Question 1

What genetic disorder is associated with the lack of an enzyme necessary for the normal metabolism of the amino acid phenylalanine?

Accepted Answer

Phenylketonuria (PKU) is associated with the lack of the enzyme necessary for the metabolism of phenylalanine. Marfan syndrome is associated with a defect in the elastic connective tissue protein called fibrillin. Huntington disease is caused by a mutation to the protein huntingtin. Sickle cell disease is an irregular shape of the red blood cells. Cystic fibrosis (CF) is associated with a faulty protein channel in the cell membrane.Bloom's

Question 2

All but one of the following experiments would allow a scientist to discover if the phenotype of an organism would be affected by environmental changes; choose the experiment that would not show environmental effects.

Accepted Answer

It is necessary to determine that the organisms involved have the same genotype so exposure to different test conditions in the experiment is the one variable that is different. Cuttings from one plant or altering the conditions for a single organism so it experiences two different conditions would meet these conditions. Even if the mice all show the same trait since it is dominant the genotype is unknown.Bloom's

Question 3

Humans can have any of several eye colors,this is because we possess a variety of

Accepted Answer

Alleles are defined as alternate forms of a gene; they are located on homologous chromosomes at the same loci on those two chromosomes.Bloom's

Question 4

Hydrangeas are a flowering plant with large showy blooms.When a plant is grown in aluminum rich soil it has blue flowers; if the same plant is transplanted into soil that is lacking aluminum the flowers produced will be pink.This is an example of

Accepted Answer

Codominance occurs when the heterozygote shows both of the parental phenotypes equally. Incomplete dominance is when the organism can express three different variations for a particular trait. Since the phenotype of the flowers depends on an external condition this is an example of environmental effects on gene expression. Polygenic inheritance is when two or more genes regulate a trait. Monohybrid inheritance is when a trait has a dominant and recessive variation.Bloom's

Question 5

Cold weather can change the ______ of a Himalayan rabbit.

Accepted Answer

Environmental factors can affect the way that the genotype is expressed; it does not change the genotype itself. This means that the alleles are still the same ones that were inherited but that the phenotype is altered.The sex of the organism is also an inherited character and it is not affected by environmental factors. The rate of genetic mutations is not controlled by temperature.Bloom's

Question 6

Consider skin color to be regulated by three genes A,B and C.All recessive alleles would be 0 or white on the color scale.All dominant alleles would be 6 or black on the color scale.What color is a person with AAbbCc genotype?

Accepted Answer

Since the darkness of the skin depends on how many dominant alleles are inherited some one with AABB would be the darkest skin possible and aabb would be the lightest skin possible. AAbb would be a color in the middle of the range of colors or a brown color.Bloom's

Question 7

You have two true-breeding rose bushes,one with red flowers and one with white flowers,a cross between these two roses yields a bush with pink flowers.What condition does this demonstrate?

Accepted Answer

Incomplete dominance occurs when the heterozygote does not show the phenotype of either parent. The combination of red and white flowers leading to pink flowers would be an example of this. Incomplete dominance is when the organism can express three different variations for a particular trait. Environmental effects is when the environment influences traits. Polygenic inheritance is when two or more genes regulate a trait. Monohybrid inheritance is when a trait has a dominant and recessive variation.Bloom's

Question 8

When two or more sets of alleles affect the same trait in an additive fashion,it is termed

Accepted Answer

Polygenic inheritance involves more than one gene and therefore more than one allele pair, these genes are located in different places in the genome and possibly on different chromosomes.Bloom's

Question 9

To try and discover if the environment has an effect on a particular characteristic scientists often examine

Accepted Answer

Monozygotic twins have the same genetic makeup so studying two individuals with the same genotype that have been exposed to two different set of environmental conditions would allow any differences in phenotype to be analyzed.Bloom's

Question 10

The leaves of a maple tree vary in size depending on the location of the leaves on the tree.Those growing at the outer region of the tree tend to be smaller than those growing closer to the trunk of the tree.This allows leaves that are growing in the shade to have a larger surface area.This show that genes have the ability to

Accepted Answer

Phenotypic variations allow organisms to respond to conditions in the environment. Leaves that receive less sunlight require a larger surface are in order to carry out photosynthesis efficiently. Those that are exposed to full sunlight do not need that same increased surface area. The plant is not showing two different genetic variations of leaves. The genes are not being turned on or off due to their position on the tree and they are not choosing to be expressed or not. Sunlight is not causing them to mutate.Bloom's

Question 11

Huntington disease is an autosomal dominant disorder that leads to progressive degeneration of brain cells.There is no effective treatment for the disorder and individuals usually die 10 to 15 years after the onset of symptoms.Which of these statements about Huntington disease is true?

Accepted Answer

Huntington disease is inherited if one dominant allele is inherited but the disease frequently does not appear until the individual has reached middle age and already has children. There is a test to detect the disorder but since there is no cure most individuals choose not to be tested.Bloom's

Question 12

Which genetic disorder is associated with a defect in the elastic connective tissue protein called fibrillin?

Accepted Answer

Marfan syndrome is associated with a defect in the elastic connective tissue protein called fibrillin. Huntington disease is caused by a mutation to the protein huntingtin. Sickle cell disease is an irregular shape of the red blood cells. Phenylketonuria (PKU) is associated with the lack of the enzyme necessary for the metabolism of phenylalanine. Cystic fibrosis (CF) is associated with a faulty protein channel in the cell membrane.Bloom's

Question 13

Indicate the genotypic and phenotypic ratios that you could expect if an individual who is heterozygous for Huntington disease has children with a normal individual.

Accepted Answer

The answer of Indicate the genotypic and phenotypic ratios that...

Question 14

You have two true-breeding rose bushes,one with red flowers and one with white flowers,a cross between these two roses yields a bush with white flowers that have red splotches.What condition does this demonstrate?

Accepted Answer

Codominance occurs when the heterozygote shows both of the parental phenotypes equally. Incomplete dominance is when the organism can express three different variations for a particular trait. Environmental effects is when the environment influences traits. Polygenic inheritance is when two or more genes regulate a trait. Monohybrid inheritance is when a trait has a dominant and recessive variation.Bloom's

Question 15

Traits that are controlled by several sets or pairs of alleles,such as skin color and height in humans,are the result of what form of inheritance?

Accepted Answer

Polygenic inheritance would mean that there were multiple genes at different locations and possibly on different chromosomes all controlling one trait. Simple Mendelian genetics would indicate a simple dominant/recessive relationship whereas codominance would be a system where alleles both show in the offspring and incomplete domanance would be a case where heterozygotes would show a different phenotype than either of the homozygotes.Bloom's

Question 16

Which genetic disorder is associated with an irregular shape of the red blood cells?

Accepted Answer

Sickle cell disease is an irregular shape of the red blood cells. Marfan syndrome is associated with a defect in the elastic connective tissue protein called fibrillin. Huntington disease is caused by a mutation to the protein huntingtin. Phenylketonuria (PKU) is associated with the lack of the enzyme necessary for the metabolism of phenylalanine. Cystic fibrosis (CF) is associated with a faulty protein channel in the cell membrane.Bloom's

Question 17

How many alleles are required to express a monohybrid trait?

Accepted Answer

Monohybrid traits are made up of 2 alleles.Bloom's

Question 18

Which of the following is an autosomal dominant disorder?

Accepted Answer

Marfan syndrome is an autosomal dominant disorder. The rest of the disorders are autosomal recessive.Bloom's

Question 19

Which allele combination represents a recessive monohybrid trait?

Accepted Answer

aa represents a recessive monohybrid trait. Aa and AA represent the dominant variation. ab and Ab do not represent a trait. Both alleles need to be represented by the same letter.Bloom's

Question 20

The skin pigment melanin is expressed differently according to exposure to sunlight,with a greater production of the molecule with greater exposure.However,the degree of production can never exceed the inherited genetic level.What evolutionary advantage would be gained from having this phenotypic range for skin pigmentation?

Accepted Answer

The production of molecules requires large amounts of cellular energy therefore, only producing the molecule when it is necessary because of exposure to increased sunlight would allow for a more efficient use of cellular energy.Bloom's

Quiz 23: Patterns of Gene Inheritance