Chapter 1 Concept 1 - Answer Our genes affect many of our physical features as well as our
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susceptibility to many diseases and disorders. Genetics contributes to advances in agriculture,
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pharmaceuticals, and medicine and is fundamental to modern biology. All organisms use similar
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genetic systems, and genetic variation is the foundation of the diversity of all life.
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"What are some of the implications of all organisms having similar genetic systems?
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A. That all life forms are genetically related
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B. That research findings on one organism's gene function can often be applied to other
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organisms
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C. That genes from one organism can often function in another organism
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D. All of the above" - Answer D
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Chapter 1 Concept 2 - Answer The three major divisions of genetics are transmission genetics,
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molecular genetics, and population genetics. Transmission genetics examines the principles of
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heredity; molecular genetics deals with the gene and the cellular processes by which genetic
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information is transferred and expressed; and population genetics concerns the genetic
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composition of groups of organisms and how that composition changes over time and space.
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Model genetic organisms are species that have received special emphasis in genetic research:
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they have characteristics that make them useful for genetic analysis.
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Would the horse make a good model genetic organism? Why or why not? - Answer No, because
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horses are expensive to house, feed, and propagate, they have too few progeny, and their
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generation time is too long.
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Chapter 1 Concept 3 - Answer Humans first applied genetics to the domestication of plants and
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animals between 10,000 and 12,000 years ago. Developments in plant hybridization and cytology
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in the eighteenth and nineteenth centuries laid the foundation for the field of genetics today.
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After Mendel's work was rediscovered in 1900, the science of genetics developed rapidly and
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today is one of the most active areas of science.
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,How did developments in cytology in the nineteenth century contribute to our modern
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understanding of genetics? - Answer Developments in cytology in the 1800s led to the
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identification of parts of the cell, including the cell nucleus and chromosomes. The cell theory
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focused biologists' attention on the cell, eventually leading to the conclusion that the nucleus
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contains the hereditary information.
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Section 1.1 Summary 1 - Answer Genetics is central to the life of every person: it influences a
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person's physical features, personality, intelligence, and susceptibility to numerous diseases.
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Section 1.1 Summary 2 - Answer Genetics plays important roles in agriculture, the
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pharmaceutical industry, and medicine. It is central to the study of biology.
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Section 1.1 Summary 3 - Answer All organisms use similar genetic systems. Genetic variation is
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the foundation of evolution and is critical to understanding all life.
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Section 1.1 Summary 4 - Answer The study of genetics can be broadly divided into transmission
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genetics, molecular genetics, and population genetics.
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Section 1.1 Summary 5 - Answer Model genetic organisms are species about which much genetic
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information exists because they have characteristics that make them particularly amenable to
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genetic analysis.
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Section 1.2 Summary 1 - Answer By studying the offspring of crosses between varieties of peas,
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Gregor Mendel discovered the principles of heredity. Developments in cytology in the nineteenth
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century led to the understanding that the cell nucleus is the site of heredity.
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Section 1.2 Summary 2 - Answer In 1900, Mendel's principles of heredity were rediscovered.
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Population genetics was established in the early 1930s, followed by bacterial and viral genetics.
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The structure of DNA was discovered in 1953, stimulating the rise of molecular genetics.
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,Section 1.2 Summary 3 - Answer The first human whole-genome sequence was completed in
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2003.
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Section 1.3 Summary 1 - Answer There are two basic types of cells: prokaryotic and eukaryotic.
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Section 1.3 Summary 2 - Answer The set of alleles that determines a trait is termed the genotype;
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the trait that they produce is the phenotype.
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Section 1.3 Summary 3 - Answer Genes are located on chromosomes, which are made up of
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nucleic acids and proteins and are partitioned into daughter cells through the process of mitosis
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or meiosis.
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Section 1.3 Summary 4 - Answer Genetic information is expressed through the transfer of
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information from DNA to RNA to proteins.
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Section 1.3 Summary 5 - Answer Evolution requires genetic change in populations.
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Chapter 2 Concept 1 - Answer Organisms are classified as prokaryotes or eukaryotes, and the
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prokaryotes consist of archaea and bacteria. A prokaryote is a unicellular organism that lacks a
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nucleus, and its genome is usually a single chromosome. Eukaryotes may be either unicellular or
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multicellular, their cells possess a nucleus, their DNA is associated with histone proteins, and
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their genomes consist of multiple chromosomes.
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List several characteristics that bacteria and archaea have in common and that distinguish them
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from eukaryotes. - Answer Bacteria and archaea are prokaryotes. They differ from eukaryotes in
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possessing no nucleus, a genome that usually consists of a single circular chromosome, and a
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smaller amount of DNA.
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, Chapter 2 Concept 2 - Answer Cells reproduce by copying and separating their genetic
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information and then dividing. Because eukaryotic cells possess multiple chromosomes,
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mechanisms exist to ensure that each new cell receives one copy of each chromosome. Most
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eukaryotic cells are diploid, and their two chromosome sets can be arranged in homologous
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pairs. Haploid cells contain a single set of chromosomes.
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"Diploid cells have tu tu
A. two chromosomes.
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B. two sets of chromosomes.
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C. one set of chromosomes.
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D. two pairs of homologous chromosomes." - Answer B
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Chapter 2 Concept 3 - Answer Sister chromatids are copies of a chromosome held together at the
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centromere. Functional chromosomes contain centromeres, telomeres, and origins of
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replication. The kinetochore is the point of attachment for the spindle microtubules. Telomeres
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are the stabilizing ends of a chromosome. Origins of replication are sites where DNA synthesis
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begins.
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What would be the result if a chromosome did not have a kinetochore? - Answer The kinetochore
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is the point at which spindle microtubules attach to the chromosome during cell division. If the
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kinetochore were missing, spindle microtubules would not attach to the chromosome, the
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chromosome would not be drawn into a newly formed nucleus, and the resulting daughter cells
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would be missing a chromosome.
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Section 2.1 Summary 1 - Answer A prokaryotic cell possesses a simple structure, with no nuclear
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membrane and usually a single circular chromosome. A eukaryotic cell possesses a more complex
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structure, with a nucleus and multiple linear chromosomes consisting of DNA complexed with
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histone proteins.
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Section 2.2 Summary 1 - Answer Cell reproduction requires the copying of genetic material,
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separation of the copies, and cell division.
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