Podcast
Questions and Answers
What cellular process is directly disrupted by inhibiting histone deacetylase (HDAC)?
What cellular process is directly disrupted by inhibiting histone deacetylase (HDAC)?
- Increasing gene expression by allowing DNA to be more accessible. (correct)
- DNA replication by preventing nucleotide incorporation.
- Decreasing gene expression by preventing DNA from unwinding.
- Protein synthesis by affecting tRNA binding.
If a protein is found localized within the nucleolus, what is its most probable function?
If a protein is found localized within the nucleolus, what is its most probable function?
- Facilitating mRNA export to the cytoplasm.
- Promoting DNA replication during cell division.
- Regulation of transcription within the nucleus.
- Participating in rRNA transcription and ribosome assembly. (correct)
Why do histone proteins have a net positive charge?
Why do histone proteins have a net positive charge?
- To repel the negatively charged phosphate groups of RNA, preventing unwanted binding.
- To maintain a neutral charge within the nucleus, preventing pH imbalances.
- To promote hydrophobic interactions with the nuclear membrane.
- To facilitate electrostatic interactions with the negatively charged DNA. (correct)
In SDS-PAGE, how are proteins separated, and what property dictates their migration rate?
In SDS-PAGE, how are proteins separated, and what property dictates their migration rate?
Why must the DNA on a microarray be single-stranded for effective cDNA hybridization?
Why must the DNA on a microarray be single-stranded for effective cDNA hybridization?
Which of the following molecules would cDNA most likely bind to?
Which of the following molecules would cDNA most likely bind to?
What is the direct consequence of reducing splicing activity in a cell?
What is the direct consequence of reducing splicing activity in a cell?
Which type of mutation results from the insertion of a single nucleotide base into a gene’s coding sequence?
Which type of mutation results from the insertion of a single nucleotide base into a gene’s coding sequence?
A mutation in a gene leads to the premature termination of translation. What type of mutation is most likely responsible?
A mutation in a gene leads to the premature termination of translation. What type of mutation is most likely responsible?
A point mutation in a gene results in the substitution of valine for alanine in the protein. What type of mutation is this?
A point mutation in a gene results in the substitution of valine for alanine in the protein. What type of mutation is this?
A mutation occurs in the DNA sequence of a gene, but the resulting protein sequence remains unchanged. What type of mutation has occurred?
A mutation occurs in the DNA sequence of a gene, but the resulting protein sequence remains unchanged. What type of mutation has occurred?
Under nonreducing conditions during SDS-PAGE, how would a disulfide-linked homodimer behave compared to a monomer?
Under nonreducing conditions during SDS-PAGE, how would a disulfide-linked homodimer behave compared to a monomer?
What can be definitively said about a sample if cDNA is present?
What can be definitively said about a sample if cDNA is present?
After three generations of replication in a medium containing only 14N, what percentage of DNA would still contain both 15N and 14N if the original DNA was 15N/14N hybrid?
After three generations of replication in a medium containing only 14N, what percentage of DNA would still contain both 15N and 14N if the original DNA was 15N/14N hybrid?
What role does RNA polymerase play in the process of inserting a gene into a vector and the subsequent replication of the plasmid?
What role does RNA polymerase play in the process of inserting a gene into a vector and the subsequent replication of the plasmid?
Which of the following is a characteristic of pre-mRNA?
Which of the following is a characteristic of pre-mRNA?
What is the natural state of DNA when interacting with histones, and how is this state generally described?
What is the natural state of DNA when interacting with histones, and how is this state generally described?
In a Meselson-Stahl experiment, what proportion of DNA molecules would be composed of one strand of heavy nitrogen (15N) and one strand of light nitrogen (14N) after two generations, starting from a DNA molecule made entirely of heavy nitrogen?
In a Meselson-Stahl experiment, what proportion of DNA molecules would be composed of one strand of heavy nitrogen (15N) and one strand of light nitrogen (14N) after two generations, starting from a DNA molecule made entirely of heavy nitrogen?
What structural level does SDS-PAGE affect in a protein?
What structural level does SDS-PAGE affect in a protein?
What type of mutation only affects the resulting amino acid if it is not in multiples of three?
What type of mutation only affects the resulting amino acid if it is not in multiples of three?
Flashcards
Pre-mRNA
Pre-mRNA
Pre-mRNA is an immature single strand of messenger RNA (mRNA) synthesized from a DNA template in the cell nucleus by transcription, preceding translation.
Histones and DNA
Histones and DNA
Histones compact DNA to form chromatin. Tightly packed chromatin (heterochromatin) reduces gene expression.
HDAC Inhibition
HDAC Inhibition
HDAC inhibitors increase gene expression by preventing the removal of acetyl groups, leading to a more open (euchromatin) state.
Nucleolus Function
Nucleolus Function
Signup and view all the flashcards
Histone Charge
Histone Charge
Signup and view all the flashcards
SDS-PAGE
SDS-PAGE
Signup and view all the flashcards
cDNA Hybridization
cDNA Hybridization
Signup and view all the flashcards
Frameshift Mutation
Frameshift Mutation
Signup and view all the flashcards
Nonsense Mutation
Nonsense Mutation
Signup and view all the flashcards
Missense Mutation
Missense Mutation
Signup and view all the flashcards
Silent Mutation
Silent Mutation
Signup and view all the flashcards
cDNA Synthesis
cDNA Synthesis
Signup and view all the flashcards
Splicing Reduction
Splicing Reduction
Signup and view all the flashcards
Study Notes
- Pre-mRNA only exists between transcription and translation.
- Histones cause DNA to be tightly wrapped (heterochromatin).
- Inhibiting histone deacetylase (HDAC) maintains DNA in an open, euchromatin state, increasing gene expression.
- Nucleolus proteins are located where ribosomes are produced, rRNA is transcribed, ribosomal subunits are assembled, and precursor ribosomes are prepared for export to the cytoplasm for maturation.
- DNA is negatively charged, so histone proteins must have a net positive charge to bind DNA.
- SDS-PAGE separates proteins by size using a highly crosslinked polyacrylamide gel with small pores allowing smaller proteins to migrate faster.
- Complementary DNA (cDNA) is single-stranded and complementary to mRNA.
- Microarrays contain single-stranded DNA matching the sense strand of genomic DNA for cDNA binding through complementary base pairing.
- Double-stranded DNA can't bind cDNA because both strands are already paired.
- Proteins don’t bind cDNA because they are made of amino acids, not nucleotides.
- Antibodies don’t bind DNA because they recognize proteins.
- Reduced splicing decreases exon joining, reducing functional mRNA transcripts and protein isoform production.
Types of Mutations
-
Frameshift: Adds or removes bases not in multiples of three, shifting the reading frame
-
Nonsense: Changes a codon into a stop codon, cutting the protein short
-
Missense: Changes one amino acid in the protein
-
Silent: Changes the DNA but not the amino acid
-
Disulfide-linked homodimers stay intact under nonreducing SDS-PAGE, migrating more slowly.
-
Mutants lacking disulfide bonds separate into smaller monomers and migrate farther in the gel.
-
cDNA indicates RNA involvement, being synthesized from mRNA during reverse transcription.
-
Hybrid (15N/14N) DNA halves with each generation; after three rounds of division, 25% remains hybrid.
-
RNA polymerase is not required for vector insertion, only for host cell transcription of the inserted gene into RNA.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
