Deck 10: From Proteins to Phenotypes

Question 1

What actually happens to the blood cells of people with sickle cell anemia that causes the cells to change their shape ("sickle")?

A) Polymerization of hemoglobin molecules into long fibers.
B) Destruction of the hemoglobin molecules.
C) Loss of hemoglobin through leaky cell membranes.
D) Attachment of phosphate groups to the hemoglobin molecules.
E) Binding of methyl groups to the heme group of the hemoglobin molecule.

Answer 1

A

Question 2

The hemoglobin molecule

A) has four subunits of two types.
B) has two subunits that can be formed from four types.
C) is involved in amino acid metabolism.
D) acts as a cell surface receptor.
E) is controlled by a single gene.

Answer 2

A

Question 3

PKU is a recessive disorder. If a woman who has PKU has a child, what is the child's possible genotype?

A) Homozygous dominant.
B) Homozygous recessive.
C) Heterozygous.
D) The genotype could be any one of these.
E) There is not enough information to determine the child's genotype.

Answer 3

D

Question 4

Dietary treatment of galactosemia

A) need not begin until one or two months after birth.
B) requires a low protein diet.
C) can be discontinued by the age 10-12.
D) completely eliminates symptoms of the disease.
E) none of these.

Question 5

What substance accumulates in the blood of people with galactosemia?

A) Galactose
B) Glucose
C) Lactose
D) Galactose-1-phosphate
E) UDP galactose

Question 6

Antonio is 27, has a severely enlarged liver, and has a kidney infection. The inherited disease Antonio has is most likely ____________.

A) glycogen storage disease
B) Pompe disease
C) amylopectinosis
D) PKU
E) lactose intolerance

Question 7

The compound that Dr. Folling isolated from the urine of the Egeland children was ____________.

A) phenylalanine
B) pyruvic acid
C) phenylpyruvic acid
D) phtalamine
E) pertussic acid

Question 8

The existence of differential drug sensitivity serves to reinforce the idea that

A) many people carry genetic defects.
B) each individual is biologically and biochemically unique.
C) drugs need to be more closely regulated.
D) metabolic blocks are a widespread phenomenon.
E) none of these is reinforced.

Question 9

What is the nature of the genetic mutation that causes lactose intolerance?

A) It is a dominant mutation that prevents lactase production.
B) It is a dominant mutation that causes a decline in adult lactase levels.
C) It is a recessive mutation that prevents lactase production.
D) It is a recessive mutation that causes a decline in adult lactase levels.
E) It is an X-linked mutation that prevents lactase production.

Question 10

PKU results from a failure to convert tyrosine to phenylalanine.

Question 11

The presence of phenylpyruvic acid in urine is an indicator of ___________.

A) heart disease
B) colon cancer
C) mental retardation
D) spina bifida
E) more than one of these

Question 12

The nervous system damage symptomatic of untreated PKU is due to

A) too much phenylalanine being transported into nerve cells.
B) too few of the other seven neutral amino acids being transported into nerve cells.
C) accumulation of the breakdown products of phenylalanine in nerve cells.
D) none of these.
E) it is not clearly known.

Question 13

Which one of the following is NOT a symptom of PKU?

A) Unusually light colored hair and skin
B) "Musty" body odor
C) Jerky arm and leg movements
D) Mental retardation
E) Vomiting and digestive upset

Question 14

Beta thalassemia is most often caused by

A) amino acid substitutions.
B) extended chains in beta globin.
C) lowered or absent synthesis of beta globin.
D) excessive synthesis of beta globin.
E) altered rates of oxygen transport.

Question 15

The research of which of the following scientists showed that genetic disorders and abnormal metabolism are related?

A) Sir Archibald Garrod
B) Francis Crick
C) Linus Pauling
D) Linda Bartoshuk
E) James Neel

Question 16

Results from the study of globin variants indicate that

A) all amino acid substitutions cause severe phenotypic effects.
B) the alteration of one amino acid can cause a genetic disease.
C) extended chains do not function to carry oxygen.
D) all mutations in globin are caused by changes in amino acids.
E) none of these is indicated.

Question 17

Almost 70 percent of women with breast cancer are estrogen-senstive. What does this mean?

A) They are made ill with prescriptions of estrogen.
B) Only a small amount of estrogen can exacerbate their symptoms.
C) Their own natural estrogen encourages the growth of cancer cells.
D) Their cancers go into remission with increased uptake of estrogen.
E) They do not produce their own estrogen.

Question 18

The element to which oxygen (O2) binds in a hemoglobin molecule is ___________.

A) nitrogen
B) carbon
C) iron
D) potassium
E) phosphorous

Question 19

The uptake of neutral amino acids such as leucine, histidine, and valine is inhibited in brain cells of PKU individuals.

Question 20

Supertasters for the chemical PTC are ____________.

A) homozygous dominant
B) heterozygous
C) homozygous recessive
D) either homozygous dominant or homozygous recessive
E) either homozygous dominant or heterozygous

Question 21

The molecular defect in sickle cell anemia is known to reside at the position ____________________ of the ____________________ globin

Question 22

Large scale alterations of the amino acid structure in alpha globin are the cause of sickle cell anemia.

Question 23

Use of succinylcholine as an anaesthetic is very dangerous for people with a genotype for the fast-acting form of the enzyme serum cholinesterase.

Question 24

Genetic goitrous cretinism is caused by lack of the enzyme to synthesize ____________________ from phenylalanine.

Question 25

A person with the genotype GD/g for the galactosemia gene would have ____________________ of the normal level of galactose-1-phosphate uridyl transferase.

Question 26

All metabolic disorders result in serious phenotypic consequences.

Question 27

The symptoms of alkaptonuria result from a build-up of ____________________ in the blood.

Question 28

Some success has been achieved in efforts to treat sickle cell disease by the process of ____________________.

Question 29

Thalassemias are hemoglobin disorders in which the production of alpha and beta chains are out of balance.

Question 30

An essential amino acid is defined as one that is not produced by the body.

Question 31

Garrod called enzyme defects ____________________.

Question 32

Phenylketonuria is a result of a deficiency of the enzyme ____________________.

Question 33

People who can taste PTC have been shown to be more likely than non-tasters to dislike broccoli and Brussels sprouts.

Question 34

Familial hypercholesterolemia is associated with a defect in mitochondrial protein synthesis.

Question 35

Different genotypes for the CYP2D6 gene produce significantly different responses to tamoxifen, the medication of choice for treatment of most cases of ____________________.

Question 36

Hydroxyurea has been shown to switch off cell division.

Question 37

Hormone therapy, if administered early, is effective in treating genetic goitrous cretinism.

Question 38

Fetal hemoglobin functions adequately in the fetus but is ineffective in adults.

Question 39

There are no mandatory screening programs for genetic defects such as PKU and galactosemia in newborns.

Question 40

Lactose intolerance is caused by a mutation in the gene that codes for lactase.

Question 41

Paraoxonase converts the insecticide ____________________ into a toxic substance called paraoxon.

Question 42

In people who have PKU, phenylalanine cannot be converted into the amino acid ____________.

Question 43

Discuss therapeutic approaches in metabolic diseases.

Question 44

What does the chapter's section on pharmacogenetics and ecogenetics tell us about the issue of the relative safety of chemicals sold to the public and used in industry?

Question 45

In Chapter 4, two forms of bleeder's disease (hemophilia A and hemophilia B) were described. Each is deficient in a clotting factor. What would you predict are the clotting capacities of a mixture of blood from these two disorders? Why?

Question 46

Discuss the various possible effects of the loss of the activity of an enzyme.

Question 47

Show how the environment, extrauterine and intrauterine factors can influence the expression of PKU.

Question 48

The inability to break down galactose is the genetic disorder called ____________.

Question 49

The chemical compound that acts as a reactant in an enzyme mediated reaction is called a ____________.

Question 50

The study of genetic variations that affect people's responses to environmental chemicals is called _____________.

Question 51

In most cases, mutations in metabolic pathways produce a recessive trait. Suggest how a mutation in a metabolic pathway might produce a dominant condition.

Question 52

Why do you think some heterozygotes produce only half the normal amount of a given enzyme and yet have a normal phenotype?

Question 53

Linus Pauling is credited with work that established ____________________ as the first "molecular disease."

Question 54

The drug used to treat sickle cell anemia that causes elevated levels of fetal hemoglobin is ____________.

Question 55

Certain traits in humans are incompletely penetrant, or show variations in expressivity. Can you suggest a biochemical explanation for these observations in such cases caused by a metabolic error?

Question 56

Why must dietary therapy for PKU be instituted soon after birth?

Question 57

The enzyme lactase splits the lactose molecule into ____________ and ____________.

Question 58

In humans, ____________________ of the 20 amino acids are "non-essential" amino acids.