SENSE ORGANS


24. Which type of cell is not found in the developing neuroretina?
a. bipolar b. pigment c. gangionic
layer d. rods and cones e. connective tissue mesenchyme
EXPLAIN WHY THE FOLLOWING ARE FALSE: Optic nerve and optic
stalk are homologous.
The pigment layer is derived from mesodermal mesenchyme.

NERVOUS SYSTEM

What general cell movement characteristics are
important in nerve cell migration? What is the realtionship of
original position in the neural plate and nerve function? What
kinds of effectors can Special visceral efferent fibers
ennervate? Repeat this for all of the kinds of motor neurons.
What is different about autonomic motor nerves conpared to
somatic? What causes Variations of diameter along the adult
spinal cord? Where are all sensory neurons (except for the
special senses) found? What is the origin of these cells?
Distinguish between motor and sensory neuron development.
Draw and Label a crosssection of the neural tube and associated ganglia showing which kinds of cells arise from which regions.

INDUCTION

What is the Primary organizer of all vertebrates
What determines the prospective fate, reduces the potency. What
results from treatment with lithium chloride. The normal
inductor for salamander balancers elicits suckers in frog, explain.

MUSCLE

WHAT attaches to the Z line DURING MYOTUBE DEVELOPMENT?
How is myotube development different from muscle development in
smooth or cardiac muscle? How is the location of origin of the
three muscle cell types different? Distinguish between the three
types in terms of cell appearance, innervation, number of nuclei.

CIRCULATION
What SENDS BLOOD TO DUCTUS ARTERIOSUS IN EMBRYOS?
What CONNECTS VEINS,LEFT SIDE OF BODY TO SUPERIOR VENA CAVA AND
RIGHT SIDE OF HEART? What FORMS FROM ANTERIOR EXTENSION OF 3RD
AORTIC ARCH AND DORSAL AORTA 23. Which veins contribute to
the posterior vena cava? Distinguish between veins draining the
splanchnic mesoderm and those draining the outer body tube. What
is The first part of the heart to fuse and beat? Which part becomes the pacemaker?
What do The vitelline veins have to do with the hepatic portal system?
Does Compartmentation of the right and left sides of the heart result from the lack of fusion
of the two tubes from the two heart fields? If not, how? Placing
a piece of cellophane in the midventral region causes two hearts
to form. Explain. Label the aortic arches of the mammal embryo
and list their derivatives in the adult. Be sure to consider
differences in right and left sides. The great veins enter the
two anterior atria of the adult mammal heart, but they enter the
posterior sinus venosus of the early embryo. What major changes
occur to allow this to happen.

SKELETON

GUT

Fill-in Liver endoderm is induced first by
_____________________ to form a diverticulum. The liver
diverticulum is induced to branch by the _____________________
which also invades the vitelline neins to form the ________________________.
Distinguish between splanchnic and somatic mesoderm in
terms of origin and derivatives. 7. Describe the branching of an
epithelium diverticulum as a result of an association with
mesenchyme. DRAW A DIAGRAM OF THE EMBRYONIC DIGESTIVE SYSTEM AND
RELATED ENDODERM DERIVATIVES. Teeth develop due to interaction
between which tissues? 12. The thymus is derived from which
visceral pouchs. What about the parathyroid? Which
extraembryonic membranes contain endoderm, and what are their
functions?

AXES


FILL IN: ---1. Becomes the dorsal side of the frog embryo
ESSAY: 1. Cite evidence for cytoplasmic localization of
determinants in early embryos.
Distinguish between determinate and regulative development.
35. The axes and planes of symmetry of the frog embryo depend
upon interactions between which factors?
How are axes set in the cytoplasm by nuclear genetic effects in
fly embryos?
Cytoplasmic gradients are involved in what ways in setting
development? How can Centrifugation be used as a tool for showing
that? Distinguish between preformation and mosaic development.

GENE


FILL-IN Different proteins in the various organs of the embryo
at any one time reflects ____________________________gene
activity.
Discuss proof of Changes in nuclear activities during
development.
Messenger RNA is copied from the DNA, then: explain how it can
be used to remake DNA. How is that cDNA different from the
original gene? Dis cuss RNA-DNA hybridizations and how they can
be used experimentally to understand development.
KEY ANSWERS TO QUESTION 7-11 A) GENE MODULATORS B)
HISTONE C) ACIDIC PROTEINS D) cDNA-DNA
HYBRIDIZATION E) HORMONES
7. Experiments on castration, pupation, and organ culture discussed in class demonstrate
evidence for an effect on development of _______. 8. Evidence of
differential and sequential gene activity are presented in
________. 9. Less RNA can be synthesized using RNA polymerase in
experiments using nude DNA than when it is with___________ from
the same species. 10. Division may be a necessary step in
induction in order for new DNA to be synthesized free of
____________. 11. Less RNA can be synthesized from DNA coated
with _________. How is the structure of hemoglobin different in
fetal homoglobin, giving it a higher affinity for oxygen.
9. Compare normal and teratoma cells and the fate of them if injected back
into inner cell mass. Distinguish between effects on genes by
ecdysone and actinomycin-D. How
has it been demonstrated that only a small percent of the genome
is transcribed into RNA in any one cell type at any one time?
Distinguish between genetic and epigenetic factors. Cite
evidence for stored mRNA in eggs. Cite evidence that new
messenger RNA is required for development, after fertilization.

SEQUENTIAL, DIFFERENTIAL TRANSCRIPTION
1. Explain how production of different types of hemoglobin during
development supports sequential gene activation. How do these
changes aid the embryo in its development?
2. Explain how transfection with viral genome containing myoD1
can change cell behavior and appearance. Why is myoD1 called a
lineage switch gene?
3. How can isozyme changes during development present a case for
sequential and differential gene expression?

GENE STRUCTURE
1. What is meant by upstream in a gene? What is the difference
between a transcription initiation site and a translation
initiation site, and are they both transcribed?
2. How can introns be important in gene activity? Can you
describe how mutants such as thalasemmic cells demonstrate this?
3. What is the difference between a cisİ and a transİregulator?
4. How can the importance and nucleotide sequence of promotor
regions be proven? Discuss mutants and DNA constructs.
5. How can enhancers controlling tissue specific gene activity be
demonstrated to be in the nuclei only of that specific tissue?
6. How can histones influence gene activity? Why is the default
condition of genes repression? What is the relation of chromosome
puffs of active genes to nucleosomes?
How is the nuclear matrix involved in gene activity? Then how
are matrix associated regions of genes important?

CONTROL OF GENES AT PROCESSING AND TRANSLATION

1. How is it possible to produce different populations of
cytoplasmic mRNA from the same set of nuclear transcripts?
2. How can you make a preparation of cDNA to blastula mRNA which
is specific for messages found only in the blastula stage?
3. How is the complexity of nuclear RNA greater than the mRNA of
a particular cell type? (There is more than one factor.)
4. How can immune cells make different antibody types from the
same geneİ some stuck in membrane, other secreted?
5. What is the evidence for masked messengerRNA in sea urchin
eggs which is utilized only after fertilization? How may pH amd
ionic concentration changes at fertilization be involved in their
unmasking?

CELL ADHESION MOLECULES
Discuss some of the cell surface properties involved in
differential cell affinities and adhesion?
2. How can cells differ in strength of adhesion?
3. What is the difference between NİCAM and EİCAM?
4. What is important about the three domains of cadherin and CAM
molecules which span the membrane?
5. What is the difference between cellİcell adhesion and cellŞcell matrix
adhesion? How can cell matrix be important in control
of cell function? How is integrin involved?
6. How do dissociation experiments with proteinase enzymes
(trypsin) and divalent cation chelators (EDTA and EGTA) give an
insight into multiple adhesion systems in embryos?

SIGNAL RECEPTION, RECEPTOR DISTRIBUTION
1. How can filter experiments show the difference between
inductions requiring contact and those requiring a diffusable
material?
2. How can the macrophage;Tİcell;Bİcell interactions be used as
amodel to prove how cellular interactions may involve growth
factors, gene activation, receptor synthesis, surface reactions
including cell adhesion since these all are involved in causing
plasma cell production due to foreign antigen presence?
3. How is the chick limb a good model for cell interaction in
development? What are the differences in function of mesenchyme
and epithelium?

AXES embryo
1. Cite evidence for cytoplasmic localization of determinants in
early embryos.
35. The axes and planes of symmetry of the frog embryo a) depend
upon the copulation path b) depend upon the point of sperm entry
c) don't get determined in altificial parthenogenesis d) depend
upon the original orientation of the egg in the ovary e) depend
upon an interaction of factors including sperm entry plane and
angle of rotation of the animal pole.
18. The plane of bilateral symmetry is set by a) the same
factors which set the first cleavage plane b) the copulation path
c) the sperm aster d) intrinsic egg factors e) the appearance of
the grey crescent in the cortex of the zygote.
Cytoplasmic gradients: a) have no effect on the fate of
embryonic areas b) cannot be the only factors responsible
for differentiation c) are not present in regulative eggs
d) result in each nucleus of a gastrula stage having a slightly
different cytoplasm around it than that found in cells of other
areas e) usually extend from animal to vegetal pole with
more material at the animal pole
Centrifugation can be used as a tool for: a) inactivating
spermatozoa b) rearranging egg or embryo contents c)
isolation of cell components d) separation of soluble cell
materials in gradients e) dissociating cells
Axiation in embryos may depend upon: a) first cleavage
path b) degree of rotation c) point of sperm entry
d) copulation path e) nuclear factors like homeotic gene
products
Which of the following statement is not true regarding the plane
of bilateral symmetry: it a) is first set at the time that
notochord appears under the ectoderm b) divides the embryo
into right and left halves c) passes through the
animal-vegetal egg axis d) is sometimes determined by the
point of sperm entry e) is sometimes determined by plane of
rotation
17. Determinate embryos cannot regulate after removal of polar
lobes or blastomeres. Distinguish between determinate and
regulative development.