Question 1

Each human body cell contains _____.

Accepted Answer

Each human body cell contains 46 chromosomes, which are organized into 23 pairs. So, option B is the correct answer.

Question 2

Heritability indicates how much of the variation of a trait within a particular population and in a particular context can be traced to genes.

Accepted Answer

This is a correct definition of heritability, which is often expressed as a number between 0 and 1 to indicate the proportion of trait variation in a particular group that is attributable to genetic differences. However, it's important to note that heritability does not necessarily mean that a trait is entirely determined by genes, as environmental factors and gene-environment interactions can also play a role.

Question 3

The instructions for making amino acids are on about 3 billion pairs of chemicals called _____.

Accepted Answer

The instructions for making amino acids are stored in DNA molecules, which are made up of about 3 billion pairs of nucleotides called base pairs.

Question 4

The first 22 chromosomes contain hundreds of genes in the same positions and sequence. If the code of the gene from one parent differs from the code on the same gene from the other parent, the gene pair is _____.

Accepted Answer

If the code of the gene from one parent differs from the code on the same gene from the other parent, the gene pair is heterozygous. Homozygous would refer to both gene codes being identical, while monozygotic and dizygotic refer to twins and not to genes.

Question 5

One of the 46 molecules of DNA (in 23 pairs) that virtually each cell of the human body contains and that, together, contain all the genes is called a(n) _____.

Accepted Answer

A chromosome is a single molecule of DNA that contains multiple genes. Humans have 46 chromosomes, 23 from each parent, which together contain all the genetic information needed for life. Alleles are different versions of the same gene, genotypes are the genetic makeup of an individual, and a zygote is a fertilized egg cell.

Question 6

Genes and alleles for alcohol use disorder have been found exclusively on the Y chromosome.

Accepted Answer

Genes and alleles for alcohol use disorder are not found exclusively on the Y chromosome, but rather on various genes located on different chromosomes.

Question 7

Every person begins life as a single cell, which is called a _____.

Accepted Answer

A single cell that is formed when a sperm cell fertilizes an egg cell is called a zygote. Chromosomes, genotype, and DNA are all important components of a person's genetic makeup, but they do not specifically refer to the stage of development when a single cell is formed.

Question 8

Differences among people begin with alleles, which can be caused by transpositions, deletions, or repetitions of base pairs, making some genes _____.

Accepted Answer

Alleles are different versions of a gene and can be polymorphic, meaning that there are multiple forms of the gene in a population. Multimorphic is not a commonly used term in genetics. Allelemorphic and transmorphic are not commonly used terms in genetics either.

Question 9

A variation that makes a gene different in some way from other genes for the same characteristics is a(n) _____.

Accepted Answer

An allele is a variation of a gene that can result in a different expression of a trait. Chromosomes are structures that contain genes, but they do not directly affect the variation of a gene. A zygote is a result of the combination of two gametes and contains alleles from both parents. Genotype refers to the genetic makeup of an individual, but it does not specify a variation of a gene.

Question 10

The nations of sub-Saharan Africa have low rates of low-birthweight babies.

Accepted Answer

According to the World Health Organization, sub-Saharan Africa has the highest rate of low-birthweight babies in the world.

Question 11

Sex (XX or XY) is a factor in explaining why women become drunk on more alcohol than men.

Accepted Answer

Women generally become drunk on less alcohol than men due to physiological differences such as body composition and metabolism, not because of their sex chromosomes (XX or XY).

Question 12

Genes, culture, and age all affect vision.

Accepted Answer

Genes play a role in determining eye structure and function, cultural practices such as reading habits can impact vision, and age is associated with a decline in visual acuity and other changes to the eye.

Question 13

Genes affect disorders such as alcohol use disorder and nearsightedness, but research indicates that the environment plays a role as well.

Accepted Answer

Both genes and the environment have been shown to contribute to the development of disorders such as alcohol use disorder and nearsightedness. While genes may predispose individuals to these conditions, environmental factors such as exposure to alcohol and eye strain can also play a significant role.

Question 14

The single cell formed from the union of two gametes, a sperm and an ovum, is called a _____.

Accepted Answer

The definition given in the question matches with that of a zygote, which is the product of fertilization between a sperm and an ovum. A chromosome refers to the long strand of DNA containing genes, a phenotype is the physical and behavioral traits of an organism resulting from the expression of its genes, and a genotype refers to the genetic makeup of an organism. None of these options fully match the definition given in the question.

Question 15

All living things are composed of cells. The work of cells is done by _____.

Accepted Answer

Proteins are responsible for carrying out the work of cells, including functions such as enzymatic reactions, transport of molecules, cell signaling, and support of cellular structure. Zygotes refer to a single cell resulting from the fusion of two gametes and are not responsible for the work of cells. Genotypes refer to an individual's genetic makeup, which influences cell function but does not directly carry out the work of cells. DNA is a macromolecule that contains genetic information, which is used by cells to produce proteins and carry out cellular processes, but DNA itself does not directly perform the work of cells.

Question 16

Each gene directs the formation of specific proteins made from a string of _____ amino acids.

Accepted Answer

There are 20 different amino acids that can be used to create proteins. Each of these amino acids has unique properties that determine how they interact with other amino acids in the protein chain. The specific sequence of amino acids determines the structure and function of the protein that is produced.

Question 17

Each molecule of deoxyribonucleic acid (DNA) is stored on a(n) _____.

Accepted Answer

DNA molecules are typically stored within the nucleus of a cell on one or more chromosomes. A chromosome is a long, coiled-up strand of DNA that contains many genes. Genes are specific sequences of DNA that provide instructions for making proteins or other molecules that perform various functions within the cell. RNA is an important molecule involved in various functions such as protein synthesis, but it is not the primary storage molecule for genetic information. A zygote is a fertilized egg cell that contains the genetic material from both parents, but it is not a storage site for DNA.

Question 18

A small section of a chromosome that is the basic unit for the transmission of heredity is a _____.

Accepted Answer

A gene is a small section of a chromosome that is responsible for transmitting hereditary traits from parent to offspring. Chromosomes are larger structures made up of many genes, and a genotype refers to the specific set of genes an organism possesses. A zygote is the result of the fusion of an egg and sperm cell, containing a complete set of chromosomes from both parents.

Question 19

The first 22 chromosomes contain hundreds of genes in the same positions and sequence. If the code of the gene from one parent is exactly like the code on the same gene from the other parent, the gene pair is _____.

Accepted Answer

Homozygous refers to having two identical versions of a gene (one from each parent) in the same position on homologous chromosomes. If the code of the gene from one parent is exactly like the code on the same gene from the other parent, then the gene pair is homozygous.

Question 20

A "small for gestational age" baby means the same as an "underweight preterm" newborn.

Accepted Answer

"Small for gestational age" means the baby is smaller than expected for their gestational age, while "underweight preterm" refers specifically to a baby born prematurely who is underweight for their gestational age. These are two different terms with different meanings.

Quiz 8: Middle Childhood: the Social World