Question 1

The human genome is the complete set of DNA in the human organism.

Accepted Answer

The human genome is composed of approximately 3 billion base pairs of DNA that encode the genetic information necessary for the development and functioning of the human body. It is present in almost all cells of the human organism.

Question 2

Humans carry all of the genes necessary to develop a tail, but we don't develop tails because those genes are never activated.

Accepted Answer

It is true that humans carry all of the genes necessary to develop a tail, but they are not activated. These "tail genes" are remnants from our evolutionary past and have been deactivated in humans.

Question 3

Females have an XY combination of chromosomes in the 23rd pair, whereas males have an XX combination.

Accepted Answer

Females have an XX combination of chromosomes in the 23rd pair, whereas males have an XY combination.

Question 4

The branch of psychology that studies how people change over the lifespan is called developmental psychology.

Accepted Answer

Developmental psychology is the branch of psychology that focuses on how individuals change over the course of their lifetimes.

Question 5

Each chromosome contains exactly 23 pairs of genes.

Accepted Answer

Each human cell contains 23 pairs of chromosomes, which makes it a total of 46 chromosomes. Each pair of chromosomes contains genes, but not each chromosome has exactly 23 pairs of genes. The number of genes on each chromosome varies.

Question 6

Studies examining the impact of early stress in humans have shown that childhood stress or adversity can cause distinct epigenetic changes in brain tissue.

Accepted Answer

Studies have shown that childhood stress or adversity can cause distinct epigenetic changes in brain tissue.

Question 7

Males are more likely than females to display various genetic disorders, such as hemophilia and red-green color blindness.

Accepted Answer

This is true. Hemophilia and red-green color blindness are sex-linked genetic disorders that are carried on the X chromosome. Males only have one X chromosome, so if they inherit a faulty X chromosome with the disorder, they will display the disorder. Females have two X chromosomes, so even if one X chromosome is faulty, the other X chromosome may compensate for it. Therefore, males are more likely to display sex-linked genetic disorders than females.

Question 8

As people make the transition from one stage of the lifespan to another they undergo sudden, age-related changes in physical, mental, and social development.

Accepted Answer

People experience gradual and continuous development throughout their lifespan, with changes in physical, mental, and social development occurring progressively rather than suddenly as they transition from one stage to another.

Question 9

As identical twins develop, differences in physical and psychological characteristics become evident. These differences are due to each twin's individual and unique genetic blueprint.

Accepted Answer

Identical twins have the same genetic blueprint; differences in physical and psychological characteristics arise from environmental factors and unique experiences, not genetic differences.

Question 10

Dr. Dillinger investigates how gene activity is regulated within a cell, what signals switch genes "on" or "off," and in particular, what determines whether a given cell will become a skin cell, a nerve cell, or a heart muscle cell. His area of research is called epigenetics.

Accepted Answer

The passage states that Dr. Dillinger's area of research is epigenetics, which investigates how gene activity is regulated and what determines a cell's specialization. Therefore, statement A is true.

Question 11

The best known, although not the most common, pattern of allele variation is the simple dominant-recessive gene pair.

Accepted Answer

This statement is correct as the dominant-recessive gene pair is the most well-known pattern of allele variation.

Question 12

Although all humans have the same basic set of genes, these genes can come in different versions called alleles.

Accepted Answer

This statement is true. Genes can exist in different versions, or alleles, which can result in variations in physical traits and biological processes among individuals.

Question 13

DNA can be damaged by environmental factors, such as exposure to ultraviolet light, radiation, or chemical toxins, and genes can mutate, or change spontaneously, from one generation to the next.

Accepted Answer

DNA can be damaged by environmental factors and genes can mutate spontaneously, which can lead to genetic disorders or increase the risk of certain diseases.

Question 14

If you inherit a dominant version of the freckles gene, you will have the potential to display freckles. But to be freckle-free, you would need to inherit two recessive "no freckles" genes, one from each biological parent.

Accepted Answer

Freckles are a dominant trait, meaning inheriting one dominant allele for freckles can result in the display of freckles. To not have freckles, an individual must inherit two recessive alleles (one from each parent), which do not code for freckles.

Question 15

The term genotype refers to the underlying genetic makeup of a particular individual.

Accepted Answer

Genotype refers to the genetic information that an individual inherits from their parents. This includes information about all of their genes and genetic variations.

Question 16

Epigenetics refers to the study of the mechanisms that control gene expression and its effect on behavior and health.

Accepted Answer

This is the correct definition of epigenetics.

Question 17

In one experimental study, researchers found that newborn rats who were genetically predisposed to be calm and stress-resistant grew up to be nervous, high-strung, and easily stressed adult rats when raised by genetically unrelated, inattentive mothers. The explanation for these results was that epigenetic changes had taken place which changed their brain chemistry and literally "reprogrammed" their behavior.

Accepted Answer

The statement accurately represents the findings of the experimental study, which suggests that epigenetic changes can alter behavior even in genetically predisposed individuals.

Question 18

You have 23 chromosomes in each of your body's cells.

Accepted Answer

Humans have 46 chromosomes in each body cell, arranged in 23 pairs, including one pair of sex chromosomes.

Question 19

Most developmental psychologists believe that gene expression is primarily influenced by the fixed, master plan, or genetic blueprint, with which people are born.

Accepted Answer

Most developmental psychologists now believe that gene expression is influenced by a complex interplay of genetic and environmental factors, with the environment playing a significant role in how genes are expressed. This view is known as the "nature via nurture" approach.

Question 20

A gene is a segment on a chromosome containing the DNA instructions for manufacturing a particular protein molecule.

Accepted Answer

This is the correct definition of a gene. Genes are the basic units of genetic information that determine hereditary traits and are responsible for the production of proteins that carry out various functions in the body. These protein molecules perform a wide range of functions, from providing structure to the body to regulating chemical reactions and processes.

Quiz 9: Section 3: Lifespan Development