Question

Choose one of the following terms to match the description given in statements (1)-(17). All of the following pertain to proteins or carbohydrates. a. aldohexose g. disaccharides \(\mathbf{m}\). ketohexoses b. saliva h. disulfide n. oxytocin c. cellulose i. globular o. pleated sheet d. \(\mathrm{CH}_{2} \mathrm{O}\) j. glycogen p. polypeptide e. cysteine k. glycoside linkage q. primary f. denaturation 1\. hydrophobic structure (1) polymer consisting of many amino acids (2) linkage that forms between two cysteine species (3) peptide hormone that triggers milk secretion (4) proteins with roughly spherical shape (5) sequence of amino acids in a protein (6) silk protein secondary structure (7) water-repelling amino acid side chain (8) amino acid responsible for permanent wave in hair (9) breakdown of a protein's tertiary and/or secondary structure (10) animal polymer of glucose (11) \(-\mathrm{C}-\mathrm{O}-\mathrm{C}-\) bond between rings in disaccharide sugars (12) empirical formula leading to the name carbohydrate (13) where enzymes catalyzing the breakdown of glycoside linkages are found (14) six-carbon ketone sugars (15) structural component of plants, polymer of glucose (16) sugars consisting of two monomer units (17) six-carbon aldehyde sugars

Short answer

The short answers are: 1. polypeptide (p) 2. disulfide (h) 3. oxytocin (n) 4. globular (i) 5. primary (q) 6. pleated sheet (o) 7. hydrophobic structure (1) 8. cysteine (e) 9. denaturation (f) 10. glycogen (j) 11. glycoside linkage (k) 12. CH2O (d) 13. saliva (b) 14. ketohexoses (m) 15. cellulose (c) 16. disaccharides (g) 17. aldohexose (a)

Step-by-step solution

1. Polymer consisting of many amino acids

The term that matches this statement is polypeptide (p).

2. Linkage that forms between two cysteine species

The term that matches this statement is disulfide (h).

3. Peptide hormone that triggers milk secretion

The term that matches this statement is oxytocin (n).

4. Proteins with roughly spherical shape

The term that matches this statement is globular (i).

5. Sequence of amino acids in a protein

The term that matches this statement is primary (q).

6. Silk protein secondary structure

The term that matches this statement is pleated sheet (o).

7. Water-repelling amino acid side chain

The term that matches this statement is hydrophobic structure (1).

8. Amino acid responsible for permanent wave in hair

The term that matches this statement is cysteine (e).

9. Breakdown of a protein's tertiary and/or secondary structure

The term that matches this statement is denaturation (f).

10. Animal polymer of glucose

The term that matches this statement is glycogen (j).

11. -C-O-C- bond between rings in disaccharide sugars

The term that matches this statement is glycoside linkage (k).

12. Empirical formula leading to the name carbohydrate

The term that matches this statement is CH2O (d).

13. Where enzymes catalyzing the breakdown of glycoside linkages are found

The term that matches this statement is saliva (b).

14. Six-carbon ketone sugars

The term that matches this statement is ketohexoses (m).

15. Structural component of plants, polymer of glucose

The term that matches this statement is cellulose (c).

16. Sugars consisting of two monomer units

The term that matches this statement is disaccharides (g).

17. Six-carbon aldehyde sugars

The term that matches this statement is aldohexose (a).

Key concepts

Polypeptides

Polypeptides are long chains of amino acids linked together by peptide bonds. They are a fundamental component of proteins. When these amino acid strings fold into complex shapes, they form functional proteins. Each polypeptide has a specific sequence of amino acids. This sequence determines the protein's three-dimensional structure and function.

• Amino acids, the building blocks of polypeptides, come in 20 different types. Each one has distinct properties.
• Peptide bonds are formed between the carboxyl group of one amino acid and the amino group of another, creating a stable and strong linkage.

The primary structure of a protein refers to its specific sequence of amino acids. Understanding this layout is crucial, because even a small change in the sequence can lead to significant changes in the protein's function. Proteins and polypeptides are essential for many processes in the body, including enzyme function, cellular structure, and transport.

Glycoside Linkage

A glycoside linkage is a type of covalent bond that connects carbohydrate (sugar) molecules. This bond forms through a dehydration reaction where a water molecule is removed. The -C-O-C- linkage typically occurs between carbon atoms in individual sugar units of carbohydrates, like disaccharides.

• Disaccharides, such as sucrose and lactose, consist of two monosaccharides joined by a glycoside linkage.
• In the human body, enzymes break down these linkages, allowing sugars to be utilized for energy.

This type of bonding is critical in carbohydrate biochemistry. It determines the form and digestibility of sugars. The type of glycoside linkage can affect the overall structure and properties of the carbohydrate. For example, cellulose in plants has strong, rigid glycoside linkages that human enzymes cannot break down, making it insoluble and indigestible in the human diet.

Ketohexoses

Ketohexoses are a type of sugar molecule with six carbon atoms and a ketone group. A common example of a ketohexose is fructose, found naturally in fruits. These sugars play vital roles in metabolism and energy production.

• Ketohexoses, like other sugars, can exist in linear or ring forms, which affect their chemical behavior and interactions.
• They act as intermediate products in various biological pathways, especially in glycolysis.

Understanding ketohexoses is important because they are fundamental to the biochemistry of life. Their structure allows them to participate in complex reactions that are necessary for energy generation and storage. Their sweet taste also makes them a popular ingredient in food products.

Denaturation

Denaturation refers to the structural change in proteins or nucleic acids. This alteration typically involves the unfolding of secondary and tertiary structures, rendering them inactive.

• Common causes of denaturation include changes in temperature, pH, or exposure to chemicals.
• Denatured proteins often lose their biological function because their specific shape is necessary for their activity.

A classic example is cooking an egg. The heat alters the egg's protein structure, transforming it from a clear liquid to a solid and opaque white. Denaturation is not always irreversible. Sometimes, the original structure can be reinstated if normal conditions are restored, but this varies depending on the protein and the extent of the denaturation.