Chapter 6 Flashcards
(127 cards)
1
Q
which atom gives the name amino to the amino acids?
A
nitrogen
2
Q
are the amino acids in a strand of protein the same?
A
no, they’re different from one another
3
Q
what’s the simple chemical backbone all amino acids have?
A
single carbon atom, amine group, and acid group
4
Q
what’s the purpose of a side chain?
A
gives each amino acid its identity and chemical nature. The side chains make the amino acids differ in size, shape, and electrical charge
5
Q
how many amino acids can the body not make on its own?
A
9
6
Q
what are the essential amino acids?
A
histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine
7
Q
can a nonessential amino acid become essential?
A
yes. could become a conditionally essential amino acid.
8
Q
can the body reuse amino acids?
A
yes
9
Q
what bond is formed between amino acids?
A
peptide bond. formed between the amine group end of one amino acid and the acid group end of the next.
10
Q
polypeptide
A
a protein fragment of about 10 to 50 amino acids bonded together
11
Q
how many highly folded protein structures form the globular hemoglobin protein?
A
4
12
Q
The amino acids whose side chains are electrically charged are..
A
attracted to water. in the body’s watery fluids, they orient themselves on the outside of the protein structure.
13
Q
The amino acids whose side chains are neutral are…
A
repelled by water and are attracted to one another; these tuck themselves into the center away from the body fluids
14
Q
The amino acids whose side chains are neutral are…
A
repelled by water and are attracted to one another; these tuck themselves into the center away from the body fluids
15
Q
collagen
A
the chief protein of most connective tissues, including scars, ligaments, and tendons, and the underlying matrix on which bones and teeth are built.
16
Q
Normal hemoglobin contains how many kinds of protein strands?
A
2
17
Q
in sickle cell disease, glutamic acid gets replaced with…
A
valine
18
Q
When a cell makes a protein, scientists say that the gene for that protein has been…
A
expressed
19
Q
do nutrients change DNA structure?
A
no, but they greatly influence gene expression
20
Q
nutritional genomics
A
the science of how food components, such as nutrients, interact with the body’s genetic material.
21
Q
denaturation
A
the irreversible change in a protein’s folded shape brought about by heat, acids, bases, alcohol, salts of heavy metals, or other agents.
22
Q
what are some denaturing agents?
A
heat, radiation, alcohol, acids, bases, the salts of heavy metals
23
Q
is denaturation useful in digestion?
A
yes, it unfolds and inactivates the proteins in food, and exposes their peptide bonds to the digestive enzymes that cleave them.
24
Q
can denaturation happen when food is cooked?
A
yes
25
Among egg proteins that heat denatures, two are notable in nutrition.
One binds the vitamin biotin and the mineral iron: when this protein is denatured, it releases biotin and iron, making them available to the body. The other slows protein digestion; denaturing this protein allows digestion to proceed normally.
26
what are some heavy metal salts? what's the antidote for swallowing these poisons?
mercury and silver; these poisons denature protein strands wherever they touch them. The common first-aid antidote for swallowing a heavy-metal poison is to drink milk. The poison then acts on the protein of the milk rather than on the protein tissues of the mouth, esophagus, and stomach.
27
what acid in the stomach denatures proteins in food?
hydrochloric acid
28
what's the pH of the acid in the stomach?
1.5
29
after the stomach, proteins enter the small intestine in the form of...
long strands, polypeptide
30
in the small intestine, what neutralizes the acid delivered by the stomach?
alkaline juice. pH from the pancreas. pH rises to about 7
31
Protein-digesting enzymes from the pancreas and intestine continue working until...
almost all pieces of protein are broken into single amino acids or into strands of two or three amino acids, dipeptides or tripeptides
32
the small intestine absorbs single, double, or triple amino acids?
single amino acids
33
can dipeptides and tripeptides be absorbed as is?
yes
34
can the larger peptide molecules act as hormones to regulate body functions and provide the body with information about the external environment?
yes. they can also stimulate an immune response and thus play a role in food allergy.
35
Chemically similar amino acids compete for the same...
absorption sites.
36
Chemically similar amino acids compete for the same...
absorption sites.
37
Once amino acids are circulating in the bloodstream, they are carried to the...
liver, where they may be used or released into the blood to be taken up by other cells of the body
38
how long do rbc live?
3-4 months
39
protein turnover
the continuous breakdown and synthesis of body proteins involving the recycling of amino acids.
40
what percentage of the body's protein exists in muscle tissue?
40%
41
enzymes act as catalysts, which..
speeds the rate of a chemical reaction without itself being permanently altered in the process.
42
what's the purpose of tyrosine?
forms parts of the neurotransmitters epinephrine and norepinephrine. make the brown pigment melanin, which gives a brown color to skin, hair, and eyes. tyrosine is converted into the thyroid hormone thyroxine, which regulates the body’s metabolism.
43
what's the importance of tryptophan?
serves as starting material for the neurotransmitter serotonin and the vitamin niacin.
43
what's the importance of tryptophan?
serves as starting material for the neurotransmitter serotonin and the vitamin niacin.
44
immunity
protection from or resistance to a disease or infection by the development of antibodies and by the actions of cells and tissues in response to a threat.
45
can proteins move freely into and out of cells?
no, water can and proteins attract water
46
proteins mounted on cell membranes act as...
pumps, constantly adjusting the cells’ fluid and electrolyte balance.
47
edema
swelling of body tissue caused by leakage of fluid from the blood vessels; seen in protein deficiency
48
is sodium concentrated inside or outside the cell?
outside the cell. potassium is concentrated inside
49
blood proteins act as...
buffers to maintain the blood’s normal pH. he protein buffers pick up hydrogens (acid) when there are too many in the bloodstream and release them again when there are too few. The secret is that negatively charged side chains of amino acids can accommodate additional hydrogens, which are positively charged.
50
buffers
molecules that can help keep the pH of a solution from changing by gathering or releasing H ions.
51
acids
compounds that release hydrogens in a watery solution.
52
bases
compounds that accept hydrogens from solutions.
53
acid-base balance
equilibrium between acid and base concentrations to maintain a proper pH in the body fluids.
54
If blood pH changes too much what can occur?
acidosis or alkalosis
55
When the proteins’ buffering capacity is filled—that is, when they have taken on all the acid hydrogens they can accommodate- what happens to them?
additional acid pulls them out of shape, denaturing them and disrupting many body processes.
56
what do proteins do in blood clotting?
proteins form a stringy net that traps blood cells to form a clot. The clot acts as a plug to stem blood flow from the wound. Later, as the wound heals, the protein collagen finishes the job by replacing the clot with scar tissue.
57
what are the important function of proteins?
help regulate gene expression; provide structure and movement; serve as enzymes, hormones, and antibodies; provide molecular transport; help regulate fluid and electrolyte balance; buffer the blood; contribute to blood clotting; and provide energy.
58
what happens when amino acids are degraded for energy or converted into glucose?
their nitrogen-containing amine groups are stripped off and used elsewhere or are incorporated by the liver into urea and sent to the kidneys for excretion in the urine.
59
if we need proteins in a dire situation, which proteins are used first?
first, small proteins from the blood, then proteins from the muscles
60
what happens when amino acids are oversupplied?
the body cannot store them. It has no choice but to remove and excrete their amine groups and then use the residues in one of three ways: to meet immediate energy needs, to make glucose for storage as glycogen, or to make fat for energy storage.
61
which energy-yielding nutrient provides concentrated energy?
fat. Carbohydrate offers energy and protein can offer energy plus nitrogen
62
is there a storage form of protein that exists in the body?
no
63
how can an amino acid be used?
The amino acid can be used as-is to build part of a growing protein.
The amino acid can be altered somewhat to make another needed compound, such as the vitamin niacin.
The cell can dismantle the amino acid to use its amine group to build a different amino acid. The remainder can be used for fuel or, if fuel is abundant, converted to glucose or fat.
64
how can an amino acid be used?
The amino acid can be used as-is to build part of a growing protein.
The amino acid can be altered somewhat to make another needed compound, such as the vitamin niacin.
The cell can dismantle the amino acid to use its amine group to build a different amino acid. The remainder can be used for fuel or, if fuel is abundant, converted to glucose or fat.
65
when does wasting of amino acids occur?
When the body lacks energy from other sources.
When the diet supplies more protein than the body needs.
When the body has too much of any single amino acid—for example, from a supplement.
When the diet supplies protein of low quality, with too few essential amino acids
65
when does wasting of amino acids occur?
When the body lacks energy from other sources.
When the diet supplies more protein than the body needs.
When the body has too much of any single amino acid—for example, from a supplement.
When the diet supplies protein of low quality, with too few essential amino acids
66
how To prevent the wasting of dietary protein and permit the synthesis of needed body protein?
the dietary protein must be of adequate quality: it must supply all essential amino acids in the proper amounts. It must also be accompanied by enough energy-yielding carbohydrate and fat to permit the dietary protein to be used as such.
67
do protein supplements like protein powders, improve athletic ability?
no, physical work is required to build muscle.
68
what arises when collagen, a protein present in bones, dissolves into the broth during long, moist cooking?
gelatin
69
will collagen or gelatin supplements improve nails?
no. Made largely of protein, nails depend on sulfur bonds between amino acids for flexible strength, fatty acids for water resistance, and sufficient water for proper hydration. In addition, the living tissues that form nails need many minerals and vitamins to put these materials into place.
70
what does leucine do?
stimulates muscle protein synthesis following exercise
70
what does leucine do?
stimulates muscle protein synthesis following exercise
71
athletes take supplemental branched chain amino acids. why is this bad?
taken in the context of a high-fat diet, may cause a buildup of metabolic products that disturbs normal energy systems, particularly concerning insulin action. it can worsen diseases
72
what's the supplemental safe dose for lysine per day?
3 grams. it could prevent or relieve the infections that cause herpes cold sores on the mouth or genital organs
73
what can tryptophan do?
relieve depression and insomnia. may be effective for inducing drowsiness,
74
what can tryptophan do?
relieve depression and insomnia. may be effective for inducing drowsiness,
75
why is it not good to take protein supplements?
because the supplements may stimulate inflammation or draw water into the digestive tract, which causes diarrhea. can also worsen kidney disease or interfere with the actions of certain medications, allowing diseases to advance unchecked.
76
what's the DRI minimum amount of protein?
10% of total calories and max is 35%
77
For adults of healthy body weight, the DRI is set at...
0.8 grams for each kilogram
78
For adults of healthy body weight, the DRI is set at...
0.8 grams for each kilogram
79
does Malnutrition or infection increase or decrease the need for protein?
increase. In malnutrition, secretion of digestive enzymes slows as the tract’s lining degenerates, impairing protein digestion and absorption. When infection is present, extra protein is needed for enhanced immune functions.
80
why must proteins be accompanied by the full array of vitamins and minerals?
To be used efficiently by the cells
81
healthy adults are in what kind of nitrogen balance?
nitrogen equilibrium, or zero balance
82
what's positive nitrogen balance?
When nitrogen-in exceeds nitrogen-out. somewhere in their bodies more proteins are being built than are being broken down and lost.
83
what's the negative nitrogen balance?
nitrogen-in is less than nitrogen-out. they are losing protein
84
what's the negative nitrogen balance?
nitrogen-in is less than nitrogen-out. they are losing protein
85
what kind of people are in a positive nitrogen balance?
a growing child, a person building muscle, and a pregnant woman
86
what kind of people are in a negative nitrogen balance?
astronaut and surgery patient
87
high quality proteins
dietary proteins containing all the essential amino acids in relatively the same amounts that human beings require. They may also contain nonessential amino acids.
88
what 2 factors influence a protein's quality?
its amino acid composition and its digestibility.
88
what 2 factors influence a protein's quality?
its amino acid composition and its digestibility.
89
what happens if the diet fails to provide enough of an essential amino acid?
the cells:
Break down more internal proteins to liberate the needed essential amino acid, and
Limit their synthesis of proteins to conserve the essential amino acid.
90
what happens if the diet fails to provide enough of an essential amino acid?
the cells:
Break down more internal proteins to liberate the needed essential amino acid, and
Limit their synthesis of proteins to conserve the essential amino acid.
91
limiting amino acid
an essential amino acid that is present in dietary protein in an insufficient amount, thereby limiting the body’s ability to build protein.
92
limiting amino acid
an essential amino acid that is present in dietary protein in an insufficient amount, thereby limiting the body’s ability to build protein.
93
what happens if a protein shortage becomes chronic?
the cells begin to break down their protein-making machinery. Consequently, when protein intakes become adequate again, protein synthesis lags behind until the needed machinery can be rebuilt. Meanwhile, the cells function less and less effectively as their proteins become depleted and are only partially replaced.
94
what if the cells are building are protein, but cannot find a needed amino acid?
synthesis stops, and the partial protein is released.
95
complementary proteins
two or more proteins whose amino acid assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other.
96
legumes provide isoleucine and lysine, but fall short in methionine and tryptophan. what's a good match for legumes?
grains
97
which is more digestible, eggs or oats?
eggs
98
which proteins are more easily absorbed?
protein from animal sources, then legumes, then grains
99
does cooking with moist heat improve protein digestibility?
yes. frying makes it harder to digest proteins
100
what are the consequences of protein deficiency?
include slow growth in children, impaired brain and kidney functions, weakened immune defenses, and impaired nutrient absorption from the digestive tract.
100
what are the consequences of protein deficiency?
include slow growth in children, impaired brain and kidney functions, weakened immune defenses, and impaired nutrient absorption from the digestive tract.
101
whats the average protein intake for men and women in the U.S.?
men- 16%
women- 15.5%
102
what's the average U.S. daily intake of protein in grams?
78 grams
103
can excess protein harm the liver?
yes. a high-protein diet increases the kidneys’ workload. In people with kidney stones or other kidney diseases a high-protein diet may speed the kidneys’ decline
104
why should we be careful of a diet high in red meats and processed meats?
they can cause heart disease and certain cancers.
105
gluten
a type of protein in certain grain foods that is toxic to the person with celiac disease.
106
gluten
a type of protein in certain grain foods that is toxic to the person with celiac disease.
107
celiac disease
a disorder characterized by an abnormal immune response, weight loss, and intestinal inflammation on exposure to the dietary protein gluten; also called gluten-sensitive enteropathy or celiac sprue.
108
celiac disease
a disorder characterized by an abnormal immune response, weight loss, and intestinal inflammation on exposure to the dietary protein gluten; also called gluten-sensitive enteropathy or celiac sprue.
109
what are the symptoms of celiac disease?
chronic diarrhea or constipation, vomiting, bloating, and pain
110
how can one find out if they have celiac disease?
A blood test revealing high concentrations of certain antibodies
111
non-celiac gluten sensitivity
Patients suffer from digestive symptoms resembling those of celiac disease or a gluten allergy, but test negative for these conditions. a poorly defined collection of digestive symptoms that improves with elimination of gluten from the diet.
111
non-celiac gluten sensitivity
Patients suffer from digestive symptoms resembling those of celiac disease or a gluten allergy, but test negative for these conditions. a poorly defined collection of digestive symptoms that improves with elimination of gluten from the diet.
112
can a gluten free diet help you lose weight?
no. Manufactured gluten-free foods are often higher in fats, added sugars, and calories than their regular counterparts
113
should we rely on fruit for protein?
no. it has small amounts
114
what are the top contributors of protein?
beef, poultry, milk, yeast bread, cheese
115
food high in protein are also high in what vitamins and minerals?
vitamin B12 and iron
116
legumes are a good veggie protein option. what are some legumes?
kidney bean, soybean, green pea, lentil, black-eyed pea, lima bean
117
what's the problem with heavy use of soy products?
inhibits iron absorption. use with small amounts of meat and/or foods rich in vitamin C in the same meal with soy products.
118
how do legumes get nitrogen?
Bacteria in the root nodules can “fix” nitrogen from the air, contributing it to the beans. Ultimately, thanks to these bacteria, the plant accumulates more nitrogen than it can get from the soil and also contributes more nitrogen to the soil than it takes out.
119
textured vegetable protein
processed soybean protein used in products formulated to look and taste like meat, fish, or poultry.
120
textured vegetable protein
processed soybean protein used in products formulated to look and taste like meat, fish, or poultry.
121
tofu
a curd made from soybeans that is rich in protein, often enriched with calcium, and variable in fat content; used in many Asian and vegetarian dishes in place of meat.
