Ubiquitination quiz #1 Flashcards
Ubiquitination quiz #1
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What is ubiquitination, and what is its primary function in eukaryotic cells?
Ubiquitination is the ATP-dependent process of covalently attaching ubiquitin peptides to a target protein, typically through the lysine's R-group via an amide (isopeptide) bond. Its primary function is to mark proteins for degradation by proteasomes, thereby regulating protein concentration and cellular processes. How are ubiquitin peptides attached to target proteins during ubiquitination, and what type of bond is formed?
Ubiquitin peptides are covalently attached to the R-group of lysine residues on target proteins, forming an amide linkage known as an isopeptide bond. Why is ubiquitination considered an important regulatory mechanism in cells?
Ubiquitination regulates enzyme activities and cellular processes by marking proteins for degradation, leading to decreased protein concentration. This post-translational modification is essential for controlling protein levels and is found in all eukaryotic organisms. What is ubiquitination and what is its main role in eukaryotic cells?
Ubiquitination is the ATP-dependent covalent attachment of ubiquitin peptides to a target protein, marking it for degradation by proteasomes. Its main role is to regulate protein concentration and cellular processes. How are ubiquitin peptides attached to target proteins during ubiquitination?
Ubiquitin peptides are covalently attached to the R-group of lysine residues on target proteins. This forms an amide linkage known as an isopeptide bond. What type of bond is formed between ubiquitin and the target protein during ubiquitination?
An amide linkage, specifically called an isopeptide bond, is formed between the carboxyl group of ubiquitin and the amino group of lysine's R-group on the target protein. Why is ATP required for the process of ubiquitination?
ATP provides the energy necessary to covalently attach ubiquitin peptides to the target protein. This makes ubiquitination an energy-intensive process. What happens to proteins that have been ubiquitinated?
Ubiquitinated proteins are targeted for degradation by proteasomes, which break them down into peptide fragments and free amino acids. How does ubiquitination regulate enzyme activity and cellular processes?
By marking proteins for degradation, ubiquitination decreases their concentration, which can reduce enzyme activity and regulate various cellular processes. What happens to ubiquitin peptides after the target protein is degraded?
Ubiquitin peptides are recycled and can be reused to target other proteins for degradation, making the process efficient and widespread.
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