Peptides and proteins are fundamental biological macromolecules composed of amino acids linked together by peptide bonds. A peptide is a short chain of amino acids, typically consisting of fewer than 50 amino acids, while proteins are longer chains that can contain hundreds or thousands of amino acids, forming complex three-dimensional structures essential for various biological functions. Peptides can act as signaling molecules, hormones, or neurotransmitters, whereas proteins play critical roles in catalyzing biochemical reactions (as enzymes), providing structural support, facilitating transport, and regulating cellular processes. The sequence and arrangement of amino acids in peptides and proteins determine their specific functions and properties, making them vital for life.
What is a peptide?
A peptide is a short chain of amino acids linked together by peptide bonds, typically consisting of fewer than 50 amino acids.
How are proteins different from peptides?
Proteins are longer chains of amino acids, usually containing 50 or more amino acids, and they often have complex three-dimensional structures that are essential for their biological functions.
What is a peptide bond?
A peptide bond is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another, resulting in the release of a water molecule during the condensation reaction.
What roles do proteins play in biological systems?
Proteins serve various functions, including acting as enzymes to catalyze biochemical reactions, providing structural support, facilitating transport of molecules, regulating cellular processes, and serving as antibodies in the immune response.
What determines the specific function of a protein?
The specific function of a protein is determined by its amino acid sequence and the resulting three-dimensional structure, which influences how it interacts with other molecules.
What is the primary structure of a protein?
a) The overall three-dimensional shape
b) The sequence of amino acids
c) The arrangement of alpha helices and beta sheets
d) The interaction between multiple polypeptide chains
Answer: b) The sequence of amino acids
Which type of bond links amino acids together in a peptide?
a) Ionic bond
b) Hydrogen bond
c) Peptide bond
d) Disulfide bond
Answer: c) Peptide bond
What is the function of enzymes?
a) To provide structural support
b) To catalyze biochemical reactions
c) To transport molecules
d) To store genetic information
Answer: b) To catalyze biochemical reactions
Which of the following is NOT a function of proteins?
a) Energy storage
b) Catalyzing reactions
c) Providing structural support
d) Transporting oxygen
Answer: a) Energy storage
What is a polypeptide?
a) A single amino acid
b) A type of nucleic acid
c) A protein with a molecular mass over 10,000
d) A chain of two or more amino acids
Answer: d) A chain of two or more amino acids