Unit 7 : Proteins

Question 1

collagen

Answer 1

a type of body protein from which connective tissues such as tendons, ligaments, scars, and the foundations of bones and teeth are made.

Question 2

enzymes

Answer 2

protein catalysts. A catalyst is a compound that facilitates a chemical reaction without itself being altered in the process.

Question 3

hemoglobin

Answer 3

the globular protein of red blood cells, whose iron atoms carry oxygen around the body via the bloodstream

Question 4

denaturation

Answer 4

the irreversible change in a protein’s shape brought about by heat, acids, bases, alcohol, salts of heavy metals, or other agents.

Proteins can be denatured by heat, acids, bases, alcohol, or the salts of heavy metals. Denaturation begins the process of digesting food protein and can also destroy body proteins.

Question 5

polypeptides

Answer 5

protein fragments of many (more than 10) amino acids bonded together (poly means “many”). A peptide is a strand of amino acids. A strand of between 4 and 10 amino acids is called an oligopeptide

Question 6

dipeptides

Answer 6

protein fragments that are two amino acids long (di means “two”)

Question 7

tripeptides

Answer 7

protein fragments that are three amino acids long (tri means “three”)

Question 8

protein turnover

Answer 8

the continuous breakdown and synthesis of body proteins involving the recycling of 300–400 g of amino acids each day.

Question 9

hormones

Answer 9

chemical messengers secreted by a number of body organs in response to conditions that require regulation. Each hormone affects a specific organ or tissue and elicits a specific response.

Question 10

serotonin

Answer 10

a compound related in structure to (and made from) the amino acid tryptophan. It serves as one of the brain’s principal neurotransmitters.

Question 11

antibodies

Answer 11

large proteins of the blood, produced by the immune system in response to an invasion of the body by foreign substances (antigens). Antibodies combine with and inactivate the antigens.

Question 12

immunity

Answer 12

protection from or resistance to a disease or infection by development of antibodies and by the actions of cells and tissues in response to a threat.

Question 13

fluid and electrolyte balance

Answer 13

the distribution of fluid and dissolved particles among body compartments

Question 14

edema

Answer 14

swelling of body tissue caused by leakage of fluid from the blood vessels; seen in protein deficiency (among other conditions).

Question 15

acids

Answer 15

compounds that release hydrogens in a watery solution.

Question 16

bases

Answer 16

compounds that accept hydrogens from solutions.

Question 17

acid–base balance

Answer 17

equilibrium between acid and base concentrations in the body fluids.

Question 18

buffers

Answer 18

compounds that help keep a solution’s acidity or alkalinity constant.

Question 19

acidosis

Answer 19

the condition of excess acid in the blood, indicated by a below-normal pH (osis means “too much in the blood”)

Question 20

alkalosis

Answer 20

the condition of excess base in the blood, indicated by an above-normal blood pH (alkalinity—alka means “base”; osis means “too much in the blood”).

Question 21

urea

Answer 21

the principal nitrogen-excretion product of protein metabolism; generated mostly by removal of amine groups from unneeded amino acids or from amino acids being sacrificed to a need for energy.

Question 22

legumes

Answer 22

plants of the bean, pea, and lentil family that have roots with nodules containing special bacteria. These bacteria can trap nitrogen from the air in the soil and make it into compounds that become part of the plant’s seeds. The seeds are rich in protein compared with those of most other plant foods.

Question 23

high-quality proteins

Answer 23

dietary proteins containing all the essential amino acids in relatively the same amounts that human beings require. They may also contain dispensable/nonessential amino acids

Question 24

amino acid pools

Answer 24

amino acids dissolved in the body’s fluids that provide cells with ready raw materials from which to build new proteins or other molecules.

Question 25

limiting amino acid

Answer 25

an essential amino acid that is present in dietary protein in an insufficient amount, thereby limiting the body’s ability to build protein.
Limiting Amino Acids Can Limit Protein Synthesis

Question 26

complementary proteins

Answer 26

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.

Question 27

mutual supplementation

Answer 27

the STRATEGY of combining two incomplete protein sources so that the amino acids in one food make up for those lacking in the other food. Such protein combinations are sometimes called complementary proteins.

Question 28

protein digestibility–corrected amino acid score (PDCAAS)

Answer 28

a measuring tool used to determine protein quality. The PDCAAS reflects a protein’s digestibility as well as the proportions of amino acids that it provides.

Question 29

gluten

Answer 29

a mixture of small proteins found in wheat, rye, and barley that helps give dough its elastic texture. It must be avoided by those diagnosed with celiac disease.

Question 30

protein-energy undernutrition (PEU)

Answer 30

the world’s most widespread malnutrition problem, including both marasmus and kwashiorkor and states in which they overlap; also called protein-Calorie malnutrition (PCM).

Protein-deficiency symptoms are always observed when either protein or energy is deficient. Extreme food energy deficiency results in marasmus; extreme protein deficiency results in kwashiorkor. The two diseases overlap most of the time and together are called PEU

Question 31

hunger

Answer 31

the physiological craving for food; the progressive discomfort, illness, and pain resulting from the lack of food.

Question 32

dysentery

Answer 32

an infection of the digestive tract that causes diarrhea.

Question 33

textured vegetable protein

Answer 33

processed soybean protein used in products formulated to look and taste like meat, fish, or poultry.

Question 34

tofu

Answer 34

a curd made from soybeans that is rich in protein, often rich in calcium, and variable in fat content; used in many Asian and vegetarian dishes in place of meat.