MCB 250 EXAM 4 2025 QUESTIONS AND
ANSWERS
D. Activation of transcription from the zygotic genome - ANS What happens at the maternal-
to-zygotic transition across species?
A. The embryo converts from a syncytial blastoderm to a monolayer of cells
B. The maternal yolk used as an energy source is depleted
C. The embryo goes from being haploid to diploid
D. Activation of transcription from the zygotic genome
A. How the body plan of the embryo is established - ANS Nusslein-Volhard and Wieschaus
conducted a genetic screen hoping to understand:
A. How the body plan of the embryo is established
B. How the Toll signal transduction pathway works
C. How transcription factors are regulated during embryogenesis
D. How mRNAs can be localized to different parts of the cell
B. In the 3'UTR - ANS The signal that localizes the bicoid mRNA is found:
A. In the promoter
B. In the 3'UTR
C. In the 5'UTR
D. In an intron
A. Dorsal - ANS What is the transcription factor that activates genes that specify ventral
identity in the Drosophila embryo?
A. Dorsal
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, B. Cactus
C. Toll
D. Spatzle
D. All of the above - ANS Why are different genes that are controlled by the same
transcription factor activated in different spatial patterns?
A. Some enhancers also have binding sites for repressors that counteract that transcription
factor activity
B. There are a different number of binding sites for the transcription factor in their enhancers
C. There are differences in the chemical affinity of the binding sites in their enhancers for the
transcription factors
D. All of the above
A. Maize - ANS The study of which model organism led to the discovery of transposons?
A. Maize
B. Fruit flies
C. Sea squirt
D. Mouse
A. Inverted repeats - ANS The ends of a transposon consist of:
A. Inverted repeats
B. Unique sequences
C. CpG islands
D. Exact repeats
D. All of the above - ANS Mobilization of a transposon can result in:
A. Small changes that influence the evolution of an organism
B. Incorporation into an existing gene to form a new gene
C. Insertional mutagenesis
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ANSWERS
D. Activation of transcription from the zygotic genome - ANS What happens at the maternal-
to-zygotic transition across species?
A. The embryo converts from a syncytial blastoderm to a monolayer of cells
B. The maternal yolk used as an energy source is depleted
C. The embryo goes from being haploid to diploid
D. Activation of transcription from the zygotic genome
A. How the body plan of the embryo is established - ANS Nusslein-Volhard and Wieschaus
conducted a genetic screen hoping to understand:
A. How the body plan of the embryo is established
B. How the Toll signal transduction pathway works
C. How transcription factors are regulated during embryogenesis
D. How mRNAs can be localized to different parts of the cell
B. In the 3'UTR - ANS The signal that localizes the bicoid mRNA is found:
A. In the promoter
B. In the 3'UTR
C. In the 5'UTR
D. In an intron
A. Dorsal - ANS What is the transcription factor that activates genes that specify ventral
identity in the Drosophila embryo?
A. Dorsal
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 1
, B. Cactus
C. Toll
D. Spatzle
D. All of the above - ANS Why are different genes that are controlled by the same
transcription factor activated in different spatial patterns?
A. Some enhancers also have binding sites for repressors that counteract that transcription
factor activity
B. There are a different number of binding sites for the transcription factor in their enhancers
C. There are differences in the chemical affinity of the binding sites in their enhancers for the
transcription factors
D. All of the above
A. Maize - ANS The study of which model organism led to the discovery of transposons?
A. Maize
B. Fruit flies
C. Sea squirt
D. Mouse
A. Inverted repeats - ANS The ends of a transposon consist of:
A. Inverted repeats
B. Unique sequences
C. CpG islands
D. Exact repeats
D. All of the above - ANS Mobilization of a transposon can result in:
A. Small changes that influence the evolution of an organism
B. Incorporation into an existing gene to form a new gene
C. Insertional mutagenesis
Copyright ©2025 BRIGHTSTARS ALL RIGHTS RESERVED 2
