What is a protein?
Complex chain of molecules made of amino acids�contain C, H, N, O
What are the functions of protein?
Transport, structure, enzymes, hormones, antibodies, fluid balance, pH, channels and pumps
What is the chemical structure of an amino acid?
Carboxyl group, amino group, hydrogen and a side chain or R group
What is the RDA for protein for adults?
Be able to calculate .8grams per kilogram body weight
What are the elements in the chemical structure of amino acids?
C, H, N, O
Define indispensable amino acid (essential amino acids)
Must be consumed in the diet-body can not make
Define dispensable amino acid (nonessential amino acid
Can be made by the body
How many amino acids are there
20
How many essential amino acids are there?
9
Define conditional indispensable (essential) amino acids
...
What is a complete protein or high quality protein?
Give food examples.
Contains all of the essential AA
All animal proteins and soybeans
What is an incomplete protein or low quality protein?
And give food examples
Does not contain all of the essential AA
All plant based protein sources: legumes, grains, nuts/seeds and vegetables
What is a limiting amino acid?
The amino acid in an incomplete protein that is in inadequate amounts.
Legumes are limited in methionine an cysteine
Grains are limited in lysine
Vegetables are limited in lysine methionine and cysteine
What does it mean to complement proteins. Give some examples
�Combining two incomplete protein sources that provide the limiting amino acids in the other thereby making a complete protein.
� Grains, nuts and seeds are high in Methionine and cysteine so consuming one of these with legumes would complement the protei
What plant source is a complete protein?
...
What is a side group of an amino acid and its role in the type of amino acid?
R group, defines which AA it is
What is a peptide bond?
Bond between AA (between carboxyl and amino group)
Define dipeptide, tripeptide, and oligopeptide and polypeptide
2 AA jointed by peptide bond
3 AA
4+ AA
What is meant by the term "primary structure of an amino acid"?
Strands of aa-joined by peptide bond
What is meant by the term "secondary structure of an amino acid?
Chemical attractions between the side groups of AA-results in bending/folding of the strand
What is meant by the term "tertiary stru
What is meant by the term "quaternary structure of an amino acid"?
>1 AA strand interacting. Establishes chemical bond between 2 or more strands to form a larger protein
Define denature
Breaking the chemical attraction btwn strands and w/in the strand.
What happens to the protein when it is denatured?
Breaks the electrical charges the chains straighten out. Lose their 3D shape and interactions to other strands of A.
Give examples of substances/circumstances that will denature a protein
Heat, enzymes, acid and force (ie whipping)
Define collagen
Connective tissue made from protein
Define antibodies
Defensive proteins that the body manufactures to destroy foreign invaders. (viruses, bacteria, allergens)
Define intravascular
Inside of the blood vessels
Define extra vascular
Outside the blood vessels
Define acidosis
Low pH-excess H ions in the blood
Define alkalosis
High pH-too few H ions in the blood
What is a buffer?
Accepts or donates H ions maintaining pH in the blood
What is ammonia and what is its relationship to protein
N from amine group is converted to ammonia when an amino acid is broken down for energy. If ammonia levels get too high in the blood it becomes more acidic. The body eliminates excess ammonia via the urea in the urine.
What is Urea?
Ammonia is converted to urea�a by product of protein metabolism that can be excreted in the urine
Define nitrogen balance
Amt of N consumed compared to amount of N excreted in the form of urea. Used to help determine if protein needs are being met.
What i
What is positive nitrogen balance and give examples of when it occurs.
The individual consumes more nitrogen (protein) then is excreted. This means that the body is retaining or adding protein. This is seen during times of growth, pregnancy, recover from illness or in protein deficiency
What is negative nitrogen balance and give examples of when it occurs.
Excretes more nitrogen then is consumed. Indicates the body is losing protein. Infection, fever, injury, burns, starvation, significant blood loss
What is the RDA for protein for adults?
.8g/kg
What is the AMDR for protein?
10-35%
Where in the digestive tract does the chemical digestion of protein occur?
Start in stomach, most in s. intestine
What is HCL and how does it effect protein digestion?
Denatures the protein
What is pepsin?
Breaks down proteins into smaller peptide chains
Where is pepsin found?
Stomach
What is chymotrypsin and where is it manufactured and where does it digest protein?
Enzyme�breaks amino acid chains into smaller pepide chains of di and tripeptides and polypeptides-manufactured in the pancreas and secreted into the duodenum of the small intestine
What is peptidase and where is it manufactured and where does it digest protein?
Enzymes�manufactured in the intestinal wall in the brush border where they also break down the dipeptides, tripeptides and polypeptides into free amino acids for absorption. This is the last step of protein digestion
How are amino acids absorbed?
Active and facilitated diffusion
Where are amino acids absorbed?
In duodenum and jejunum via active and facilitate transport
Define transamination
The transfer of the amine group from one amino acid to a carbon skeleton to form a different amino acid
Define Deamination
Removal of the amino group. Occurs when amino acids are broken down for energy
What are the steps in protein synthesis
DNA is read by mRNA in the nucleus of the cell
mRNA takes code to the ribosome where tRna reads the code and "fetches" the correct amino acid from the amino acid pool.
The amino acid is bonded to adjacent amino acids to form a peptide bond.
Once all the a
What is the relationship between DNA/RNA and protein synthesis
DNA determines the type and placement of AA in the protein strand. The type of protein that is manufactured is determined by the genetic code of the DNA which tells RNA which AA to place where. If a particular AA can not be found then the protein cannot b
What happens if an amino acid is missing during protein synthesis
Protein synthesis stops
What is produced when amino acids are broken down for energy
The amino group is removed and the nitrogen is incorporated into urea which is then eliminated in the urine
What is the amino acid pool?
Free AA found in the general circulation, cells, tissues and liver--from breakdown of cells and protein consumption. Used to build proteins, make nonessential AA, and for energy.
Define protein turnover
Breaking down of protein containing compounds in the body to AA where the AA can be recycled into new proteins
What nutrients maybe deficient in a vegan diet?
B12, Vitamin D, Riboflavin, Iron, Calcium and zinc
What are the risks associated with too much protein
There is some research indicating that high intakes of protein increase may effect the following: Kidney function , increased calcium losses leading to osteoporosis, obesity, heart disease, cancer, gout
What is Kwashiorkor
A type of protein energy malnutrition characterized by significant protein inadequacy with moderate energy deficiency. Symptoms: edema, muscle wasting, increased infection
What is Marasmus
A Type of protein energy malnutrition characterized by severe inadequate intake of both calories and protein. Symptoms: NO edema, severe loss of muscle, fat and other body tissue