Proteins & Amino Acids — Quiz

1. Which two functional groups are found on every amino acid?

a) Alkene (C=C) and aldehyde (–CHO)
b) Amine (–NH₂) and carboxyl (–COOH)
c) Alcohol (–OH) and ether (–O–)
d) Ketone (C=O) and alkane (C–C)

2. The link formed between two amino acids is called a(n):

a) Glycosidic bond
b) Peptide (amide) bond
c) Disulfide bond
d) Hydrogen bond

3. A dipeptide is formed when how many amino acids join together?

a) One
b) Two
c) Three
d) Many

4. When two amino acids join in a condensation reaction, a molecule of is released and a bond is formed.

5. The primary structure of a protein refers to its:

a) Overall 3D shape
b) α-helices and β-sheets
c) Sequence of amino acids
d) Arrangement of multiple subunits

6. A polypeptide has 9 amino acids. How many peptide bonds does it contain?

7. Which statement best describes polypeptides versus proteins?

a) Polypeptides always contain over 200 amino acids
b) Polypeptides and proteins are identical terms
c) Polypeptides contain only glycine and alanine
d) Polypeptides are typically up to ~50 amino acids; longer chains are usually called proteins

8. In sickle-cell anaemia, a single amino-acid change (Glu → Val) in haemoglobin primarily:

a) Alters solubility and encourages abnormal aggregation
b) Changes the number of peptide bonds
c) Converts the amino acid into a carboxylic acid
d) Converts amino acids to sugars

9. Approximately how many different amino acids are commonly found in proteins?

a) Less than 10
b) About 20
c) 2
d) more than 50

10. Forming a single, unbranched chain of 6 amino acids releases how many water molecules?

a) 5
b) 4
c) 6
d) 1