Chapter 22, Problem 60E

Interpretation Introduction

(a)

Interpretation:

Whether the statement “The most common primary protein structures are the $\text{α-}$ helix and the $\text{β-}$ pleated sheet” is true or false is to be stated.

Concept introduction:

Proteins are the polymers of amino acids also known as polypeptides. They are formed by the peptide bonding between two acids formed by the elimination of the water molecule between the carboxylic acid and amine group leading to the formation of the amide group. Various structure or forms of the proteins are found in the body.

Answer to Problem 60E

The statement “The most common primary protein structures are the $\text{α-}$ helix and the $\text{β-}$ pleated sheet” is a false statement.

Explanation of Solution

Primary structure of a protein is straight chain polymer of amino acids linked by the amide linkages. The $\text{α-helix,}$ and $\text{β- pleated sheets}$ are the forms of the secondary structure of protein obtained by the modification in the primary protein structure. Therefore, the statement “The most common primary protein structures are the $\text{α-}$ helix and the $\text{β-}$ pleated sheet” is false.

Conclusion

The statement “The most common primary protein structures are the $\text{α-}$ helix and the $\text{β-}$ pleated sheet” is a false statement.

Interpretation Introduction

(b)

Interpretation:

Whether the statement “Sulfur-sulfur bonds called disulfide linkages are important in the tertiary protein structure of many proteins” is true or false is to be stated.

Concept introduction:

Proteins are the polymers of amino acids also known as polypeptides. They are formed by the peptide bonding between two acids formed by the elimination of the water molecule between the carboxylic acid and amine group leading to the formation of the amide group. Various structure or forms of the proteins are found in the body.

Answer to Problem 60E

The statement “Sulfur-sulfur bonds called disulfide linkages are important in the tertiary protein structure of many proteins” is a true statement.

Explanation of Solution

The tertiary structure of the proteins is curling of the secondary protein structure on itself. The stability of the tertiary structure of many tertiary proteins is enhanced by the sulfur-sulfur linkages between the sulfur-containing amino acids, for example, Cysteine.

Therefore, the statement “Sulfur-sulfur bonds called disulfide linkages are important in the tertiary protein structure of many proteins” is true.

Conclusion

The statement “Sulfur-sulfur bonds called disulfide linkages are important in the tertiary protein structure of many proteins” is a true statement.

Interpretation Introduction

(c)

Interpretation:

Whether the statement “An enzyme substrate is the product of an enzyme-catalyzed reaction” is true or false is to be stated.

Concept introduction:

Enzymes are the biochemical catalysts present in the human body or livings organism to catalyst their biochemical process. Enzymes fasten up the rate of reaction by a very large factor. Substrate comes to the active site of the enzyme for the catalysis.

Answer to Problem 60E

The statement “An enzyme substrate is the product of an enzyme-catalyzed reaction” is a false statement.

Explanation of Solution

The substrate in an enzyme-catalyzed reaction is the reactant reacting with the enzyme to give a back product. Substrate attaches to the active site of the enzyme for the catalysis. Therefore, the statement “An enzyme substrate is the product of an enzyme-catalyzed reaction” is a false statement.

Conclusion

The statement “An enzyme substrate is the product of an enzyme-catalyzed reaction” is a false statement.

Interpretation Introduction

(d)

Interpretation:

Whether the statement “The catalytic properties of an enzyme exist at its active site” is true or false is to be stated.

Concept introduction:

Enzymes are the biochemical catalysts present in the human body or livings organism to catalyst their biochemical process. Enzymes fasten up the rate of reaction by a very large factor. Substrate comes to the active site of the enzyme for the catalysis.

Answer to Problem 60E

The statement “The catalytic properties of an enzyme exist at its active site” is a true statement.

Explanation of Solution

The substrate in an enzyme-catalyzed reaction is the reactant reacting with the enzyme to give a back product. Substrate attaches to the active site of the enzyme for the catalysis. Therefore, the statement “The catalytic properties of an enzyme exist at its active site” is true.

Conclusion

The statement “The catalytic properties of an enzyme exist at its active site” is a true statement.

Interpretation Introduction

(e)

Interpretation:

Whether the statement “Carbohydrates are the hydrates of carbon; that is, compounds that consist of carbon and water molecules” is true or false is to be stated.

Concept introduction:

Sugar molecules are examples of carbohydrates. Sugars are the aldehydes or ketone with two or more hydroxide $\left(-\text{OH}\right)$ groups. Glucose, fructose, sucrose are the example of carbohydrates.

Answer to Problem 60E

The statement “Carbohydrates are the hydrates of carbon; that is, compounds that consist of carbon and water molecules” is a false statement.

Explanation of Solution

Carbohydrates are thought to be “hydrates of carbon” as suggested by the name but they are classified as the aldehydes or ketones containing two or more hydroxide $\left(-\text{OH}\right)$ groups. Therefore, the statement “Carbohydrates are the hydrates of carbon; that is, compounds that consist of carbon and water molecules” is false.

Conclusion

The statement “Carbohydrates are the hydrates of carbon; that is, compounds that consist of carbon and water molecules” is a false statement.

Interpretation Introduction

(f)

Interpretation:

Whether the statement “Glucose is also called blood sugar” is true or false is to be stated.

Concept introduction:

Glucose is a sugar molecule also known as carbohydrates. It is a six carbon aldose sugar which means it contains aldehyde and hydroxide groups. Glucose has two forms $\text{α-}$ glucose and $\text{β-}$ glucose.

Answer to Problem 60E

The statement “Glucose is also called blood sugar” is a true statement.

Explanation of Solution

Glucose is a sugar molecule also known as carbohydrates. It is a six carbon aldose sugar which means it contains aldehyde and hydroxide groups. Glucose has two forms $\text{α-}$ glucose and $\text{β-}$ glucose. Glucose is also known as dextrose, corn sugar, and blood sugar. Glucose is the bloodstream provides the energy to all the type of cells. Therefore, the statement “Glucose is also called blood sugar” is true.

Conclusion

The statement “Glucose is also called blood sugar” is a true statement.

Interpretation Introduction

(g)

Interpretation:

Whether the statement “Sucrose is a glucose-fructose combination” is true or false is to be stated.

Concept introduction:

Carbohydrates are classified as the compounds that are aldehydes or ketone containing two or more $-\text{OH}$ groups. Sugars are one of the compounds that are carbohydrates. Sugars are classified into three categories monosaccharides, disaccharides, and polysaccharides.

Answer to Problem 60E

The statement “Sucrose is a glucose-fructose combination” is a true statement.

Explanation of Solution

The disaccharide is the combination of two monosaccharides may be identical or different. Sucrose is one of the most famous examples of disaccharides. It is the combination of two monosaccharide units glucose and fructose. Therefore, the statement “Sucrose is a glucose-fructose combination” is true.

Conclusion

The statement “Sucrose is a glucose-fructose combination” is a true statement.

Interpretation Introduction

(h)

Interpretation:

Whether the statement “Fats and oils are distinguished by their state of matter at room temperature” is true or false is to be stated.

Concept introduction:

Lipids are the water-insoluble compounds found in the living organisms. Lipids are parted into three classes (1) Fats, oils and phospholipids, (2) waxes, and (3) steroids.

All these compounds are insoluble in polar solvents like water because of the large presence of hydrophobic groups in them.

Answer to Problem 60E

The statement “Fats and oils are distinguished by their state of matter at room temperature” is a true statement.

Explanation of Solution

Fats and oils are the triesters of long-chain carboxylic acids known as fatty acids. The ester is formed from simple alcohol glycerol. The fats and oils are also referred to as triacylglycerols. The fats at room temperature are solid while the oils are liquid at room temperature. Therefore, the statement “Fats and oils are distinguished by their state of matter at room temperature” is true.

Conclusion

The statement “Fats and oils are distinguished by their state of matter at room temperature” is a true statement.

Interpretation Introduction

(i)

Interpretation:

Whether the statement “Steroids have three cyclopentane rings and one cyclohexane ring fused” is true or false is to be stated.

Concept introduction:

Lipids are the water-insoluble compounds found in the living organisms. Lipids are parted into three classes (1) Fats, oils and phospholipids, (2) waxes, and (3) steroids.

All these compounds are insoluble in polar solvents like water because of the large presence of hydrophobic groups in them.

Answer to Problem 60E

The statement “Steroids have three cyclopentane rings and one cyclohexane ring fused” is a false statement.

Explanation of Solution

Steroids contain a four ring fused system. Three are six carbon and one is five carbon ring. Six carbon ring is known as cyclohexane and five carbon ring is known as cyclopentane. Therefore, the statement “Steroids have three cyclopentane rings and one cyclohexane ring fused” is false.

The structure of one of the steroids cholesterol is shown below.

Figure 1

Conclusion

The statement “Steroids have three cyclopentane rings and one cyclohexane ring fused” is a false statement.

Interpretation Introduction

(j)

Interpretation:

Whether the statement “Nucleic acid monomers are called nucleotides” is true or false is to be stated.

Concept introduction:

Nucleotides are the monomers of nucleic acids. DNA and RNA are examples of nucleotides. Nucleotides consist of three parts (a) cyclic nitrogenous base (b) a sugar (ribose or deoxyribose sugar) (c) phosphate group.

Answer to Problem 60E

The statement “Nucleic acid monomers are called nucleotides” is a true statement.

Explanation of Solution

Nucleic acids are the polymer of nucleotides. Nucleotides are phosphate and base-sugar combination. Nucleotides contain two types of sugars in them one is ribose sugar and other is deoxyribose sugar.

Therefore, the statement “Nucleic acid monomers are called nucleotides” is true.

Conclusion

The statement “Nucleic acid monomers are called nucleotides” is a true statement.

Interpretation Introduction

(k)

Interpretation:

Whether the statement “DNA is a nucleotide (phosphate-sugar-base) polymer” is true or false is to be stated.

Concept introduction:

Nucleotides are the monomers of nucleic acids. DNA and RNA are examples of nucleotides. Nucleotides consist of three parts (a) cyclic nitrogenous base (b) a sugar (ribose or deoxyribose sugar) (c) phosphate group.

Answer to Problem 60E

The statement “DNA is a nucleotide (phosphate-sugar-base) polymer” is a true statement.

Explanation of Solution

Nucleic acids are nucleotide polymers. Nucleotides are a combination of phosphate and base-sugar. DNA is one of the examples of nucleic acids. DNA contains nucleotides having deoxyribose sugar and specific bases (adenine, guanine, thymine, and cytosine).

Therefore, the statement “DNA is a nucleotide (phosphate-sugar-base) polymer” is true.

Conclusion

The statement “DNA is a nucleotide (phosphate-sugar-base) polymer” is a true statement.