Question 1

If a person with two different alleles has a phenotype that is an intermediate between the two types favored by each allele on its own, the trait may be considered to __________.

Accepted Answer

When the phenotype of a heterozygous individual is intermediate between the two homozygous types, it is referred to as incomplete dominance. This means that neither allele is dominant or recessive, but rather they both contribute to the phenotype in a blended or mixed manner.

Question 2

Gregor Mendel __________.

Accepted Answer

Gregor Mendel is credited with discovering the basic principles of genetic inheritance, which are now known as Mendelian genetics. He conducted experiments with pea plants in the mid-1800s and published his results in 1866. Mendel's work provided a foundation for modern genetics. The other choices are incorrect because Mendel did not write the Origin of Species, did not believe in the inheritance of acquired characteristics, and did not fight against the theory of evolution.

Question 3

If an individual is homozygous for a particular gene, __________.

Accepted Answer

If an individual is homozygous for a particular gene, it means that both alleles of that gene are the same. Since an individual inherits one allele from each parent, if they are homozygous, it means they received the same identical gene from both parents.

Question 4

If an individual is heterozygous for a particular gene, __________.

Accepted Answer

When an individual is heterozygous for a particular gene, it means they have received two different alleles for that gene, one from each parent. This is in contrast to being homozygous, where an individual has received the same allele from both parents. The gene could be either dominant or recessive.

Question 5

Carolyn has an allele for red hair and an allele for brown hair. She has brown hair. Which of the following statements is true about Carolyn?

Accepted Answer

Carolyn is heterozygous because she carries two different alleles for the hair color gene (red and brown). Her phenotype (brown hair) does not match one of her genotypes (red hair allele), indicating that the red hair allele is recessive and the brown hair allele is dominant, as the dominant allele's trait (brown hair) is expressed in her phenotype.

Question 6

A brother and sister born from the same parents __________.

Accepted Answer

A brother and sister each receive half of their chromosomes from their mother and half from their father. While it is possible for them to share all the same chromosomes, it is unlikely. Therefore, on average, siblings share roughly 50% of their chromosomes.

Question 7

Carrie has two alleles for red hair, and she has red hair. Which of the following statements is true about Carrie?

Accepted Answer

If Carrie has two alleles for red hair and exhibits the trait of red hair, she must be homozygous for the gene. This means that both of her alleles are the same and she inherited the red hair gene from both of her parents. Therefore, her phenotype (red hair) matches her genotype (two alleles for red hair). Additionally, the fact that she has red hair indicates that the gene for red hair is expressed, meaning that it is either dominant or codominant. However, we cannot determine from this information whether the gene is dominant or codominant, so statement C is not necessarily true.

Question 8

A gene is said to be dominant. What is the likelihood that the trait controlled by that gene will be expressed?

Accepted Answer

If a gene is dominant, it means that it will be expressed in the presence of at least one copy of itself. Therefore, the trait controlled by that gene has a high likelihood of being expressed.

Question 9

If an individual changes his diet because it is discovered he has phenylketonuria (PKU), then one can conclude that although he had the __________ for PKU, it did not lead to the __________ of retardation.

Accepted Answer

PKU is caused by a recessive gene, meaning an individual must inherit two copies of the gene (one from each parent) in order to develop the condition. This would result in a specific genotype. However, it is only when the condition leads to the phenotypic expression of retardation (via an inability to metabolize phenylalanine) that it becomes clinically relevant. Thus, changing the diet to prevent the phenotypic expression of PKU indicates that the individual had the genotype for PKU but not the phenotype of retardation.

Question 10

Which of the following is NOT a trait based on a distinct set of recessive trait gene pairings?

Accepted Answer

Intelligence is not solely determined by genetics and is influenced by a variety of factors such as environment and upbringing. The other traits listed have known genetic determinants.

Question 11

Which of the following is NOT an example of polygenic inheritance?

Accepted Answer

Phenylketonuria (PKU) is an example of a genetic disorder that follows a Mendelian pattern of inheritance, which means it is caused by a mutation in a single gene. The other options listed are examples of complex traits influenced by multiple genes, also known as polygenic inheritance.

Question 12

The serotonin transporter gene is an example of a __________ gene effect.

Accepted Answer

The serotonin transporter gene is an example of incomplete dominance, where the phenotype is a blend of the dominant and recessive traits, rather than one completely masking the other.

Question 13

Phenylketonuria __________.

Accepted Answer

Phenylketonuria (PKU) is a genetic disorder that is caused by a recessive gene pairing. The inability to metabolize phenylalanine, an amino acid in proteins, can lead to a buildup of toxic substances that can cause mental retardation. Therefore, all the choices are correct.

Question 14

Genotype refers to __________.

Accepted Answer

Genotype refers to the specific genes that an organism carries. This includes both the dominant and recessive traits that determine an organism's traits and characteristics. It is distinct from phenotype, which refers to the physical expression of those genes.

Question 15

Blood type is an example of __________ gene effects.

Accepted Answer

Blood type is an example of codominant gene effects, where both alleles contribute to the phenotype. For example, individuals with the AB blood type have both the A and B alleles expressed, resulting in a unique phenotype.

Question 16

Phenotype refers to __________.

Accepted Answer

Phenotype refers to the observable traits and characteristics of an organism, which can include physical traits, biochemical characteristics, and behaviors. It is the result of the interaction between an organism's genotype (its genetic makeup) and its environment. While genes play a role in determining phenotype, it is not only determined by an organism's genes, but also by how those genes interact with the environment. Therefore, options A, C, and D are incorrect.

Question 17

The locus of a gene refers to __________.

Accepted Answer

The locus of a gene refers to its specific position within a chromosome.

Question 18

If both genes in a pair of genes affect the phenotype, then the alleles may be considered __________.

Accepted Answer

When both alleles in a pair of genes affect the phenotype, they are considered codominant. This means that both alleles are expressed equally in the phenotype. In incomplete dominance, one allele is partially dominant over the other, resulting in an intermediate phenotype. "Phenotypical" and "genotypical" are not terms used to describe the relationship between alleles in a pair of genes.

Question 19

A gene is said to be recessive. What is the likelihood that the trait controlled by that gene will be expressed?

Accepted Answer

If a gene is recessive, the trait it controls will only be expressed if two copies of the recessive gene are present (one from each parent). Therefore, the trait will be expressed only if the paired gene is identical.

Question 20

Polygenic inheritance refers to __________.

Accepted Answer

Polygenic inheritance refers to how a trait is influenced by many genes. While multiple inherited traits and the influence of both environment and genetics may be related to polygenic inheritance, they do not fully define it.

Quiz 2: Evolutionary and Genetic Influences on Behavior

If a person with two different alleles has a phenotype that is an intermediate between the two types favored by each allele on its own, the trait may be considered to __________.

Gregor Mendel __________.

If an individual is homozygous for a particular gene, __________.

If an individual is heterozygous for a particular gene, __________.

Carolyn has an allele for red hair and an allele for brown hair. She has brown hair. Which of the following statements is true about Carolyn?

A brother and sister born from the same parents __________.

Carrie has two alleles for red hair, and she has red hair. Which of the following statements is true about Carrie?

A gene is said to be dominant. What is the likelihood that the trait controlled by that gene will be expressed?

If an individual changes his diet because it is discovered he has phenylketonuria (PKU) , then one can conclude that although he had the for PKU, it did not lead to the of retardation.

Which of the following is NOT a trait based on a distinct set of recessive trait gene pairings?

Which of the following is NOT an example of polygenic inheritance?

The serotonin transporter gene is an example of a __________ gene effect.

Phenylketonuria __________.

Genotype refers to __________.

Blood type is an example of __________ gene effects.

Phenotype refers to __________.

The locus of a gene refers to __________.

If both genes in a pair of genes affect the phenotype, then the alleles may be considered __________.

A gene is said to be recessive. What is the likelihood that the trait controlled by that gene will be expressed?

Polygenic inheritance refers to __________.

Quiz 2: Evolutionary and Genetic Influences on Behavior

If a person with two different alleles has a phenotype that is an intermediate between the two types favored by each allele on its own, the trait may be considered to __________.

Gregor Mendel __________.

If an individual is homozygous for a particular gene, __________.

If an individual is heterozygous for a particular gene, __________.

Carolyn has an allele for red hair and an allele for brown hair. She has brown hair. Which of the following statements is true about Carolyn?

A brother and sister born from the same parents __________.

Carrie has two alleles for red hair, and she has red hair. Which of the following statements is true about Carrie?

A gene is said to be dominant. What is the likelihood that the trait controlled by that gene will be expressed?

If an individual changes his diet because it is discovered he has phenylketonuria (PKU) , then one can conclude that although he had the __________ for PKU, it did not lead to the __________ of retardation.

Which of the following is NOT a trait based on a distinct set of recessive trait gene pairings?

Which of the following is NOT an example of polygenic inheritance?

The serotonin transporter gene is an example of a __________ gene effect.

Phenylketonuria __________.

Genotype refers to __________.

Blood type is an example of __________ gene effects.

Phenotype refers to __________.

The locus of a gene refers to __________.

If both genes in a pair of genes affect the phenotype, then the alleles may be considered __________.

A gene is said to be recessive. What is the likelihood that the trait controlled by that gene will be expressed?

Polygenic inheritance refers to __________.

If an individual changes his diet because it is discovered he has phenylketonuria (PKU) , then one can conclude that although he had the for PKU, it did not lead to the of retardation.