18.2.1 Amino Acids

• Amino acids are organic compounds that contain both an amino group (-NH2) and a carboxyl group (-COOH) attached to a central carbon atom
• Match the key feature of amino acids with its description:

  Structure ↔️ Contain -NH2 and -COOH groups

  Role ↔️ Building blocks of proteins

  Number ↔️ Over 20 different types

  Diversity ↔️ Variations in the R-group
• The R-group determines the chemical properties of an amino acid.


  True
• Essential amino acids cannot be synthesized by the human body and must be obtained from the diet
• Essential amino acids are synthesized by the human body.

  False
• Essential amino acids cannot be synthesized by the human body and must be obtained from the diet
• Essential amino acids are synthesized by the human body.

  False
• In aqueous solutions, amino acids exist in a zwitterionic form, which has a net zero
• Order the forms of amino acids in different pH environments based on their net charge:

  1️⃣ Acidic (pH < pI): Positive (+) charge

  2️⃣ Neutral (pH = pI): Zero (0) charge

  3️⃣ Basic (pH > pI): Negative (-) charge
• What are the fundamental units that make up proteins?

  Amino acids
• The general structure of an amino acid consists of a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a side
• The variability in R-groups allows for the diverse properties and functions of amino acids, making them essential for protein structure and function
• Essential amino acids can be synthesized by the human body.

  False
• Essential amino acids are crucial for growth and repair because the body cannot synthesize
• Amino acids can act as both acids and bases due to their amphoteric nature.

  True
• Amino acids are the fundamental units that make up proteins.

  True
• The general structure of an amino acid includes a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a side chain called the R-group
• Arrange the components of a general amino acid structure in order of their chemical properties (basic to acidic):

  1️⃣ Amino Group (-NH2)

  2️⃣ Central Carbon

  3️⃣ R-Group

  4️⃣ Carboxyl Group (-COOH)
• Non-essential amino acids can be synthesized by the body.


  True
• Essential amino acids are crucial for growth and repair
• Why are essential amino acids crucial for growth and repair?

  The body cannot synthesize them
• Match the type of amino acid with examples:

  Essential Amino Acids ↔️ Histidine, Lysine, Valine

  Non-Essential Amino Acids ↔️ Alanine, Asparagine, Tyrosine
• What is meant by the amphoteric nature of amino acids?

  Act as both acids and bases
• What is the isoelectric point (pI) of an amino acid?

  No net charge
• Understanding the properties of amino acids is crucial for understanding protein structure and function.


  True
• Match the function of proteins with examples:

  Structural ↔️ Collagen, Keratin

  Enzymatic ↔️ Biological catalysts

  Transport ↔️ Hemoglobin
• The general structure of an amino acid includes a central carbon bonded to an amino group, a carboxyl group, a hydrogen atom, and a side
• The amino group of an amino acid is acidic and can donate a proton.

  False
• Steps to form a zwitterionic structure in an amino acid:

  1️⃣ Amino group accepts a proton

  2️⃣ Carboxyl group donates a proton

  3️⃣ Net charge becomes zero
• The isoelectric point (pI) is the pH at which the amino acid has no net charge
• In a basic pH environment, the net charge of an amino acid is negative.


  True
• Amino acids are the fundamental units that make up proteins
• Structural proteins provide support to cells and tissues.


  True
• Match the protein function with an example:

  Enzymatic ↔️ Biological catalysts

  Transport ↔️ Hemoglobin

  Defensive ↔️ Antibodies
• The diversity of amino acids allows proteins to adopt complex structures and perform their vital functions