Protein

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