chapter 6 protein
_______________ does not eat any animal foods and consumes only plant products.
a vegan
Proteins help regulate ______ in the blood.
acid-base balance
What is a peptide bond?
A chemical bond formed between amino acids in a protein.
Changing a protein's shape often destroys its ability to function normally, such that it loses its
biological activity.
Blood proteins help maintain
body fluid balance.
The release of pepsin is controlled by the hormone
gastrin
the immune system no longer functions efficiently when it lacks key proteins, thereby increasing the risk of __________
infections, disease, and death.
The branched-chain amino acids are the primary amino acids used by _______ for energy needs.
muscles
What enzyme is released by the stomach to digest protein?
pepsin
The chemical bond joining adjacent amino acids is called a(n) _____________ bond.
peptide
Within body cells, amino acids are linked together by chemical bonds—technically called ____________—to form proteins
peptide-bonds
You often need a _________ protein balance when you are recovering from an illness.
positive
Proteins are crucial to the _____ and _____ of the body.
regulation and maintenance
Proteins are created from amino acids in a cell's _________.
ribosomes
Each amino acid has an _________ specific to the amino acid.
"acid" group, an "amino" group, and a "side" or R group
what is denaturation
Alteration of a protein's three-dimensional structure, usually because of treatment by heat, enzymes, acid or alkaline solutions, or agitation.
what is a nonessential amino acid
Amino acids that can be synthesized by a healthy body in sufficient amounts; there are 11 nonessential amino acids. These are also called dispensable amino acids.
what is sickle cell disease (sickle cell anemia)
An illness that results from a malfor-mation of the red blood cell because of an incorrect structure in part of its hemoglobin protein chains.
_______ are poor protein sources.
Fruits and oils
what types of food contain low-quality proteins
Individual plant sources of proteins (except for soy beans and quinoa seed)
Amino acid absorption in the small intestine requires energy. T/F
TRUE
what are essential amino acids
The amino acids that cannot be synthesized by humans in sufficient amounts or at all and therefore must be included in the diet; there are nine essential amino acids. These are also called indispensable amino acids.
Many legumes are deficient in the essential amino-acid ________________ , while grains are limited in _________________.
methionine; lysine
The most nutrient-dense sources of protein are
milk products (8 to 10 grams of protein per serving) meat and beans (7 grams of protein per serving)
Sickle cell anemia is not a nutritional disease but is caused by a ________, the protein that carries oxygen in red blood cells
mutation in the genetic code for hemoglobin
Amino acids contain a special form of the element _________, which plants get from the soil.
nitrogen
Some of the _________-, which are usually synthesized in the body, can become essential during times of
nonessential amino acids rapid growth, disease, or metabolic stress.
Which of these foods contains the least amount of protein per serving? Olive oil Chicken Beans Yogurt
olive oil
Which of these foods would a vegan eat? Cheese Scrambled eggs Yogurt Pasta
pasta
Which of these plant foods is the best source for plant proteins? Celery Oranges Bananas Peas
peas
Once in the cytoplasm, mRNA travels to the ________. The _____ read the mRNA code and translate those instructions to produce a _______. Amino acids are added one at a time to the growing polypeptide chain according to the instructions on the _____
ribosomes (x2) specific protein mRNA
Enzymes in the nucleus read the code (a gene) on a DNA base sequence that encodes one or more proteins and transcribe that information into a _______ that is ready to leave the nucleus
single-stranded mRNA molecule
Exposure to acid or alkaline substances, heat, or agitation (e.g., whipping egg whites) can alter a protein's _______
structure, leaving it uncoiled or otherwise deformed.
Peptide bonds form between
the amino group of one amino acid and the acid (carboxyl) group of another.
Plant proteins do provide other benefits that animal proteins lack, however, such as
fiber and phytochemicals
Proteins play important roles in
fluid balance, lipoprotein transport, immune function, and production of tissues, such as skin, cells lining the GI tract, and hair.
The mutation (sickle cell) causes the amino acid ______ to be replaced with the amino acid _____. This error produces a profound change in
glutamic acid valine hemoglobin structure
What is a fruititarian?
A person who primarily eats fruits, nuts, honey, and vegetable oils.
what is pepsin
A protein-digesting enzyme produced by the stomach.
what is trypsin
A protein-digesting enzyme secreted by the pancreas to act in the small intestine.
what is positive protein balance
A state in which protein intake exceeds related protein losses, as is needed during times of growth.
what is protein equilibrium
A state in which protein intake is equal to related protein losses; the person is said to be in protein balance.
what is negative protein balance
A state in which protein intake is less than related protein losses, as is often seen during acute illness.
What is satiety?
A state in which there is no longer a desire to eat; a feeling of satisfaction.
what are gruels
A thin mixture of grains or legumes in milk or water.
what are lower-quality (incomplete) proteins
Dietary proteins that are low in or lack one or more essential amino acids.
what are high-quality (complete) proteins
Dietary proteins that contain ample amounts of all nine essential amino acids.
whats a pool?
The amount of a nutrient stored within the body that can be mobilized when needed.
What is amino acid?
The building block for proteins containing a central carbon atom with nitrogen and other atoms attached.
what is edema
The buildup of excess fluid in extracellular spaces.
What is a limiting amino acid?
The essential amino acid in lowest concentration in a food or diet relative to body needs.
Animal proteins contain ample amounts of
all nine essential amino acids.
If it lacks the proper structure, a _______ cannot function.
protein
Kwashiorkor usually is associated with a deficiency of
protein
the DNA code used for synthesis of a specific protein must be
transferred from the nucleus to the cytoplasm to allow for protein synthesis.
What is a polypeptide?
A group of amino acids bonded together, from 50 to 2000 or more.
what is protein-calorie malnutrition (PCM), Also known as protein-energy malnutrition.
A condition resulting from regularly consuming insufficient amounts of calories and protein. The deficiency eventually results in body wasting, primarily of lean tissue, and an increased susceptibility to infections.
what is kwashiorkor
A disease occurring primarily in young children who have an existing disease and consume a marginal amount of calories and insufficient protein in relation to needs. The child generally suffers from infections and exhibits edema, poor growth, weakness, and an increased susceptibility to further illness.
what is marasmus
A disease resulting from consuming a grossly insufficient amount of protein and calories; one of the diseases classed as protein-calorie malnutrition. Victims have little or no fat stores, little muscle mass, and poor strength. Death from infections is common.
What is a lactovegetarian?
A person who consumes plant products and dairy products.
What is a lactoovovegetarian?
A person who consumes plant products, dairy products, and eggs
Which of the following is not true about pepsin? a. Amino acid chains are the digestive products of its action. b. Pepsin works best in an alkaline environment. c. Acid activates pepsin. d. Pepsin acts on food in the stomach.
B: Pepsin works best in an alkaline environment.
Which of the following is true about protein intake in the United States? a. Plant sources of protein predominate in the United States. b. We eat less animal sources of protein than people in Asia and Africa. c. About 70 percent of the protein we eat in the United States comes from animal products. d. Chicken is our main animal source of protein.
C: About 70 percent of the protein we eat in the United States comes from animal products.
what are buffers?
Compounds that cause a solution to resist changes in acid-base conditions.
Amino acids are carried to the liver through the lymph system. T/F
FALSE
Amino acids are used only by the body to create proteins for cells. T/F
FALSE
Protein digestion begins in the small intestine. T/F
FALSE
Because the ____________________________ diet is recognized as being low in meat, rich in fresh fruit and vegetables, low in added sugar and saturated fatty acids, it has been recommended as a sustainable alternative to the MyPlate dietary pattern.
Mediterranean
what is a capillary bed
Network of one-cell-thick vessels that create a junction between arterial and venous circulation. It is here that gas and nutrient exchange occurs between body cells and the blood.
what is urea
Nitrogenous waste product of protein metabolism; major source of nitrogen in the urine,.
If a person's diet is low in protein for a long period, the processes of rebuilding and repairing body proteins will slow down. what happens to the body?
Over time, skeletal muscles; blood proteins; and vital organs, such as the heart and liver, will decrease in size or volume.
__________ occurs when the body can't break down and use the essential amino acid phenylalanine to create the amino acid tyrosine.
Phenylketonuria (PKU)
Sickle red blood cells become hard and sticky, which causes them to clog blood flow and break apart. what can this cause?
This can cause severe bone and joint pain, abdominal pain, headache, convulsions, paralysis, and even death due to the lack of oxygen.
what are complementary proteins
Two food protein sources that make up for each other's inadequate supply of specific essential amino acids; together, they yield a sufficient amount of all nine and so provide high-quality (complete) protein for the diet.
It is predicted that the increasing intake of meat and dairy will have profound impacts on our _________, and our ability to provide food in the future.
agricultural and ecological resources
Because the depletion of just one of the essential amino acids prevents protein synthesis, the process illustrates the
all-or-none principle: Either all essential amino acids are available, or none can be used.
Plants combine nitrogen from the soil with carbon and other elements to form
amino acids
Proteins are made up of _________.
amino acids
_________ proteins usually contain all the essential amino acids.
animal
plant proteins are a nutritious alternative to
animal proteins
What types of foods contain high-quality proteins?
animal proteins except gelatin
North Americans get most of their protein from which source?
animals
The major symptoms of kwashiorkor are
apathy, diarrhea, listlessness, failure to grow and gain weight, changes in hair color, potassium deficiency, flaky skin, fatty liver, reduced muscle mass, and massive edema in the abdomen and legs and withdrawal from the environment.
Body functions such as _____, _______, ____, _____, ______, ______ require specific proteins.
blood clotting, fluid balance, hormone and enzyme production, visual processes, transport of many substances in the bloodstream, and cell repair
Edema appears when there is a severe lack of dietary protein because
blood protein levels fall and fluid shifts to the tissues.
what organ resists protein breakdown?
brain
___________ are leucine, isoleucine, and valine.
branched-chain amino acids
Arginine and glutamine are two examples of
conditionally essential amino acids.
what is a vegan
consumes only plant foods
Instead of forming normal circular disks, the red blood cells collapse into
crescent (or sickle) shapes
This process of altering the three-dimensional structure of a protein is called
denaturation
_________ occurs when excess fluid pools between cells.
edema
Your body cannot make its own _________ amino acids.
essential
what is a conditionally essential amino acids
Amino acids that must be made from essential amino acids if insufficient amounts are eaten.
what is a branched-chain amino acids
Amino acids with a branching carbon backbone; these are leucine, isoleucine, and valine. All are essential amino acids. ex: whey protein
what is a carbon skeleton?
Amino-acid structure that remains after the amino group (—NH2) has been removed.
What does preterm mean?
An infant born before 37 weeks of gestation; also referred to as premature.
what is a protein?
Food and body compounds made of amino acids; proteins contain carbon, hydrogen, oxygen, nitrogen, and sometimes other atoms in a specific configuration. Proteins contain the form of nitrogen most easily used by the human body.
________ may ultimately be able to correct many gene defects in humans by placing the correct DNA code in the nucleus, so that the correct protein can be made by the ribosomes.
Genetic engineering
what is protein turnover
The process by which cells break down old proteins and resynthesize new proteins. In this way, the cell will have the proteins it needs to function at that time.
what is extracellular space?
The space outside cells; represents one-third of body fiuid.
Through peptide bonding of amino acids, cells can synthesize
dipeptides (joining of two amino acids), tripeptides (joining of three amino acids), oligopeptides (joining of four to nine amino acids), and polypeptides (joining of 10 or more amino acids).
The nine amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) the body cannot make in sufficient amounts or at all are known as _______ because they must be obtained from foods.
essential
what are the three types of amino acids?
essential, nonessential, and semiessential
Most plant proteins do not match our needs for essential amino acids and therefore are called _______________ proteins.
incomplete
Denaturation of proteins is useful for some body processes, especially digestion. why????
it gets rid of bacteria (safer to eat) and `it increases exposure of the polypeptide chain to digestive enzymes,
If the DNA code contains errors, an incorrect _______ will be produced. The _______ will then read this incorrect message and an incorrect amino acid will be added and an incorrect ______ will be produced.
mRNA, ribosomes, polypeptide chain
The disease _________ can damage an infant's brain development.
marasmus
Vegetables and grains are a moderately _______ of protein (2 to 3 grams of protein per serving)
nutrient-dense source