Understanding Protein Structure and Function

Proteins are complex organic substances essential for various bodily functions. They are composed of amino acids, which form peptide bonds to create protein molecules. Proteins have a three-dimensional structure held by hydrogen bonds, which can be denatured by heat or pH changes. Digestion breaks down proteins into amino acids for absorption. Proteins are vital for growth, repair, enzyme composition, and energy. A deficiency can lead to diseases like kwashiorkor.

What additional elements, besides carbon, hydrogen, and oxygen, are commonly found in proteins?

• Magnesium and zinc

• Potassium and sodium

• Calcium and iron

• Nitrogen and sulfur

What is the basic unit of proteins?

• Amino acids

• Nucleotides

• Fatty acids

• Monosaccharides

What does the 'R' group in an amino acid structure represent?

• A fixed hydrogen atom

• A variable side chain

• A constant carbon atom

• A stable oxygen molecule

How many naturally occurring amino acids are there in plant and animal proteins?

• 20

• 22

• 24

• 18

What type of reaction occurs when two amino acids link together?

• Reduction

• Hydrolysis

• Condensation

• Oxidation

What is the bond called that forms between two amino acids?

• Hydrogen bond

• Peptide bond

• Ionic bond

• Covalent bond

What happens to protein molecules when they are exposed to heat, acids, or alkalis?

• They become more stable

• They denature

• They form new bonds

• They dissolve

Why can't protein molecules pass through cell membranes directly?

• They are too reactive

• They are too stable

• They are too large

• They are too small

What is the protein deficiency disease that can affect children?

• Kwashiorkor

• Rickets

• Anemia

• Scurvy

Which of the following is NOT a function of proteins in the body?

• Enzyme composition

• Growth and repair

• Formation of antibodies

• Energy storage