BIOL 303 – Study Questions 2
Genome equivalence and differential gene expression
Enhancers, promoter genes, and reporter constructs
Alternative (or differential) RNA splicing
1. What is the ultimate test for genomic equivalence?
Genomic equivalence: theory that every cell in an organism carries the same
Ultimate test: somatic nuclear transfer. Created the first clone, “Dolly” the sheep.
A mature fertile sheep was cloned from a somatic nucleus, fully proving genomic
2. Histones are commonly subjected to what types of modifications? What general
effects are associated with these modifications?
Histones: proteins that package chromatin
Histone modification can strengthen or relieve the default repressive condition of
chromatin. Highly modified – tightly packed chromatin.
Acetylation (addition of COCH3) activates transcription – addition to lysine
neutralizes basic charge and loosens histones
Methylation (addition of CH3) can repress or activate transcription depending on
which lysine residue is being methylated and nearby modifications
3. Why do you think enhancer elements are so important during development?
Enhancer (aka cis-regulatory elements): a DNA sequence that controls the
efficiency and rate of transcription from a specific promoter.
I think enhancer elements are so important during development because this
period of time involves precisely regulated patterns of gene expression. They
mediate spatial and temporal control in development by turning on certain
genes at certain times.
4. If you were examining the sequence of an unknown protein, how might you be able
to determine whether or not it functions as a transcription factor?
Look at amino acid sequences. If you see a protein motif (transcription factor DNA
binding domain) such as HLH, homeodomain, bZip, zinc finger
Presence of these motifs predicts that the sequence is acting as a transcription
factor 5. Name and describe a technique that would allow you to define the DNA sequence
to which a given transcription factor binds. What are the prer