.
(i)Homozygous mutant females appear phenotypically normal but produce larvae that have two posterior ends.
(ii)The flies contain four wings rather than two.
(iii)The wings are oriented backward.
(iv)The flies are missing two pairs of legs due to a shortened thoracic region.

Question 32

What characteristics allowed Drosophila melanogaster (an insect)to emerge as the leading genetic model of animal development?

Question 33

The nematode worm Caenorhabditis elegans is comprised of approximately ______ somatic cells.

A)10
B)100
C)1,000
D)100,000
E)100,000,000

Question 34

The formation of stripe 2 in a Drosophila embryo is controlled by the binding of four transcription factors to the eve stripe 2 cis-acting regulatory element.This includes:

A)one maternal protein and three gap proteins.
B)one paternal protein and three gap proteins.
C)one pair-rule,one segment-polarity,and two gap proteins.
D)two pair-rule and two gap proteins.
E)all maternal proteins.