Proteins

Question 1

What is wasting?

Answer 1

The breakdown of body tissue such as muscle and organs for use as a protein source when the diet lacks protein.

Question 2

Define essential (indispensable) amino acids.

Answer 2

Amino acids that the body cannot make at all or cannot make enough of to meet physiological needs.

Question 3

What are nonessential (dispensable) amino acids?

Answer 3

Amino acids that the body can make if supplied with adequate nitrogen.

Question 4

What are conditionally essential amino acids?

Answer 4

Amino acids that are normally made in the body but become essential under certain circumstances, such as during critical illness.

Question 5

What are the building blocks of proteins?

Answer 5

Amino acids.

Question 6

What is a peptide bond?

Answer 6

The bond between two amino acids formed when a carboxyl group of one amino acid joins an amino group of another, releasing water.

Question 7

What is a dipeptide?

Answer 7

Two amino acids joined by a peptide bond.

Question 8

What is a tripeptide?

Answer 8

Three amino acids joined by peptide bonds.

Question 9

What defines an oligopeptide?

Answer 9

Four to 10 amino acids joined by peptide bonds.

Question 10

What is a polypeptide?

Answer 10

More than 10 amino acids joined by peptide bonds.

Question 11

What is hemoglobin?

Answer 11

The oxygen carrying protein in red blood cells that consists of four heme groups and four globin polypeptide chains.

Question 12

Define hydrophilic amino acids.

Answer 12

Amino acids that are attracted to water.

Question 13

Define hydrophobic amino acids.

Answer 13

Amino acids that are repelled by water.

Question 14

What is a disulfide bridge?

Answer 14

A bond between the sulphur components of two sulphur-containing amino acids that helps stabilize the structure of protein.

Question 15

What is denaturation?

Answer 15

An alteration in the three-dimensional structure of a protein resulting in an unfolded polypeptide chain.

Question 16

What is the most abundant fibrous protein in the body?

Answer 16

Collagen.

Question 17

What is keratin?

Answer 17

A water-insoluble fibrous protein that is the primary constituent of hair, nails, and the outer layer of the skin.

Question 18

What are motor proteins?

Answer 18

Proteins that use energy and convert it into some form of mechanical work.

Question 19

What are antibodies?

Answer 19

Large blood proteins produced by B lymphocytes in response to exposure to particular antigens.

Question 20

What is the immune response?

Answer 20

A coordinated set of steps taken by the immune system in response to an antigen.

Question 21

What is intracellular fluid?

Answer 21

The fluid in the body’s cells, high in potassium and phosphate and low in sodium and chloride.

Question 22

What is extracellular fluid?

Answer 22

The fluid located outside of cells, composed largely of plasma and interstitial fluid.

Question 23

What is interstitial fluid?

Answer 23

The fluid between cells in tissues, also called intercellular fluid.

Question 24

What is intravascular fluid?

Answer 24

The fluid portion of the blood (plasma) contained in arteries, veins, and capillaries.

Question 25

What is oedema?

Answer 25

Swelling caused by the buildup of fluid between cells.

Question 26

What are buffers?

Answer 26

Compounds that can take up and release hydrogen ions to keep the pH of a solution constant.

Question 27

What is acidosis?

Answer 27

An abnormally low blood pH resulting from increased acidity.

Question 28

What is alkalosis?

Answer 28

An abnormally high blood pH resulting from increased alkalinity.

Question 29

What is deamination?

Answer 29

The removal of the amino group from an amino acid.

Question 30

What are the vital functions of proteins?

Answer 30

Enzymes, hormones, immune protection, fluid and acid-base balance, and transport substances.

Question 31

What is a precursor?

Answer 31

A substance that is converted into another active substance.

Question 32

What are proteases?

Answer 32

Enzymes that break down protein into peptides and amino acids.

Question 33

What is trypsinogen?

Answer 33

A protease produced by the pancreas converted to the active form trypsin in the small intestine.

Question 34

What is chymotrypsinogen?

Answer 34

A protease produced by the pancreas converted to the active form chymotrypsin in the small intestine.

Question 35

What are peptidases?

Answer 35

Enzymes that act on small peptide units by breaking peptide bonds.

Question 36

What is celiac disease?

Answer 36

A chronic autoimmune disorder that involves an inability to tolerate gluten.

Question 37

What is cystic fibrosis?

Answer 37

An inherited disorder causing dysfunction of the exocrine glands.

Question 38

Where does protein digestion begin?

Answer 38

In the stomach with the enzyme pepsin.

Question 39

What is DNA?

Answer 39

The carrier of genetic information.

Question 40

What is messenger RNA (mRNA)?

Answer 40

Molecules that carry the amino acid sequence of proteins from the cell nucleus to the cytoplasm.

Question 41

What is transfer RNA (tRNA)?

Answer 41

A type of RNA that inserts the appropriate amino acid during protein synthesis.

Question 42

What is ribosomal RNA (rRNA)?

Answer 42

A major component of ribosomes providing a structural framework for protein synthesis.

Question 43

What is the amino acid pool?

Answer 43

The amino acids in body tissues and fluids available for new protein synthesis.

Question 44

What is protein turnover?

Answer 44

The constant synthesis and breakdown of proteins in the body.

Question 45

What are neurotransmitters?

Answer 45

Substances released at the end of a stimulated nerve cell that bind to another nerve or muscle cell.

Question 46

What is urea?

Answer 46

The main nitrogen-containing waste product in mammals.

Question 47

What is positive nitrogen balance?

Answer 47

Nitrogen intake exceeds the sum of all sources of nitrogen excretion.

Question 48

What is negative nitrogen balance?

Answer 48

Nitrogen intake is less than the sum of all sources of nitrogen excretion.

Question 49

What is nitrogen equilibrium?

Answer 49

Nitrogen intake equals the sum of all sources of nitrogen excretion.

Question 50

What are complete (high-quality) proteins?

Answer 50

Proteins that supply all the essential amino acids in the proportions the body needs.

Question 51

What are incomplete (low-quality) proteins?

Answer 51

Proteins that lack one or more essential amino acids.

Question 52

What are complementary proteins?

Answer 52

An incomplete food protein that, when combined with another, provides sufficient essential amino acids.

Question 53

What is protein-energy malnutrition (PEM)?

Answer 53

A condition resulting from long-term inadequate intakes of energy and protein.

Question 54

What is kwashiorkor?

Answer 54

A type of malnutrition occurring primarily in young children with marginal energy and protein intake.

Question 55

What is marasmus?

Answer 55

A type of malnutrition characterized by severe wasting of muscle, fat, and other body tissue.

Question 56

What is gout?

Answer 56

An intensely painful form of inflammatory arthritis resulting from deposits of uric acid crystals.

Question 57

True or False: Protein-energy malnutrition (PEM) can manifest in two forms: kwashiorkor and marasmus.

Answer 57

True.