Question 1

Vince and Juan are playing basketball.Vince shoots the ball,and Juan blocks the shot.Vince says,"Wow,I didn't realize how tall you were until you did that!" Vince's comment refers to Juan's:

Accepted Answer

Vince's comment is referring to Juan's physical appearance, which is determined by his phenotype, or the expression of his genetic traits. Factors such as height are determined by a combination of genetics and environmental factors, so Vince's comment is likely an observation of Juan's overall physical traits rather than a specific genetic factor like an allele or genotype. Gametes are reproductive cells, and are not relevant to the discussion of Juan's height.

Question 2

Brown-eyed Inez has a blue-eyed mother and a brown-eyed father.In this case,her brown eyes were determined by a _____ allele.

Accepted Answer

Since Inez has brown eyes and her mother has blue eyes, it can be inferred that the brown eye trait is dominant over the blue eye trait. Therefore, Inez's brown eyes were determined by a dominant allele inherited from her father.

Question 3

Epigenetics means that a trait:

Accepted Answer

Epigenetics refers to the study of changes in gene expression, or the way in which genes are turned on or off, that are caused by environmental factors. This means that a trait can be influenced by both genes and the environment, making choice C the best answer. While genes may play a role in determining certain traits, such as eye color, environmental factors can also impact gene expression and therefore influence the expression of certain traits.

Question 4

Lara has a recessive gene in her genotype that is not expressed in her phenotype.She is a(n)_____ of that gene.

Accepted Answer

Lara is a carrier of the recessive gene because she has it in her genotype but it is not expressed in her phenotype. A recipient is a term used in transplantation, not genetics. Expressor and reactor are not commonly used terms in genetics.

Question 5

Jamal was born with genes to be a professional athlete,but his environmental experiences never supported the development of his potential athletic ability,so he never became a professional athlete.This example illustrates the concept of a trait being:

Accepted Answer

The example illustrates the concept of a trait being multifactorial, meaning that it is influenced by both genetic and environmental factors. While Jamal may have had genetic potential for athleticism, his environmental experiences prevented the development of this potential. This highlights the need to consider both genetic and environmental factors when examining complex traits like athleticism. The other answer choices do not accurately reflect the concept illustrated by the example.

Question 6

Almost every trait is _____,which means it is affected by many genes.

Accepted Answer

Polygenic traits are determined by multiple genes, often interacting with each other and with environmental factors. Most human traits, such as height, weight, intelligence, and susceptibility to diseases, are polygenic in nature.

Question 7

Which of the following women is MOST likely to conceive dizygotic twins?

Accepted Answer

The likelihood of having dizygotic (fraternal) twins increases with age and is highest in women over 35 years old. Therefore, Olu, who is 35 years old, is the most likely to conceive dizygotic twins. Age is a significant factor in the likelihood of conceiving twins, and advanced maternal age can increase the chance of dizygotic twins due to hormonal changes that stimulate the ovaries to release more than one egg.

Question 8

The interaction of a heterozygous pair of alleles in such a way that the phenotype reflects one allele more than the other is referred to as a(n):

Accepted Answer

The description given best fits the dominant-recessive pattern of inheritance, where the dominant allele is expressed in the phenotype even in the presence of a recessive allele. This results in the phenotype reflecting the dominant allele more than the recessive allele.

Question 9

An individual's phenotype describes all the following EXCEPT an individual's:

Accepted Answer

Phenotype refers to the observable characteristics of an individual, such as appearance, behavior, and physical traits, which result from the interaction of its genotype with the environment. Genetic potential, however, is more about the capabilities and limits set by an individual's genes and is not directly observable, making it not a part of the phenotype.

Question 10

Samantha learned from her science teacher that her height resulted from about 180 genes,each contributing a tiny amount of genetic information.She learned that her height was due to:

Accepted Answer

The fact that Samantha's height is determined by about 180 genes, each making a small contribution to her overall height, suggests that her height is determined by additive genes. Additive genes are those that contribute small amounts to a trait, and when combined with other genes in the same pathway, can have a larger impact on the overall expression of the trait.

Question 11

When the effects of genes combine to create the phenotype,they are called "_____ genes."

Accepted Answer

Additive genes refer to genes that contribute to the phenotype in an additive manner, meaning that their effects combine together. This is in contrast to dominant genes, which overpower the effects of recessive genes, and nonadditive genes, which exhibit complex interactions with other genes.

Question 12

Nate is color-blind.His gene for color blindness is MOST likely a:

Accepted Answer

Color blindness is a sex-linked recessive trait, meaning that the gene for color blindness is located on the X chromosome. Since males have only one X chromosome, they are more likely to express the trait when they inherit one copy of the gene from their mother. Females, on the other hand, must inherit two copies of the gene (one from each parent) to express the trait. Therefore, Nate's gene for color blindness is most likely a recessive gene on his X chromosome.

Question 13

The _____ is a person's appearance,personality,intelligence,and all other traits.

Accepted Answer

The phenotype is the observable traits of an organism, including its physical appearance, behavior, and other characteristics that result from the interaction of its genotype (genetic makeup) and environmental factors. It encompasses all of the traits mentioned in the statement. Alleles refer to different versions of a gene, genotype refers to an individual's genetic makeup, and gametes are reproductive cells (sperm or eggs) that carry genetic information.

Question 14

_____ refers to a trait that is affected by many variables,both genetic and environmental,that enhance,halt,shape,or alter the expression of genes,resulting in a phenotype that may differ markedly from the genotype.

Accepted Answer

Multifactorial refers to a trait that is influenced by both genetic and environmental factors, and the expression of genes can be enhanced, halted, shaped, or altered resulting in a phenotype that may differ from the genotype. Polygenic refers to a trait that is influenced by multiple genes, Nonadditive refers to genetic effects that are not simply additive, and Monozygotic refers to having developed from a single fertilized egg, which is not relevant to the definition given.

Question 15

Upon the completion of the Human Genome Project,several surprise findings were made,including all the following EXCEPT that:

Accepted Answer

The completion of the Human Genome Project revealed that humans are actually genetically very similar to each other, with over 99.9% of DNA sequences being identical between any two individuals. This finding contradicts option B, which states that humans are extremely genetically different from one another.

Question 16

_____ refers to a gene carried on the X chromosome.

Accepted Answer

X-linked genes are those carried on the X chromosome and can exhibit sex-linked inheritance patterns. These genes are affected by the presence or absence of the X chromosome and can lead to differences in phenotypic expression between males and females.

Question 17

Wayne has inherited genes that put him at risk for developing diabetes,but he never develops diabetes due to a healthy diet and exercise.This example demonstrates that human characteristics,including diabetes,are:

Accepted Answer

This example illustrates the concept of epigenetics, where gene expression is influenced by environmental factors and lifestyle choices, such as diet and exercise, rather than the genetic code itself.

Question 18

Nancy rushed into the house after school and announced to her parents,"My personality is _____! So many genes make me who I am!"

Accepted Answer

Polygenic traits are those controlled by multiple genes. This means that a person's personality, for example, is likely not determined by just one gene, but rather by many different genes working together.

Question 19

The _____ was a worldwide effort to map all human genes.

Accepted Answer

The Human Genome Project was a worldwide effort to map all human genes. The Hap Map is a database of human genetic variations, the Apgar scale is a medical scoring system used to assess the health of newborns, and the Brazelton Assessment is a standardized test used to evaluate the neurological and behavioral responses of newborns.

Question 20

Dizygotic twins have _____ of their genes in common.

Accepted Answer

Dizygotic (fraternal) twins share, on average, 50% of their genes due to sharing the same amount of genetic material as siblings.

Quiz 2: The Beginning: From Conception to Birth