Question 1

Denaturation destroys the primary structure of proteins.

Accepted Answer

Denaturation disrupts the secondary, tertiary, and sometimes quaternary structures of proteins, but the primary structure (the linear sequence of amino acids) remains intact.

Question 2

All of the following are functions of proteins except .&#10;A)defense&#10;B)structural support&#10;C)energy production&#10;D)major plasma membrane component

Accepted Answer

Proteins are not the major component of plasma membranes; lipids, particularly phospholipids, are the primary components.

Question 3

Regulatory sites separate from the active site on proteins are called sites.&#10;A)binding&#10;B)allosteric&#10;C)inhibitory&#10;D)competitive

Accepted Answer

Regulatory sites separate from the active site on proteins are called allosteric sites. These sites can bind molecules and alter the shape or activity of the protein's active site, leading to either an increase or decrease in enzymatic activity. They can also be used to control protein function and serve as targets for drug development. Choices A, C, and D are not correct because they do not specifically refer to regulatory sites on proteins.

Question 4

When a single polypeptide chain is coiled and held together by hydrogen bonds,this is called aan)and occurs in the structure of proteins.&#10;A)beta sheet;secondary&#10;B)alpha helix;secondary&#10;C)beta sheet;tertiary&#10;D)alpha helix;tertiary

Accepted Answer

When a single polypeptide chain is coiled and held together by hydrogen bonds, this is called an alpha helix and occurs in the secondary structure of proteins. The beta sheet refers to a different type of secondary structure where the polypeptide chain is stretched out and stabilized by hydrogen bonds between neighboring strands. Tertiary structure refers to the overall 3D shape of a protein, which is determined by interactions between different regions of the polypeptide chain, such as hydrophobic interactions and disulfide bonds.

Question 5

Quarternary structure results when a single polypeptide chain folds into multiple domains.

Accepted Answer

Quaternary structure refers to the structure formed by the assembly of multiple polypeptide chains or subunits, not the folding of a single polypeptide chain into domains.

Question 6

The binding of a regulatory molecule to an allosteric site on a protein that results in the inhibition of the protein is an example of .&#10;A)non-competitive inhibition&#10;B)allosteric activation&#10;C)competitive inhibition&#10;D)positive regulation

Accepted Answer

Non-competitive inhibition occurs when a regulatory molecule binds to an allosteric site on a protein and inhibits the protein's activity without competing directly with the substrate's binding site. In contrast, competitive inhibition occurs when a molecule competes with the substrate for the active site of an enzyme. Allosteric activation refers to the binding of a regulatory molecule to an allosteric site on a protein that results in the activation of the protein, while positive regulation generally refers to any process that increases the protein's activity.

Question 7

The tertiary structure of proteins is primarily maintained by .&#10;A)hydrogen bonds&#10;B)covalent bonds&#10;C)hydrophobic interactions&#10;D)disulfide bonds

Accepted Answer

The answer of The tertiary structure of proteins is primarily...

Question 8

Changes in can cause proteins to denature.&#10;A)pH&#10;B)salt concentration&#10;C)temperature&#10;D)all of the above

Accepted Answer

All of the above factors can cause changes in protein structure and lead to denaturation. High or low pH values can disrupt ionic and hydrogen bonds that are critical to protein folding. Changes in salt concentration can change the overall charge and polarity of the environment, interfering with interactions between amino acid residues. Higher temperatures increase the kinetic energy of molecules, disrupting the weak interactions that hold proteins together.

Question 9

Polar amino acids are hydrophilic and would be located on the exterior of proteins.

Accepted Answer

Polar amino acids have a partial or full charge separation within their side chains, making them hydrophilic and attracted to water molecules. Therefore, they tend to be located on the exterior of proteins where they can interact with the aqueous environment. This is in contrast to nonpolar amino acids, which are hydrophobic and tend to be located on the interior of proteins where they can be shielded from water.

Question 10

Dissociation refers to the loss of structure of proteins.&#10;A)primary&#10;B)secondary&#10;C)tertiary&#10;D)quaternary

Accepted Answer

Dissociation refers to the loss of quaternary structure, which involves the separation of protein subunits that are non-covalently bonded.

Question 11

In the tertiary structure of proteins,the amino acids are found in the interior of proteins and away from water.&#10;A)polar&#10;B)hydrophilic&#10;C)hydrophobic&#10;D)charged

Accepted Answer

The answer of In the tertiary structure of proteins,the amino...

Question 12

Enzymes the activation energy of the reaction.&#10;A)lower&#10;B)raise&#10;C)inhibit&#10;D)stabilize

Accepted Answer

The answer of Enzymes the activation energy of the reaction.&#10;A)lower&#10;B)raise&#10;C)inhibit&#10;D)stabilize...

Deck 14: Protein Structure and Function