30 Questions
What are transposons, also known as?
Jumping genes
What happens when a transposon jumps into a gene?
The gene is insertionally inactivated
What did Barbara McClintock observe in her studies of corn kernels?
Transposons moving into and out of genes controlling pigment synthesis
What was unique about Barbara McClintock's approach to her research?
She worked long hours in a small laboratory
What is the effect of transposons on the expression of downstream genes in the same operon?
They stop the expression of downstream genes
Which of the following best describes the process of transposition?
The movement of a transposon from one location to another in a cell's genome
What is the primary advantage of rapidly degrading mRNA transcripts in cells?
It allows cells to quickly regulate protein production levels
Which statement accurately describes the process of DNA replication?
It is a bidirectional process that starts from an origin of replication
What is the purpose of bidirectional DNA replication?
To reduce the time required for complete replication of a chromosome
What is a replication fork?
A region where DNA synthesis is actively occurring
What is the composition of the two DNA molecules created after replication?
Each molecule contains one original strand and one newly synthesized strand
What happens when the replication forks meet during DNA replication?
The process of replication terminates at a specific site
What is the consequence of adding or deleting three nucleotide pairs during DNA replication?
It adds or removes one codon, leading to an additional or fewer amino acid in the resulting protein
What is a frameshift mutation?
A mutation that changes the reading frame of the mRNA, resulting in a different set of codons being translated
What is the likely consequence of a frameshift mutation?
It results in a shortened, non-functional protein (a knockout mutation)
How does a point mutation occur?
By a replication error that results in a mismatch between the two DNA strands, followed by DNA replication using the altered strand as a template
What can cause guanine nucleobases to be mispaired with adenine during DNA replication?
The oxidation of guanine nucleobases
What is the effect of adding or deleting one or two nucleotide pairs during DNA replication?
It results in a frameshift mutation
What is largely responsible for the rapid spread of antibiotic resistance?
Horizontal gene transfer
Why are mutants useful in studying horizontal gene transfer?
Mutants provide a way to distinguish donor and recipient cells
Which of the following is NOT a mechanism of horizontal gene transfer mentioned in the text?
Transposition
What is a requirement for a transferred DNA fragment to be maintained in a population?
It must be integrated into a replicon
What process is required for a transferred chromosomal fragment to be integrated into the recipient cell's genome?
Homologous recombination
Which of the following is a characteristic of a replicon, according to the text?
It has an origin of replication
What is the primary function of intercalating agents?
They increase the frequency of frameshift mutations
How do intercalating agents cause frameshift mutations?
They cause the addition or deletion of base pairs during replication
Which of the following is an example of an intercalating agent?
Chloroquine
What is the primary function of transposons in generating mutations?
They inactivate genes by inserting into the cell's genome
What is a characteristic of transposable elements?
They have the ability to 'jump' from one piece of DNA to another
Why is ethidium bromide, an intercalating agent, considered potentially harmful?
It can cause frameshift mutations, leading to cancer
Test your knowledge on the fundamental aspect of gene regulation related to the rapid degradation of mRNA in cells. Understand how regulating mRNA synthesis plays a crucial role in gene expression control.
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