This set of Cell Biology Multiple Choice Questions & Answers (MCQs) focuses on “Chemical Basis of Life – Chaperones”.
1. What are molecular chaperones?
b) Cell mass
d) Helper proteins
Explanation: Molecular chaperones are helper proteins that help unfolded or misfolded polypeptide chains to assume a certain folded state. The role of these proteins is to prevent the proteins from non-selectively interacting with other components in the cell.
2. Chaperones bind to which type of amino acids?
Explanation: The molecular chaperones also called the helper proteins attach to short stretches of hydrophobic amino acids which are exposed in nonnative proteins and are found deep within the core in a native protein.
3. Which of the following molecules bind to nascent polypeptides synthesized on the ribosomes?
Explanation: Hsp70 is a class of molecular chaperones that bind to nascent proteins being synthesized on ribosomes. Hsp70 chaperones prevent the newly synthesized proteins from binding to other proteins in the cytosol which could lead to misfolding or aggregation.
4. TriC is a _____________
Explanation: TriC is a chaperonin that helps stabilize long polypeptides. It contains chambers in which peptides can reside without any interference from the external environment.
5. Heat-shock response was first observed in which organism?
a) C. elegans
Explanation: Heat shock response on the form of production of heat shock proteins was first observed in Drosophila. In 1962, an Italian biologist was studying the development of Drosophila when it was observed that increasing the temperature, at which larvae grow new heat shock proteins appear on the chromosome.
6. Rubisco is a ________________
a) nucleic acid
Explanation: Rubisco is a protein found in chloroplasts of plant cells, it catalyzes the reaction in which carbon dioxide taken up from the atmosphere is covalently linked to organic molecules.
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