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________ is found in proteins but not in carbohydrates and fats.


What makes proteins unique in comparison to the composition of carbs and fats?


What is the primary factor that differentiates one amino acid from another?

the side group

______ is found in certain amino acids.


What are terms used to classify amino acids in the diet?

Essential, nonessential and conditionally essential

How many different kinds of amino acids make up proteins?


What are contained in an amino acid?

An acid group, an amino group and a central carbon atom

How many different amino acids are used in the synthesis of proteins?


What is the simplest amino acid?


Proline is not an ___________ in human nutrition.

essential amino acid

What can the body not use for the synthesis of a nonessential amino acid?

an essential mineral

What is classified as conditionally essential when dietary intake of phenylalanine is insufficient or the body cannot normally metabolize phenylalanine.


What type of amino acid has to be supplied by the diet?

Essential amino acid

What is required to bind two molecules of glycine together and to release a molecule of water?


What is the resulting structure when two amino acids ore bound together chemically?


what is the composition of a tripeptide?

three amino acids bound together.

What is the amino acid sequence of a protein referred to?

the order of amino acids in a peptide chain

what type of amino acid can be synthesized by the body?

dispensable amino acid

In comparison to the well-defined structure of starch, what is the most important factor that allows for the synthesis of thousands of different proteins?

the number of different amino acids

20 amino acids would be classified as what?

a polypeptide

what do you get when you bind glycine, lysine and valine?


what accounts for the secondary structures in proteins?

the weak electrical attractions

how many polypeptide chains is hemoglobin made up of?

4 polypeptide chains

what is an example of a protein with a quaternary polypeptide structure?


What is the process by which heat or acidity disrupts the normal shape of a protein chain?


The application of heat or acid to a protein that causes its shape to change is known as what?


what is the process that results in hardening of an egg when exposed to heat?


After a hamburger is eaten, in what organ is the hydrolysis of its proteins initiated?


In what organ is pepsin active?


What digestive enzyme would be most affected in people who are unable to produce hydrochloric acid?


Protein-hydrolyzing enzymes are commonly known as what?


what is the function of a protease?

hydrolyze proteins

What is the name of the inactive form of the protein-splitting enzyme in the stomach?


what is the chief function of pepsin?

cleaves proteins into smaller polypeptides

what percentage of dietary protein is hydrolyzed in the mouth?


what is pepsinogen also known as?


what products are absorbed into the circulation after digestion of proteins?

free amino acids, and a few dipeptides and tripeptides

what is the usual fate of orally ingested enzyme supplements?

Digested by gastrointestinal proteases

What is an oligopeptide?

A string of about 4-9 amino acids

what are some characteristics of enzymes?

they are all catalysts, they have a protein structure and they can be destroyed by heat.

the structure of pepsin is also the structure of what?


what are some of the fates of amino acids in the intestinal tract?

some may be used for energy by the intestinal cells, some may be used for synthesis of proteins by the intestinal cells, and they may be transported across the intestinal cell membrane to the capillaries.

what source of amino acids would be best absorbed in normal, healthy people?

whole proteins

Approximately how many different proteins are present in the human body?


The code to make a protein is carried by a strand of messenger RNA is a process of what?

protein synthesis

Messenger RNA is constructed from a DNA template to carry instructions is a characteristic of what?

protein synthesis

The process whereby messenger RNA is made from a DNA template is called what?


What is a ribosome?

A structure upon which proteins are assembled

what are some features of protein in nutrition?

the study of the body's proteins in known as proteomics, protein synthesis requires messenger RNA and transfer RNA, and the synthesis of a protein by following the genetic code is known as gene expression.

What type of anemia is from having abnormally-shaped hemoglobin.

sickle-cell anemia

A common genetic variation which causes a change in the amino acid sequence in the structure of hemoglobin leads to what disease?

sickle-cell anemia

what is a characteristic of sickle-cell anemia?

the abnormal structure of the hemoglobin alters the shape of the red blood cell.

What is the structure of an enzyme?


What protein is intimately involved in the formation of scar tissue in wound healing?


What type of protein would the body make in order to heal a wound?


Which of the following is a characteristic of hormones?

Act as messenger molecules

Collagen does not function as what type of protein?

transport protein

What is the relationship between body proteins and water?

Proteins attract water

what are some associations between protein nutrition and the body's water balance?

inadequate protein intake may lead to edema, insufficient protein synthesis by the liver may lead to edema, and excessive protein intake burdens the kidneys to excrete unused nitrogen.

what do the conditions known as acidosis and alkalosis refer to?

the disruption of the body's pH balance

Tissue swelling that results from water accumulating between cells is known as what?


Proteins, because they attract hydrogen ions, can act as what?


What function does a buffer perform?

Helps maintain a constant pH

What is regulated primarily by the buffering action of proteins?

pH balance

How do sodium and potassium travel into and out of cells?

There are transport proteins within the cell membrane that pick up and release the minerals across the membrane

What is opsin?

A light-sensitive protein

what protein inactivates foreign bacteria and viruses?


The body's usual response to detection of antigens is to synthesize what?


Which of the following describes the structure of an antibody?

huge protein molecule

Which of the following is involved in the clotting of blood?


How many grams of nitrogen are contained in a 2500-kcalorie diet that provides 15% of the energy as protein?


Which of the following may be used to determine protein utilization?

nitrogen balance

When nitrogen taken into the body exceeds nitrogen losses, we say the person is in what?

positive nitrogen balance.

The sum of protein synthesis and degradation defines what?

protein turnover

What is the amino acid pool?

A mix of essential and nonessential amino acids derived from protein breakdown and dietary protein intake

What describes the state of nitrogen balance for a normal, healthy 35-year-old person who weighs 60 kg and consumes a diet that provides 75 g of protein and adequate energy?


what does the body's amino acid pool consists of?

both essential and nonessential amino acids.

What is the nitrogen balance of a person who consumed a 3500-kcalorie diet containing 10% protein and excreted a total of 12 grams of nitrogen?

+2 g

what would describe the state of nitrogen balance of a person who ingested 16 g of food nitrogen and lost 19 g of nitrogen?

negative balance

What is the usual state of nitrogen balance for healthy infants, children, and pregnant women?

positive balance

What amino acid is used to synthesize the neurotransmitter serotonin and the vitamin niacin?


What is meant by protein turnover?

The synthesis and degradation of body proteins

What is the fate of excess dietary protein?

After absorption, the extra amino acids will be rapidly degraded

When amino acids are deaminated, the immediate products are ammonia and often a ______.

keto acid

Protein sparing in the body is best achieved when a person ingests ______.

adequate levels of carbs and fat

A person who is starving is losing _____.

glycogen, protein, and fat.

Removal of the amino group from an amino acid is an illustrations of what?

a deamination reaction

what is the most likely side effect of a high-protein, low-carbohydrate diet?

increased thirst

what are some compounds that contain nitrogen?

urea, enzymes and ammonia

what is a consequence of excess protein intake?

Increased production and excretion of urea

what precursors of urea synthesis?

increased production and excretion of urea

What is the process whereby an amino group is combined with a keto acid to form an amino acid?


In the metabolism of amino acids for energy, what is the fate of the amino group?

Excreted as urea

The body's need for water increases on a diet high in _____.


The body's need for water increases on a diet high in

Liver dysfunction

What is the most likely reason for having an abnormally high blood urea level?

Kidney dysfunction

A prominent result of transamination reactions is the synthesis of ____.

nonessential amino acids.

a man who has a high blood ammonia concentration, most likely has a poorly functioning _________.


a woman who has a high blood urea content, most likely has a poorly functioning ________.


A reference protein equals or exceeds the essential amino acid requirements of what population groups?

preschool aged children, adolescents, and the elderly.

What is the percent digestibility of most plant proteins?


What is the percent digestibility of most animal proteins?


Which of the following food proteins has the best assortment of essential amino acids for the human body?


what is related to the quality of a food protein?

essential amino acid balance

What primary factor governs the quality of a food protein?

Essential amino acid content

In the study of protein nutrition, what term describes the amount of amino acids absorbed from a given amount of protein consumed?


what is not considered to be a source of high-quality protein in human nutrition?


what animal-derived proteins is classified as a poor-quality protein?


What is a "limiting" amino acid in a protein?

An essential amino acid present in insufficient quantity for body protein synthesis to take place

If the diet is lacking an essential amino acid, what will be the course of action?

Protein synthesis will be limited

what is not be a limiting amino acid in the diet?


what is characteristic of protein nutrition in vegetarians?

Most vegetarians eating a variety of foods need not balance essential amino acid intake at each meal

What is the Daily Value for protein based on a 2000-kcalorie intake?


What is complementary protein nutrition?

A strategy that combines plant proteins in the same day to improve the balance of essential amino acids

In general, the protein quality in grains would be most improved by the addition of a plant protein rich in what?


In general, the protein quality of legumes would be most improved by the addition of a plant protein rich in what?


Relative to animal proteins, what amino acid is present in lesser amounts in proteins of legumes?


Approximately what percentage of children worldwide have protein-energy malnutrition?


Acute protein-energy malnutrition in children is characterized by _____.

low weight for height

Chronic protein-energy malnutrition in children is characterized by ______.

short height for age,

what are some are characteristics of protein-energy malnutrition?

it is found in hospitalized adults, it is found in elderly living alone, and it is common in people with anorexia nervosa.

Marasmus occurs most commonly in children of what ages?

6-18 months

what would you expect to see in a person with kwashiorkor?

Edema, Dysentery, and Increased infection rate

what is associated with the presence of tissue edema in kwashiorkor?

Low concentration of blood protein

what are some characteristics of marasmus?

Results in a low resistance to disease, Occurs most commonly in children aged 6 to 18 months, and Results in little or no fat under the skin to insulate against cold.

what is a feature of malnutrition?

Dysentery is common and leads to diarrhea and nutrient depletion.

how does the rapid onset of protein-energy malnutrition occurs in kwashiorkor?

It is typically seen in patients who are 1-3 years old due to the sudden change in diet arising from their being weaned from breast milk after the birth of a sibling

What term describes the illness a child develops when the next child is born?


what is a condition is associated with edema?

Diminished concentration of blood proteins and hormones, which causes fluid to leak from the blood vessels

Kwashiorkor typically develops in children of what ages?

18-24 months

In kwashiorkor, what is the loss of hair color is indirectly related to?

inadequate intake of tyrosine

In kwashiorkor, what mineral is often present in an unbound form that promotes bacterial growth?


What is the most likely explanation for the fatty liver that develops from protein deficiency?

Inability of the liver to synthesize lipoproteins for fat export

what is a feature of kwashiorkor?

It is typically precipitated in the undernourished child who has an infection`

What is the usual initial therapy for the treatment of kwashiorkor?

Fluid balance restoration

Excessive amounts of homocysteine in the blood are thought to increase the risk for ______.

heart disease

Supplements of what amino acid is reported to lower blood pressure and reduce homocysteine levels?


what are known to raise the levels of homocysteine?

alcohol intake, cigarette smoking and coffee consumption.

What type of diet is advised to rehabilitate a severely malnourished child?

low protein

what is a feature of homocysteine?

it is increased in the blood of coffee drinkers

what is a description of a relationship between protein/amino acids and heart disease?

Elevated blood homocysteine levels are associated with smoking cigarettes and drinking alcohol

What ratio (mg:g) of calcium to protein intake is believed to promote optimal bone health?


what is a description of an association between protein intake and kidney function?

restricting protein intake may slow the progression of kidney disease

In relation to the range of protein intake as a percentage of energy intake, what would be the highest safe level of protein intake for a 60-kg adult ingesting 2500 kcalories?


what is a description of a relationship between protein intake and calcium metabolism?

Calcium excretion rises with increasing intake of animal-derived proteins

What is the RDA for protein for a 48-kg woman?

38 g

What is the ratio of calcium to protein intake (mg to g) for most U.S. women?


What would be the primary principle of wise diet planning as related to protein nutrition?


what is a feature of the protein RDA?

The recommendations are generous`

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