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- 1. Multiple Choice
If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then:
the amino acid inactivates the repressor
the repressor is active in the presence of the amino acid
the amino acid acts as a corepressor
the amino acid turns on transcription of the operon
- 2. Multiple Choice
Muscle cells differ from nerve cells mainly because they:
express different genes
contain different genes
use different genetic codes
have unique ribosomes
- 3. Multiple Choice
The functioning of enhancers is an example of:
a eukaryotic equivalent of prokaryotic promoter functioning
transcriptional control of gene expression
stimulation of translation by initiation factors
post-translational control that activates certain proteins
- 4. Multiple Choice
Cell differentiation always involves:
transcription of the myoD gene
the movement of cells
the production of tissue-specific proteins
the selective loss of certain genes from the genome
- 5. Multiple Choice
Which of the following is an example of post-transcriptional control of gene expression?
the addition of methyl groups to cytosine bases of DNA
the binding of transcription factors to a promoter
the removal of introns and alternative splicing of exons
gene amplification contributing to cancer
- 6. Multiple Choice
What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?
irreversible binding of the repressor to the promoter
reduced transcription of the operon’s genes
buildup of a substrate for the pathway controlled by the operon
continuous transcription of the operon’s genes
- 7. Multiple Choice
Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts. This is evidence that the product of the bicoid gene:
normally leads to formation of head structures
normally leads to formation of tail structures
is transcribed in the early embryo
is a protein present in all head structures
- 8. Multiple Choice
Which of the following statements about the DNA in one of your brain cells is true?
Most of the DNA codes for protein
The majority of genes are likely to be transcribed
It is the same as the DNA in one of your liver cells
Each gene lies immediately adjacent to an enhancer
- 9. Multiple Choice
Within a cell, the amount of protein made using a given mRNA molecule depends partly on:
the degree of DNA methylation
the rate at which the mRNA is degraded
the number of introns present in the mRNA
the types of ribosomes present in the cytoplasm
- 10. Multiple Choice
Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?
Proto-oncogenes first arose from viral infections.
Proto-oncogenes are mutant versions of normal genes.
Proto-oncogenes are genetic “junk.”
Proto-oncogenes normally help regulate cell division.
- 11. Multiple Choice
In a cell in which only gene 5 is transcribed, which colored activators would be present? (Select all that apply)
Purple
Blue
Green
Black
Red
- 12. Multiple Choice
If green, blue, and yellow activators are present, which gene(s) would be transcribed? (Select all that apply)
Gene 1
Gene 2
Gene 3
Gene 4
Gene 5
- 13. Multiple Choice
Imagine that genes 1, 2, and 4 code for nerve-specific proteins. Which activators would have to be present? (Select all that apply)
Yellow
Blue
Green
Black
Purple
- 14. Multiple Choice
Imagine that genes 3 and 5 are skin specific. Which activators would need to be present?
Red
Black
Purple
Blue
Green
- 15. Multiple Choice
What does the operon model attempt to explain?
The coordinated control of gene expression in bacteria
Bacterial resistance to antibiotics
How genes move between homologous regions of DNA
The mechanism of viral attachment to a host cell
Horizontal transmission of plant viruses
- 16. Multiple Choice
Which element(s) from the following list is/are part(s) of a bacterial operon? (Select all that apply)
Repressor gene
Promoter
Inducer
Repressor protein
- 17. Multiple Choice
A specific gene is known to code for three different but related proteins. This could be due to which of the following?
premature mRNA degradation
alternative RNA splicing
use of different enhancers
protein degradation
differential transport
- 18. Multiple Choice
Scientists showed that bicoid mRNA, and then its Bicoid protein, is normally found in highest concentrations in the fly’s anterior. What would happen if Bicoid were injected at the posterior end?
Anterior structures would form at both ends
Posterior structures would form at both ends
The embryo would have no dorsal-ventral axis
Bicoid mRNA wouldn’t be translated into protein
- 19. Multiple Choice
Mutations in _____ genes caused the development of legs in the place of antennae.
homeotic
embryonic lethal
myoD
Ras
operon
- 20. Multiple Choice
Which of the following would not typically cause a proto-oncogene to become an oncogene?
gene suppression
translocation
amplification
point mutation
retroviral activation
- 21. Multiple Choice
Group the following operon-related terms as to whether they are composed of protein or DNA: RNA polymerase, repressor, promoter, operator.
operator = DNA;
promoter, RNA polymerase, repressor = protein
promoter = DNA;
operator, RNA polymerase, repressor = protein
operator, promoter, repressor = DNA;
RNA polymerase = protein
operator, promoter = DNA;
RNA polymerase, repressor = protein
operator, repressor = DNA;
RNA polymerase, promoter = protein
- 22. Multiple Choice
Histone acetylases are enzymes that add acetyl groups to histone proteins. In what way do histone acetylases affect
transcription?
Activate transcription by opening chromatin
Activate transcription by condensing chromatin
Repress transcription by opening chromatin
Repress transcription by condensing chromatin
- 23. Multiple Choice
The insulin gene is transcriptionally expressed in certain pancreatic cells, but not in skin cells. Which statement explains this?
Skin cells lack an enhancer in the insulin gene
Skin cells lack the insulin gene
Pancreas cells have an extra enhancer in the insulin gene
Pancreas cells express an activator protein that binds
the insulin enhancer
- 24. Multiple Choice
A eukaryotic gene has a pre-mRNA with four exons
(1, 2, 3, 4). Which of the following arrangements of exons would not be possible during alternative splicing of a mature mRNA? (Select all that apply)
1, 2, 3, 4
1, 3, 4
1, 3, 3, 4
1, 3, 2, 4
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