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 wo.

1. 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.

2. 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.