SAS #10: Protein Metabolism

Question 1

It’s in the mouth and has no effect on digestion

Answer 1

Saliva

Question 2

In the stomach which denatures protein

Answer 2

HCl

Question 3

In the stomach, which hydrolyzes peptide bonds

Answer 3

Pepsin

Question 4

Pepsin makes _____

Answer 4

Large polypeptides

Question 5

Amino acids that is in the small intestine, which hydrolyze peptide bonds

Answer 5

Trypsin
Chymotrypsin
Carboxypeptidase
Aminopeptidase

Question 6

The intestinal lining uses _____ transport

Answer 6

Active

Question 7

Dietary protein entering the stomach effects the release of the hormone ________ by stomach mucosa cells.

Answer 7

gastrin

Question 8

its antiseptic properties kill most bacteria

Answer 8

Hydrochloric acid

Question 9

its denaturing action “unwinds” globular proteins, making peptide bonds more accessible to digestive enzymes

Answer 9

Hydrochloric acid

Question 10

its acidity leads to the activation of pepsinogen, which is the inactive form of the digestive enzyme pepsin

Answer 10

Hydrochloric acid

Question 11

Gastrin’s presence causes both

Answer 11

hydrochloric acid and pepsinogen secretion

Question 12

is the repetitive process in which proteins are degraded and resynthesized within the human body.

Answer 12

protein turnover

Question 13

in the liver (nonessential amino acids only)

Answer 13

biosynthesis of amino acids

Question 14

is the state that results when the amount of nitrogen taken into the human body as protein equals the amount of nitrogen excreted from the body in waste materials.

Answer 14

Nitrogen balance

Question 15

TWO TYPES OF NITROGEN BALANCE:

protein degradation exceeds protein synthesis, the amount of nitrogen in the urine exceeds the amount of nitrogen ingested (dietary protein).

Answer 15

negative nitrogen balance

Question 16

TWO TYPES OF NITROGEN BALANCE:

accompanies a state of “tissue wasting,” because more tissue proteins are being catabolized than are being replaced by protein synthesis.

Answer 16

negative nitrogen balance

Question 17

TWO TYPES OF NITROGEN BALANCE:

Protein-poor diets, starvation, and wasting illnesses produce a negative nitrogen balance.

Answer 17

negative nitrogen balance

Question 18

TWO TYPES OF NITROGEN BALANCE:

nitrogen intake exceeds nitrogen output, indicates that the rate of protein anabolism (synthesis) exceeds that of protein catabolism.

Answer 18

positive nitrogen balance

Question 19

TWO TYPES OF NITROGEN BALANCE:

state indicates that large amounts of tissue are being synthesized, such as during growth, pregnancy, and convalescence from an emaciating illness.

Answer 19

positive nitrogen balance

Question 20

FOUR WAYS to use the amino acids from the body’s amino acid pool:

75% of the free amino acids in a healthy, well-nourished adult go into ____________. Proteins are continually needed to replace old tissue (protein turnover) and also to build new tissue (growth).

Answer 20

protein synthesis

Question 21

FOUR WAYS to use the amino acids from the body’s amino acid pool:

Amino acids are regularly withdrawn from the amino acid pool for the synthesis of nonprotein nitrogen-containing compounds. Such molecules include the purines and pyrimidines of nucleic acids (A, C, G, T, and U), the heme of hemoglobin, the choline and ethanolamine of phosphoglycerides, hormones such as adrenaline, and neurotransmitters such as norepinephrine, dopamine, and serotonin. The neurotransmitter serotonin is synthesized from the amino acid tryptophan, and the neurotransmitters norepinephrine and dopamine are synthesized from the amino acid tyrosine

Answer 21

Synthesis of nonprotein nitrogen-containing compounds.

Question 22

FOUR WAYS to use the amino acids from the body’s amino acid pool:

When required, the body draws on the amino acid pool for raw materials for the production of nonessential amino acids that are in short supply. The “roadblock” preventing the synthesis of the essential amino acids is not lack of nitrogen but lack of a correct carbon skeleton upon which enzymes can work. In general, them essential amino acids contain carbon chains or aromatic rings not present in other amino acids or the intermediates of carbohydrate or lipid metabolism.

Answer 22

Synthesis of nonessential amino acids.

Question 23

FOUR WAYS to use the amino acids from the body’s amino acid pool:

Because excess amino acids cannot be stored for later use, the body’s response is to degrade them. The degradation process is complex because each of the 20 standard amino acids has a different degradation
pathway.

Answer 23

Production of energy

Question 24

In all the degradation pathways, the amino nitrogen atom is removed and ultimately is excreted from the body as ______.

Answer 24

urea

Question 25

always involve two amino acids (one as a reactant and one as a product) and two keto acids (one as a reactant and one as a product). Two keto/amino acid pairs are involved, with the members of a pair having a common carbon-chain base.

Answer 25

Transamination Reactions

Question 26

is a biochemical reaction that involves the interchange of the amino group of an a-amino acid with the keto group of an a-keto acid.

Answer 26

transamination reaction

Question 27

The needed enzyme for a transamination reaction is an ______________.

Answer 27

aminotransferase

Question 28

is a biochemical reaction in which an a amino acid is converted into an a- keto acid with release of an ammonium ion.

Answer 28

oxidative deamination reaction

Question 29

Oxidative deamination occurs primarily in ______ and ______ mitochondria.

Answer 29

liver and kidney

Question 30

Oxidative deamination of glutamate requires the enzyme ___________.

Answer 30

glutamate dehydrogenase.

Question 31

is a cyclic biochemical pathway in which urea is produced, for excretion, using ammonium ions and aspartate molecules as nitrogen sources.

Answer 31

urea cycle

Question 32

Three amino acids are involved as intermediates in the operation of the urea cycle: _____________

Answer 32

arginine, ornithine, and
citrulline

Question 33

The “fuel” for the urea cycle. This fuel is formed from ammonium ion (from oxidative deamination), carbon dioxide (from the citric acid cycle), water, and two ATP molecules.

Answer 33

Carbamoyl Phosphate

Question 34

The removal of the amino group of an amino acid by transamination/oxidative deamination produces an _____________ that contains the carbon skeleton from the amino acid. Because each of the 20 amino acids has a different carbon skeleton, each amino acid has a different degradation pathway for its carbon skeleton.

Answer 34

α-keto acid

Question 35

Amino acids that are degraded to citric acid cycle intermediates can serve as glucose precursors and are called ________.

Answer 35

glucogenic

Question 36

is an amino acid that has a carbon-containing product that can be used to produce glucose via gluconeogenesis.

Answer 36

Glucogenic amino acid

Question 37

Amino acids that are degraded to acetyl CoA or acetoacetyl CoA can contribute to the formation of fatty acids or ketone bodies and are called ___________.

Answer 37

ketogenic

Question 38

acid is an amino acid that has a carbon-containing degradation product that can be used to produce ketone bodies.

Answer 38

ketogenic amino acid

Question 39

Amino acids that are degraded to pyruvate can be either ____________ or _______.

Answer 39

glucogenic or ketogenic

Question 40

Two amino acids that are purely ketogenic

Answer 40

Leucine and lysine

Question 41

amino acid that can be converted into glucose through gluconeogenesis.

Answer 41

KETOGENIC (2)

Question 42

L,K

Answer 42

KETOGENIC (2)

Question 43

Amino acids that are degraded to pyruvate

Answer 43

BOTH KETO & GLUCO (9)

Question 44

pyruvate coverted to oxaloacetate (glucogenic) or acetyl CoA (ketogenic

Answer 44

BOTH KETO & GLUCO (9)

Question 45

Y, F, I, A,G,C,S,TW

Answer 45

BOTH KETO & GLUCO (9)

Question 46

are converted into ketone bodies.

Answer 46

GLUCOGENIC (9)

Question 47

V, P, M, N, Q, E, D, H, R

Answer 47

GLUCOGENIC (9)

Question 48

The classification of amino acids as essential or nonessential for humans roughly parallels the number of steps in their ___________ and the energy required for their synthesis.

Answer 48

biosynthetic pathways

Question 49

Three of the nonessential amino acids—__________________— are biosynthesized by transamination of the appropriate a-keto acid starting material.

Answer 49

alanine, aspartate, and glutamate

Question 50

The nonessential amino acid ______ is obtained from the essential amino acid phenylalanine in a one-step oxidation that involves molecular O2, NADPH, and the enzyme phenylalanine hydroxylase.

Answer 50

tyrosine

Question 51

highly specialized cells whose primary function is to deliver oxygen to, and remove carbon dioxide from, body tissues.

Answer 51

Red blood cells

Question 52

have no nucleus or DNA. Instead, they are filled with the red pigment hemoglobin.

Answer 52

Mature red blood cells

Question 53

The life span of a red blood cell is about ______________.

Answer 53

four months (120 days)

Question 54

The oxygen-carrying ability of red blood cells is due to the ________________.

Answer 54

protein haemoglobin.

Question 55

The protein portion of Hemoglobin is called

Answer 55

globin

Question 56

the prosthetic group (nonprotein portion) of hemoglobin is called

Answer 56

heme

Question 57

The iron atom of heme becomes part of ________, an iron-storage protein, which saves the iron for use in the biosynthesis of new hemoglobin molecules.

Answer 57

ferritin

Question 58

Degradation of heme begins with a ring-opening reaction in which a single carbon atom is removed. The product is called _____,

Answer 58

biliverdin

Question 59

Biliverdin is converted later to

Answer 59

bilirubin.

Question 60

is a colored tetrapyrrole degradation product present in bile

Answer 60

Bile pigment

Question 61

green bile

Answer 61

biliverdin

Question 62

red bile

Answer 62

Bilirubin

Question 63

urine bile

Answer 63

Urobilin

Question 64

dung bile

Answer 64

Stercobilin

Question 65

is the condition that occurs when this balance is upset such that bilirubin concentrations in the blood become higher than normal. The skin and the white of the eyes acquire a yellowish tint because of the excess bilirubin in the blood.

Answer 65

Jaundice

Question 66

caused by a deficiency of phenylalanine hydroxylase, is the most common clinically encountered inborn error of amino acid metabolism

Answer 66

Phenylketonuria (PKU)

Question 67

is a rare (1:185,000), autosomal recessive disorder in which there is a partial or complete deficiency in branched chain α-keto acid dehydrogenase, an enzyme complex that decarboxylates leucine, isoleucine, and valine. These amino acids and their corresponding α keto acids accumulate in the blood, causing a toxic effect that interferes with brain functions.

Answer 67

Maple syrup urine disease (MSUD)

Question 68

The disease is characterized by feeding problems, vomiting, dehydration, severe metabolic acidosis, and a characteristic maple syrup odor to the urine. If untreated, the disease leads to mental retardation, physical disabilities, and even death.

Answer 68

Maple syrup urine disease (MSUD)

Question 69

refers to a group of conditions in which a defect in tyrosine metabolism results in a deficiency in the production of melanin.

Answer 69

Albinism

Question 70

These defects result in the partial or full absence of pigment from the skin, hair, and eyes.

Answer 70

Albinism

Question 71

are a group of disorders involving defects in the metabolism of homocysteine. The diseases are inherited as autosomal recessive illnesses, characterized by high plasma and urinary levels of homocysteine and methionine and low levels of cysteine.

Answer 71

Homocystinuria

Question 72

is a rare metabolic condition involving a deficiency in homogentisic acid oxidase, resulting in the accumulation of homogentisic acid.

Answer 72

Alkaptonuria

Question 73

The condition has three characteristic symptoms: homogentisic aciduria (the patient’s urine contains elevated levels of homogentisic acid, which is oxidized to a dark pigment on standing, large joint arthritis, and black ochronotic pigmentation of cartilage and collagenous tissue.

Answer 73

Alkaptonuria