Question 1

While ____ refers to a person's genetic makeup, ____ refers to a person's observable characteristics.

Accepted Answer

The answer of While ____ refers to a person's genetic...

Question 2

Stephanie and her four sisters are all artistically inclined and enjoy working on creative projects. When she meets her three cousins for the first time, Stephanie is somewhat surprised to find that none of them have any interest at all in art. The differences between Stephanie's sisters and her cousins could be used as evidence to suggest that

Accepted Answer

The answer of Stephanie and her four sisters are all...

Question 3

Polygenic traits involve characteristics that are influenced by

Accepted Answer

Polygenic traits involve multiple pairs of genes, each of which contributes to the phenotype of the trait. These genes can come from both parents, so choice C is the only option that fits this description. Choices A and B describe simple Mendelian inheritance, where traits are determined by a single pair of genes. Choice D is not possible, as polygenic traits require multiple genes.

Question 4

Skin color is determined by three to five gene pairs. This makes skin color

Accepted Answer

Skin color is determined by multiple gene pairs, making it a polygenic trait.

Question 5

A person's genotype refers to his or her

Accepted Answer

A person's genotype refers to their genetic makeup, which encompasses all of their inherited genes from both parents. It is not the same as their observable characteristics or traits. Additionally, there is no dominant contribution from either the paternal or maternal side; the genotype is a combination of both.

Question 6

Kelly and Shelly are identical twins who have been raised apart, in separate adoptive homes. Shelly has developed a psychological disorder, but Kelly does not appear to have the same disorder. This information could be used as evidence to suggest that

Accepted Answer

The fact that the identical twins, who have the same genetic makeup, were raised in different environments and only one has developed the disorder suggests that environmental factors have played a role in the development of the disorder. If genetic factors were solely responsible, then both twins would be expected to have the disorder. Therefore, option B is the best choice.

Question 7

Donald and Ronald are identical twins who have been raised apart, in separate adoptive homes. However, both brothers have developed the same psychological disorder. This information could be used as evidence to suggest that

Accepted Answer

The fact that identical twins, who share the same genetic makeup, have developed the same psychological disorder despite being raised in different environments suggests that genetic factors play a significant role in the development of this disorder. Therefore, genetic factors have more influence than environmental factors in this disorder.

Question 8

The specific pattern of genes inherited at conception defines an individual's

Accepted Answer

The specific pattern of genes inherited at conception is an individual's genotype. Phenotype refers to the observable traits that result from the interaction between genotype and environment, while polygenic inheritance refers to traits that are determined by multiple genes. Stereotype refers to a widely held and oversimplified belief about a particular group or individual.

Question 9

We would expect the greatest degree of phenotypic similarity among

Accepted Answer

Identical twins, also known as monozygotic twins, come from a single fertilized egg that splits into two embryos. Therefore, they have virtually identical genetic material, resulting in the greatest degree of phenotypic similarity. Fraternal twins, on the other hand, come from two separately fertilized eggs and share approximately 50% of their genetic material, while siblings and parents and their children share only 50% and 25% of their genetic material, respectively, leading to less phenotypic similarity.

Question 10

Londra and Sondra are identical twins who have been raised together in the same home. Londra has developed a psychological disorder, but Sondra does not appear to have the same disorder. This information could be used as evidence to suggest that

Accepted Answer

Since Londra and Sondra are identical twins who have been raised in the same home, it can be inferred that their environmental factors are largely similar. However, since only Londra has developed the psychological disorder, it is likely that environmental factors have less impact on this disorder than genetic factors. This supports the idea that genetic factors have more influence than environmental factors in this disorder. Therefore, option B is the best choice.

Question 11

Assume that developing a sixth toe is a recessive trait that is controlled by a single pair of genes. If a child has six toes, but both the child's biological parents have normal feet, you can conclude that

Accepted Answer

Since developing a sixth toe is a recessive trait, both parents must be carriers of the gene but not express it. This means that both parents must be heterozygous for the trait. When they have a child, there is a 25% chance that the child will inherit two recessive genes for the trait and express it, resulting in six toes. Therefore, the best choice is B, both parents are heterozygous for the trait.

Question 12

If Tom is heterozygous for a specific gene pair, which of the following must be true?

Accepted Answer

If Tom is heterozygous for a specific gene pair, it means he has two different alleles for that gene. Therefore, option C is the correct choice. Option A cannot be true because if both genes were dominant, Tom would be homozygous dominant, not heterozygous. Likewise, option B cannot be true for the same reason. Option D cannot be true because if the two genes were the same, Tom would be homozygous, not heterozygous.

Question 13

The observable characteristics of an individual are referred to as that person's

Accepted Answer

Phenotype refers to the physical and observable characteristics of an individual, such as hair color, eye color, and height. Zygotype is not a commonly used term in genetics. Genotype refers to the genetic makeup of an individual, including both dominant and recessive alleles. Heritability refers to the proportion of variation in a trait that can be attributed to genetic factors.

Question 14

Sally has blue eyes and blond hair. Genetically, this description refers to Sally's

Accepted Answer

The description of Sally's physical characteristics (blue eyes and blond hair) refers to her observable traits or phenotype, which is determined by her genetic makeup or genotype. Somatotype refers to a classification of body types based on physical characteristics, and prototype refers to a typical or idealized example of something.

Question 15

It appears that most human characteristics are influenced by

Accepted Answer

Most human characteristics are influenced by more than one pair of genes. This is known as polygenic inheritance, where multiple genes contribute to a trait, and the interaction between those genes can also affect the expression of the trait. Additionally, environmental factors can also play a role in determining the expression of certain traits.

Question 16

Shane and Blane are identical (monozygotic) twins; however, people seldom get the two brothers mixed up because Blane is almost 2 inches shorter than Shane. The difference in height means that

Accepted Answer

The fact that Shane and Blane are identical twins means they have the same genotype. However, the difference in their height indicates that they display different phenotypes. This can be due to environmental factors such as nutrition, exercise, or lifestyle choices. It is also possible that random mutations could have occurred during their development, leading to subtle differences in their gene expression or protein synthesis. However, since they are monozygotic twins, any genetic differences between them would be minimal. Therefore, the most likely explanation for their different heights is that they display the same genotype (i.e. they are genetically identical) but exhibit different phenotypes due to a variety of factors, most likely environmental.

Question 17

Which of the following is determined at conception and is fixed forever?

Accepted Answer

The genotype refers to an individual's specific genetic makeup, which is determined at conception and remains fixed throughout life. The phenotype, on the other hand, refers to the observable physical and behavioral characteristics that result from the interaction between genes and the environment, and can change throughout an individual's lifespan. Somatotype and prototype are not genetic concepts and are not determined at conception.

Question 18

Family studies, twin studies, and adoption studies are primarily designed to

Accepted Answer

Family studies, twin studies, and adoption studies are all methods used to examine the relative contributions of genetics and environment to various traits and behaviors. These studies are used to disentangle the two and determine how much of a particular trait is influenced by genetic factors and how much is influenced by environmental factors.

Question 19

Adoption studies of intelligence suggest that

Accepted Answer

Adoption studies have shown that both genetics and environment contribute to intelligence. Children who are adopted have different genetics than their adoptive parents, but they may share some environmental factors. On the other hand, they may also share genetics with their biological parents, but have a different environment. By comparing the intelligence of adopted children to both their biological and adoptive families, researchers have found that genetics and environment both play a role in intelligence.

Question 20

A recessive gene is a gene that is

Accepted Answer

A recessive gene is only expressed when paired with a similar recessive gene. Therefore, it is masked when paired with a dominant gene or when paired heterozygously with another recessive gene. Hence, option B, masked when paired genes are different, is the correct answer.

Quiz 6: The Biological Bases of Behavior Part 2

While refers to a person's genetic makeup, refers to a person's observable characteristics.