Answer below 46 TO 50 all question in your own 46 sentences

Answer below 46 TO 50 all question in your own 4-6 sentences of Biology subject that I have difficulty with from of my homework. thank you I really appreciate for your help. I hope those question comes out right and helpful. Thank you.

46. Define the following: negative supercoil, positive supercoil, topoisomerase l (note the role of tyrosine), topoisomerase ll (note the role of ATP) 47. Why can RNA form more complex structure than DNA? 48. Explain how riboswitches work 49. Explain the RNA world hypothesis. How does the ribosome structure support this model? 50. What is the role of protein domains, and why do most proteins contain more than one domain

Solution

46.Right handed supercoiling = negative supercoiling
Left handed supercoiling = positive supercoiling

If DNA is in the form of a circular molecule, or if the ends are rigidly held so that it forms a loop, then overtwisting or undertwisting leads to the supercoiled state. Supercoiling occurs when the molecule relieves the helical stress by twisting around itself. Overtwisting leads to postive supercoiling, while undertwisting leads to negative supercoiling.

Type I topoisomerases are enzymes that cut one of the two strands of double-stranded DNA, relax the strand, and reanneal the strand by creating transient breaks in the DNA using a conserved tyrosine as the catalytic residue.

Type II topoisomerases cut both strands of the DNA helix simultaneously in order to manage DNA tangles and supercoils. They use the hydrolysis of ATP.

47. RNA is more complex than DNA as because of major structural differences: each of the ribose rings contains a 2´-hydroxyl, and
RNA uses uracil in place of thymine. RNA molecules are capable of base pairing,
but generally will not form large regions of stable RNA-RNA double helix.
RNA can form complex three-dimensional structures.


48.Riboswitches are specific components of an mRNA molecule that regulates gene expression. The riboswitch is a part of an mRNA molecule that can bind and target small target molecules. The riboswitch displays the ability to regulate RNA by responding to concentrations of its target molecule.

49.RNA can also exhibit catalytic activity. The combination of the ability to store
genetic information with the ability to catalyze reactions has resulted in a proposal
for the origin of life: the “RNA World”. The RNA world hypothesis proposes that
RNA molecules once filled all of the roles of protein and nucleic acid
macromolecules, and acted in both an information storage capacity and as the
source of the enzymatic activity required for metabolic reactions.

The discovery of ribozymes supported a hypothesis, known as the RNA World Hypothesis, that earlier forms of life may have relied solely on RNA to store genetic information and to catalyze chemical reactions.The ribosome, a large molecular machine that drives protein synthesis, is a ribozyme

50.A protein domain is a conserved part of a given protein sequence and (tertiary) structure that can work independently. Each domain forms a compact three-dimensional structure and often can be independently stable and folded.
Most proteins contain more than 1 domain needed for the more complex cellular functions.