46. Calcium and CAMP cause many intraccellular proteins to show increased activi
ID: 255769 • Letter: 4
Question
46. Calcium and CAMP cause many intraccellular proteins to show increased activity. These two substances achieve this by A) causing allosteric changes in proteins to which they are bound. 8) increasing feedback inhibition of target enzymes C) cleaving specific target enzymes D) binding to the alpha helix subunit of calmodulin 47. The photosys tems in chloroplasts contain hundreds of chlorophyll molecules, most of which are part of B) the antenna complexes D) the ferredoxin complexes A) plastoquinones C) the reaction centers 48. Which of the following mechanisms is not directly involved in inactivating an activa ted enzyme- coupled receptor RTK? A) dephosphorylation by serine/threonine phosphatases B) dephosphorylation by protein tyrosine phosphatases C) removal of the RTK from the plasma membrane by endocytosis D) digestion of the RTK in lysosomes are fold shorter than the corresponding DNA double helix 49. A mitotic chromosomes molecule in its extended form. A) 10,000 C) 1000 B) 100,000 D) 100 50. Methylation and acetylation are common changes made to histone H3, and the specifc combination of these changes is sometimes referred to as the "histone code." Which of the following patterns will probably lead to gene silencing? A) lysine 9 methylation B) lysine 4 methylation and lysine 9 acetylation C) serine 10 phosphorylation and lysine 14 acetylation D) lysine 9 acetylationExplanation / Answer
46. Both Calcium and cAMP interact with the specific sites on proteins and bring about changes in the shape and structure of proteins.
option b is incorrect as first they trigger reaction by target enzymes and not inhibition, option c is incorrect as there is no cleavage that they cause, Option d is incorrect as calmodulin is present only in certain sites and only binds to calcium.
The correct answer option is A.
47.Photosystems in plant are large multiprotein complexes that capture light energy and convert it into chemical energy and they are made up of antenna complexes and a reaction center.
The reaction centers contain pigments that hold less energy.More energy is held in antennae complexes, because of large number of pigments present here. Both Plastoquinone and ferredoxin complexes pass teh energy from the antennae to the reaction center.
The correct option is B.
48. The answer option is A
49.Th correct answer is that the mitotic chromosome is 10,000 times shorter than the corresponding DNA .
Correct answer option is A.
50. Lysine 9 methylation actually silences cancer cells.Therefore option A is the correct one.
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