Deck 1: Cell Differentiation and Neural Induction

Question 1

The earliest metazoans to have neurons were the

A) sponges.
B) nematodes.
C) echinoderms.
D) cnidarians.

Answer 1

D

Question 2

The first organisms to have more than one type of cell were the

A) metazoans
B) protozoans
C) vertebrates
D) protostomes

Answer 2

A

Question 3

The theory that an organism develops by gradually changing to acquire new, more complex structures is called

A) preformation.
B) micrographia.
C) epigenesis.
D) rationalism.

Answer 3

C

Question 4

The modern synthesis of evolution postulated that

A) parents passed along a blend of their traits to their offspring.
B) parents passed along discrete units of inheritance.
C) parents only passed along their dominant traits.
D) a new trait is lost after breeding with "normal" individuals.

Question 5

The phenotype of an individual organism or cell refers to the

A) physical characteristics displayed at a particular time.
B) total genetic makeup inherited.
C) physical characteristics that remain stable and unchanged throughout life.
D) stage of development reached once all major organs and body parts are in place.

Question 6

Regions of a gene that do not encode for any mRNA are

A) remnants of ancestral genes that are no longer needed.
B) degraded during gene transcription.
C) used to regulate gene expression.
D) no longer existent in vertebrates.

Question 7

Molecules that regulate gene expression are called

A) promoters.
B) transcription factors.
C) exons.
D) translation factors.

Question 8

If cells follow their particular fate regardless of what their neighboring cells do, they are said to have _______ specification.

A) conditional
B) mosaic
C) regulatory
D) spontaneous

Question 9

How can an organism like C. elegans, which follows an invariant pattern of mitosis, develop different cell types in a dividing zygote?

A) The mother deposits different transcription factors in different parts of the egg.
B) The dividing cells communicate with each other to determine their fate.
C) Gravity influences cells differently depending on their position in the zygote.
D) Different cell types cannot arise from an invariant pattern of mitosis.

Question 10

The first recognizable structure that embryos form is the

A) gastric system.
B) nervous system.
C) epidermis.
D) respiratory system.

Question 11

From earliest to latest in development, what is the correct order of vertebrate embryological ontogeny?

A) Blastula, neurula, gastrula
B) Neurula, gastrula, blastula
C) Blastula, gastrula, neurula
D) Gastrula, blastula, neurula

Question 12

Which germ layer provides the cellular precursors to the nervous system?

A) Endoderm
B) Mesoderm
C) Ectoderm
D) Neuroderm

Question 13

The crease formed by the primitive streak is more pronounced at one end, called the node, which will form the

A) spinal cord.
B) brain and head.
C) vertebral column.
D) epidermis.

Question 14

The neural tube will give rise to the _______, while the neural crest will give rise to the _______.

A) peripheral nervous system; central nervous system
B) central nervous system; epidermis
C) central nervous system; peripheral nervous system
D) epidermis; central nervous system

Question 15

What experimental result demonstrates the concept of self-regulation?

A) Killing one cell in a two-cell embryo results in half an embryo.
B) Killing one cell in a developing C. elegans results in a worm with one less cell than normal.
C) Scooping out a clump of cells from a blastula results in a neurula with a chunk missing.
D) Surgically removing a chick limb bud causes remaining nearby cells to create a new one.

Question 16

If you introduce stem cells with a new gene into a mouse blastula, and that mouse grows up to produce pups that also have that transgene, what can you conclude about the fate of those original transgenic stem cells?

A) They were passed directly to the offspring.
B) They did not become incorporated into the parent's genome.
C) They became sperm or eggs.
D) They allowed the mouse to self-fertilize.

Question 17

The process by which one tissue directs the differentiation of another tissue is called

A) transduction.
B) induction.
C) reduction.
D) retroduction

Question 18

If developing cells communicate with one another to induce a particular fate in neighboring cells, the very first cells must receive their instructions of what to become from

A) an organizer.
B) mosaic specification.
C) mitotic linage.
D) conditional specification.

Question 19

In their search for the organizer signal, the hypothesis the researchers developed after exposing frog embryos to lithium chloride was that lithium chloride may

A) eliminate the organizer.
B) induce another organizer to develop.
C) increase expression of the organizer.
D) decrease expression of the organizer.

Question 20

Organizer proteins _______ TGFβ receptor signaling, thus inducing _______ development.

A) activate; epithelial
B) block; neural
C) activate; neural
D) block; epithelial

Question 21

If you were to remove the mesoderm of a developing embryo, you would expect to happen to the embryo?

A) It would develop an abundance of neural cells.
B) It would not develop any skin cells.
C) It would develop an abundance of muscle cells.
D) It would not develop any neural cells.

Question 22

Which protein, secreted by endodermal cells, induces organizer proteins to start being made?

A) Bone morphogenetic protein
B) Chordin
C) Follistatin
D) β-catenin

Question 23

If you wanted to disrupt blastopore formation on a blastula, you could

A) disrupt the contents of the egg's cytoplasm.
B) disrupt the contents of the blastocoel.
C) scoop out the part of the blastula where the blastopore will form.
D) remove the ectoderm of the blastula.

Question 24

In insects, the expression of _______ is the first step ectodermal cells must take on the path to becoming neural cells.

A) noggin
B) achaete-scute complex
C) Notch
D) chordin

Question 25

When Delta and Notch bind together, a Notch fragment joins with _______ to create a transcription factor that _______ proneural gene expression.

A) protease; inhibits
B) enhancer of split; enhances
C) protease; enhances
D) enhancer of split; inhibits

Question 26

Describe the difference between cellular differentiation and ontogeny.

Question 27

Researchers implanted the nucleus of an albino frog's skin cell into an enucleated egg from a pigmented frog, and a whole albino frog developed. What did this tell us about how genes direct cellular differentiation, and how might transcription factors play a role in this?

Question 28

List three characteristics of C. elegans that make it particularly useful for studying genetic mutations.

Question 29

One of the earliest experimental embryology experiments was conducted by Wilhelm Roux, who used a hot needle to kill one of the cells in an amphibian embryo at the two-cell stage. In the experiment, the remaining living cell formed only half of an embryo. However, later vertebrate experiments showed that by completely separating cells in early embryos, each can make complete individuals. What could explain the discrepancy in these experiments?

Question 30

Why is the C. elegans strategy of development referred to as the "European plan" and the vertebrate strategy of development referred to as the "American plan?" Name the two animal development strategies referred to by each, and explain why each is akin to "European" or "American" ideals.

Question 31

Refer to the figure.
If the optic cup normally induces the overlying epithelium to differentiate into a lens and cornea, why might it not be able to induce the trunk epithelium to do the same?

Question 32

Transplanting the dorsal lip of the blastopore of one newt blastula onto another part of a differently pigmented newt blastula results in what kind of newt with what kind of pigment? What does this tell us about the dorsal lip of the blastopore?

Question 33

Refer to the figure.
A normal wild-type mouse is shown in (A), a mutant mouse with an arrow pointing to its missing ear is shown in (B), and a mutant mouse with an arrow pointing to a missing brain is shown in (C). What specific mutations might (B) and (C) have?

Question 34

What is an advantage of having many inductive steps (e.g., an organizer to organize another organizer) in an embryo?

Question 35

In the Achaete-scute complex, all cells in the ectodermal rosette begin by expressing AS-C, but only one ends up expressing AS-C. What does this suggest about how the cells in each rosette determine which will become the neuroblast? How was this suggestion confirmed experimentally?