proteins Flashcards
(26 cards)
What does the primary structure of a protein refer to?
The amino acid sequence that comprises a polypeptide chain.
What determines the properties of a protein’s primary structure?
The properties of the amino acids.
What type of bonds link amino acids in the primary structure?
Peptide bonds.
What does the secondary structure of proteins refer to?
Localized folding of protein chains due to hydrogen bonding.
What are the two main types of secondary structures in proteins?
- Alpha helix
- Beta sheets
Describe an α-helix.
A right-handed coil stabilized by hydrogen bonds between amino groups and carbonyl groups.
What characterizes a β-pleated sheet?
Hydrogen bonds between adjacent amino acids resulting in extended polypeptide chains.
What does the tertiary structure of a protein describe?
The three-dimensional structure of the protein.
What are the two forms of tertiary structure?
- Fibrous (long parallel coils)
- Globular (compact and almost spherical)
Provide an example of a fibrous protein.
Collagen.
Provide an example of a globular protein.
Myoglobin.
What does the quaternary structure of a protein describe?
How proteins come together to form large aggregates.
What is the structure of hemoglobin?
Consists of two alpha and two beta chains.
What is one function of proteins in organisms?
Transporting different molecules.
What role do enzymes play in biological processes?
They act as biological catalysts to speed up reactions.
What is an example of a structural protein?
Keratin.
What are antibodies?
Proteins produced by the immune system for defense against pathogens.
Which proteins are involved in muscle contraction?
- Actin
- Myosin
What are amino acids?
Building blocks of proteins containing an amino group and a carboxylic group.
How many amino acids are commonly found in proteins?
20.
What differentiates amino acids from each other?
Their different R groups or side chains.
What is a zwitterion?
A dipolar ion form of an amino acid at physiological pH.
What is the bond called that links amino acids together?
Peptide bond.
What is the difference between polypeptides and proteins?
Polypeptides are formed from many amino acids, while proteins consist of one or more polypeptide chains.
