NDFS 1020 Chapter 7: Protein

High-quality (complete) protein

Protein that contains all essential amino acids in amounts that support the deposition of protein in tissues and the growth of a young person; Meat, fish, poultry, eggs, milk

Chymotrypsin

Protein-splitting enzyme secreted from the pancreas

Trypsin

Protein-splitting enzyme secreted from the pancreas

Polypeptides

Proteins comprised of 50 or more amino acids

Amino Acid Composition Score

Measure of the amount of each essential amino acid in a gram of the food protein divided by the "ideal" amount of each essential amino acid in a reference protein (usually egg white protein)

How is PDCAAS calculated?

Multiply the amino acid composition score of the protein by the protein's digestibility score

Most plant foods are sources of high-quality protein. (TRUE/FALSE)

False; Most plant foods are NOT sources of high-quality protein; EXCEPT Quinoa and soy protein

Amino Acids

Nitrogen-containing chemical units that comprise proteins

Amino Acid Derivatives

Nitrogen-containing compounds that are not proteins but have important physiological roles

What can result from diets that do not supply adequate amounts of essential amino acids leading to inadequate protein synthesis?

Poor growth, slowed recovery from illness, death

What Amino Acid Composition Score would a protein lacking one of the essential amino acids have?

0

What are the 3 ways to measure protein quality?

1) Biological Value (BV) 2) Protein digestibility corrected amino acid score (PDCAAS) 3) Protein Efficiency Ratio (PER)

What are the 9 major functions/uses of Proteins in the body?

1) Build new cells/components of cells 2) Make up hardened structures (hair and nails) 3) Enzymes 4) Lubricants to ease movement 5) Blood-clotting component 6) Build antibodies 7) Help maintain fluid and pH balance (Albumin) 8) Transporters/ hormones 9) Energy source (minor function)

What is the Acceptable Macronutrient Distribution Range (AMDR) for protein?

10 to 35% (energy from protein)

Which Amino Acids are Nonessential? (11)

Alanine Aspartic acid Asparagine Glutamic acid Serine Arginine Cysteine Glutamine Glycine Proline Tyrosine

Conditionally Essential Amino Acids

Amino acids that become essential under certain conditions

Essential Amino Acids

Amino acids the body cannot make or cannot make enough of to meet its needs; 9; "Non-dispensable"

What determines if a protein has high or low BV?

Amount of limiting amino acids

Do plant or animal protein sources have higher BV?

Animal

Protein Turnover

Cellular process of breaking down proteins and recycling their amino acids

What is formed when 2 amino acids bond? What is released in the process?

Dipeptide; Water

Limiting Amino Acid

Essential amino acid found in the lowest concentration in a protein source

What accounts for most of the body's nitrogen loss?

Excretion of urea and creatinine in urine

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

Non-essential Amino Acids

Group of amino acids that the body can make; 11; "Dispensable"

The typical Western diet (high animal proteins and saturated fat) increases the risk of what illnesses?

Heart disease, colorectal cancer, prostate cancer

What is an example of a protein that has a Quaternary structure?

Hemoglobin

Reference Protein

High-quality protein against which quality of other proteins is measured (usually egg white protein)

Undernutrition

Lack of food

Proteins

Large, complex organic molecules made up of amino acids; Contain Nitrogen, Carbon, Hydrogen, Oxygen

The be labeled as "Gluten-free" by the FDA how much gluten can be contained in a food?

Less than 6mg/serving

Where does the synthesis of amino acids primarily occur?

Liver

Acid-Base Balance

Maintaining the proper pH of body fluids

Urine Urea Nitrogen (UUN)

Measure of the concentration of urea in urine

How can Celiac Disease be diagnosed?

Microscopic examination of the condition of villi; Damaged villi help confirm Celiac disease

Complementary Combinations

Mixing certain plant foods to provide all essential amino acids without adding animal protein

Creatinine

Nitrogen-containing waste produced by muscles

What is the cure for Celiac Disease?

No cure; Can maintain good health with gluten-free diet

Protein-Energy Malnutrition (PEM)

Occurs when the diet lacks sufficient protein and energy; Marasmus, kwashiorkor, and marasmic kwashiorkor forms

Genes

Portion of DNA

What is the most commonly used tool to measure protein quality?

Protein digestibility corrected amino acid score (PDCAAS)

Albumin

Protein in the blood that maintains the proper distribution of fluids in blood and body tissues

Low-quality (incomplete) protein

Protein that lacks or has inadequate amounts of one or more of the essential amino acids

tRNA (Transfer RNA)

RNA molecule that conveys a particular amino acid the the ribosome

Primary Structure (Protein)

Refers to the basic structure of protein; a linear chain of amino acids linked by peptide bonds

Secondary Structure (Protein)

Refers to the coiling of a polypeptide chain

Quaternary Structure (Protein)

Refers to the structure of protein that is comprised of two or more polypeptide chains arranged together in a unique manner; Example: Hemoglobin

Carbon Skeleton

Remains of an amino acid following deamination and removal of the nitrogen-containing component of the amino acid

Deamination

Removal of the nitrogen-containing group from an amino acid

Positive Nitrogen Balance

State in which the body retains more nitrogen than it loses as proteins are being added to tissues

Tuna fish, apples, eggs, and milk are all examples of complete protein sources. (TRUE/FALSE)

True

What transfers the information about the amino acid sequence from the cell nucleus to the ribosomes for protein synthesis (translation)?

mRNA

What 5 parts to all Amino Acids contain?

1)Central Carbon 2) Hydrogen 3) Amino group (N) 4) R group (side chain) 5) Carboxylic Acid group

A healthy human body can make ___ of the 20 amino acids.

11 (Nonessential AA)

If someone consumes excess energy (kcals) from protein, the extra protein is ultimately converted to muscle. (TRUE/FALSE)

False; Converted to fat

DNA (deoxyribonucleic acid)

Hereditary material that provides instructions for making proteins

Casein

High-quality protein found in milk

Which Amino Acids are Essential? (9)

Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine

What are the treatments for kwashiorkor, marasmic kwashiorkor, and marasmus?

Hospitalization, controlled refeedings, frequent health assessments to recover from PEM

Sickle Cell Anemia

Inherited form of anemia caused by genetic defect

When do normal protein needs exceed the RDA?

Pregnancy, breastfeeding, periods of rapid growth, recovery from serious illnesses, blood losses, burns

Transamination

Transfer of the nitrogen-containing group from an unneeded amino acid to a carbon skeleton to form an amino acid

A food that is gluten-free is not necessarily nutrient dense and a healthy addition to the diet. (TRUE/FALSE)

True

Although nearly all foods contain protein, no naturally occurring food is 100% protein. (TRUE/FALSE)

True

High-protein diets may lead to higher-than-normal urinary losses of calcium. (TRUE/FALSE)

True

Plants, animals, bacteria, and even viruses contain proteins. (TRUE/FALSE)

True

Ribosomes are organelles that reside in the cytoplasm of living cells. Their role during protein synthesis is to "translate" or decode the mRNA strand. (TRUE/FALSE)

True

Gluten Sensitivity

Uncomfortable symptoms develop following consumption of gluten, but the individual does not have damage to the small intestine

Every organism synthesizes proteins that are ______ to that specific organism.

Unique

In general, most plant foods provide less than ___g of protein per ounce.

3g

What is a healthy adult's RDA for protein?

0.8 g/kg of body weight; Multiply his or her weight in kilograms by 0.8 g

What are the 2 key factors to determining the quality of a protein?

1) Digestibility 2) Amino Acid Composition

What are the 3 forms of PEM (Protein-Energy Malnutrition)?

1) Marasmus 2) Kwashiorkor 3) Marasmic kwashiorkor

What are the 3 priorities for protein in the body?

1) Provide amino acids to make new body proteins (Protein Turnover) 2) Provide energy 3) Be stored as fat as a long-term energy source

What are some signs and symptoms of Celiac Disease?

Abdominal bloating, chronic diarrhea, weight loss; Anemia, osteoporosis, liver disease, intestinal cancer (if untreated)

Edema

Accumulation of fluid in tissues; "swelling"

What can excess amino acid or protein intake lead to? Why?

Dehydration; kidneys need more water to dilute and eliminate the toxic waste products of amino acid metabolism in urine

Protein digestibility corrected amino acid score (PDCAAS)

Measure of protein quality based on amino acid composition score and digestibility of a protein food; Most animal proteins and soy protein have a PDCAAS of 1.0

Biological Value (BV)

Measure of protein quality based on how well and quickly the body converts food protein into body tissue protein

Protein Efficiency Ratio (PER)

Measure of protein quality based on the ability of a protein to support weight gain in a laboratory animal; Milk protein is usually reference protein

Blood Urea Nitrogen (BUN)

Measure of the concentration of urea in blood; Used to measure kidney function

Peptides

Small chains of amino acids (2 or more)

Starvation

State in which the body lacks food energy and/or protein

Negative Nitrogen Balance

State in which the body loses more nitrogen than it retains; Occurs during starvation, serious illnesses, severe injuries

Where does protein digestion begin?

Stomach

Buffer

Substance that can protect the pH of a solution

What pH does blood and tissue need to be in the body to function properly?

pH 7.35 to 7.45 (slightly basic)

How many different Amino Acids make up the proteins found in the body?

20

Denaturation

Altering a protein's natural shape and function by exposing it to conditions such as heat, acids, and physical agitation

Nitrogen balance (equilibrium)

Balancing nitrogen intake with nitrogen losses

What happens to extra amino acids consumed?

Body does not store; Deamination results in some excess NH2 being transported to the liver which forms ammonia (NH3). Liver uses NH3 to make urea that is released into the blood and filtered by the kidneys to be eliminated in urine

Carboxylic acid group

Carboxylic acid portion of a compound (amino acid)

Peptide Bond

Chemical attraction that connects two amino acids together; Between Amine and Acid groups

What are 2 examples of structural protein? Where are they found?

Collagen: Cartilage, ligament, bone tissues Keratin: Hair, nails, skin

Tripeptides

Compounds that consist of three amino acids

Dipeptides

Compounds that consist of two amino acids

Amines

Compounds that include amino groups in their chemical structure

______ proteins in muscles allow movement.

Contractile

How do you calculate BV (Biological Value)?

Divide grams of nitrogen absorbed by grams of nitrogen retained

What are some results of PEM in children?

Do not grow, weak, irritable, vulnerable to dehydration and infections (measles), stunted growth, lower intelligence

What food source has the highest BV?

Egg white protein

Celiac Disease

Inherited condition in which the protein gluten cannot be absorbed; results in damage to the small intestine and poor absorption of nutrients

All cells in the body contain ______.

Protein

All amino acids have the same basic structure except for what group, which is different in each one?

R group

Tertiary Structure (Protein)

Refers to the three-dimensional, twisted structure of a polypeptide chain that includes interactions between various amino acid groups on the chain

What will eating foods from soybeans possible reduce?

Risk of osteoporosis, cardiovascular disease, and certain cancers

The ______ of a protein is important because it influences the compound's function in the body.

Shape

When the shape of a protein changes, it's called denaturation. When the nitrogen group is removed from a protein (so it can be used as energy), it's called deamination. (TRUE/FALSE)

True

What are some Limiting Amino Acids in foods?

Tryptophan, threonine, lysine, methionine, cysteine

Gluten

Type of protein found in many grains; provides texture and shape to baked products

To determine an individual's RDA for protein, you multiply their weight (in pounds) by 0.8. (TRUE/FALSE)

False; Multiply weight in kg

Denaturation "kills" a protein. (TRUE/FALSE)

False; Proteins are not living, but does permanently alter shape and function

Kwashiorkor

Form of undernutrition (PEM) that results from consuming adequate energy and insufficient high-quality protein; Stunted growth, unnaturally blond, sparse, brittle hair, discolored skin patches, misleading appearance

Marasmus

Form of undernutrition (PEM) that results from starvation; Diet lacks energy and nutrients; Signs: Weakness/wasting

The consumption of red meats and processed meats, such as ham and sausage, is associated with the increased risk of what cancers?

Pancreatic, stomach, esophageal, breast cancers

R group (side chain)

Part of an amino acid that determines the molecule's physical and chemical properties

Who are at risk of Protein Deficiency?

People suffering from alcoholism, anorexia nervosa, certain intestinal tract disorders, individuals with low incomes, elderly

Legumes

Plants that produce pods with a single row of seeds; Peas, peanuts, lentils, beans

Amino (nitrogen-containing) group

Portion of an amino acid that contains nitrogen