MCB POST LEC 7

What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed?

their phosphate groups

You have an enzymatic reaction proceeding at the optimum pH and optimum temperature. You add a competitive inhibitor to the reaction and notice that the reaction slows down. What can you do to speed the reaction up again?

Add more substrate; it will outcompete the inhibitor and increase the reaction rate.

You have added an irreversible inhibitor to a sample of enzyme and substrate. At this point, the reaction has stopped completely. What can you do to regain the activity of the enzyme?

The enzyme is inactive at this point. New enzyme must be added to regain enzyme activity.

When nucleotides polymerize to form a nucleic acid _____.

a covalent bond forms between the sugar of one nucleotide and the phosphate of a second

HIV is the virus that causes AIDS. In the mid-1990s, researchers discovered an enzyme in HIV called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block it. If this strategy for stopping HIV infections were successful, it would be an example of what phenomenon?

competitive inhibition

Identify three possible components of a DNA nucleotide.

deoxyribose, phosphate group, thymine

Part A - Components of nucleotides Sort these nucleotide building blocks by their name or classification.

https://docs.google.com/document/d/1J4FFxKA1uD1B9drV2W-Aq-qTvm-xgsoDtg93KAb-1EQ/edit?usp=sharing

Part B - Comparing RNA and DNA Part complete Sort the parts of a nucleic acid according to whether each occurs exclusively in DNA, exclusively in RNA, or in both types of nucleic acid.

https://docs.google.com/document/d/1J4FFxKA1uD1B9drV2W-Aq-qTvm-xgsoDtg93KAb-1EQ/edit?usp=sharing

The condensation reaction that forms nucleic acid polymers occurs between a _____ group on one nucleotide and a _____ group on a second nucleotide.

phosphate, hydroxyl

For each of the following features of nucleic acids, indicate whether it is true of DNA only, of RNA only, of both DNA and RNA, or of neither. Sort each feature into the appropriate bin.

True of DNA only Contains the nucleotide deoxythymidine monophosphate. True of RNA only Is involved in the process of protein synthesis in the cytoplasm of the cells in the liver. True of both DNA and RNA Contains the base adenine. Is synthesized by a process that involves base pairing. True of neither Occurs only in single-stranded form Is an inherently directional molecule, with an N-terminus on one end and a C-terminus on the other end.

Complete this vocabulary exercise relating to the three types of enzyme inhibitors. Drag the words on the left to the appropriate blanks in the sentences on the right. Each word is used only once.

1. A (n)competitive inhibitor has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate. 2. A (n)noncompetitive inhibitor binds to a site on the enzyme that is not the active site. 3. Usually, a(n) irreversible inhibitor forms a covalent bond with an amino acid side group within the active site, which prevents the substrate from entering the active site or prevents catalytic activity. 4. The competitive inhibitor competes with the substrate for the active site on the enzyme. 5. When the noncompetitive inhibitor is bonded to the enzyme, the shape of the enzyme is distorted. 6. Enzyme inhibitors disrupt normal interactions between an enzyme and its substrate.

Which statement most accurately explains how allosteric regulation can change an enzyme's catalytic activity?

In allosteric activation, a regulatory molecule binds to a location other than the active site, resulting in a change in enzyme shape that allows the active site to bind substrate.