Developmental Animal Biology
Control of different fates within the ectoderm (i.e. neural versus epidermis) is due to a gradient of ______ that originates during ____.
BMP; gastrulation
The effect of teratogens can only be passed through the maternal lineage, but not the paternal lineage.
False
What do tail extension and limb development have in common?
Fgf8 mediates outgrowth in both
Which is NOT accurate about somites and their derivatives?
Fgf8 promotes somite formation
Mitosis during cleavage does NOT include the ____ phase of the cell cycle. Holoblastic versus meroblastic divisions is influenced by ____.
G2; amount of yolk
Which of these statements are accurate about early human development?
Gastrulation in humans is similar to gastrulation in birds. Cleavage stages are controlled by maternal factors. The timing of implantation is determined by when the blastocyst and zone pellucida separate. The first cell fate decision is when the trophectoderm is specified
Four of these result in a failure of angiogenesis. Which one has SUCCESSFUL angiogenesis?
HIF1alpha levels are increased due to a heart attack
What germ layer is the placenta derived from?
Mesoderm and Endoderm )
In which of these is the molecule/structure and its role in development paired correctly
Notch/Delta signaling: regulates the timing of somite development
What controls thumb identity?
Shh signaling
What do the notochord, somites, and the neural tube have in common?
While their derivatives are found in adults, these structures themselves are only found in the embryo
What defines which epithelia cells are absorptive or not?
Wnt signaling
You dissect the ZPA from a limb bud. You also implant a bead soaked in Shh in the anterior part of the hand plate. What does the developing hand look like?
a typical number of digits, but with the pinky on the anterior and a thumb on the posterior of the hand
Which of these will happen to someone that takes growth hormone at age 30?
acromegaly
The dorsal lip of frog, primitive streak of mammals, and ventral furrow in Drosophila are all formed by what cell movement?
apical-constriction
neural crest cells
are what Dr. Powder researches
When is the majority of the baby's microbiome colonized?
at birth
You identify an animal that has a higher proliferation in tail extension during somitogenesis than humans, but no changes to the somite clock. What would the effect be?
bigger somites with the same number as humans
How does thalidomide exposure result in limb truncation?
blocks angiogenesis
In what way are keratinocytes and radial glial cells NOT similar?
both divide continuously in adults
zygote
cell produced by fusion of egg and sperm nuclei
Which of the following is the LEAST accurate description of Notch-Delta signaling?
conditional signal
What is NOT true about the microbiome?
constitute relatively few of our body's total cells, but serve as a potent inductive signal
These Janus cats have part or all of the face duplicated and are named after Janus, the Roman god with two faces. Which is most accurate about this condition?
due to changes in Shh signaling
During human gastrulation, which cell layer does NOT move through the primitive streak?
ectoderm
From what germ layer does the eye derive?
ectoderm
From what germ layer does the heart derive?
ectoderm and mesoderm
From what germ layer does the tooth derive?
ectoderm and mesoderm
You generate a mutant fly, which has a type of bristles growing out of the eye that are normally only found on the abdomen. What is the most likely mutation you generated?
ectopic expression of a hox gene
Why is embryonic development so susceptible to the effects of teratogens?
embryos have rapidly dividing cells
What is the importance of the zona pellucida separating?
enable implantation to occur
The primary function of the acrosome reaction is to
enable membranes to meet
Which is the innermost layer of cells in an animal?
endoderm
Mutation of which of these parts of a gene is LEAST likely to have a pleiotropic effect?
enhancer
Deletion of a pair rule gene is most likely to cause which of the following phenotypes?
every other segment is missing (T1, T3, A2, A4, etc present but not T2, A1, A3, etc)
Teratogen come from what?
external effects
Secondary sex determination controls the development of?
external genitalia
Mesenchyme is always from mesoderm
false
The heart and circulatory system do not need to function during embryonic development because of the mother's circulatory system.
false
The notochord secrets BMP
false
Which is accurate about Hox genes?
function as transcription factors
Pair rule gene expression in Drosophila is regulated by
gap genes
Exposure to teratogens during which developmental stage is most likely to result in death of embryo death versus malformation of the embryo?
gastrulation and cleavage
Which is true about the skin?
high levels of eumelanin in skin are protective of UV damage
What is true about growth hormone signaling?
higher in a hippo than a yorkie
Open chromatin structure would result from _____ and cause _____ gene expression.
histone acetylation; higher
Secondary sex determination is based on what?
hormones
Which is accurate about kidney development?
includes branching morphogenesis
What is the primary function of the endoderm in an embryo?
induction of other germ layers
The chase and run model
involves cells that originate near the neural folds
Which is true about left-right axis determination in mammals?
is generated by primary cilia
What does it mean when a cell is specified?
it has acquired a cell fate, but that fate can be changed
What does NOT start as an outgrowth of the digestive tract?
kidney
Epithelial-to-mesenchymal transitions (EMTs) occur during bird and mammal gastrulation. Which of the following is involved in EMT?
loss of cadherin proteins
ventricular zone
lumen
Why is there not typically a lot of variation in the gastrulation stages of development?
major variation in these stages is most likely lethal
What breaks symmetry to initialize axes?
maternal contributions in Drosophila and sperm entry in frogs
If gene gap expression is changed, which class of genes is LEAST likely to have a resulting change in expression?
maternal effect genes
From what germ layer does the somites derive?
mesoderm
The wollfian duct is derived from?
mesoderm
Which germ layer is the femur bone from?
mesoderm
Which germ layer is the muscles of the esophagus?
mesoderm
Which statements are true? - in utero alcohol exposure can result in decreased cell death during neural development - herbicides only act as endocrine disruptors if an animal eats the crop treated with the chemical - morphogens that are necessary for development can act as a teratogen if induced by environmental exposure - the effect endocrine disruptors like diethylstilbestrol may not be obvious at birth
morphogens that are necessary for development can act as a teratogen if induced by an environmental exposure The effect of endocrine disruptors like diethylstilbestrol may not be obvious at birth
The drugs sorafenib and sunitnib are both used in chemotherapy. Both block signal transduction by VEGFR. Which of the following is LEAST likely to be true in a patient taking these drugs?
most cells will have cleaved Notch intracellular domain
Which of these has the developmental steps in the correct order?
movement through the primitive streak--> separation of the dermatome from the myotome--> differentiation of mammary glands in females --> when keratinocytes stop dividing
What is NOT examples of potential teratogens?
mutation in B-catenin gene
Myostatin inhibition has been proposed to treat muscular dystrophy. This works because myostatin
negatively regulates muscle development
How many of these have the molecule/structure and its role in development paired correctly?
opsins: red-green colorblindness AER: proximal-distal limb development Fgf8: where tissue is competent to form somites hox genes: cervical versus thoracic vertebrae fate
What stage follows calcification in bone development?
ossification
Gap gene expression in Drosophila is regulated by
other gap genes
Which of these correct?
placode: thickening of epithelia
The spinal cord forms from what tissue or structure?
posterior of neural tube
There are lots of ways for neural crest cell migration to fail. But one of these will have normal neural crest cell migration--which one?
presence of contact inhibition of locomotion
Which of the following is NOT true about Bisphenol A (BPA)?
present in crude oil
Which of these pairs of structures have similar roles during gastrulation?
primitive streak and blastopore
When GenX is deleted from a tiger, it no longer has stripes anywhere on its body. What is the normal function of GeneX?
promote stripe formation
Which of the following best describes a morphogen?
protein that can generate different cell fates based on concentration
An epithelia layer causes the underlying mesenchyme to change fate. Then, the mesenchyme signals the epithelia to have a change in morphology. What is this called?
reciprocal induction
Gastrulation in all animals features a major reorganization of cells. Why is this important?
results in new neighbors and new patterns of induction
Why is heart looping important?
results in new neighbors and new patterns of induction
Which of these has mammalian development steps in the correct order?
slow block --> first cell division --> maternal-zygotic transition --> formation of primitive streak
Monozygotic twins can result from
splitting of the inner cell mass during compaction
What is true about exercise and bone health?
stress of exercise produces micro-fractures that are remodeled
Why don't males get osteoporosis as often as females?
testosterone is produced throughout life and can be converted to estradiol
Which of these is accurate about human gametes?
the acrosome and the cortical granules are analogous structures
What's most likely going on with the excessive hairy guinea pig on the right compared to the "normal" guinea pig on the left?
the one on the right has higher expression of a molecule that alters the rest and growth phases of hair
You mix a yellow-labeled cell type and a red-labeled cell type, then leave them for a day. In which of these scenarios would the red cells be on the interior of the resulting cell mass and the yellow on the outside?
the yellow cells express N-cadherin, which has less force than the P-cadherin expressed by the red cells
What do the lung, kidney, placenta, and mammary glands have in common?
they all have branching to maximize exchange
Which is true about gonads?
they differentiate into either testes or ovaries during primary sex determination
Tip cells in blood vessels, the growth cone of axons, and migrating neural crest cells all have what in common?
they require actin reorganization
During endochondral ossification, what happens to the chondrocytes?
they undergo apoptosis
Why is there folate/folic acid in products like Froot Loops?
to promote closure of the neural tube
In order to activate or repress gene expression, proteins called ___ bind regulatory elements via DNA binding domains. This protein will then interact with ____.
transcription factors; RNA polymerase
(T/F) Pleiotropy is when the same gene is used throughout development in formation or patterning of multiple structures.
true
Dual BMP and Shh expression gradients regulate motor versus sensory neuron fate in the spinal cord. In this way, these molecules act as a morphogen.
true
Estradiol is necessary for typical development in both sexes.
true
The mullerian duct....
undergoes apoptosis in an XY individual
Which is NOT true about hCG chronic gonatrophin?
upregulates prolactin to produce breast milk during the first trimester of pregnancy
Which is true about the brain?
white matter consists of myelinated axons of neurons
Which of these is NOT accurate about tooth development?
will transform to a scale fate with changes to Hox gene expression
