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What primarily ensures correct folding of proteins after their synthesis?
Which modifications are described as the most frequent in proteins after translation?
Polyribosomes function to:
What is the significance of quality-control mechanisms like nonsense-mediated mRNA decay?
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Which structure is essential for a polypeptide to acquire its tertiary structure?
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The assembly of proteins often requires which additional molecules?
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In cellular gene expression regulation, transcription factors primarily affect which process?
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The completion of a polypeptide chain involves which of the following steps?
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What phenomenon occurs when both transgene and endogenous CHS are inactivated?
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Which process involves the degradation of mRNA to control gene expression post-transcriptionally?
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In the context of gene silencing, what role does dsRNA play?
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What is the primary mechanism by which plants achieve gene knock-down through RNA interference?
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Which of the following identifies the first microRNA gene discovered?
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What is the significance of cosuppression in gene expression modulation?
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What type of RNA is involved in silencing pathways in eukaryotes?
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What was the primary discovery made by Fire et al. in 1998 regarding RNA interference?
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What mechanism contributes to gene repression in eukaryotic cells?
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Genomic imprinting results in genes being expressed differently based on their:
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What role does the Rev protein play in HIV infection?
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What is a consequence of alternative RNA splicing?
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How does mRNA localization occur within the cytosol?
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What does the regulation of nuclear export in HIV primarily depend on?
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Which of the following is a requirement for mRNA localization mechanisms?
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The compact genome of HIV utilizes which of the following strategies for gene expression?
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Study Notes
Gene Expression and Its Control (III)
- Proteins are synthesized on polyribosomes: A series of ribosomes can simultaneously translate the same eukaryotic mRNA molecule
- Nonsense-mediated mRNA decay is a quality-control mechanism that prevents the translation of damaged mRNAs
- Steps involved in creating a functional protein: A growing polypeptide chain must fold correctly into its 3D conformation, bind any cofactors required, and assemble with its partner protein chains
- Different chaperones cooperate to ensure correct protein folding: Hsp proteins are involved in this process.
- Two post-transcriptional controls mediated by iron: The stability and translation of mRNAs are regulated by iron.
- RNA Silencing, also known as RNA Interference (RNAi), is a mechanism used by eukaryotes to regulate gene expression.
- In 1990, the phenomenon of cosuppression (also called post-transcriptional gene silencing, PTGS) was discovered in plants.
- The first microRNA gene, lin-4, was identified in 1993.
- In 1998, RNA interference was discovered in C. elegans.
- Several mechanisms can produce especially stable gene repression, including DNA and histone modifying enzymes working together.
- Genomic imprinting can cause non-Mendelian patterns of inheritance: Genes are expressed or not depending on their parental origin.
- Five patterns of alternative RNA splicing: A single type of RNA transcript is spliced in several alternative ways to produce distinct mRNAs.
- The compact genome of HIV, the Human Immunodeficiency Virus, exhibits alternative RNA splicing.
- The Rev protein of HIV regulates nuclear export: Rev binds to the viral RNA and interacts with Crm1, a nuclear receptor that directs the movement of viral RNAs through the nuclear pores into the cytosol.
- Some mRNAs are localized to specific regions of the cytosol: These mRNAs are held in place by anchor proteins.
- Different mechanisms are used to localise mRNAs in the cytosol. These require specific signals on the mRNA, often located in the 3' UTR.
RNA silencing, RNA Interference (RNAi)
- RNA silencing or RNA interference (RNAi) is a mechanism used by eukaryotes to regulate gene expression.
- Discovered in 1990, cosuppression, also known as post-transcriptional gene silencing (PTGS), is a form of RNA silencing that occurs in plants.
- The first microRNA gene (lin-4) was discovered in 1993. These miRNAs are known as small temporal (st) RNAs.
- RNA interference (RNAi) was discovered in 1998 in C.elegans.
- In RNAi, double-stranded RNA (dsRNA) induces silencing in plants and other organisms.
- RNAi can be used to "knock-down" genes through RNA interference in worms.
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Description
Dive into the complex mechanisms of gene expression and its regulation in eukaryotes. This quiz covers aspects such as protein synthesis, quality control mechanisms, and RNA interference. Test your understanding of how various factors influence gene expression and protein folding.
