gene expression Flashcards
What is gene expression?
The process by which the information in a gene is used to synthesize a functional gene product, typically a protein.
What is transcription?
The process of copying a segment of DNA into RNA, specifically mRNA, by RNA polymerase.
What is translation?
The process of synthesizing a protein from mRNA by ribosomes, where tRNA brings amino acids based on the mRNA sequence.
What is RNA polymerase?
The enzyme responsible for synthesizing RNA from a DNA template during transcription.
What is a promoter?
A specific DNA sequence where RNA polymerase binds to initiate transcription of a gene.
What is a terminator?
A sequence of nucleotides in DNA that signals the end of transcription.
What is an intron?
Non-coding segments of a gene that are removed during mRNA processing.
What is an exon?
Coding regions of a gene that remain in the mature mRNA and are expressed as part of the protein.
What is a ribosome?
A cellular structure that facilitates the translation of mRNA into a protein.
What is tRNA?
A type of RNA that transports specific amino acids to the ribosome during translation, matching its anticodon with the mRNA codon.
What is a codon?
A sequence of three nucleotides on mRNA that codes for a specific amino acid.
What is an amino acid?
The building blocks of proteins, linked together by peptide bonds to form a polypeptide chain.
What is a polypeptide chain?
A chain of amino acids that folds into a functional protein.
What is splicing?
The process of removing introns and joining exons together in pre-mRNA to form mature mRNA.
What is a 5’ cap?
A modified guanine nucleotide added to the 5’ end of eukaryotic mRNA, important for stability and initiation of translation.
What is a poly-A tail?
A sequence of adenine nucleotides added to the 3’ end of eukaryotic mRNA that protects the mRNA from degradation.
What is a transcription factor?
A protein that regulates gene expression by binding to specific DNA sequences and influencing RNA polymerase’s activity.
What is a frameshift mutation?
A genetic mutation caused by insertions or deletions of nucleotides that shift the reading frame of the codons.
What is a missense mutation?
A mutation that changes a single amino acid in a protein sequence, potentially affecting its function.
What is a nonsense mutation?
A mutation that introduces a premature stop codon, resulting in a truncated and usually nonfunctional protein.
What is a ribozyme?
An RNA molecule capable of catalyzing specific biochemical reactions, similar to a protein enzyme.
What is the redundant genetic code?
The property of the genetic code in which multiple codons can code for the same amino acid, providing a buffer against mutations.
What is transcriptional activation?
The process by which certain proteins (activators) enhance the transcription of a gene, increasing its expression levels.
What is transcriptional repression?
The process by which certain proteins (repressors) inhibit the transcription of a gene, decreasing its expression levels.
What is an operon?
A cluster of genes under the control of a single promoter, often found in prokaryotes, allowing coordinated expression of functionally related genes.
What is an enhancer?
A regulatory DNA sequence that can increase the likelihood of transcription of a particular gene, often located far from the gene itself.
What is a silencer?
A DNA sequence that can repress the transcription of a gene when bound by specific repressor proteins.
What is alternative splicing?
A process during mRNA processing that allows for the production of multiple protein isoforms from a single gene by including or excluding certain exons.
What is post-translational modification?
The chemical modification of a protein after translation, which can affect the protein’s function, activity, and stability.
What are chaperone proteins?
Proteins that assist in the proper folding and assembly of polypeptides into functional proteins.
What is gene regulation?
The mechanisms that control the expression of genes, ensuring that the appropriate genes are expressed at the right time and in the right amounts.
What is epigenetics?
The study of changes in gene expression that do not involve alterations to the underlying DNA sequence, often influenced by environmental factors.
What is a mutation?
A permanent alteration in the DNA sequence that can affect genetic information, potentially leading to changes in gene expression or function.
What is a transcription bubble?
The region of unwound DNA where transcription occurs, allowing RNA polymerase to access the DNA template.
What is a signal transduction pathway?
A series of molecular events and reactions that occur when a signal, such as a hormone, binds to a receptor, ultimately leading to changes in gene expression.
What is RNA processing?
The modifications made to pre-mRNA, including capping, polyadenylation, and splicing, that result in the formation of mature mRNA.
What is genetic engineering?
The manipulation of an organism’s DNA using biotechnology, often to achieve desired traits or produce specific proteins.
What is a reporter gene?
A gene that is attached to a regulatory sequence of another gene of interest to study the expression and regulation of that gene.
What is a nuclear pore complex?
A large protein complex that spans the nuclear envelope and regulates the transport of molecules, including mRNA, between the nucleus and cytoplasm.
What is mature mRNA?
The final form of mRNA after splicing and other modifications, ready for translation in the cytoplasm.
What is histone acetylation?
The addition of an acetyl group to histone proteins, which can increase gene expression by loosening the chromatin structure, making DNA more accessible for transcription.
What is histone methylation?
The addition of methyl groups to histone proteins, which can either activate or repress gene expression depending on the specific context and location.
What is chromatin?
The complex of DNA and proteins (histones) that makes up chromosomes, existing in a condensed form during cell division and a more relaxed form during transcription.
What is a transcription initiation complex?
A large protein complex that assembles at the promoter region of a gene, consisting of RNA polymerase and various transcription factors, to initiate transcription.
What is the 3’ untranslated region (3’ UTR)?
The section of mRNA that follows the coding region and is not translated into protein, playing a role in regulation of gene expression and mRNA stability.
What is the 5’ untranslated region (5’ UTR)?
The region of mRNA located upstream of the start codon that is not translated but can influence the efficiency of translation.
What is microRNA (miRNA)?
A small non-coding RNA molecule that regulates gene expression by binding to complementary sequences on target mRNAs, often leading to mRNA degradation or inhibition of translation.
What is small interfering RNA (siRNA)?
Short, double-stranded RNA molecules that play a role in the RNA interference (RNAi) pathway, leading to the silencing of specific genes.
What is translational control?
The regulation of the translation of mRNA into protein, which can affect the amount of protein produced from a specific mRNA.
What is a proteasome?
A cellular complex that degrades unneeded or damaged proteins by tagging them with ubiquitin, thus regulating protein levels in the cell.
What is ubiquitination?
The process of adding ubiquitin molecules to a protein, marking it for degradation by the proteasome.
What is a polyribosome?
A cluster of ribosomes that are translating the same mRNA strand simultaneously, allowing for efficient protein synthesis.
What is a nucleotide?
The basic building block of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.
What is a template strand?
The DNA strand that serves as a template for RNA synthesis during transcription.
What is non-coding RNA (ncRNA)?
RNA molecules that do not encode proteins but have regulatory roles in gene expression and other cellular processes.
What is the lac operon?
A well-studied example of gene regulation in prokaryotes, consisting of genes that code for enzymes needed for lactose metabolism, regulated by the presence of lactose and glucose.
What is an alternative promoter?
Different starting points for transcription on the same gene that can lead to the production of different mRNA variants and protein isoforms.
What is a chimeric gene?
A hybrid gene formed from two different genes or gene fragments, often created through genetic engineering techniques.
What is gene therapy?
A medical intervention that involves altering the genes inside a person’s cells to treat or prevent disease, often by correcting defective genes or introducing new genes.
What is a ribonucleoprotein complex?
A complex composed of RNA and proteins that plays roles in various cellular processes, including splicing, translation, and RNA degradation.
