Question 1

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

Accepted Answer

The zygote is the cell that results from the fusion of two gametes, a sperm and an ovum. It contains a full set of chromosomes and is the beginning stage of a new organism. Chromosomes are the structures within a cell that contain genetic information. Phenotype refers to the physical and observable characteristics of an organism, and genotype refers to an organism's genetic makeup. While both of these terms are important in genetics, they are not directly related to the formation of a zygote.

Question 2

Dr. Garcia studies how environmental factors affect gene expression-enhancing, halting, shaping, or altering the expression of genes. Dr. Garcia studies _____.

Accepted Answer

The study of how environmental factors impact gene expression is known as epigenetics. Therefore, Dr. Garcia is studying epigenetics.

Question 3

Humans have 23 pairs of _____, which contain the instructions to make the proteins needed for life and growth.

Accepted Answer

Chromosomes contain the genetic information in the form of DNA, which provides the instructions to make proteins needed for life and growth. Alleles refer to alternative forms of a gene, genotypes refer to the genetic makeup of an individual, and zygotes refer to the first cell that results from the fusion of sperm and egg during fertilization. Therefore, the best choice is A) chromosomes.

Question 4

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

Accepted Answer

While genes can predispose individuals to certain disorders, research shows that environmental factors also play a role in the development of these disorders. For example, alcoholism may be influenced by environmental factors such as stress or access to alcohol, in addition to genetic factors. Likewise, nearsightedness can be influenced by both genetic factors and environmental factors such as prolonged use of electronic devices or not spending enough time outdoors.

Question 5

One aspect of both nature and nurture that profoundly affects each person is the _____, which refers to all microbes that live within every part of the body.

Accepted Answer

The microbiome, which refers to all of the microbes that live within every part of the body, is a factor influenced both by genetics and by environmental factors such as diet and hygiene. The microbiome has been linked to a range of health outcomes, from digestive disorders to mental health.

Question 6

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

Accepted Answer

A zygote is the fertilized egg that results from the fusion of sperm and egg. It is the first cell that begins the process of embryonic development. Chromosomes, genotype, and genome are all terms used to describe genetic material and do not specifically refer to the single cell stage of development.

Question 7

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

Accepted Answer

Cells contain many different types of proteins that carry out various cellular functions, such as enzymatic activity, structural support, and signaling. Proteins are the main workhorses of cells, performing many necessary tasks for the survival and function of the organism. Zygotes are cells that form during fertilization and develop into embryos, but they are not responsible for the ongoing work of cells. Genotypes and phenotypes are terms used to describe an organism's genetic makeup and physical traits, respectively, and are not directly involved in the work of cells.

Question 8

Consultation and testing by trained experts that enable individuals to learn about their genetic heritage, including harmful conditions they could pass along to any children they might conceive, is referred to as "couples counseling."

Accepted Answer

The given definition is incorrect. Couples counseling refers to counseling sessions for couples to improve their relationship, while genetic testing and counseling is a separate process that helps individuals learn about their genetic heritage and risks of passing on inherited conditions to their children.

Question 9

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

Accepted Answer

Each molecule of DNA is packaged and stored on a chromosome, which is a structure made up of DNA and proteins in the nucleus of a cell. RNA is a different type of nucleic acid that is involved in protein synthesis, but it is not where DNA is stored. Genes are segments of DNA that contain the instructions for making specific proteins, but they are not the location of where all DNA is stored. Zygote is a cell that results from fertilization, but it is not a structure where DNA is stored.

Question 10

Genes, culture, and age all affect vision.

Accepted Answer

Genes determine the basic structure of the eye and how it functions, culture may influence visual perception and practices such as eye contact or visual attention, and age can lead to changes in the optic nerve and gradual decline in vision.

Question 11

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 or different form of a gene that exists at the same locus on homologous chromosomes. Therefore, D is the correct answer as it directly matches the given definition. A chromosome refers to a structure that consists of DNA and protein and contains genetic information. A zygote is the result of fusion of two haploid gamete cells and contains one set of chromosomes from each parent. Genotype refers to the genetic makeup of an individual or organism.

Question 12

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 form proteins. Each gene contains the information necessary to determine the order of amino acids in a particular protein.

Question 13

Some genes are _____, which means "many forms."

Accepted Answer

Polymorphic genes exist in multiple alleles within a population. They have multiple forms due to natural variations in their DNA sequence, and these variations are responsible for differences in traits between individuals.

Question 14

Each human body cell contains _____ chromosomes.

Accepted Answer

Each human body cell contains 46 chromosomes.

Question 15

Each human has a total of about _____ genes.

Accepted Answer

Recent estimates have shown that humans have approximately 20,000 genes in their genome. This number is significantly lower than what was initially predicted, as it was believed that humans would have around 100,000 genes. However, with advancements in genomic sequencing, we now have a more accurate understanding of the number of genes in the human genome.

Question 16

The most common extra-chromosome condition is fragile X syndrome.

Accepted Answer

The most common extra-chromosome condition is Down syndrome, not fragile X syndrome.

Question 17

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

Accepted Answer

A gene is the basic unit of heredity and is a small section of a chromosome that contains the instructions for a specific trait. Chromosomes contain many genes, and their arrangement and expression determine an individual's genotype and phenotype. A zygote is a fertilized egg cell formed by the fusion of sperm and egg nuclei, and a chromosome is a thread-like structure that carries genetic information.

Question 18

The process of methylation can do all the following to genetic instructions EXCEPT _____ them.

Accepted Answer

Methylation can alter, connect, and even transcribe genetic instructions, but it cannot remove them. Methylation involves adding a methyl group to the DNA molecule, which can affect gene expression and impact how the genetic instructions are interpreted by the cell.

Question 19

Heritability indicates how much of the variation of a trait can be traced to genes.

Accepted Answer

Heritability is a measure of how much of the variation of a trait can be attributed to genetic differences among individuals. Therefore, it is true that heritability indicates how much of the variation of a trait can be traced to genes.

Question 20

The name of the full set of genes that provides the instructions for making living organisms is the _____.

Accepted Answer

The genome is the full set of genes in an organism, while the phenotype is the physical manifestation of those genes, and the genotype is the specific combination of genes an individual has. An allele is a specific version of a gene.

Quiz 3: Heredity and Environment