Genetics - Chapter 10

​Parathion is effective and highly toxic to only about 5% of the human population.

False

Certain anti-cancer drugs alter the pattern of gene expression in individuals with sickle cell anemia and offer a potential new effective treatment for the disease.

True

DNA mutations that lead to defective proteins may result in phenotypic changes in the individual.

True

During metabolism, enzymes catalyze the conversion of substrate molecules into products.

True

Genetic variations explain differences in phenotypes, including differences in how individuals respond to certain drugs.

True

Hemoglobin defects lead to deficiencies in oxygen transport by the red blood cells.

True

Identification of phenylketonuria in newborns is crucial to avoid neurological damage in the first month of life.

True

Individuals affected by galactosemia are unable to breakdown the monsaccharide galactose.

True

Many blocked enzymatic reactions in the phenylalanine pathway lead to genetic disorders

True

Mutated genes can produce abnormal, non-functioning, or partially functioning proteins and can also prevent the production of proteins.

True

Mutated proteins produce changes in phenotype that range from insignificant to deadly.

True

New research shows that genotype should be considered as an important factor in choosing drugs and determining dosage rates for breast cancer treatment.

True

People who find phenylthiocarbamide (PTC) and another related compound called PROP very bitter tasting, also usually don't like kale, cabbage, broccoli or Brussels sprouts.

True

Proteins are essential parts of all structures and biological processes in the cells - they are the glue that holds the cells and tissues together.

True

The ability of a woman to metabolize the breast cancer drug tamoxifen determines the dose that she must receive in order for the treatment to be effective.

True

The accumulation of phenylpyruvic acid in the urine of children with phenylketonuria is due to a genetic mutation that affects metabolism of the amino acid phenylalanine.

True

The altered hemoglobin sickle cell anemia was the first direct proof that gene mutations result in changes in the amino acids of proteins.

True

​In most human populations, lactase levels are highest soon after birth and drop off in middle-to-late childhood.

True

​People who can taste PTC are more likely than non-tasters to dislike broccoli and Brussels sprouts.

True

Archibald Garrod called genetic disorders of biochemical pathways

inborn errors of metabolism

​Human diet must be varied enough to provide ______ of the 20 amino acids from the foods we eat.

9

Lactose is the primary sugar found in fruit.

False

An individual's sensitivity to the pesticide parathion depends on his or her ability to metabolize its toxic metabolite, paraoxon.

True

Dwarfism, a genetic disorder that results in short stature, is caused by mutations in genes that are responsible for ________. a. immune responses b. biochemical reactions c. egg and sperm development d. DNA replication e. growth

e. growth

​Certain anticancer drugs change patterns of gene expression and have created a new and effective treatment for

sickle cell anemia

​The specific chemical compound that is acted on by an enzyme is called a(n)

substrate

alpha and beta globins

the oxygen containing protein compounds in red blood cells that carry the iron containing heme group

While PKU is caused by the accumulation of dietary amino acid and its breakdown products, genetic goitrous cretinism, another metabolic disorder in the phenylalanine pathway is caused by the failure to synthesize

thyroid hormone

Taste preference is a matter of choice and is not related to an underlying genotype.

False

The highest populations of tasters are found in Australia.

False

The mutation that causes sickle cell anemia is due to three nucleotide substitutions in the codons of normal adult beta globin.

False

The science of ecogenetics describes how well a pesticide or insecticide works to rid crops of pests.

False

There is no treatment for phenylketonuria.

False

​Even if detected early, PKU cannot be treated to prevent the development of intellectual disability.

False

Dr. Asbjorn Folling discovered that the blood of children affected by PKU reacted with ferric chloride to produce a green color indicating the presence of phenylalanine.

False

Many of the differences people experience in response to drugs are not genetically controlled.

False

Pharmacogenetics is the branch of genetics that centers on developing drugs and drug treatments that are tailored to an individual's genetic make up.

False

Phenylketonuria is the only disorder that results from errors of phenylalanine metabolism.

False

Sickle cell anemia results when many genetic mutations in one individual cause production of abnormal hemoglobin molecules.

False

Studies have found no correlation between the genetics of taste preferences and body weight.

False

substrate

a chemical compound acted on by an enzyme

product

a new chemical compound that results from the enzyme activity on a previous compound

Women with genotypes that lead to decreased CYP2D6 activity ________. a. need high doses of tamoxifen for treatment of breast cancer b. do not develop breast cancer c. should not be given the anesthetic succinylcholine d. need low doses of tamoxifen for treatment of breast cancer e. are unable to taste PTC

a. need high doses of tamoxifen for treatment of breast cancer

​The presence of phenylpyruvic acid in urine is directly linked to ____. a.​intellectual disability b.​spina bifida c.​colon cancer d.liver cirrhosis e.​heart disease

a.​intellectual disability

A pregnant woman with PKU who maintains a normal diet during pregnancy will deliver a child that is

afflicted with PKU and mental disabilities

​A mutation that leads to the buildup of homogentisic acid causes

alkaptonuria

metabolism

all biochemical reactions through which cells convert and utilize energy

hemoglobin variant

amino acid sequence changes in any of the four proteins that make up this molecule

sickle cell anemia

an autosomal recessive trait caused by the mutation of beta globins in the red blood cells causing them to stick together

The disorder ________ results when an error of phenylalanine metabolism causes the inability to synthesize the thyroid hormone thyroxine. a. phenylketonuria b. genetic goitrous cretinism c. lactose intolerance d. dwarfism e. alkaptonuria

b. genetic goitrous cretinism

Individuals who are lactose intolerant do not make ________; therefore, they cannot metabolize lactose. a. galactose-1-phosphate uridyl transferase (GALT) b. lactase c. galactosemia enzymes d. glucose-6-phosphatase e. ABO blood types

b. lactase

Individuals who are able to taste PTC are ________. a. broccoli and Brussels sprout lovers b. more sensitive to strong tastes, such as capsaicin c. more obese than nontasters d. unable to taste sugars e. unable to taste fats

b. more sensitive to strong tastes, such as capsaicin

HbA, the adult form of hemoglobin, consists of ________ and ________. a. two gamma globins; two beta globins b. two alpha globins; two beta globins c. two alpha globins; two gamma globins d. four alpha globins; four heme groups e. two zeta globins; two epsilon globins

b. two alpha globins; two beta globins

​In the 1930s, Dr. Asbjor Folling described the metabolic disorder he called ____. a.​galactosemia b.​phenylketonuria c.​phenylthiocarbamide d.​lactose intolerance e.​sickle cell anemia

b.​phenylketonuria

Galactosemia is an inherited disorder caused by ____ galactose. a.​metabolizing excess fat molecules and attaching them to b.​the inability to break down c.​the over-consumption of d.​the excess break down of the protein e.​the overproduction of

b.​the inability to break down

Different genotypes for the CYP2D6 gene produce significantly different responses to tamoxifen, the medication often used to treat

breast cancer

Since the urine of children with phenylketonuria contains phenylpyruvic acid, the defective enzyme in these individuals must normally ________ during the metabolism of phenylalanine. a. convert phenylpyruvic acid to phenylalanine b. prevent digestion of phenylalanine c. convert phenylpyruvic acid to other end products d. be inactive e. make phenylpyruvic acid

c. convert phenylpyruvic acid to other end products

The simple sugars that comprise sucrose are ________. a. glycogen and starch b. glucose and galactose c. glucose and fructose d. maltose and lactose e. glucose, fructose, and galactose

c. glucose and fructose

Phenylalanine hydroxylase (PAH) converts ________ to ________; when the PAH gene is mutated, this biochemical step cannot occur. a. phenylpyruvic acid; phenylalanine b. tyrosine; phenylalanine c. phenylalanine; tyrosine d. DOPA; melanin e. phenylalanine; phenylpyruvic acid

c. phenylalanine; tyrosine

The accumulation of phenylpyruvic acid is most dangerous in newborns because ________. a. their skin is lighter b. they cannot eat a low phenylalanine diet c. significant neurological development occurs in newborns d. they cannot produce the PAH enzyme until adulthood e. there is no reliable test for phenylketonuria in newborns

c. significant neurological development occurs in newborns

​Results from the study of globin variants indicate that ____. a.​extended chains of phosphorus molecules function to carry oxygen b.​all of the changes in globin are due to changes in amino acid sequences c.​a change in a single nucleotide is sufficient to cause a genetic disorder d.​sickle cell anemia is not primarily an inherited disease e.​all amino acid substitutions cause severe phenotypic effects

c.​a change in a single nucleotide is sufficient to cause a genetic disorder

Women with breast cancers that are estrogen-sensitive ____. a.​can exacerbate their symptoms with only a small increase in estrogen levels b.​do not produce their own estrogen and must obtain it through diet or supplements c.​are in danger of faster growth of cancer cells in the presence of estrogen d.​become ill when taking prescription estrogen e.​will often experience cancer remission with increased uptake of estrogen

c.​are in danger of faster growth of cancer cells in the presence of estrogen

​The red blood cells of people with sickle cell anemia have abnormal shapes due to ____. a.destruction of the hemoglobin molecules​ b.​the binding of methyl groups to the heme group of the hemoglobin molecule causing desiccation of the cells c.​hemoglobin molecules with mutant beta globin subunits sticking together and forming long fibers in the cytoplasm d.​loss of hemoglobin through leaky cell membranes e.​the attachment of phosphate groups to the hemoglobin molecules

c.​hemoglobin molecules with mutant beta globin subunits sticking together and forming long fibers in the cytoplasm

​Thalassemias are associated with a(n) ____. a.​amino acid substitution b.​extended chain in beta globin c.​imbalance in the production of alpha or beta globin d.​excessive synthesis of beta globin e.​altered rate of oxygen transport

c.​imbalance in the production of alpha or beta globin

Lactose intolerance is caused by a(n) ____. a.​accumulation of galactose-1-phosphate b.​excess in lactose production c.​inability to digest lactose d.​nucleotide substitution that prevents lactose production e.​variant manifestation of galactosemia

c.​inability to digest lactose

​In the United States, parathion is the most widely used member of a class of ____. a.​organophosphate herbicides b.​chlorophosphate fungicides c.​organophosphate insecticides d.​chlorophosphate herbicides e.​chlorophosphate insecticides

c.​organophosphate insecticides

The ability to taste PTC and other bitter chemicals is controlled by ____. a.​the amount of PTC exposure as a child b.​hormone levels that change throughout life c.​proteins on the surface of receptor cells d.​the amount of capsaicin present in taste buds e.​the presence of fats and sugars in the food being eaten

c.​proteins on the surface of receptor cells

​Dietary treatment of galactosemia ____. a.​consists of very low protein intake b.​can usually be discontinued by the age of twelve c.​should be started within a few days after birth d.​completely eliminates symptoms of the disease e.​need not begin until one or two months after birth

c.​should be started within a few days after birth

In individuals who are most resistant to the toxic effects of parathion, the paraoxonase enzyme is/has ________ due to genetic variations. a. unable to metabolize the toxic metabolite of parathion b. not found in the bloodstream c. protein folding defects d. able to rapidly metabolize the toxic metabolite of parathion e. ten amino acid substitutions compared to the enzyme in sensitive individuals

d. able to rapidly metabolize the toxic metabolite of parathion

The science that describes an individual's sensitivity to chemical toxins is known as ________. a. pharmacogenomics b. olfactory sensitivity c. chemosensory perception d. ecogenetics e. pharmacogenetics

d. ecogenetics

The science of developing drugs that are personalized to an individual's genotype is known as ________. a. ecogenetics b. pharmacogenetics c. chemosensory abilities d. pharmacogenomics e. olfactory sense

d. pharmacogenomics

​Supertasters for the chemical PTC are ____ for the trait. a.​homozygous recessive b.​either homozygous dominant or heterozygous c.​either homozygous dominant or homozygous recessive d.​homozygous dominant e.​heterozygous

d.​homozygous dominant

Women with PKU who eat a normal diet during pregnancy will have children with ____. a.​only a 25% chance of developing PKU b.​intellectual disability only if the child's phenotype is homozygous recessive c.​no greater chance of having PKU than if she ate a special PKU diet d.​intellectual disability regardless of the child's genotype e.​intellectual disability only if the child's phenotype is heterozygous

d.​intellectual disability regardless of the child's genotype

The hemoglobin molecule ____. a.​is involved in amino acid metabolism b.​is controlled by a single gene c.​prevents sickle cell anemia when present in high enough concentrations in the blood d.​transports oxygen from the lungs to the cells of the body e.​acts as a cell surface receptor

d.​transports oxygen from the lungs to the cells of the body

Why are the red blood cells sickle-shaped in individuals with sickle cell anemia? a. Several amino acid substitutions in the defective hemoglobin cause abnormal protein folding. b. Genetic mutations cause fetal hemoglobin to be produced in adults. c. Genetic mutations cause an imbalance in the production of alpha and beta globins. d. Treatment of these patients with hydroxyurea alters hemoglobin folding. e. The defective hemoglobin molecules form long fibers, which distort and harden the cell membrane.

e. The defective hemoglobin molecules form long fibers, which distort and harden the cell membrane.

Gaucher's disease is caused by a mutation in the GBA gene, which results in the build-up of fat in the liver, spleen, and bone marrow; therefore, the GBA protein must normally function to ________. a. synthesize fat b. prevent fat metabolism c. remove fat from the bloodstream d. deliver fat to the liver, spleen, and bone marrow e. break down fat

e. break down fat

In the early years of the twentieth century, ____ proposed that some genetic disorders and abnormalities of metabolism are related. a.​Linda Bartoshuk b.​Linus Pauling c.​Gregor Mendel d.​Francis Crick e.​Sir Archibald Garrod

e.​Sir Archibald Garrod

Phenylalanine is a(n) ____ and the starting point for a network of metabolic pathways. a.​sub-type of hemoglobin b.​carbohydrate by-product of respiration c.​lactase precursor molecule d.​phenylthiocarbamide e.​essential amino acid

e.​essential amino acid

​The study of genetic variations that affect people's responses to environmental agents, including man-made chemicals, is called

ecogenetics

metabolic pathways

enzymatic chains of reactions

Proteins that act as _______ catalyze biochemical reactions and are vital components of the cell's metabolic pathways.

enzymes

The nine amino acids that humans cannot produce and which must be included in the diet are called:

essential amino acids

thalassemias

genetic disorder caused by an imbalance in the production of alpha and beta globin

inborn errors of metabolism

genetic traits that result from alterations in metabolic pathways

PKU individuals must remain on a life-time diet of:

low protein

The enzyme that normally converts phenylalanine to tyrosine - the mutation of which causes PKU is:

phenylalanine hydroxylase

An autosomal recessive disorder of amino acid metabolism that causes intellectual disability is:

phenylketonuria (PKU)