Biology Chapter on Genetics
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Questions and Answers

Which blood type is considered the universal donor?

  • Type AB
  • Type A
  • Type B
  • Type O (correct)

    • What percentage of the US population has the A+ blood type?

  • 34% (correct)
  • 0.6%
  • 37%
  • 72%

    • Which of the following statements about polygenic traits is true?

  • They result in only two possible traits.
  • They are influenced by multiple genes. (correct)
  • They are controlled by a single gene.
  • They cannot show a variety of phenotypes.

    • What is the end result of meiosis II?

    <p>4 haploid cells</p> Signup and view all the answers

    Which blood type is the most common in the US population?

    <p>Type O+</p> Signup and view all the answers

    How many different genes are involved in controlling skin color in humans?

    <p>More than four</p> Signup and view all the answers

    What happens during crossing-over in meiosis I?

    <p>Sections of chromatids are exchanged between homologous chromosomes</p> Signup and view all the answers

    How many possible combinations of chromosomes can be produced in humans due to the random alignment of homologous chromosomes?

    <p>8,388,608</p> Signup and view all the answers

    What structure forms when homologous chromosomes pair up during meiosis I?

    <p>Tetrad</p> Signup and view all the answers

    What is the name of the two divisions that occur in meiosis?

    <p>Meiosis I and Meiosis II</p> Signup and view all the answers

    What was the phenotype of the F1 generation from Mendel's experiment?

    <p>Round and Yellow</p> Signup and view all the answers

    In the F2 generation, which of the following correctly describes the occurrence of recombinant offspring?

    <p>Offspring that does not resemble the parents</p> Signup and view all the answers

    How many seeds were recorded as round and yellow in the F2 generation?

    <p>315</p> Signup and view all the answers

    According to Mendel's principles, how many copies of each gene does an adult organism possess?

    <p>Two, one from each parent</p> Signup and view all the answers

    Which of the following statements is true regarding alleles in Mendelian genetics?

    <p>Two or more alleles may exist, with some being dominant.</p> Signup and view all the answers

    What term describes the passing of traits from parent to offspring?

    <p>Heredity</p> Signup and view all the answers

    How many chromosomes are present in a haploid cell for Drosophila?

    <p>n=4</p> Signup and view all the answers

    Which term is used to describe cells that contain two sets of homologous chromosomes?

    <p>Diploid</p> Signup and view all the answers

    The diploid number for Drosophila is indicated by which of the following expressions?

    <p>2n=8</p> Signup and view all the answers

    Which of the following statements about body cells and gametes is correct?

    <p>Body cells have two sets of chromosomes.</p> Signup and view all the answers

    What role does meiosis play in genetics?

    <p>It provides genetic variation.</p> Signup and view all the answers

    In terms of chromosome pairs, what characterizes homologous chromosomes?

    <p>One comes from each parent.</p> Signup and view all the answers

    Which is true about mitosis compared to meiosis?

    <p>Mitosis results in identical daughter cells.</p> Signup and view all the answers

    What type of organism has two identical alleles for a particular trait?

    <p>Homozygous</p> Signup and view all the answers

    What does the genotype Tt represent?

    <p>Heterozygous</p> Signup and view all the answers

    Which of the following reflects the definition of a phenotype?

    <p>The physical appearance of a trait</p> Signup and view all the answers

    What does a Punnett Square predict?

    <p>The outcomes of genetic crosses</p> Signup and view all the answers

    In a monohybrid cross, how many traits are examined?

    <p>One trait</p> Signup and view all the answers

    What is the term for the genetic makeup of an organism?

    <p>Genotype</p> Signup and view all the answers

    How many alleles do individuals have for each trait?

    <p>Two</p> Signup and view all the answers

    What does it mean for an organism to be heterozygous?

    <p>It has different alleles for the same trait</p> Signup and view all the answers

    What phenomenon explains the reappearance of traits controlled by a disappearing allele in the F2 generation?

    <p>Segregation of alleles</p> Signup and view all the answers

    What is the correct definition of alleles?

    <p>Alternative versions of genes controlling variations</p> Signup and view all the answers

    Which of the following best describes Mendel's P generation?

    <p>True-breeding plants with identical alleles</p> Signup and view all the answers

    What happens when the two alleles at a locus differ?

    <p>The dominant allele determines the appearance</p> Signup and view all the answers

    What does the law of segregation state?

    <p>Two alleles for a character segregate during gamete formation</p> Signup and view all the answers

    What is the phenotype ratio observed in Mendel's F2 generation?

    <p>3:1 dominant to recessive</p> Signup and view all the answers

    How many alleles does an organism inherit for each character?

    <p>Two, one from each parent</p> Signup and view all the answers

    What does the term 'probability' refer to in genetics?

    <p>The likelihood that a specific event will occur</p> Signup and view all the answers

    What is a hybrid plant in Mendel’s experiments?

    <p>A plant with two different alleles</p> Signup and view all the answers

    What concept explains why some traits are masked in an organism's phenotype?

    <p>Dominant and recessive alleles</p> Signup and view all the answers

    Study Notes

    Introduction to Genetics

    • Genetics is the study of heredity
    • Traits are inherited characteristics
    • Inherited traits can be physical features, like eye shape, or characteristics like hair color.
    • The passing of traits from parents to offspring is called heredity.

    Objectives

    • Contrast the chromosome number of body cells and gametes
    • Summarize the events of meiosis
    • Contrast meiosis and mitosis
    • Explain the importance of meiosis in providing genetic variation

    Meiosis

    • Meiosis is the process that creates gametes (sex cells)
    • Meiosis involves two divisions, meiosis I and meiosis II
    • Unlike mitosis, meiosis results in four haploid cells, rather than two diploid cells.
    • During meiosis I, homologous chromosomes pair up and exchange genetic material in a process called crossing over.
    • Sister chromatids separate during meiosis II.
    • In male animals, meiosis produces four equal-sized gametes called sperm.
    • In female animals, meiosis produces one egg cell and three smaller cells called polar bodies.

    Meiosis and Mitosis

    • Mitosis produces two identical diploid cells
    • Meiosis produces four genetically different haploid cells

    Terminology

    • Chromosome number: The total number of chromosomes in a cell
    • Diploid (2n): A cell containing two sets of chromosomes
    • Haploid (n): A cell containing one set of chromosomes
    • Homologous chromosomes: Chromosomes that have the same genes at the same loci
    • Gametes: Sex cells (sperm and egg)
    • Zygote: The fertilized egg cell
    • Alleles: Different versions of a gene
    • Genotype: The set of alleles an individual has for a specific trait
    • Phenotype: The physical appearance of a trait resulting from the genotype

    Mendel's Work

    • Gregor Mendel was an Austrian monk who conducted experiments with garden peas to study heredity.
    • Mendel's experiments involved cross-pollination to produce seeds with different characteristics
    • Self-pollination produced seeds that were identical to the parent
    • Mendel discovered the concepts of dominance, segregation, and independent assortment.
    • The offspring created by the combination of male and female reproductive cells was called a hybrid.

    Mendel's Principles

    • Genes are passed from parents to offspring.
    • If two or more alleles of a gene for a single trait exist, some forms of the gene may be dominant and others may be recessive.
    • In sexually reproducing organisms, each adult has two copies of each gene
    • The alleles for different genes usually segregate independently of one another.

    Non-Mendelian Inheritance

    • Some alleles are neither dominant nor recessive, and some traits controlled by multiple alleles or multiple genes
    • Incomplete dominance
    • Codominance: Both traits are fully expressed
    • Multiple alleles
    • Polygenic traits: Traits controlled by two or more genes. Skin color in humans is an example of a polygenic trait

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    Chapter 10 Intro Genetics PDF

    Description

    Test your knowledge on key concepts in genetics from this chapter, including blood types, polygenic traits, and the processes of meiosis. Understand foundational principles established by Mendel and their implications in inheritance. Ideal for students studying biology at any level.

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