Macromolecules Review

Which of the following questions would a researcher most likely ask if they wanted to know whether a hydrolysis reaction or a dehydration synthesis reaction is occurring?

• Which polymer is involved in the reaction?

• Is an enzyme involved in the reaction?

• Are the monomers identical to one another?

• Is water a reactant or product of the reaction?

Which of the following best describes the role that water plays in the reaction depicted?

• In the reverse of this reaction, water is used to promote hydrolysis.

• Water is a product of this dehydration synthesis reaction.

• When water is added, the two monomers form a covalent bond that holds the dimer together.

• As a reactant, water cleaves the covalent bond that holds the dimer together.

The human body is capable of digesting the complex polymer starch into simpler subunits. This digestive process requires the presence of water and the enzyme amylase in order to break down starch into maltose.

Which of the following statements best describes the digestion of starch into maltose?

• This is a hydrolysis reaction that requires water to break down a complex polymer into simpler subunits.

• This is a dehydration synthesis reaction that requires water to form a complex polymer from simpler subunits.

• This is a hydrolysis reaction that forms water by breaking down a complex polymer into simpler subunits.

• This is a dehydration synthesis reaction that produces water when forming a complex polymer from simpler subunits.

In the reaction, two glucose monomers combine to form the dimer maltose.

Which of the following best explains the process of this reaction?

• Water is added to the reaction to promote the formation of a covalent bond between the glucose monomers.

• A covalent bond forms through dehydration synthesis, which results in the formation of maltose and water.

• An ionic bond forms through dehydration synthesis, which combines the two glucose monomers and forms the maltose dimer.

• To form a covalent bond, the monomers underwent a hydrolysis reaction.

What role do the highlighted hydroxyl group (–OH) and hydrogen atom (H) play in the depicted reaction above?

• Through dehydration synthesis, they condense out of the reaction as a water molecule and a covalent bond forms in their place.

• Through dehydration synthesis, a water molecule is added to those regions of the monomers to produce a covalent bond in the dimer.

• Through hydrolysis, they condense out of the reaction as a water molecule and a covalent bond forms in their place.

• Through hydrolysis, a water molecule is added to those regions of the monomers to produce a covalent bond in the dimer.

If water was removed from the reaction depicted above, which of the following describes the most likely outcome of this removal?

• The reverse of the reaction would occur and a covalent bond would spontaneously form between the two monomers.

• The covalent bond that holds the dimer together would not be cleaved because dehydration synthesis would not occur.

• The reverse of the reaction would occur and the dimer would spontaneously form from the two monomers.

• The covalent bond that holds the dimer together would not be cleaved because hydrolysis would not occur.

In order to develop antibiotics, scientists need to understand how bacteria grow and reproduce. One factor that is essential for bacterial growth and reproduction is protein synthesis. By understanding how bacteria synthesize proteins, scientists can then attempt to develop antibiotics that block bacterial protein synthesis during an infection.

Which of the following questions will best direct an investigation on how to develop an antibiotic that inhibits protein synthesis in bacteria?

• How can the formation of covalent bonds between amino acids be blocked?

• How can the formation of hydrogen bonds between amino acids be blocked?

• How can the phosphate end of the growing polypeptide chain be blocked?

• How can the hydroxyl end of the growing polypeptide chain be blocked?

In the cell membrane, carbohydrate chains can be covalently linked to membrane proteins to form glycoproteins. They can also be covalently linked to membrane phospholipids to form glycolipids. These two cell membrane structures are shown in the image.

During an investigation, researchers discover a new toxin that enters a cell after binding to a carbohydrate on the cell membrane.

Which of the following best describes how the toxin attaches to the cell membrane?

• The toxin attaches to specific fatty acids on the cell membrane.

• The toxin attaches to specific monosaccharides on the cell membrane.

• The toxin attaches to specific phospholipids on the cell membrane.

• The toxin attaches to specific amino acids on the cell membrane.

The image below depicts how the bacterial protein barnase undergoes modifications that involve changing its conformation, or shape. In order to function in the cell, barnase has to be folded from a nonfunctional conformation into a functional conformation.

Based on the information above, which of the following best describes the functional conformation of barnase?

• The functional conformation of barnase has a secondary structure because it consists of a single alpha-helix.

• The functional conformation of barnase has a primary structure because it consists of a linear chain of amino acids.

• The functional conformation of barnase has a tertiary structure because it consists of a polypeptide chain folded into a three-dimensional shape.

• The functional conformation of barnase has a quaternary structure because it consists of interactions between multiple polypeptide units.

Which of the following statements accurately describes a similarity between the nucleotides of DNA and RNA?

• The nucleotides of DNA and RNA contain the same nitrogenous bases.

• The nucleotides of DNA and RNA contain a five-carbon sugar bonded to a phosphate group and a nitrogenous base.

• The nucleotides of DNA and RNA are connected through hydrogen bonds to form the sugar-phosphate backbone.

• The nucleotides of DNA and RNA contain the same five-carbon sugar.