PROTEIN SECTION LECTURE #2 (Part 2) Flashcards
What is transamination in the context of amino acids?
Transamination is the process by which a nonessential amino acid is synthesized in the body by transferring the amino group from one amino acid to an intermediate that has a carboxylic acid group, forming another non-essential amino acid.
Where does transamination typically occur?
Transamination generally occurs in the liver.
Can transamination occur for essential amino acids?
No, transamination typically involves the synthesis of nonessential amino acids, as essential amino acids must be obtained from the diet.
What is deamination in the context of amino acids?
Deamination is the process of removing an amino group from an amino acid to make other substances.
Where does deamination typically take place?
Deamination takes place in the liver.
What happens to the rest of the amino acid after deamination?
The rest of the amino acid, which is made mostly of carbon and hydrogen, is recycled into something else or oxidized for energy.
What is the fate of the ammonia produced during deamination?
The ammonia produced during deamination turns into toxic ammonia, which is quickly converted to urea and then excreted in urine.
What is a condensation reaction in protein synthesis?
A condensation reaction in protein synthesis is a chemical process that takes an OH group from the carboxyl-end of one amino acid and an H atom from the amino end of another amino acid, joining them to form a water molecule and creating a peptide bond between the two amino acids.
What is formed as a byproduct of a condensation reaction between two amino acids?
A water molecule is formed as a byproduct of a condensation reaction between two amino acids.
What type of bond is created between two amino acids during a condensation reaction?
A peptide bond is created between two amino acids during a condensation reaction.
What is a hydrolysis reaction in the context of proteins?
A hydrolysis reaction is the process that breaks a dipeptide bond between two amino acids, using water to split the bond.
Peptide bonds:
link amino acids together through condensation reactions
Dipeptides:
two amino acids; joined by their backbone, not side chain usually
Oligopeptide:
less than 10 AA
Polypeptide:
many amino acids (10 or more)
Protein:
one or more polypeptide chains folded into a 3D shape
Primary structure:
initial sequence of amino acids by peptide bonds
Secondary structure:
alpha-helix, beta-pleated (H-bonding)
Tertiary structure:
formation of 3D structure of 1 polypeptide chain through hydrophobic/philic interactions and disulfide bridges
Quaternary Structure:
3D structure of the interaction of 2 or more polypeptide chains
Both _____________ and________________ are polypeptide proteins that have quaternary structures
Hemoglobin
Insulin
What does protein denaturation involve?
Protein denaturation involves a change to the 3D structure of a protein, affecting its function by altering its shape rather than its primary structure or amino acid sequence.
What are some factors that can cause protein denaturation?
Heat, pH changes, UV radiation, x-rays, and agitation can all cause protein denaturation.
Is protein denaturation usually reversible or irreversible?
Protein denaturation is usually a permanent change that renders the protein nonfunctional.
Can you give an example of protein denaturation that is commonly observed in cooking?
An example of protein denaturation is the change observed in egg whites when they are cooked or beaten; the clear egg whites become opaque and solid.
How can a fever or a change in pH affect proteins in the body?
If you have a fever or if your pH changes, it can have a great effect on the protein functions in the body, potentially leading to denaturation and loss of protein function.
Why is it important for proteins to function at an optimal temperature and pH?
Proteins function optimally at a certain temperature and pH because their structure is adapted to these conditions. Deviations can lead to denaturation and loss of function, which can affect the metabolism and overall functioning of the body.
How is a mutation different from denaturation?
A mutation is a change in the base sequence of genes, which alters the primary structure of the polypeptide and subsequently affects the secondary, tertiary, and quaternary structures, changing their function.
Denaturation, on the other hand, refers to the alteration of the protein’s structure without changing the primary sequence of amino acids.
What causes a mutation?
A mutation occurs when there is an alteration in the base sequence of genes. This genetic change can affect the protein’s primary structure, leading to functional changes
Can you describe the process that leads from DNA to a functional protein?
The process from DNA to a functional protein involves transcription, where DNA is transcribed into RNA, followed by translation, where RNA and ribosomes synthesize the protein.
DNA → RNA + ribosomes = protein
What is an example of a condition caused by a mutation affecting the shape of a protein?
Sickle cell anemia is a condition caused by a mutation that alters the primary structure of the polypeptide in red blood cells (RBCs), affecting their shape and reducing their oxygen-carrying capacity.
