Download Exam 3 Answer Key | Developmental Biology for Honors | BIO 5620 and more Exams Developmental biology in PDF only on Docsity!
Name__________________________________ Date___________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Each question is worth 2.5 points.
- Below is a picture a mutant foot. This foot might have:
A) a cell-specific loss-of-function mutation in the CED-4/Apaf1 protein B) a cell-specific gain-of-function mutation in the EGL-1/BAD protein, where this protein is always active C) a cell-specific loss-of-function mutation in the CED-9/Bcl2 protein D) Two of the above E) All of the above
- A human hand has a loss-of-function mutation in GLI. Which of the following will more likely occur?
A) Only digit 5 is formed B) Only digits 2 - 5 are formed C) Only digit 1 is formed D) Only digits 3 - 5 are formed
- Which statement is true?
A) The notochord and neural crest cells are derived from the mesoderm, whereas the somites are derived from the ectoderm B) The notochord and somites are derived from the mesoderm, whereas the neural crest cells are derived from the ectoderm C) The notochord is derived from the mesoderm, whereas the neural crest cells and the somites are derived from the ectoderm D) None of the above
- The retinoic acid receptor has acquired a loss-of-function mutation. Which of the following will NOT happen?
A) Wild-type somites will be formed along the anteroposterior axis of the mammalian embryo B) The distal structures of the chick limb will not be formed C) The proximal structures of the mammalian limb will not be formed D) Two of the above E) All of the above
Name__________________________________ Date__________________
- Which of the following approaches should be used to make tissue-specific gene knockouts? A) in situ hybridization B) Cre-Lox C) RNAi D) polymerase chain reaction (PCR)
- Which statement is true?
A) Strong interactions between ephrin and its semaphorin receptor lead to endocytosis of the ephrin-semaphorin complex and repulsion between the ephrin-expressing cell and sempahorin-expressing cell B) Strong interactions between ephrin and its Eph receptor lead to endocytosis of the ephrin-Eph complex, where the ephrin-expressing cell and Eph-expressing cell remain tightly bound to each other C) Strong interactions between ephrin and its semaphorin receptor lead to endocytosis of the ephrin-semaphorin complex, where the ephrin-expressing cell and sempahorin-expressing cell remain tightly bound to each other D) Strong interactions between ephrin and its Eph receptor lead to endocytosis of the ephrin-Eph complex and repulsion between the ephrin-expressing cell and Eph-expressing cell
- Which statement is true?
A) Vertebrate limb development exemplifies mosaic development, where splitting of the prospective limb bud gives rise to a limbless animal B) Vertebrate limb development exemplifies regulative development, where splitting of the prospective limb bud gives rise to a limbless animal C) Vertebrate limb development exemplifies mosaic development, where splitting of the prospective limb bud gives rise to a many-limbed animal D) Vertebrate limb development exemplifies regulative development, where splitting of the prospective limb bud gives rise to a many-limbed animal
- If the vertebrate segment mesenchyme (mesoderm):
A) expresses a Hox protein that represses the activity of a Tbx transcription factor (Tbx4 or Tbx5), this would lead to (i) activation of an FGF signal and (ii) limb formation B) expresses a Hox protein that activates the activity of a Tbx transcription factor (Tbx4 or Tbx5), this would lead to (i) activation of an FGF signal and (ii) limb formation C) expresses a Hox protein that represses the activity of a Tbx transcription factor (Tbx4 or Tbx5), this would lead to (i) inactivation of an FGF signal and (ii) limb formation D) expresses a Hox protein that activates the activity of a Tbx transcription factor (Tbx4 or Tbx5), this would lead to (i) inactivation of an FGF signal and (ii) limb formation
- Which statement is true?
A) Dosage compensation equalizes X-linked gene expression between the sexes B) Dosage compensation equalizes autosome-linked gene expression between the sexes C) Loss of dosage compensation in Drosophila leads to female-specific lethality D) Two of the above E) All of the above
Name__________________________________ Date__________________
- Sex determination in C. elegans is dependent:
A) on the X:A ratio B) on the presence/absence of the Y chromosome C) only on the X chromosome D) Two of the above E) All of the above
- Below is an X-ray of a mutant hand. Which of the following conditions could lead to this phenotype?
A) Patched is activated in the posterior mesoderm of the developing limb bud B) Smoothened is activated in the posterior mesoderm of the developing limb bud C) Patched is activated in the anterior mesoderm of the developing limb bud D) Smoothened is activated in the anterior mesoderm of the developing limb bud
- Neural crest cell migration requires:
A) both attractive and repulsive guidance cues B) inhibition of cadherin expression C) All of the above D) None of the above
- A Sox transcription factor:
A) promotes the epithelial-to-mesenchymal transition of neural tube floor plate cells B) promotes the epithelial-to-mesenchymal transition of neural crest cells C) All of the above D) None of the above
Name__________________________________ Date__________________
- Neural crest cells arise from:
A) ectodermal cells that express Wnt, which would activate BMP followed by downregulation of Wnt B) ectodermal cells that express Wnt, which would activate BMP that is then co - expressed with Wnt C) mesodermal cells that express Wnt, which would activate BMP followed by downregulation of Wnt D) mesodermal cells that express Wnt, which would activate BMP that is then co - expressed with Wnt E) None of the above
- Shh is expressed from the roof plate of the neural tube. Which of the following could occur?
A) Dorsal structures, like the sclerotome, will develop from the somites B) Dorsal structures, like the dermomyotome, will develop from the somites C) Ventral structures, like the sclerotome, will develop from the somites D) Ventral structures, like the dermomyotome, will develop from the somites
- Somite development:
A) depends on the activation of a nuclear hormone receptor B) is periodic along the anteroposterior axis C) depends on signals from the notochord D) Two of the above E) All of the above
- A loss-of-function mutation in Frizzled, where this protein is always active, could lead to:
A) duplicated legs B) loss of dorsal structures in the somites C) loss of ventral structures in the somites D) Two of the above E) All of the above
- Cardiac neural crest cells:
A) express Plexins that are repelled by Sempahorin 3C, which is expressed along the migration route of the neural crest cells B) express Plexins that are attracted by Sempahorin 3C, which is expressed in the cardiac tract, the target of these neural crest cells C) express Plexins that are repelled by Eph receptors, which are expressed along the migration route of the neural crest cells D) express Plexins that are attracted by Eph receptors, which are expressed in the cardiac tract, the target of these neural crest cells E) None of the above
Name__________________________________ Date__________________
- A wild-type animal has 300 neurons. Mutant C has both a loss - of-function mutation in the EGL-1/BAD protein and a gain-of-function mutation in the CED-3/caspase protein, where this caspase is always active. Which of the following could most likely occur?
A) Mutant C will have fewer neurons than the wild type B) Mutant C will have more neurons than the wild type C) Mutant C will have the same number of neurons as the wild type
- Which statement is true?
A) Anterior somites are formed before the posterior somites B) Somite identity depends on Hox genes C) All of the above D) None of the above
- Which stage of cell commitment is reversible under normal developmental conditions?
A) Determination B) Differentitation C) Specification D) Two of the above E) All of the above
- Dosage compensation in C. elegans :
A) involves inactivation of one X chromosome in hermaphrodites B) involves halving the level of gene transcription in both X chromosomes of hermaphrodites C) involves a 2 - fold upregulation of transcription of the X chromosome in males D) is non-existent
- The FGF signal requires the presence of ___________ in the receiving cell.
A) a receptor tyrosine kinase B) a heteromeric serine/threonine kinase C) a GTPase D) Two of the above E) All of the above
- The BMP signal requires the presence of ___________ in the receiving cell.
A) a receptor tyrosine kinase B) a heteromeric serine/threonine kinase C) a GTPase D) Two of the above E) All of the above
Name__________________________________ Date__________________
- Which statement is true?
A) The proximal-distal axis specification in limb development is dependent on the state of the limb mesenchymal mesoderm B) The proximal-distal axis specification in limb development is dependent on the state of the limb mesenchymal ectoderm C) All of the above D) None of the above
- The dorsoventral axis of the limb is specified by:
A) the ventral expression of Wnt 7A B) the ventral expression of Shh C) the dorsal expression of Wnt 7A D) the dorsal expression of Shh
SHORT ANSWER. Write your answers within the space provided.
Describe the process of mammalian sex determination. (7 points)
Name the protein that is secreted to inhibit hermaphroditic fate in C. elegans. (1 point)
Answer Key
Testname: EXAM 3
1) A
2) C
3) B
4) A
5) B
6) D
7) D
8) B
9) A
10) E
11) D
12) C
13) C
14) A
15) D
16) C
17) B
18) B
19) C
20) E
21) B
22) B
23) C
24) A
25) E
26) B
27) A
28) C
29) C
30) B
31) D
32) B
33) A
34) C
