Amino Acids, Proteins, and Enzymes Flashcards
What are proteins primarily responsible for in cells?
Performing most of the work in cells
How many different proteins are found in humans?
At least 20,000
What is one function of hemoglobin?
Carries oxygen from the lungs to tissue
What role do hormones play in the body?
Communicate messages between cells
What is the function of protease?
Breaks down proteins in cells
What is collagen?
A structural protein found in cartilage, skin, and tendons
What do antibodies do?
Fight foreign invaders in the body
What are the building blocks of proteins?
Amino acids
What two functional groups do amino acids contain?
Amine functional group and carboxylic acid functional group
What is the unique part of each amino acid called?
Side chain (R)
At physiological pH (7.4), how do carboxylic acid groups appear?
They lose the -COOH hydrogen group
What characterizes non-polar aliphatic amino acids?
They are straight chain amino acids
What is a unique feature of proline?
Its side chain bonds to the backbone nitrogen
What distinguishes non-polar aromatic amino acids from aliphatic ones?
They contain a ring of carbons as an aromatic functional group
Where are polar, neutral amino acids typically found in proteins?
On the outside of the protein and in contact with water
What defines acidic amino acids?
They have side chains with pKa values smaller than 7
What is the typical charge of basic amino acids at physiological pH?
Positively charged
What is unique about histidine’s side chain at pH 7.4?
It does not have a charged group
What can two cysteine amino acids form?
A disulfide bond
What is the role of disulfide bonds in proteins?
Stabilize protein structure
What protein component holds the shape of hair?
Keratin
Fill in the blank: All proteins are constructed from the same _______ standard amino acids.
20
True or False: All amino acids have the same structure.
True
What type of interactions do aliphatic amino acids typically engage in?
They interact with other groups in the protein’s interior
