Fundamentals of Nutrition Ch.6 Proteins and Amino Acids

What element is in the Amine group?

Nitrogen

What is the only macronutrient that supplies the body with nitrogen?

proteins

In amino acids, what is the side chain?

unique and creates differences in size, shape, and electrical charge

what are essential amino acids?

AA that the body cannot make at all or in significant quantities to meet needs; must be obtained in diet

what are nonessential amino acids?

AA that are made in the body

what are conditional essential amino acids?

AA that are usually nonessential but, under certain conditions, must be supplied by diet. Often due to a medical condition.

How many amino acids are considered proteinogenic, or necessary for the synthesis of body proteins?

20

How many are essential amino acids

9

how many are non essential amino acids?

11

AA are linked together to form _______

proteins

What kind of chemical bonds are formed between amine group end of one AA and the acid group end of the next?

peptide bond

A string of how many amino acids is known as polypeptide

10-50 AA

Most body proteins contain how many AA

several hundred to several thousand

the human genome codes has _______ unique proteins

20,000

for each protein, there exists a standard ______ ________ sequence, and that sequence is specified by our ______.

amino acid; genes

If a wrong AA is inserted, the result can be….

disastrous to health

What is sickle cell anemia?

a genetic mutation in the AA sequence that forms hemoglobin, resulting in abnormally shaped RBC

When a cell builds a protein, we often say that the gene for that protein has been ______.

“expressed”

Every cell ______ contains the DNA for making every human ______, but no one cell builds them all

nucleus; protein

What protein do cells in the pancreas make?

peptide hormone insulin

what proteins do skeletal muscle cells make?

the contractile proteins actin and myosin

What is acid-base balance in proteins?

proteins form the immune system molecules that fight diseases

How does protein affect blood clotting?

proteins provide the netting on which blood clots are built

How does protein affect energy and glucose?

proteins provide some fuel for the body’s energy needs

how do proteins affect enzymes?

proteins facilitate needed chemical reaction

How do proteins affect fluid and electrolyte balance?

proteins help to maintain the water and mineral composition of the various body fluids

how do proteins affect gene expression?

proteins associate and interact with DNA, regulating gene expression

how do proteins affect hormones?

some hormones are proteins or are made from amino acids

how to proteins affect transports in the body?

proteins help transport needed substances, such as lipids, minerals, and oxygen, around the body

how do proteins affect structure and movement in the body?

proteins form integral parts of the most body tissues and confer shape and strength on bones, skin, tendons, and other tissues

structural proteins of muscles execute body movement

What is the DRI value for protein intake designed for?

to cover to replace protein-containing tissue that healthy adults break down daily

What is the RDA intake for proteins?

8g/kg, 19 years and older

What is the AMDR for protein intake?

10-35% of calorie from protein

True or False: a healthy dietary pattern includes little variety of protein foods.

false: a large variety

True or false: The DRI for protein assumes a normal mixed diet-that is, a dietary pattern that provides sufficient nutrients and protein from a combination of animal and plant sources.

true

what are high-qualities proteins?

dietary proteins containing all the EAA in relatively the same amounts that human beings require.

True or false: high quality proteins never contain NEAA

false, some do

true or false: meat, fish poultry, cheese, eggs, milk, and most soybean products are all low quality proteins.

false, they are all high quality proteins

What are the 2 primary factors determining protein quality?

AA compassion

digestibility

What are complementary proteins?

2 or more proteins whose AA assortments complement each other in such a way that the EAA missing from one are supplied by the other

true or false: in general, proteins from animals sources, such as chicken, beef, and pork, are most difficultly digested and absorbed.

false, they are the most easily digested and absorbed

How much protein do people need? What is it determined by?

determined by nitrogen balance studies

What is nitrogen balance?

the amount of nitrogen consumed with the amount excreted over time

What is a positive nitrogen balance?

when nitrogen intake exceeds nitrogen excretion

What is negative nitrogen balance?

when nitrogen excretion exceeds nitrogen intake

under normal circumstances, healthy adults are in nitrogen _________.

equilibrium

When does positive nitrogen balance occur?

during periods of growth. Childhood, pregnancy, athlete putting on muscle

when does negative nitrogen balance occur?

when muscle or other protein tissue is broken down and lost. Starvation, illness, injury, immobiizatiom

Protein digestion begins in the ________ via _________ acid and the digestive enzyme _______.

stomach, hydrochloric, pepsin

TRUE OR FALSE: HCl denatures proteins.

true

what does denaturing of proteins by HCl do?

uncoils the proteins tangled strands so that molecules of the stomach’s protein-digest enzyme, pepsin, can attack the pepside

what does pepsin break down proteins into?

into small polypeptides

Protein-digesting enzymes from the pancreas and small intestine continue to do what?

breaking down the polypeptides into single amino acids or into strands of 2 or 3 amino, called dipeptides, and tripeptides

What happens to amino acids after protein is digested?

the cells of the SI, enterocytes, absorb AA through transport proteins similar to uptake of the monosaccharides

Where do individual AA, dipeptides, and tripeptides be absorbe?

into the enterocytes

What happens after the dipeptides and tripeptides are absorbed into the enterocytes

most of the dipeptides and tripeptides are further digested into AA, which enter the bloodstream

What do tissues (liver, muscles, kidney) do with AA?

synthesis of protein

synthesis of other compounds

synthesis of NEAA

the AA can be used for energy

Convert AA to glucose or lipid

How do the tissues synthesize NEAA?

the cell can dismantle the AA to use its amine group to build a different AA

What is required for AA to be used for energy?

requires removal and excretion of the amino group

What is required for AA to be converted into glucose or lipids?

requires removal and excretion of the amino group

What are some arguments against high protein diets?

kidney damage- from excretion of excess nitrogen

bone disease- because protein rich foods are acidic and “leach” calorie from Bones

What are the best sources of dietary protein?

meat, poultry, fish, legumes, eggs, nuts, and seeds

milk yogurt, and cheese

What is the most important stumulie for muscle maintenance/ growth?

exercise, however, nutrition, and more specifically, dietary protein intake, plays an important role too

dietary protein considerations to optimize muscle growth/maintenance include:

amount of protein

timing of protein

type of protein

24-hour total protein intake is by far the ______ important

most

One area that many individuals can improve on is……

their protein distribution between meals