Biol 441 Review questions for first
test:
18 What kinds of reactions due to
signal transduction occur in both sperm and eggs in spite of different sets of
receptors in each?
19. How does the amount of yolk
influence development?
21. What is different about signals for
meiosis to occur and mitosis after fertilization?
FERTILIZATION
1. What
changes are formed in egg cortex following fertilization?
2.
Distinguish between artificial activation of egg surface and nuclear events
by agents
causing early or late events.
3. What
factors are involved with changes in membrane potential in egg and sperm
activation
and what are the results?
What are the
functions of actin in the fertilization cone and cleavage furrow?
Whast process
is Necessary for making mammal sperm capable of fusion with egg.
What special
structures are present in eggs and sperm to allow fertilization?
Describe Cell
control mechanisms which
work in early
gametogenesis and development, including: a)changes in pH b) changes in amount
of
free calcium
c) phosphorylation of proteins to alter the metabolic activity or structure d)
hormone-receptor
internalization c) secretion of enzymes to alter the surface
Distinguish
between artificial egg activation and parthenogenesis.
What evidence
do we have that either Ca++ release or pH change alone are not
able to
activate development?
What role do
surface molecules such as ZP3 and bindin play in egg activation by sperm?
MATURATION
Fill-in:
The effect of
the steroid hormone _______________________ on ova is mediated
by the
____________________________________________factor which is produced
in the
______________________________________, as a result of this many other
effects occur
including breakdown of the _________________
__________________________,
production of factors with effects on
______________________
and ________________________.
What results
from production of maturation promoting factor in eggs?
How do we
know that stored messenger RNA in eggs is important in early
development?
3. Do you
think that an unfertilized egg is a differentiated cell? Defend
your answer.
Where is The
animal-vegetal axis set?
CLEAVAGE
How is
cleavage important to development?
Separation of
the first two blastomeres of amphibians does not always result
in two nromal
but half-sized embryos. Explain.
4. How can
the cleavage planes be altered and what effect does that have on the
development?
What
determines the plane of the first cleavage and how is that different
from
determining the plane of bilateral symmetry?
GASTRULATION
Discuss:
_____
Morphogenetic movement of the ectoderm
_____
Type of chordamesoderm movement
_____
Causes appearance of dorsal lip of blastopore
_____
What type of cell moves by unipolar ingression
_____
Causes exogastrulation
_____
Regions anterior to primitive streak
_____
Cause cell elongation
____
Result in stopping cell movement
Dissociated ___________________________cells
always cover mesoderm cells but
can be
covered by _____________________________ cells.
---1. Forms on the side of the embryo
opposite sperm entry
in most cases.
---4. factors other than sperm can cause
grey
crescent formation
---17. Sum of the competences
ESSAY:
What is the
significance of gastrulation?
What
determines the location of the grey crescent in amphibians?
What is a
fate map and how is it obtained?
Why are the
dorsal lip of the amphibian blastopore and the chicken
primitive
streak considered homologous?
Distinguish
between contact guidance and contact inhibition.
Describe one
type of morphogenetic movement; specify cell type and animal.
What enters
the lateral lips of the blastopore?
Present
evidence that cell characteristics of grey crescent cells are
different
from other embryo cells. How do you think they became different?
1 CELL BEHAVIOR
CHANGES DUE TO SIGNALS
Name some second messengers, an example of a
receptor with a specific ligand which releases each, and a known chain reaction
resulting from each. Give some evidence that these are used in activation of
eggs or sperm. Describe one drug which affects the process at each type of
receptor, second messenger, or chain reaction.
12 CYTOPLASMIC
FACTORS Cytoplasmic gradients are involved in what ways in setting development?
Discuss examples in which maternal mRNA or
proteins laid down in the egg can cause setting of axes by influence on : a)
other genes b) other proteins or receptors .
What do we mean by a rescue experiment,
using normal cytoplasm?
How can an homogeneously distributed
protein like "dorsal" or receptor like "toll" be important
in axes setting?
How can Centrifugation be used as a tool
for showing that?
13 AXES FILL IN:
‑‑‑1. Becomes the dorsal side of the frog embryo
ESSAY: 1. Cite evidence for cytoplasmic
localization of determinants in early embryos. Determinate embryos cannot
regulate after removal of polar lobes or blastomeres. Distinguish between determinate and regulative development.
Distinguish between preformation and mosaic development. 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?
Pick a subtopic
that particularly interested you about each of the following areas of
development, and write a 7 min essay about it.
1. Signal
transduction.
2. Fertilization.
3. Cleavage.
4. gastrulation
5. Cell Movements
leading to morphogenesis
6. Chordamesoderm
7. Nervous system
development of different areas and nerve types.