Chapter 7: Proteins: Amino Acids
Negative nitrogen balance
state in which the body loses more nitrogen than it retains
Positive nitrogen balance
state in which the body retains more nitrogen than it loses
Nutrigenomics
study of how nutrients affect the expression of a person's genome
Nutritional genomics
study of nutrigenomics and nutrigenetics
Quaternary structure
the structure of protein that is comprised of two or more polypeptide chains arranged together in a complex matter
Tertiary structure
the three dimensional, twisted structure of a polypeptide chain that includes interactions between various amino acid groups on the chain
creatinine
Kidneys filter urea, ammonia, and
Vegan diet
diet based solely on plant foods, with complete elimination of animal foods and products
Personalized nutrition
dietary recommendations based on individual response to food and nutrients
Marasmus
form of undernutrition that results from starvation; diet lacks energy and nutrients
Nonessential amino acids
group of amino acids that the body can make
Vegetarian diet
plant-based eating pattern that may or may not include some animal foods
Legumes
plants that produce pods with a single row of seeds
Transamination
transfer of the nitrogen-containing group from an unneeded amino acid to a carbon skeleton to form an amino acid
nitrogen balance (equilibrium)
In a healthy adult, the body maintains its protein content by maintaining
urea
Liver converts NH3 to
Marasmus
Loss of subcutaneous fat and deeper fat stores
amino acid derivatives
Nitrogen-containing compounds that are not proteins but have important physiological roles
R group (side chain)
Part of an amino acid that determines its physical and chemical properties
Polypeptides
proteins comprised of 50 or more amino acids
high-protein diet
provides an amount of protein greater than the RDA, usually 20 to 35% of calories
Nutrigenetics
study of how inherited genetic variations influence the body's responses to specific nutrients and nutrient combinations
Kwashiorkor
- form of undernutrition that results from consuming adequate energy and insufficient high-quality protein
creatinine
a nitrogen- containing waste produced by muscles
Gene
a portion of DNA that codes for a protein
urea
a waste product of amino acid metabolism
Conditionally essential amino acid
amino acids that are normally nonessential but became essential under a certain condition
Essential amino acids
amino acids the body cannot make or cannot make enough of to meet its needs
Proteins
are large, complex organic molecules made up of amino acids
Protein turnover
cellular process of breaking down proteins and recycling their amino acids
Mutation
change in the normal DNA sequence of a gene
Complementary combinations
combining certain plant foods to provide all essential amino acids
High-quality proteins
complete proteins that are well-digested, absorbed, and used by the body
Amines
compounds that include amino groups in their chemical structure
Inborn errors of metabolism
conditions that occur when genes undergo mutations that disrupt metabolism of specific nutrients
Undernutrition
inadequate consumption of nutritious food
Low-quality proteins
incomplete and generally less digestible, making their amino acids less bioavailable than high-quality proteins
Protein-energy malnutrition (PEM)
malnutrition that occurs when the diet lacks sufficient protein and energy
Blood urea nitrogen (BUN)
measure of the concentration of urea in blood
Urine urea nitrogen (UUN)
measure of the concentration of urea in urine
Tripeptides
molecules that consist of three amino acids
Dipeptides
molecules that consist of two amino acids
Exogenous
outside the body (dietary or other external source)
Carbon skeleton
remains of an amino acid following deamination
Deamination
removal of the nitrogen-containing group from an amino acid
Primary structure
the basic structure of protein; a linear chain of amino acids linked by peptide bonds
Secondary structure
the coiling of a polypeptide chain
Limiting amino acid
the essential amino acid found in the lowest concentration in an incomplete protein
amino or nitrogen-containing group
the portion of an amino acid that contains nitrogen
Endogenous
within the body
Trypsin and chymotrypsin
After polypeptides enter the small intestine, the pancreas secretes protein-splitting enzymes:
denaturation
Altering a protein's natural shape and function by exposing it to conditions such as heat, acids, and physical agitation
peptide bond
Amino acids are chemically linked together via the acid group of one amino acid and the amino group of the next one, forming a
nitrogen balance (equilibrium)
Balancing nitrogen intake with nitrogen losses
Carboxylic acid group
Carboxylic acid portion of a compound
amino acid derivatives
The body uses amino acids as precursors to form
peptide bond
The chemical attraction that connects two amino acids together
DNA, or deoxyribonucleic acid
The hereditary material that provides instructions for making proteins
DNA, or deoxyribonucleic acid
The human body makes proteins by assembling the 20 amino acids in specific sequences according to the information coded in
20
There are _____ different amino acids found in the proteins of the human body
denaturation
When exposed to certain conditions, a protein undergoes unfolding in a process called
Amino acids
are nitrogen-containing chemical units that constitute proteins
Trypsin and chymotrypsin
break down polypeptides into shorter peptides and amino acids
Complete protein
food source of protein that contains an adequate proportion of each of the nine essential amino acids
Incomplete protein
food source of protein that contains inadequate amounts of one or more of the essential amino acids
Marasmic Kwashiorkor
form of undernutrition that results in a child with kwashiorkor who then starts to not consume enough energy; characterized by edema and wasting
Carbon skeleton
the remains of an amino acid following removal of the nitrogen-containing component (amino group) of the amino acid
