Chapter 2 Section 3 Review Questions

1. Proteins are large, organic molecules formed by joining together

Fats

Carbohydrates

Amino acids

Simple sugars

Proteins are large, organic molecules formed by joining together amino acids. Amino acids are the building blocks of proteins, and when they are linked together through peptide bonds, they form long chains called polypeptides. These polypeptides then fold into specific three-dimensional structures, giving proteins their unique functions. Fats and carbohydrates are also organic molecules, but they do not form proteins. Simple sugars, on the other hand, are monosaccharides and are not directly involved in protein synthesis.

Explanation

Proteins are large, organic molecules formed by joining together amino acids. Amino acids are the building blocks of proteins, and when they are linked together through peptide bonds, they form long chains called polypeptides. These polypeptides then fold into specific three-dimensional structures, giving proteins their unique functions. Fats and carbohydrates are also organic molecules, but they do not form proteins. Simple sugars, on the other hand, are monosaccharides and are not directly involved in protein synthesis.

2. A protein that acts as a biological catalyst is a(n)

Enzyme

Fat

Hormone

Simple sugar

Enzymes are proteins that act as biological catalysts, meaning they speed up chemical reactions in living organisms. They do this by lowering the activation energy required for a reaction to occur, allowing it to happen more quickly. Enzymes are highly specific, meaning they only catalyze specific reactions. They are not fats, hormones, or simple sugars, which have different functions in the body. Therefore, the correct answer is enzyme.

Explanation

Enzymes are proteins that act as biological catalysts, meaning they speed up chemical reactions in living organisms. They do this by lowering the activation energy required for a reaction to occur, allowing it to happen more quickly. Enzymes are highly specific, meaning they only catalyze specific reactions. They are not fats, hormones, or simple sugars, which have different functions in the body. Therefore, the correct answer is enzyme.

3. Which formula on page 57 of the text represents an amino acid?

Formula A

Formula B

Formula C

Formula D

not-available-via-ai

Explanation

not-available-via-ai

4. Which is NOT an organic molecule found in living organisms?

Protein

Sugar

Water

Carbohydrate

Water is not considered an organic molecule because it does not contain carbon. Organic molecules are defined as compounds that contain carbon and hydrogen atoms bonded together in a specific way. Water, on the other hand, consists of hydrogen and oxygen atoms, making it an inorganic molecule. Despite being essential for life, water is not classified as an organic molecule.

Explanation

Water is not considered an organic molecule because it does not contain carbon. Organic molecules are defined as compounds that contain carbon and hydrogen atoms bonded together in a specific way. Water, on the other hand, consists of hydrogen and oxygen atoms, making it an inorganic molecule. Despite being essential for life, water is not classified as an organic molecule.

5. Examples of large complex molecules formed by joining together many small molecules include

Proteins and amino acids

Carbohydrates and monosaccharides

DNA and proteins

Mitochondria and vacuoles

DNA and proteins are examples of large complex molecules formed by joining together many small molecules. DNA is composed of nucleotides, which are small molecules consisting of a sugar, a phosphate group, and a nitrogenous base. These nucleotides are joined together through phosphodiester bonds to form a long strand of DNA. Proteins, on the other hand, are composed of amino acids, which are small molecules consisting of an amino group, a carboxyl group, and a side chain. Amino acids are joined together through peptide bonds to form a polypeptide chain, which then folds into a functional protein.

Explanation

DNA and proteins are examples of large complex molecules formed by joining together many small molecules. DNA is composed of nucleotides, which are small molecules consisting of a sugar, a phosphate group, and a nitrogenous base. These nucleotides are joined together through phosphodiester bonds to form a long strand of DNA. Proteins, on the other hand, are composed of amino acids, which are small molecules consisting of an amino group, a carboxyl group, and a side chain. Amino acids are joined together through peptide bonds to form a polypeptide chain, which then folds into a functional protein.

6. Which type of molecule is represented by formula D on page 57 in the text?

Amino acid

Monosaccharide

Disaccharide

Protein

The correct answer is disaccharide. This means that the molecule represented by formula D on page 57 in the text is a disaccharide.

Explanation

The correct answer is disaccharide. This means that the molecule represented by formula D on page 57 in the text is a disaccharide.

7. Which class period are you in?

1

4

7