Gene Expression and Regulation
Which aspect of tRNAs' tertiary structure allows them to deliver specific amino acids during translation?
Acceptor stem associates with specific amino acid based on anticodon sequence.
Modification of bases in loop structures determines which amino acid is bound.
Ribosomal binding site matches with messenger RNA molecule's sequence.
Double-stranded regions of the tRNA create bonds with appropriate amino acids.
What effect does altering helicase activity so that it unwinds double-stranded RNA instead of double-stranded DNA have on cellular processes?
Improperly targeted helicase may enhance recombination events between RNAs, increasing genomic stability.
Transcription could be hindered due insufficient availability double stranded template required accurate synthesis new complementary RNA.
By unwinding dsRNA preferentially, helices activities promote selective degradation viral genomes only.
Helicase targeting dsRNA actually augments post-transcriptional regulation allowing quicker response environmental changes.
What process could lead to increased allelic variation but potentially reduce natural selection's efficacy in adapting a species' gene pool over time?
Homozygous advantage promoting specific alleles increasing survival and reproduction.
Gene flow introducing similar fitness alleles from neighboring populations, diluting adaptive differences.
Mutation events exclusively causing detrimental changes, decreasing organism survivability.
Non-random mating favoring certain traits, enhancing selective pressures.
During replication, which enzyme adds complementary nucleotides to form new strands of DNA?
Topoisomerase
DNA polymerase
RNA ligase
Helicase
Why does adenine pair with thymine in DNA instead of cytosine?
Cytosine pairs exclusively with guanine due to triple covalent bonding preference.
Adenine cannot physically approach cytosine within the helical twist constraints.
Adenine forms two hydrogen bonds specifically with thymine’s shape and chemical structure.
Adenine shares more electrons with thymine than it would with cytosine.
What sugar is found in RNA backbone?
Glucose
Deoxiribose
Sucrose
Ribose
Given that adenine makes up 18% of the nucleotides in a sample section of double-stranded DNA, what percentage should thymine make up?
Thymine would also make up approximately 18% due to base pairing rules.
Thymine would make up approximately 32%, as it complements adenine's concentration indirectly due to Chargaff's rules.
Thymine would not be present since cytosine pairs with guanine exclusively in double-stranded sections.
Thymine would make up approximately 64%, as it must account for both its own presence and that of adenine's complementarity.

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What is the monomer or basic building block of DNA?
A phosphate
A nitrogen base
A nucleotide
A sugar
If a spontaneous mutation occurred in the DNA of an organism that changed an adenine-thymine base pair to a guanine-cytosine base pair, what would be the most likely immediate effect on the DNA molecule's physical properties?
Increased stability due to the additional hydrogen bond.
No change in stability but increased susceptibility to further mutations.
A decrease in stability due to reduced hydrogen bonding.
Shortening of the DNA molecule due to tighter coiling around histones.
Which structural feature is most crucial for allowing tRNA molecules to bring specific amino acids to ribsomes during translation?
Anticodon loop that pairs with mRNA codons
Ribosomal binding site on small subunit
Aminoacyl-tRNA synthetase binding site
Peptidyl transferase activity site