Deck 6: Protein: Amino Acids

Question 1

Which of the following is the primary factor that differentiates one amino acid from another?

A)The side group
B)The central carbon atom
C)The number of oxygen atoms
D)The number of nitrogen atoms

Answer 1

A

Question 2

Any of the following can be used by the body for the synthesis of a nonessential amino acid EXCEPT

A)a fragment of fat.
B)an essential mineral.
C)an essential amino acid.
D)a fragment of carbohydrate.

Answer 2

B

Question 3

Which of the following is NOT an essential amino acid in human nutrition?

A)Proline
B)Threonine
C)Methionine
D)Tryptophan

Answer 3

A

Question 4

What is meant by the amino acid sequence of a protein?

A)Number of side chains in the protein
B)Folding arrangement of the peptide chain
C)Order of amino acids in the peptide chain
D)Order of only the essential amino acids in the protein

Question 5

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

A)Number of cell ribosomes
B)Number of different amino acids
C)Availability of amino acids containing sulfur
D)Availability of amino acids containing hydroxyl groups

Question 6

What element is found in proteins but NOT in carbohydrates and fats?

A)Carbon
B)Oxygen
C)Calcium
D)Nitrogen

Question 7

How many different kinds of amino acids make up proteins?

A)8
B)10
C)14
D)20

Question 8

Which of the following is NOT contained in an amino acid?

A)An acid group
B)An amino group
C)An aldehyde group
D)A central carbon atom

Question 9

A dispensable amino acid is one that

A)is not needed by the body.
B)can be synthesized by the body.
C)can be used to synthesize an indispensable amino acid.
D)cannot be synthesized by the body because of a genetic defect.

Question 10

Which of the following terms is NOT used to classify amino acids in the diet?

A)Essential
B)Nonessential
C)Partially essential
D)Conditionally essential

Question 11

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

A)Hydrolysis
B)Deamination
C)Denaturation
D)Condensation

Question 12

What is the simplest amino acid?

A)Valine
B)Glycine
C)Alanine
D)Methionine

Question 13

Which of the following is a feature of an essential amino acid?

A)It is not necessary in the diet
B)It must be supplied by the diet
C)It can be made from fat in the body
D)It can be made from glucose in the body

Question 14

In comparison to the composition of carbohydrates and fats,which element found in proteins makes them unique?

A)Carbon
B)Oxygen
C)Nitrogen
D)Hydrogen

Question 15

Which of the following would be classified as a polypeptide?

A)1 amino acid
B)3 amino acids bonded together
C)9 fatty acids bonded together
D)20 amino acids bonded together

Question 16

Which of the following elements is found in certain amino acids?

A)Iron
B)Sulfur
C)Calcium
D)Potassium

Question 17

What is the composition of a tripeptide?

A)One amino acid with three carbons
B)Three amino acids bonded together
C)One amino acid with three acid groups
D)Three small protein chains bonded together

Question 18

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

A)Cysteine
B)Tyrosine
C)Glutamine
D)Isoleucine

Question 19

When two amino acids are chemically joined together,the resulting structure is called a

A)dipeptide.
B)diglyceride.
C)polypeptide.
D)disaccharide.

Question 20

Approximately how many different amino acids are used in the synthesis of body proteins?

A)5
B)10
C)20
D)35

Question 21

What is the usual fate of orally ingested enzyme supplements?

A)Digested by gastrointestinal proteases
B)Rapidly degraded by salivary secretions
C)Mostly absorbed in original form from the stomach
D)Completely absorbed in original form from the jejunum

Question 22

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

A)Pepsin
B)Transaminase
C)Pancreatic protease
D)Intestinal peptidase

Question 23

The weak electrical attractions within polypeptide chains account for the protein's

A)primary structure.
B)secondary structure.
C)tertiary structure.
D)quaternary structure.

Question 24

What is the chief function of pepsin?

A)Emulsifies dietary proteins
B)Activates hydrochloric acid
C)Activates pancreatic proteases
D)Cleaves proteins into smaller polypeptides

Question 25

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

A)Mouth
B)Stomach
C)Small intestine
D)Large intestine

Question 26

The function of a protease is to

A)hydrolyze proteins.
B)synthesize proteins.
C)hydrolyze ribosomes.
D)synthesize ribosomes.

Question 27

Which of the following describes the structure of pepsin?

A)Lipid
B)Protein
C)Nucleic acid
D)Carbohydrate

Question 28

Which of the following is a feature of hemoglobin?

A)It has no tertiary structure
B)It holds the mineral calcium
C)It is constructed of 4 polypeptide chains
D)It has no primary or secondary structure

Question 29

After digestion of proteins,what products are absorbed into the circulation?

A)Free amino acids only
B)Free amino acids and oligopeptides
C)Free amino acids and dipeptides only
D)Free amino acids,and a few dipeptides and tripeptides

Question 30

The following amino acids are linked together: glycine-lysine-valine.This compound is a

A)dipeptide.
B)tripeptide.
C)polypeptide.
D)oligopeptide.

Question 31

In what organ is pepsin active?

A)Stomach
B)Pancreas
C)Small intestine
D)Large intestine

Question 32

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

A)stiffening.
B)condensation.
C)denaturation.
D)destabilization.

Question 33

Protein-hydrolyzing enzymes are commonly known as

A)proteases.
B)hydrolyzers.
C)prodigestins.
D)denaturases.

Question 34

An example of a protein with quaternary polypeptide structures is

A)insulin.
B)tryptophan.
C)hemoglobin.
D)disulfide bridges.

Question 35

What process results in the hardening of an egg when it is exposed to heat?

A)Solidification
B)Denaturation
C)Condensation
D)Protein interaction

Question 36

Which of the following statements is NOT characteristic of enzymes?

A)They are all catalysts
B)They have a protein structure
C)They can be destroyed by heat
D)They are involved in synthesis reactions only

Question 37

All of the following are fates of amino acids within the small intestine EXCEPT

A)some may be used for energy by the intestinal cells.
B)some may be used for synthesis of gastric protease.
C)some may be used for synthesis of proteins by the intestinal cells.
D)they may be transported across the intestinal cell membrane to the capillaries.

Question 38

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

A)Digestion
B)Condensation
C)Denaturation
D)Hydrogenation

Question 39

What percentage of dietary protein is hydrolyzed in the mouth?

A)0
B)5-10
C)15-20
D)25-30

Question 40

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

A)Peptidase
B)Propepsin
C)Pepsinogen
D)Propeptidase

Question 41

What is the relationship between body proteins and water?

A)Proteins attract water
B)Water attracts proteins
C)Water degrades proteins
D)Proteins form polymers of water

Question 42

Which of the following does NOT describe an association between protein nutrition and the body's water balance?

A)Inadequate protein intake may lead to edema.
B)Insufficient protein synthesis by the liver may lead to edema.
C)Excessive protein losses by the kidney may lead to dehydration.
D)Excessive protein intake burdens the kidneys to excrete unused nitrogen.

Question 43

Your cousin Wanda was born with a genetic defect affecting her digestion,namely,a lack of intestinal villus tripeptidases and dipeptidases.Which of the following digestive processes would NOT take place?

A)Protein → oligopeptides
B)Peptides → amino acids
C)Amino acids → peptides
D)Polypeptides → tripeptides

Question 44

Which of the following does NOT describe a feature of protein in nutrition?

A)The study of the body's proteins in known as proteomics
B)Protein synthesis requires messenger RNA and transfer RNA
C)Most of the body's thousands of proteins have been studied thoroughly
D)The synthesis of a protein by following the genetic code is known as gene expression

Question 45

What is a ribosome?

A)A template for protein synthesis
B)A hard knot of subcutaneous protein mass
C)A structure upon which proteins are assembled
D)An antibody synthesized by specialized immune cells

Question 46

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

A)diabetes.
B)marasmus.
C)phenylketonuria.
D)sickle-cell anemia.

Question 47

Your college dormitory roommate,James,told you that he's had anemia for quite some time and that it's from having abnormally-shaped hemoglobin.What type of anemia does James have?

A)Sickle-cell anemia
B)Macrocytic anemia
C)Iron-deficiency anemia
D)Low oxygen-carrying anemia

Question 48

Of the following sources of amino acids,which would be best absorbed in normal,healthy people?

A)Whole proteins
B)Predigested proteins
C)Proteins from raw foods
D)Mixture of free amino acids

Question 49

Which of the following is a characteristic of protein synthesis?

A)Mitochondria are bound to DNA to initiate peptide bond synthesis
B)Messenger RNA is constructed from a DNA template to carry instructions
C)Hormones carry messages from RNA to DNA to direct peptide bond synthesis
D)RNA transfers up to 6 amino acids simultaneously to the mitochondria for peptide elongation

Question 50

Which of the following is characteristic of sickle-cell anemia?

A)The disorder can be serious but not fatal
B)The disorder leads to depression of energy expenditure
C)The abnormal structure of the hemoglobin alters the shape of the red blood cell
D)The hemoglobin amino acid sequence is abnormal in all four of the polypeptide chains

Question 51

Which of the following describes a process in protein synthesis?

A)The code to make a protein is carried by a strand of messenger RNA
B)The final step in completing the protein is carried out in the mitochondria
C)The function of transfer RNA is to assist in absorption of amino acids into the cell
D)The DNA binds to ribosomes and directs uptake of specific amino acids to form the peptide chain

Question 52

What term signifies when a cell makes a protein under the directions of a gene?

A)Gene encoding
B)Gene expression
C)Protein secretion
D)Protein amplification

Question 53

The process whereby messenger RNA is made from a DNA template is

A)expression.
B)sequencing.
C)transcription.
D)ribosome assembly.

Question 54

Which of the following is a characteristic of hormones?

A)Inactivate bacteria
B)Act as messenger molecules
C)Coordinate visual response
D)Act as buffers in the bloodstream

Question 55

What is the structure of an enzyme?

A)Lipid
B)Protein
C)Nucleic acid
D)Carbohydrate

Question 56

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

A)Albumin
B)Thrombin
C)Collagen
D)Hydroxyproline

Question 57

Which of the following do(es)NOT function as a transport protein?

A)Collagen
B)Transferrin
C)Hemoglobin
D)Lipoproteins

Question 58

The conditions known as acidosis and alkalosis refer to a disruption of the body's

A)pH balance.
B)protein balance.
C)nitrogen balance.
D)endogenous metabolism.

Question 59

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

A)edema.
B)acidosis.
C)alkalosis.
D)extravascularization.

Question 60

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

A)Ferritin
B)Albumin
C)Collagen
D)Hemoglobin

Question 61

Which of the following describes the structure of an antibody?

A)Tripeptide
B)Small nucleic acid
C)Huge protein molecule
D)Large peptide molecule

Question 62

The body's amino acid pool consists of

A)essential amino acids only.
B)endogenous amino acids only.
C)nonessential amino acids only.
D)both essential and nonessential amino acids.

Question 63

Which of the following processes is regulated primarily by the buffering action of proteins?

A)pH balance
B)Fluid balance
C)Blood clotting
D)Synthesis of visual pigments

Question 64

Which of the following proteins inactivates foreign bacteria and viruses?

A)Enzymes
B)Collagen
C)Hormones
D)Antibodies

Question 65

What is the amino acid pool?

A)The total amino acid content derived from a 24-hour dietary intake
B)A measure of the circulating essential amino acid levels available for protein synthesis
C)The total amount of free amino acids in the circulation destined for deamination and excretion
D)A mix of essential and nonessential amino acids derived from protein breakdown and dietary protein intake

Question 66

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

A)Glycine
B)Tyrosine
C)Methionine
D)Tryptophan

Question 67

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

A)a healthy state.
B)nitrogen equilibrium.
C)positive nitrogen balance.
D)negative nitrogen balance.

Question 68

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

A)Opsin
B)Fibrin
C)Collagen
D)Transferrin

Question 69

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? (Protein is 16% nitrogen.)

A)0 g
B)-3 g
C)-1 g
D)+2 g

Question 70

Proteins,because they attract hydrogen ions,can act as

A)acids.
B)buffers.
C)enzymes.
D)antibodies.

Question 71

Given that protein is 16% nitrogen,how many grams of nitrogen are contained in a 2500-kcalorie diet that provides 15% of the energy as protein?

A)2.5
B)5
C)10
D)15

Question 72

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

A)Calorimetry
B)Nitrogen balance
C)Amino acid pool
D)Supplementary value

Question 73

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

A)Antidiuretic hormone transports potassium and prodiuretic hormone carries sodium
B)There are specific transport proteins in the blood that deliver the minerals to the cell cytoplasm
C)The balance of insulin and glucagon determines the movement of these minerals into and out of cells
D)There are transport proteins within the cell membrane that pick up and release the minerals across the membrane

Question 74

What function does a buffer perform?

A)Helps emulsify fats
B)Helps maintain a constant pH
C)Facilitates chemical reactions
D)Helps protect against plaque buildup

Question 75

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

A)Equilibrium
B)Metabolic
C)Positive
D)Negative

Question 76

Which of the following defines protein turnover?

A)The sum of protein in food and the body
B)The sum of protein synthesis and degradation
C)The amount of protein absorbed from the diet
D)The amount of protein used to synthesize glucose

Question 77

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

A)mutations.
B)antibodies.
C)erythrocytes.
D)whey protein.

Question 78

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

A)Equilibrium
B)Positive balance
C)Negative balance
D)Exogenous balance

Question 79

Which of the following 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?

A)Equilibrium
B)Positive balance
C)Negative balance
D)Endogenous balance

Question 80

What is opsin?

A)An antigen
B)An antibody
C)A light-sensitive protein
D)A blood transport protein