Deck 6: Protein: Amino Acids

Question 1

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

Answer 1

B

Question 2

Which of the following terms that are used to classify amino acids in the diet apply to alanine?

A) essential
B) nonessential
C) indispensable
D) conditionally essential

Answer 2

B

Question 3

Which of the following elements found in proteins makes them unique compared to the composition of carbohydrates and fats?

A) carbon
B) oxygen
C) nitrogen
D) hydrogen

Answer 3

C

Question 4

Where does the body obtain indispensable amino acids?

A) diet only
B) diet or synthesis from other amino acids
C) diet or synthesis from other amino acids or carbohydrate fragments
D) diet or synthesis from other amino acids, carbohydrate fragments or fragments of fat

Question 5

How is an essential amino acid distinguished from a non-essential amino acid??

A) It has a branched chain in its side group.
B) It can be made in the body only if a source of nitrogen is present.
C) It is required by the brain..
D) It must be supplied by the diet.

Question 6

Which of the following is the approximate number of different amino acids used in the synthesis of body proteins?

A) 5
B) 10
C) 15
D) 20

Question 7

Which of the following, when bonded together, would form a polypeptide?

A) 1 amino acid, 2 fatty acids and a glycerol molecule.
B) 3 fatty acids
C) 10 or more fatty acids
D) 20 amino acids

Question 8

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

A) iron
B) sulphur
C) calcium
D) potassium

Question 9

Of the following elements associated with macronutrients, which is found exclusively in proteins?

A) carbon
B) oxygen
C) hydrogen
D) nitrogen

Question 10

Which of the following factors represents 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 11

What type of reaction is required to bind 2 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

How many different kinds of amino acids make up proteins?

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

Question 14

When 2 amino acids are chemically joined together, the resulting structure is called which of the following?

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

Question 15

Which of the following combinations represents the composition of a tripeptide?

A) 1 amino acid with 3 carbons
B) 3 amino acids bonded together
C) 1 amino acid with 3 acid groups
D) 3 small protein chains bonded together

Question 16

Which of the following is a dispensable amino acid in human nutrition?

A) proline
B) threonine
C) methionine
D) tryptophan

Question 17

Which of the following groups are all contained in an amino acid?

A) an amino group, an acid group, an aldehyde group
B) an amino group, an alcohol group, a sulfur group
C) an amino group, an acid group, a side group
D) an amino group, and aldehyde group, an aromatic group

Question 18

Which of the following properties applies to a dispensable amino acid?

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

Question 19

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 sulphur
D) availability of amino acids containing hydroxyl groups

Question 20

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

Question 21

Which of the following factors accounts for the weak electrical attractions within a protein's polypeptide chains?

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

Question 22

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 23

Which of the following is an example of a protein with a quaternary polypeptide structure?

A) insulin
B) tryptophan
C) hemoglobin
D) two dipeptides bonded together

Question 24

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 25

Pepsinogen is also known as which of the following compounds?

A) a zymogen
B) an oligopeptide
C) a postenzyme
D) a cofactor for pancreatic enzymes

Question 26

The following amino acids are linked together: glycine-lysine-valine. This compound is which of the following peptides?

A) a dipeptide
B) a tripeptide
C) a polypeptide
D) an oligopeptide

Question 27

What is the function of a protease?

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

Question 28

Which of the following describes the structure of pepsin?

A) lipid
B) protein
C) nucleic acid
D) carbohydrate

Question 29

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

A) peptidase
B) peptic acid
C) pepsinogen
D) propeptidase

Question 30

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

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

Question 31

Your cousin Wanda has a genetic defect causing lack of intestinal villus tripeptidases and dipeptidases. Which of the following digestive processes would be affected?

A) protein $\rightarrow$ oligopeptides
B) peptides $\rightarrow$ amino acids
C) amino acids $\rightarrow$ peptides
D) polypeptides $\rightarrow$ tripeptides

Question 32

Pepsin is active in which one of the following organs?

A) stomach
B) pancreas
C) small intestine
D) large intestine

Question 33

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 34

What is the usual fate of orally ingested enzyme supplements?

A) digestion by gastrointestinal proteases
B) rapid degradation by salivary secretions
C) nearly complete absorption in original form from stomach
D) complete absorption in original form from jejunum

Question 35

After a hamburger is eaten, the hydrolysis of its proteins is initiated in which one of the following parts of the digestive system?

A) mouth
B) stomach
C) small intestine
D) large intestine

Question 36

What is the chief function of pepsin?

A) to emulsify dietary proteins
B) to activate hydrochloric acid
C) to activate pancreatic proteases
D) to cleave proteins into smaller polypeptides

Question 37

Protein-hydrolyzing enzymes are commonly known as which of the following?

A) proteases
B) hydrolyzers
C) zymogens
D) denaturases

Question 38

Which of the following products are absorbed into the circulation after digestion of proteins?

A) free amino acids only
B) free amino acids and oligo-peptides only
C) free amino acids and dipeptides only
D) free amino acids, and a few dipeptides and tripeptides

Question 39

How much of the dietary protein is hydrolyzed in the mouth?

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

Question 40

Which of the following distinguishes hemoglobin from a polypeptide chain?

A) Hemoglobin is a tertiary structure.
B) Hemoglobin is denatured.
C) Hemoglobin is a complex of 4 polypeptide chains.
D) Hemoglobin contains a globin molecule within the heme structure.

Question 41

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 42

Which of the following is a fate of amino acids in the intestinal tract?

A) used for energy by the intestinal cells
B) Some diffuse into intestinal cells for transport to the blood.
C) fermented by gut bacteria
D) undergo active transport from intestinal cells to the lymphatic system

Question 43

Which of the following statements best describes the fate of anabolic enzymes?

A) They are integrated into molecules formed by the reactions they catalyze.
B) They are denatured after catalyzing a reaction.
C) They are unchanged after catalyzing the formation of a new product.
D) They can catalyze only one reaction before being broken down.

Question 44

Approximately how many different proteins are present in the human body?

A) 500
B) 10,000
C) 20,000
D) 30,000

Question 45

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

A) diabetes
B) marasmus
C) kwashiorkor
D) sickle-cell anemia

Question 46

Which of the following can lead to edema??

A) excessive protein intake
B) insufficient protein synthesis by the liver
C) excessive protein retention by the kidneys
D) insufficient protein in the interstitial spaces

Question 47

Which of the following best represents the study of the body's proteins?

A) It is known as proteomics.
B) All proteins of the proteome participate in the same basic functions.
C) Most of the body's thousands of proteins have been studied and characterized.
D) An individual's genetic code changes across their lifecycle.

Question 48

Which of the following sources of amino acids 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

What is the structure of an enzyme?

A) lipid
B) protein
C) nucleic acid
D) carbohydrate

Question 50

Which of the following is the process whereby messenger RNA is made from a DNA template?

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

Question 51

Tissue swelling that result from water accumulating between cells is known as which of the following conditions?

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

Question 52

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 53

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 54

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 55

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

A) albumin
B) thrombin
C) collagen
D) hydroxyproline

Question 56

Which of the following is a correct sequence of steps within protein synthesis?

A) mRNA separates from ribosomes, tRNA lines up amino acids in sequence along mRNA, mRNA copies DNA in the nucleus.
B) DNA is a template for mRNA, mRNA travels from nucleus to ribosomes, tRNA lines up amino acids in sequence along mRNA
C) tRNA collects amino acids from cell fluid, mRNA travels from nucleus to ribosome, a new protein strand replicating mRNA is complete
D) DNA is a template for tRNA, mRNA collects amino acids from cell fluid, tRNA separates from rebosomes

Question 57

Which of the following is a characteristic of hormones?

A) inactivates bacteria
B) acts as messenger molecules
C) coordinates visual response
D) acts as buffers in the bloodstream

Question 58

What is an oligopeptide?

A) a sulphur-containing amino acid
B) a string of about 4-9 amino acids
C) a carbohydrate-containing protein
D) a protein containing only essential amino acids

Question 59

Why are red blood cells altered in shape in sickle-cell anemia?

A) Iron is no longer present within the haemoglobin molecule.
B) Haemoglobin is missing two of its polypeptide chains.
C) Lack of oxygen interferes with haemoglobin replication.
D) The amino acid sequence is abnormal in two of the polypeptide chains.

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

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

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

Question 62

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 63

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 64

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 65

What is meant by protein turnover?

A) nitrogen equilibrium
B) the antibody-antigen complex
C) the synthesis and degradation of body proteins
D) the secondary structure of proteins that initiates folding

Question 66

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 67

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 68

The body's usual response to detection of antigens is to synthesize which of the following?

A) thyroxin
B) antibodies
C) erythrocytes
D) ammonia

Question 69

How many grams of nitrogen are contained in a 2500-kcalorie diet that provides 15 percent of the energy as protein?

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

Question 70

Which of the following terms 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 71

Which of the following proteins inactivates foreign bacteria and viruses?

A) enzymes
B) collagen
C) hormones
D) antibodies

Question 72

What is the nitrogen balance of a person who consumed a 3500-kcalorie diet containing 10 percent protein and excreted a total of 12 g of nitrogen?

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

Question 73

What is opsin?

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

Question 74

Which of the following functions as a transport protein?

A) collagen
B) antibodies
C) thyroxin
D) lipoproteins

Question 75

Which of the following values 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 76

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 77

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

A) equilibrium
B) metabolic
C) positive
D) negative

Question 78

When nitrogen taken into the body exceeds nitrogen losses, we say the person is in which of the following states?

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

Question 79

Proteins, because they attract hydrogen ions, can act as which of the following?

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

Question 80

The body's amino acid pool consists of which of the following groups?

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