Protein Note Flashcards
What do proteins do in cells?
Do most of the work in cells
Proteins serve various functions including structural support, enzymatic activity, and transport.
How are proteins classified?
By function (ex: structure, enzyme, carrier)
Proteins can be classified based on their roles in biological processes.
What is the role of proteins as fuel?
Used as a fuel - excess may be burned as a last resort in crisis
What are proteins made of?
Chains of amino acids folded into specific 3D shapes
What determines a protein’s function?
A protein’s structural characteristics
How many different R groups are commonly found in living organisms?
20 different R groups
What term describes amino acids having both acidic and basic functional groups?
Amphiprotic
List the essential amino acids.
- Histidine
- Isoleucine
- Leucine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Valine
What are essential amino acids?
Amino acids that cannot be synthesized by humans and must be consumed
What is a key deficiency in some plant proteins?
Some are lacking some amino acids in proper amounts for humans
What is a polypeptide?
A chain of amino acids (>10 aa)
What type of reaction connects amino acids?
Condensation reaction
Which end of the growing polypeptide chain do amino acids get added to?
Carboxyl end (C-terminus)
How are polypeptides broken down?
In a hydrolysis reaction
What is the primary structure of a protein?
Unique sequence of amino acids in a polypeptide chain
What determines the amino acid sequence?
DNA (the nucleotide sequence of a gene)
What condition can result from changing one amino acid in a sequence?
Loss of function
What is an example of a disease related to amino acid substitution?
Sickle Cell Anemia
What characterizes secondary structure in proteins?
Immediate folding and formation of hydrogen bonds
What are two types of secondary structures?
- α-helix
- β-pleated sheet
What causes tertiary structure in proteins?
Forces of attraction and repulsion between the polypeptide and its environment
What types of interactions contribute to tertiary structure?
- Hydrogen bonds
- Ionic bonds
- Van der Waals forces
What is the quaternary structure of a protein?
Two or more polypeptide chains come together to form a functional protein
What is an example of a protein with quaternary structure?
Hemoglobin
