protein Flashcards
What elements are proteins made of?
carbon, hydrogen, oxygen, and nitrogen atoms.
Some also contain sulfur atoms.
How are proteins arranged?
amino acids linked in a chain.
What are the two main groups in an amino acid?
basic (amino) group (-NH₂)
acidic (carboxyl) group (-COOH).
What is the distinguishing feature of amino acids?
amine group, which is the body’s source of nitrogen.
What are the building units that make up proteins?
Amino acids
How many amino acids are used to make up the chemical structure of proteins?
20
How many amino acids are typically linked together in a protein?
100
What is a peptide bond?
bond that connects the acid end of one amino acid with the amino group of another, forming a link in a protein chain.
What is the amino acid sequence for hemoglobin?
V-H-L-T-P-G-G.
What is the amino acid sequence for sickle-cell hemoglobin?
V-H-L-T-P-V-G.
What causes the difference between hemoglobin and sickle-cell hemoglobin?
The difference is caused by a single amino acid substitution: glycine (G) is replaced by valine (V).
What does “indispensable amino acid” mean?
required in the diet because the body cannot synthesize them.
How many indispensable amino acids are there?
9:
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
What are dispensable amino acids?
they are essential for the body, can be made from essential amino acids, so not required in the diet
How many dispensable amino acids are there? AAAGS
5:
Alanine
Aspartic Acid
Asparagine
Glutamic Acid
Serine
What are conditionally indispensable amino acids?
normally dispensable but become indispensable in certain nutritional, disease stages, or developmental conditions.
What is an example of a conditionally indispensable amino acid?
In phenylketonuria (PKU), phenylalanine cannot be converted to tyrosine, making tyrosine conditionally indispensable.
What defines a high-quality protein?
provides all 9 indispensable amino acids in amounts adequate to maintain nitrogen balance and support growth.
What defines a low-quality protein?
lacks sufficient quantities of one or more indispensable amino acids for optimal protein synthesis.
Can low-quality proteins support life and growth?
can support life but not normal growth. Other proteins are needed to support normal growth.
What are some plant sources of low-quality protein?
Legumes
Peas
Beans
Grains
Nuts
What are some animal sources of high-quality protein?
Chicken
Pork
Beef
Eggs
Lamb/veal
Turkey/Duck/Wild Game
All seafood
How can a complete protein be made from low-quality protein foods?
combining two low-quality protein foods in the same meal.
Give an example of a combination that creates a complete protein.
Rice and beans, or macaroni and cheese