Deck 2: Development of a Body Pattern

Question 1

In humans, the pharyngeal arches develop into the

A) neural crest cells.
B) throat.
C) gills.
D) rhombomeres.

Answer 1

B

Question 2

Which maternal factor in the Drosophila egg accumulates at the end of the embryo that will become the head?

A) Bicoid
B) Nanos
C) Caudal
D) Syncytium

Answer 2

A

Question 3

If bicoid mRNA is injected into the middle of a bicoid-deficient Drosophila egg syncytium, the embryo will develop a

A) head at one end, a tail at the other, and another head in the middle.
B) head at one end, a tail at the other, and another tail in the middle.
C) tail at both ends and a head in the middle.
D) head at both ends and a tail in the middle.

Answer 3

C

Question 4

Which class of genes initially establishes the anterior-posterior axis of the body plan?

A) Pair-rule genes
B) Gap genes
C) Maternal polarity genes
D) Hox genes

Question 5

Which class of genes directly influences the expression of pair-rule genes?

A) Realizator genes
B) Gap genes
C) Maternal polarity genes
D) Hox genes

Question 6

Which is the first class of Drosophila regulatory genes to use cell-cell signaling across the membrane?

A) Pair-rule genes
B) Gap genes
C) Maternal polarity genes
D) Segment polarity genes

Question 7

Which statement regarding homeobox and Hox genes is true?

A) Every homeobox gene is a Hox gene.
B) Every transcription factor is a homeobox gene.
C) Every Hox gene is a homeobox gene.
D) Every transcription factor is a Hox gene.

Question 8

Which set of genes shows colinearity?

A) Pair-rule genes
B) Gap genes
C) Hox genes
D) Segment polarity genes

Question 9

Hox genes in Drosophila are similar to Hox genes in vertebrates because they _______ in both organisms.

A) are located on one chromosome
B) show colinearity
C) have two complexes
D) developed by gene duplication and divergence

Question 10

Which segment in early human brain development contributes to the cerebellum?

A) Telencephalon
B) Rhombencephalon
C) Prosencephalon
D) Mesencephalon

Question 11

In normal vertebrate development, the hindbrain is distinguished from the forebrain and midbrain by the differential expression of

A) homeobox genes.
B) pair-rule genes.
C) maternal polarity genes.
D) Wnt1.

Question 12

The homeobox gene _______ is only expressed in the posterior portion of the midbrain and marks the boundary between midbrain and hindbrain.

A) engrailed
B) Gbx2
C) Wnt1
D) fibroblast growth factor

Question 13

If scientists implant an acrylic bead infused with fibroblast growth factor into the middle of a developing chick embryo brain,

A) the brain will form an additional forebrain.
B) the embryo will die.
C) the brain will form an additional midbrain.
D) the brain will develop normally.

Question 14

As vertebrate development proceeds, the hindbrain becomes segmented into eight swellings called

A) rhombomeres.
B) rhombencephalons.
C) rhombiclips.
D) rhomboids.

Question 15

The structurally distinct swellings in the developing vertebrate hindbrain are demarcated by differential expression of

A) fibroblast growth factor.
B) ephrins.
C) bone morphogenetic protein.
D) retinoic acid.

Question 16

Ephrins are _______ that affect gene expression by _______.

A) transcription factors; binding to DNA
B) proteins; binding to DNA
C) proteins; altering signaling pathways within the cell
D) transcription factors; altering signaling pathways within the cell

Question 17

Exposure to _______ prevents the posterior neural plate cells from becoming epithelial cells by making those cells _______ sensitive to BMP signaling.

A) FGF; less
B) Wnt; less
C) FGF; more
D) Wnt; more

Question 18

Which developmental signal is also a powerful teratogen?

A) Fibroblast growth factor
B) Wnt
C) Retinoic acid
D) Bone morphogenetic protein

Question 19

If a vertebrate embryo develops an enlarged posterior nervous system and little or no forebrain, what may have happened in development?

A) The embryo was over-exposed to fibroblast growth factor.
B) The embryo was over-exposed to retinoic acid.
C) The embryo was under-exposed to fibroblast growth factor.
D) The embryo was under-exposed to BMP.

Question 20

The developmental signal _______ directs the development of the ventral portion of the spinal cord, and _______ directs the development of the dorsal portion of the spinal cord.

A) Sonic hedgehog; bone morphogenetic protein
B) retinoic acid; Sonic hedgehog
C) bone morphogenetic protein; Sonic hedgehog
D) Sonic hedgehog; retinoic acid

Question 21

Sonic hedgehog is secreted from the

A) neural tube.
B) ectoderm.
C) notochord.
D) roof plate.

Question 22

Bone morphogenetic protein is secreted from the

A) neural tube.
B) ectoderm.
C) notochord.
D) floor plate.

Question 23

An animal can be born with a single telencephalon and a single eye if _______ signaling is disrupted during development.

A) bone morphogenetic protein
B) Sonic hedgehog
C) fibroblast growth factor
D) retinoic acid

Question 24

If the anterior-posterior axis of the spinal cord is disrupted, what can you conclude happened in development?

A) Sonic hedgehog signaling was blocked
B) Sonic hedgehog signaling was increased
C) Bone morphogenetic protein signaling was increased
D) Homeobox genes were dysfunctional

Question 25

In the evolution of the human brain there were four crucial steps; which event was the first?

A) Social experience began to guide neural development
B) Sensory experience began to guide neural development
C) Cell-cell interactions began to determine cell fate
D) Electrical activity of neurons began to affect the fate of other cells

Question 26

Describe the possible reasons why embryonic structure across species is so similar.

Question 27

In insects, the early embryo consists of a single cell with one continuous cytoplasm containing many nuclei. How can those nuclei become different types of cells if they all started out in the same cytoplasm?

Question 28

Refer to the graph.
Where is the highest concentration of hunchback protein expressed in the Drosophila embryo, and how do the antagonistic actions of maternal polarity genes bicoid and nanos result in sharper boundaries of hunchback gene expression?

Question 29

What is the relationship between Hox genes and realizator genes? How is their function different?

Question 30

What is a potential benefit of a random mutation that leads to a duplication in a gene?

Question 31

Refer to the figure.
A normal wild-type mouse is shown in (A), a mutant mouse with enlarged rostral cortex centers is shown in (B), and a mutant mouse with enlarged caudal cortical centers is shown in (C). What specific mutations might (B) and (C) have?

Question 32

In vertebrate nervous system development, what system is responsible for sharpening the homeobox gene expression boundaries between rhombomeres? How does this system work with respect to what the key players are, where they are located, how they interact, and how they influence gene expression and rhombomere boundaries? What does this mean for the fate of the cells that make up each rhombomere?

Question 33

What four factors in the vertebrate neurula direct cells to take on a fate appropriate for the caudal end of the animal? What two characteristics do these factors share?

Question 34

In vertebrate nervous system development, what would happen to the neural tube if the notochord was removed? What would happen if a second notochord was transplanted to another part of the neural tube? What does this suggest about the function of the notochord?

Question 35

How is it that the body can randomly assign cells to a particular fate based solely on where they are located, and how is this accomplished?