Download Test One Answer Key - Developmental Biology-Honors | BIO 5620 and more Exams Developmental biology in PDF only on Docsity!
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MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Questions 1 - 34 are each worth 2.5 points. Question 35 is worth 3.5 points.
- In wild type, microRNA A binds to messenger RNA X. Messenger RNA X promotes finger formation. Mutant I has a loss-of-function mutation in microRNA A, and mutant II has a loss-of-function mutation in messenger RNA X. Which of the following mutant phenotypes would you most likely expect?
A) Mutant I will have no fingers, whereas mutant II will have extra fingers B) Mutant I will have extra fingers, whereas mutant II will have no fingers C) Both mutant I and mutant II will have extra fingers D) Both mutant I and mutant II will have no fingers E) Both mutants will have a wild-type number of fingers
- Epithelial cells
A) are loose, unconnected cells that can migrate B) can arise from the mesoderm C) can arise from the ectoderm D) Two of the above E) All of the above
- A loss-of-function mutation in gene A leads to an embryo with no head. A gain - of-function hypermorphic mutation in gene B leads to an embryo with extra heads, while a loss - of-function mutation in gene C leads to an embryo with extra heads. Which of the following conclusions would be most likely true?
A) Gene A and gene B act antagonistic of each other B) Gene A and gene C act antagonistic of each other C) Gene B and gene C act non-antagonistic of each other D) Gene A and gene C act non-antagonistic of each other E) Two of the above
- Which of the statements below would be true? A) Fertilization occurs before oogenesis is completed in all animals B) Fertilization occurs after oogenesis is completed in all animals C) Fertilization can occur anytime during oogenesis and this is species - dependent D) Fertilization can occur anytime during oogenesis and this is species - independent
- Which of the following illustrates regulative development?
A) A human embryo B) A C. elegans embryo C) Cells at the two-cell stage are not totipotent D) Two of the above E) All of the above
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- The sperm cell membrane of species A expresses protein X, which is recognized by protein Y that is expressed from the egg of the same species. Mutant I has acquired a mutation in protein X that now repels wild-type protein Y. In contrast, mutant II has acquired a mutation in protein Y that repels wild-type protein X, but is attracted to mutant protein X from mutant I. Which of the following statements below would most likely be true based on the information given?
A) Fertilization can occur between wild type and mutant I or between wild type and mutant II B) Fertilization can occur between mutant I and mutant II, leading to a new species C) All of the above D) None of the above
- A Wnt loss-of-function mutation leads to a hairy embryo, whereas a Wnt gain - of-function hypermorphic mutation leads to a naked embryo. Which of the following below would you most likely expect based on the informaton given?
A) A Smoothened (Smo) loss-of-function mutation leads to a naked embryo B) A GSK3 gain-of-function hypermorphic mutation leads to a naked embryo C) A Frizzled (Fz) loss-of-function mutation leads to a hairy embryo D) A Patched (Ptc) loss-of-function mutation leads to a hairy embryo E) None of the above
- A Hedgehog (Hh) loss-of-function mutation leads to a limbless vertebrate, whereas a Hh gain-of-function hypermorphic mutation leads to a vertebrate with extra limbs. Which of the following would you most likely expect based on the information given?
A) A Smoothened (Smo) loss-of-function mutation leads to a vertebrate with extra limbs B) A GSK3 gain-of-function hypermorphic mutation leads to a vertebrate with extra limbs C) A Frizzled (Fz) gain-of-function hypermorphic mutation leads to a limbless vertebrate D) A Patched (Ptc) loss-of-function mutation leads to a limbless vertebrate E) None of the above
- A geneʹs promoter sequence has 5 ʹ-ATCGACTC- 3 ʹ. What would you expect will most likely happen when a DNA methyltransferase becomes activated?
A) The guanosine will become methylated B) All cytosines will become methylated C) Only the cytosine 5 ʹ of the guanosine will become methylated D) The promoter will become demethylated
- In the embryo, the promoter of the maternal copy of gene A is methylated, whereas the promoter of the paternal copy of gene A is unmethylated. Which of the following statements would most likely be true?
A) Both parental copies of the gene will be expressed B) Both parental copies of the gene will not be expressed C) Only the maternal copy of the gene will be expressed D) Only the paternal copy of the gene will be expressed
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- Which statement(s) would most likely be true? A) In most animals, the fertilized egg uses the oocyte centrosome/centriole as the microtubule organizing center B) In most animals, the fertilized egg uses the sperm centrosome/centriole as the microtubule organizing center C) In most animals, the fertilized egg uses either the egg or the sperm centrosome/centriole as the microtubule organizing center and the choice will depend on which organelle is less damaged D) In most animals, the fertilized egg uses both the egg and sperm centrosomes/centrioles as the microtubule organizing centers
- During oocyte maturation, A) the cell divides symmetrically at the end of telophase I and telophase II B) the cell divides asymmetrically at the end of telophase I, but it divides symmetrically at the end of telophase II C) the cell divides symmetrically at the end of telophase I, but it divides asymmetrically at the end of telophase II D) the cell divides asymmetrically at the end of telophase I and telophase II E) the cell does not undego cytokinesis at the end of either telophase I or telophase II
- Which of the following below would be required to make cell A competent to respond directly to the BMP signal? A) Cell A expresses Beta-catenin B) Cell A expresses a BMP receptor tyrosine kinase C) Cell A expresses a BMP heterodimeric receptor serine/threonine kinase D) Two of the above E) All of the above
- Which of the following below would be required to make cell A competent to respond to the FGF signal? A) Cell A expresses Beta-catenin B) Cell A expresses an FGF receptor tyrosine kinase C) Cell A expresses an FGF heterodimeric receptor serine/threonine kinase D) Two of the above E) All of the above
- What releases a vertebrate oocyte from secondary arrest? A) A rise in intracellular Ca2+^ ions, which come from the extracellular space B) A rise in intracellular Ca2+^ ions, which come from the endoplasmic reticulum C) The cytostatic factor D) The maturation promoting factor E) Two of the above
- Which statement is true? A) The acrosome is derived from the endoplasmic reticulum B) The acrosome is not involved in egg-sperm recognition C) All of the above D) None of the above
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- The maturation promoting factor
A) stimulates the cell to enter mitosis from G2 during the cell cycle B) stimulates the oocyte to continue through meiosis C) consists of a cyclin and a cyclin-dependent kinase D) Two of the above E) All of the above
- Epithelial-to-mesenchymal transition
A) can occur in the developing vertebrate embryo or in the adult B) only occurs in the developing vertebrate embryo C) only occurs in the vertebrate adult D) does not occur in vertebrates
- Which statement is true?
A) In vertebrates, the digestive system and musculoskeletal system arise from the endoderm B) In vertebrates, the digestive system arises from the endoderm, whereas the musculoskeletal system arises from the ectoderm C) In vertebrates, the digestive system arises from the endoderm, whereas the musculoskeletal system arises from the mesoderm D) In vertebrates, the digestive system and the musculoskeletal system arise from the mesoderm E) None of the above
- The dorsoventral axis of the frog Xenopus embryo
A) is determined by the site of sperm entry during fertilization B) involves the dorsal enrichment of GSK3 during the blastula stage C) involves the cortical rotation of the egg cytoplasm during the gastrula stage D) None of the above
- The idea that an embryo has one allele from its mother and another allele from its father is illustrated by Mendel’s Law of:
A) Segregation B) Independent Assortment C) All of the above D) None of the above
- Which statement is true?
A) Activation of the Ci transcription factor ( Drosophila Gli) has no effect on its subcellular localization B) Activation of the Ci transcription factor ( Drosophila Gli) causes it to shuttle from the nucleus to the cytoplasm C) Activation of the Ci transcription factor ( Drosophila Gli) causes it to shuttle from the cytoplasm to the nucleus D) None of the above
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- The cells below are starting to undergo cleavage. The cell on the right will divide along
A) the A and Aʹ axis B) the B and Bʹ axis C) the C and Cʹ axis D) Two of the above E) All of the above
- A gain-of-function hypermorphic mutation in gene R or gene S leads to an embryo with no eyes and a loss-of-function mutation in gene T also leads to an embryo with no eyes. However, an embryo carrying a loss-of-function mutation in gene S and a loss-of-function mutation in gene T has no eyes, while an embryo carrying a loss-of-function mutation in gene R and a gain-of-function hypermorphic mutation in gene S also has no eyes. In addition, an embryo carrying a gain-of-function hypermorphic mutation in gene R and a gain-of-function hypermorphic mutation in gene T has extra eyes. Which of the following conclusions would be most likely true? (3.5 points)
A) Gene T is epistatic to both gene R and gene S B) Gene S is epistatic to both gene R and gene T C) Gene R is epistatic to both gene S and gene T
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SHORT ANSWERS. Write your answers within the space provided.
From the information given in question 35, draw a possible pathway that would best depict the interactions between genes R, S and T, if they are acting within a linear pathway. (4 points)
What is the difference between an instructive inductive signal and a permissive inductive signal? (2.5 points) Name an example for each type of signal. (2 points)
Answer Key
Testname: EXAM 1
1) B
2) D
3) B
4) C
5) A
6) B
7) C
8) E
9) C
10) D
11) C
12) A
13) B
14) A
15) D
16) B
17) B
18) D
19) C
20) B
21) B
22) D
23) E
24) A
25) C
26) A
27) A
28) C
29) E
30) C
31) D
32) B
33) B
34) A
35) A
