General Biology 1: Introduction to Genetics
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Questions and Answers

What does the term 'genotype' refer to?

  • The expression of a specific trait
  • The process of gamete formation
  • The total set of alleles an individual contains (correct)
  • The physical appearance of an individual
  • What is the genotype of the F1 generation when one true-breeding purple and one true-breeding white plant are crossed?

  • PP
  • Pp (correct)
  • pp
  • Pp and pp
  • What does Mendel's Law of Segregation imply about the inheritance of alleles?

  • All offspring inherit both alleles from one parent
  • Alleles are passed on together without separation
  • Genes segregate equally into gametes (correct)
  • One allele is always dominant over another
  • Which of the following describes the possible gametes produced by a true-breeding purple parent?

    <p>P only</p> Signup and view all the answers

    According to Mendel's Law of Independent Assortment, what is true about genes on different chromosomes?

    <p>Every possible combination of alleles is equally likely</p> Signup and view all the answers

    In a Punnett square analysis of true-breeding parents, what types of gametes do they produce?

    <p>Only one type of gamete each</p> Signup and view all the answers

    What phenotype will a plant with the genotype pp exhibit?

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

    In the analysis of Mendel's cross, how many different phenotypes can F2 offspring display?

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

    What is indicated by the presence of a dominant purple allele in a cross between a purple and a white flower?

    <p>There is a chance of white offspring being produced</p> Signup and view all the answers

    In the context of Mendelian genetics, what does the term 'true-breeding' imply?

    <p>Organisms consistently produce offspring with the same phenotype</p> Signup and view all the answers

    What is the term for the offspring produced from the cross of two true-breeding parents?

    <p>F1 generation</p> Signup and view all the answers

    Which of the following correctly describes gametes produced by true-breeding parents in Mendelian crosses?

    <p>Homogeneous in genotype</p> Signup and view all the answers

    Which genotype represents a homozygous dominant organism in Mendelian genetics?

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

    How does the principle of independent assortment affect offspring traits?

    <p>Alleles for different traits assort independently into gametes</p> Signup and view all the answers

    How do true-breeding parents in Mendel's experiments contribute to the gametes?

    <p>They produce only one type of gamete.</p> Signup and view all the answers

    What is the main purpose of a test cross?

    <p>To identify whether an individual is homozygous or heterozygous</p> Signup and view all the answers

    What is the appearance of all F1 generation offspring from a purple and a white true-breeding parent cross?

    <p>All purple flowers</p> Signup and view all the answers

    In a test cross involving a purple-flowered pea plant, what are the possible genotypes of the plant being tested?

    <p>PP or Pp</p> Signup and view all the answers

    What can be concluded if all offspring from a test cross produce the recessive phenotype?

    <p>The original plant is homozygous dominant.</p> Signup and view all the answers

    If a purple-flowered pea plant (Pp) is crossed with a homozygous recessive plant (pp), what ratio of phenotypes would be expected?

    <p>1:1</p> Signup and view all the answers

    Which of the following best describes the term 'homozygous recessive'?

    <p>An individual with two recessive alleles.</p> Signup and view all the answers

    What observable trait is caused by the dominant allele in pea plants?

    <p>Purple flowers</p> Signup and view all the answers

    Which of the following statements about Punnett squares is true?

    <p>They are used to determine genotype ratios from genetic crosses.</p> Signup and view all the answers

    If a homozygous purple-flowered pea plant is crossed with a homozygous white-flowered pea plant, what will be the phenotype of the offspring?

    <p>All purple flowers</p> Signup and view all the answers

    What is the purpose of a test cross in genetics?

    <p>To identify the genotype of an organism with a dominant phenotype.</p> Signup and view all the answers

    In a monohybrid cross, what is being studied?

    <p>Only one variation of a single trait.</p> Signup and view all the answers

    Which of the following best describes a dihybrid cross?

    <p>It examines two traits inherited independently from two true-breeding parents.</p> Signup and view all the answers

    What phenotype does the F1 generation of a dihybrid cross display?

    <p>Only dominant traits for each individual trait.</p> Signup and view all the answers

    What is indicated by the notation RR YY in genetics?

    <p>It indicates true-breeding individuals for two dominant traits.</p> Signup and view all the answers

    How can you differentiate between homozygous and heterozygous genotypes?

    <p>By using a Punnett square for a test cross.</p> Signup and view all the answers

    What does a homozygous genotype mean in the context of Punnett squares?

    <p>It contains two identical alleles for a given trait.</p> Signup and view all the answers

    Which trait combination represents recessive phenotypes in a dihybrid cross?

    <p>rr yy</p> Signup and view all the answers

    What was one reason Mendel chose to study garden peas for his experiments?

    <p>Many pea varieties were available and they can self-fertilize.</p> Signup and view all the answers

    Which of the following best describes Mendel's hypothesis regarding his experiments?

    <p>Traits are inherited independently and randomly.</p> Signup and view all the answers

    In a mono- or dihybrid cross, what is the significance of identifying the parental generation?

    <p>It helps in calculating the probabilities of trait inheritance.</p> Signup and view all the answers

    What is a test cross and why is it important?

    <p>A test cross involves a dominant phenotype and a homozygous recessive, revealing genotype.</p> Signup and view all the answers

    Which figure from Mendel’s work is essential for understanding the outcomes of genetic crosses?

    <p>Figure 12.8, which illustrates Punnett squares.</p> Signup and view all the answers

    Which of the following statements accurately reflects Mendel’s principle of segregation?

    <p>Each individual has two alleles for each trait, which segregate during gamete formation.</p> Signup and view all the answers

    Why are Punnett squares useful in Mendelian genetics?

    <p>They predict the genotypes of offspring from known parents.</p> Signup and view all the answers

    What is the primary advantage of using a dihybrid cross in Mendelian genetics?

    <p>It allows for the observation of interactions between two different traits.</p> Signup and view all the answers

    What is the expected phenotypic ratio in the F2 generation according to Mendel's findings?

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

    In Mendel's model, what term describes organisms with two identical alleles?

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

    Which of the following statements best describes alleles in Mendel’s model?

    <p>Alleles remain discrete and do not blend.</p> Signup and view all the answers

    What is the expected genotypic ratio resulting from a monohybrid cross according to Mendel's findings?

    <p>1:2:1</p> Signup and view all the answers

    What defines a dominant allele in Mendel's model?

    <p>It is always expressed in the phenotype regardless of the presence of alleles.</p> Signup and view all the answers

    What ratio indicates the proportion of dominant to recessive traits in the F2 generation?

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

    What happens to a recessive trait in the presence of a dominant allele?

    <p>It is masked and not expressed.</p> Signup and view all the answers

    What did Mendel conclude about the inheritance of traits?

    <p>Traits are inherited in a numerical ratio.</p> Signup and view all the answers

    What is the probability of obtaining a green phenotype from a heterozygous pea plant in a cross?

    <p>1/4</p> Signup and view all the answers

    If two heterozygous pea plants are crossed, what is the expected probability that an offspring will be both round and green?

    <p>3/16</p> Signup and view all the answers

    What does the genotype 'yyRr' represent in terms of seed color and texture?

    <p>Green and wrinkled seeds</p> Signup and view all the answers

    In a Punnett square analysis, if a pea plant with a genotype of 'YyRr' is crossed with another of the same genotype, what is the total number of possible genotypes for the offspring?

    <p>16</p> Signup and view all the answers

    What is the probability of an event that is certain to occur?

    <p>1</p> Signup and view all the answers

    If the probability of an event occurring is defined as q, what does (1 - q) represent?

    <p>The probability of the event not occurring</p> Signup and view all the answers

    Which phenotype combination represents all combinations from crossing two heterozygous round and green pea plants?

    <p>Round green, round yellow, wrinkled green, wrinkled yellow</p> Signup and view all the answers

    Which equation represents the addition of the probabilities of all possible outcomes of a dependent event?

    <p>p + q = 1</p> Signup and view all the answers

    For mutually independent events, how is the overall probability calculated?

    <p>P = P1 × P2 × P3...</p> Signup and view all the answers

    What is the probability of rolling a specific number on a six-sided die?

    <p>1/6</p> Signup and view all the answers

    If an event has a probability of 0, what can be concluded about its occurrence?

    <p>It is impossible to happen</p> Signup and view all the answers

    What does a probability of 0.5 indicate about an event's chances?

    <p>The event has an equal chance of occurring or not occurring</p> Signup and view all the answers

    What is the probability of obtaining 'heads' when flipping a fair coin?

    <p>1/2</p> Signup and view all the answers

    What phenotype ratio is typically observed in the F2 generation of a dihybrid cross?

    <p>9:3:3:1</p> Signup and view all the answers

    Which statement best describes the principle of independent assortment?

    <p>The alleles of different genes segregate independently during gamete formation.</p> Signup and view all the answers

    According to Law 2 of probability, if the probability of an event occurring is defined as q, what represents the probability that the event does not occur?

    <p>P = 1 - q</p> Signup and view all the answers

    What is the significance of the dihybrid cross showing a phenotypic ratio of 9:3:3:1?

    <p>It illustrates the law of independent assortment.</p> Signup and view all the answers

    Which aspect does not contribute to the probability calculations of multiple characters using the law of probability?

    <p>Assuming events are completely unrelated.</p> Signup and view all the answers

    What occurs during metaphase I in meiosis that contributes to independent assortment?

    <p>Homologous chromosomes align randomly at the equatorial plate.</p> Signup and view all the answers

    What would be the probability of a specific trait if it is certain to occur?

    <p>1</p> Signup and view all the answers

    Which of the following accurately reflects the approach to using a Punnett square for probability calculations?

    <p>It provides an exact count of possible offspring genotypes.</p> Signup and view all the answers

    What is the probability of rolling either a 2 or a 6 on a standard six-sided die?

    <p>1/3</p> Signup and view all the answers

    What is the probability of rolling a 2 and a 6 when using two six-sided dice?

    <p>1/36</p> Signup and view all the answers

    When crossing two heterozygous plants (Pp), what is the probability of obtaining the heterozygous genotype Pp?

    <p>1/2</p> Signup and view all the answers

    What principle explains that the probability of independent events occurring together is the product of their individual probabilities?

    <p>Multiplication Rule</p> Signup and view all the answers

    In a genetic cross between two heterozygous parents (Pp x Pp), what fraction of the offspring is expected to be homozygous recessive (pp)?

    <p>1/4</p> Signup and view all the answers

    If the probability of event P is 1/6 and the probability of event Q is 1/6, what is the probability of both events occurring if they are independent?

    <p>1/36</p> Signup and view all the answers

    When rolling a single six-sided die, what is the probability of not rolling a number higher than 4?

    <p>4/6</p> Signup and view all the answers

    What is the probability of obtaining a genotype of pp from a self-pollination of two heterozygous pea plants?

    <p>1/4</p> Signup and view all the answers

    What is the expected probability of rolling an even number (2, 4, or 6) on a single six-sided die?

    <p>1/2</p> Signup and view all the answers

    What genotype represents a plant that has both dominant traits for seed color and texture?

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

    In the context of a Punnett square, what does a genotype of Pp indicate?

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

    What is the expected phenotypic outcome when two heterozygous plants (YyRr) are crossed?

    <p>1 round yellow, 1 round green, 1 wrinkled yellow, and 1 wrinkled green</p> Signup and view all the answers

    What is the combined probability of obtaining either a round and green seed or a wrinkled and yellow seed from a dihybrid cross?

    <p>1/2</p> Signup and view all the answers

    Which statement accurately reflects Mendel's law of independent assortment?

    <p>Alleles segregate independently during gamete formation</p> Signup and view all the answers

    What is the significance of identifying the genotype of the parental generation in a genetic cross?

    <p>It is needed to calculate offspring probabilities</p> Signup and view all the answers

    When two peas with the genotype YyRr are crossed, what fraction of the offspring will be expected to have green and wrinkled seeds?

    <p>1/16</p> Signup and view all the answers

    What does a dihybrid cross primarily investigate?

    <p>Two separate traits simultaneously</p> Signup and view all the answers

    What is the significance of true-breeding parents in Mendel's experiments?

    <p>They ensure consistent trait expression in offspring</p> Signup and view all the answers

    In a test cross, what is the primary goal?

    <p>To determine the genotype of a dominant phenotype</p> Signup and view all the answers

    What is indicated by a phenotypic ratio observed in the F2 generation?

    <p>The inheritance patterns of alleles</p> Signup and view all the answers

    How did Mendel's use of garden peas contribute to his findings in genetics?

    <p>Their traits were easily observable and controlled</p> Signup and view all the answers

    What is the expected outcome when analyzing the F1 generation of a dihybrid cross?

    <p>Only dominant phenotypes for each trait are expressed</p> Signup and view all the answers

    In genetic crosses, what is the role of a Punnett square?

    <p>To predict possible offspring genotypes and phenotypes</p> Signup and view all the answers

    What is a characteristic feature of a monohybrid cross?

    <p>It focuses on two variations of one trait</p> Signup and view all the answers

    What type of cells are gametes, and how many sets of chromosomes do they contain?

    <p>Haploid, 1 set of chromosomes</p> Signup and view all the answers

    Which statement correctly describes the sex chromosomes in humans?

    <p>Males are hemizygous due to non-homologous sex chromosomes.</p> Signup and view all the answers

    What genetic mechanism prevents females from expressing double the amount of X chromosome genes?

    <p>Dosage compensation</p> Signup and view all the answers

    What is the function of the SRY gene in human development?

    <p>To trigger masculinization of genitalia</p> Signup and view all the answers

    In terms of genetic variation, offspring result from what process involving parental genetic material?

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

    How many pairs of homologous chromosomes do humans possess?

    <p>23 pairs</p> Signup and view all the answers

    In birds, which sex is typically hemizygous for sex chromosomes?

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

    Why do female cells not produce double the amount of proteins from X-linked genes?

    <p>Only one X chromosome is active.</p> Signup and view all the answers

    What is the purpose of amniocentesis in high-risk pregnancies?

    <p>To extract amniotic fluid for fetal cell analysis</p> Signup and view all the answers

    Which condition is characterized by the presence of an extra X chromosome in males?

    <p>Klinefelter syndrome</p> Signup and view all the answers

    Which symptom is NOT commonly associated with Turner syndrome?

    <p>Increased fertility</p> Signup and view all the answers

    What characterizes individuals with triple X syndrome?

    <p>Normal physical and mental appearance</p> Signup and view all the answers

    Which sex chromosome aneuploidy condition typically results in females with one fewer X chromosome?

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

    Which physical characteristic is associated with Jacob syndrome?

    <p>Slightly taller and thinner</p> Signup and view all the answers

    Which of the following is a possible outcome of nondisjunction of sex chromosomes?

    <p>Variations in sex chromosome count leading to aneuploidies</p> Signup and view all the answers

    Individuals with Klinefelter syndrome often exhibit which of the following conditions?

    <p>Small testicles and infertility</p> Signup and view all the answers

    What does the presence of Barr bodies indicate in female cells?

    <p>Inactivation of one X chromosome</p> Signup and view all the answers

    What is the typical phenotype representation in calico cats due to Barr bodies?

    <p>Mosaic fur</p> Signup and view all the answers

    What was the dominant trait observed in the F1 progeny when Thomas Hunt Morgan crossed a white-eyed male fly with a red-eyed female fly?

    <p>Red eyes</p> Signup and view all the answers

    How many X chromosomes are inactivated in female mammals?

    <p>One X chromosome</p> Signup and view all the answers

    What unique pattern was observed in the F2 generation of Morgan's crosses involving the red-eyed and white-eyed fruit flies?

    <p>Three red-eyed and one white-eyed fly, with white eyes only in males</p> Signup and view all the answers

    Who first discovered Barr bodies?

    <p>Murray Barr</p> Signup and view all the answers

    What chromosomal composition do human females inherit?

    <p>23 chromosomes from mothers and 23 from fathers</p> Signup and view all the answers

    Which of the following conclusions did Thomas Hunt Morgan reach regarding the gene for eye color in fruit flies?

    <p>The eye color gene is sex-linked and resides on the X chromosome.</p> Signup and view all the answers

    What impact does X chromosome inactivation have on female traits?

    <p>It creates variability in trait expression.</p> Signup and view all the answers

    What notation is used to represent a homozygous mutant genotype in Thomas Hunt Morgan's studies?

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

    What type of inheritance pattern is shown by the fur colors in calico cats?

    <p>X-linked inheritance</p> Signup and view all the answers

    Which scientist is credited with the chromosomal theory of inheritance that involved the pairing of similar chromosomes during meiosis?

    <p>Walter Sutton</p> Signup and view all the answers

    What was the basis of Thomas Hunt Morgan's experiments with Drosophila melanogaster?

    <p>Exploring sex-linkage through eye color variation.</p> Signup and view all the answers

    What is the structural characteristic of a Barr body?

    <p>Highly condensed</p> Signup and view all the answers

    What was the significance of Morgan's testcross involving F1 female and white-eyed male flies?

    <p>It demonstrated the dominance of red eyes over white eyes.</p> Signup and view all the answers

    What term describes all the cells in a multicellular organism that are not involved in reproduction?

    <p>Somatic cells</p> Signup and view all the answers

    What is the likelihood that a sibling will be genetically identical to you, given 223 possible combinations of chromosome pairs?

    <p>1 in 8,324,608</p> Signup and view all the answers

    How do homologous chromosomes differ from sister chromatids during meiosis?

    <p>Homologous chromosomes come from different parents.</p> Signup and view all the answers

    Why is red-green color blindness more common in males than females?

    <p>Males have only one X chromosome, leading to unmasked recessive alleles.</p> Signup and view all the answers

    What does the term 'recombinant' refer to in the context of meiosis?

    <p>A gamete that has undergone crossing over.</p> Signup and view all the answers

    Which of the following statements about crossing over is accurate?

    <p>It leads to genetic variation among gametes.</p> Signup and view all the answers

    What is the significance of the X and Y chromosomes being non-homologous in males?

    <p>It allows for the expression of recessive traits in males.</p> Signup and view all the answers

    What does aneuploidy refer to in genetics?

    <p>An abnormal number of chromosomes</p> Signup and view all the answers

    Which factor influences the frequency of crossing over between two alleles?

    <p>The physical distance between the alleles on the chromosome.</p> Signup and view all the answers

    Which statement about monosomic individuals is correct?

    <p>They have lost one copy of an autosome.</p> Signup and view all the answers

    What is the primary effect of having two X chromosomes in females compared to males?

    <p>Females are less likely to express recessive traits.</p> Signup and view all the answers

    What is one characteristic of trisomies involving chromosomes 13, 15, and 18?

    <p>They typically do not survive past infancy.</p> Signup and view all the answers

    What correlation exists between maternal age and Down syndrome?

    <p>Older mothers have a higher chance of having a child with Down syndrome.</p> Signup and view all the answers

    What is the main consequence of nondisjunction during meiosis?

    <p>An incorrect number of chromosomes in gametes.</p> Signup and view all the answers

    What typically happens to monosomic individuals during development?

    <p>They do not survive embryonic development.</p> Signup and view all the answers

    Which chromosome pair is referred to as the sex chromosomes?

    <p>The 23rd pair</p> Signup and view all the answers

    What is an important factor when studying the occurrences of Down syndrome?

    <p>Maternal age at conception.</p> Signup and view all the answers

    In a family pedigree, how are male individuals represented?

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

    Which pattern of inheritance is associated with juvenile glaucoma?

    <p>Dominant trait pedigree</p> Signup and view all the answers

    What type of dominance occurs when both alleles contribute to the phenotype equally?

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

    What is the condition called where the pigment melanin is not produced?

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

    Which pattern of inheritance allows for multiple alleles to exist for a single trait?

    <p>Multiple alleles</p> Signup and view all the answers

    In pedigrees, what visual element indicates mating between two individuals?

    <p>Horizontal line</p> Signup and view all the answers

    In a pedigree showing hemophilia, which group is more frequently affected?

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

    What term describes when one gene's expression is affected by another gene?

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

    Why might not all offspring in a dominant trait pedigree exhibit the dominant disease?

    <p>One parent is a heterozygote</p> Signup and view all the answers

    Which pattern of inheritance involves a single gene affecting multiple traits?

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

    Which of the following is NOT a characteristic of a recessive trait pedigree?

    <p>All offspring of affected parents are affected</p> Signup and view all the answers

    In a dominant trait pedigree, what does a heterozygous genotype indicate?

    <p>The individual carries one mutated allele</p> Signup and view all the answers

    What does it mean if a trait is said to be influenced by the environment?

    <p>Phenotype can change due to external factors.</p> Signup and view all the answers

    In which type of dominance is the phenotype of heterozygotes intermediate between the phenotypes of the two homozygotes?

    <p>Incomplete dominance</p> Signup and view all the answers

    What type of trait is hemophilia categorized as?

    <p>Sex-linked trait</p> Signup and view all the answers

    Which of the following statements about carrier individuals in a pedigree is true?

    <p>Carriers can pass the trait to their offspring</p> Signup and view all the answers

    What is a characteristic of codominance in genetics?

    <p>Both alleles contribute to the phenotype equally.</p> Signup and view all the answers

    Which of the following statements is NOT an assumption of Mendel's model of inheritance?

    <p>There can be multiple phenotypes for a single gene.</p> Signup and view all the answers

    What occurs in incomplete dominance?

    <p>The heterozygote displays a phenotype that is a mix of both homozygotes.</p> Signup and view all the answers

    Which example illustrates Mendel's model of complete dominance?

    <p>Purple flowers completely masking the expression of white flowers.</p> Signup and view all the answers

    What role do alleles play in the ABO blood group system?

    <p>They can showcase both dominant and recessive traits.</p> Signup and view all the answers

    Which statement about Mendel’s findings is true?

    <p>Mendel's concepts laid the foundation for modern genetics.</p> Signup and view all the answers

    Why are Mendel's simple ratios not always observed in other traits?

    <p>Many traits are controlled by multiple genes.</p> Signup and view all the answers

    What phenotype ratios arise when pink flowers (incomplete dominance) are self-crossed?

    <p>1 red : 2 pink : 1 white</p> Signup and view all the answers

    What is one effect of the dominant frizzle gene in chickens?

    <p>Causes feathers to curl outward</p> Signup and view all the answers

    How does epistasis affect phenotypic expression?

    <p>It can suppress the expression of another gene</p> Signup and view all the answers

    In the example of Labrador dogs, which alleles determine the coat color?

    <p>B and E</p> Signup and view all the answers

    What term describes alleles that exhibit simultaneous expression in a heterozygote's phenotype?

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

    What indicates an environmental influence on phenotype?

    <p>Pigment production occurs only below 33°C</p> Signup and view all the answers

    Which statement about pleiotropy is correct?

    <p>One gene affects multiple traits</p> Signup and view all the answers

    Which blood type is a universal recipient due to its compatibility with all other blood groups?

    <p>Type AB</p> Signup and view all the answers

    What was observed in the F2 generation when two true-breeding corn varieties lacking anthocyanin were crossed?

    <p>Produced both pigmented and colorless seeds</p> Signup and view all the answers

    What do the alleles IA and IB contribute to the ABO blood group system?

    <p>They express both A and B antigens</p> Signup and view all the answers

    Which of the following traits did the frizzle gene affect in chickens?

    <p>Feather direction</p> Signup and view all the answers

    What is a potential consequence for a person with type O blood receiving a blood transfusion from type A blood?

    <p>Severe hemolytic reaction</p> Signup and view all the answers

    Which phenotype would be exhibited by a person with the genotype IAi?

    <p>Type A blood</p> Signup and view all the answers

    What role does the 'E' allele play in the color of Labrador dogs?

    <p>Allows pigment deposition to occur</p> Signup and view all the answers

    In terms of blood transfusion, what do antibodies present in the blood plasma target?

    <p>Antigen sugars on blood cells</p> Signup and view all the answers

    What is defined as the phenomenon where multiple genes contribute to a single trait, resulting in continuous variation?

    <p>Polygenic inheritance</p> Signup and view all the answers

    Which best describes the concept of pleiotropy?

    <p>A single gene affecting multiple traits</p> Signup and view all the answers

    What characteristic is NOT true of Type O blood?

    <p>Is a universal recipient</p> Signup and view all the answers

    In the ABO blood group system, which function do the IA and IB alleles serve in heterozygous individuals?

    <p>They demonstrate codominance</p> Signup and view all the answers

    In the context of genetics, what distinguishes multiple alleles from polygenic inheritance?

    <p>Multiple alleles involve more than two forms of a single gene</p> Signup and view all the answers

    What is an example of polygenic inheritance?

    <p>Human eye color</p> Signup and view all the answers

    Which of the following statements about pleiotropy is true?

    <p>A gene can influence multiple phenotypic traits</p> Signup and view all the answers

    How does the vestigial gene in Drosophila exemplify pleiotropy?

    <p>It influences both wing development and reproductive traits</p> Signup and view all the answers

    Which of the following traits is NOT typically influenced by polygenic inheritance?

    <p>Blood type</p> Signup and view all the answers

    Which inheritance pattern involves the interaction between multiple genes and environmental factors to affect phenotype?

    <p>Polygenic inheritance</p> Signup and view all the answers

    Study Notes

    General Biology 1 - Fall 2024

    • Course: General Biology 1
    • Term: Fall 2024
    • Topic: Introduction to Genetics (Part 1)
    • Professor: Dr. Vincent Gagnon
    • Textbook: Raven, Biology, 13th edition, Chapter 12: Patterns of Inheritance

    Mendel's Principles and Experiments

    • Mendel's experiments used garden peas due to their easily observable traits and ability for self-fertilization/cross-fertilization.
    • Numerous pea varieties with distinct characteristics were available.
    • Mendel's experiments followed a three-step process:
      • Creating true-breeding strains for different traits.
      • Cross-fertilizing true-breeding strains with contrasting traits. Mendel meticulously removed anthers from one parent plant to prevent self-pollination.
      • Allowing the hybrid offspring to self-fertilize for multiple generations and counting the traits of the offspring.
    • True-breeding strains consistently produce offspring with the same trait over multiple generations.
    • Mendel studied 7 different traits in pea plants: flower color, seed color, seed texture, pod color, pod shape, flower position, and plant height.
    • Each trait had identifiable contrasting variations.

    Principles of Inheritance

    • Mendel's Law of Segregation - paired unit factors (genes) segregate equally into gametes, meaning offspring have an equal chance of inheriting either factor.
    • Mendel's Law of Independent Assortment - genes do not influence each other's transmission to gametes, and every possible allele combination is equally likely if the genes are on different chromosomes.

    Monohybrid and Dihybrid Crosses

    • Monohybrid crosses examine the inheritance of a single trait.
      • Example: flower color
    • Dihybrid crosses examine the inheritance of two traits simultaneously.
      • Example: seed color and seed shape

    F1 and F2 Generations

    • F1 generation: the first set of offspring from a cross of two true-breeding parents with contrasting traits. The F1 generation consistently showed one trait in common with one parent.
    • F2 generation: the second set of offspring from self-pollination of the F1 generation.
    • A 3:1 phenotypic ratio of dominant to recessive traits were apparent in the F2 generation.
    • The 3:1 phenotypic ratio reflects Mendel's law of segregation, with 3 showing the dominant trait and one showing the recessive trait.

    Mendel's Five-element Model

    • Parents transmit discrete factors (genes) that code for traits.
    • Each individual receives one copy of a gene from each parent.
    • Not all gene copies are identical (alleles).
    • Alleles remain separate, without blending.
    • The presence of an allele does not guarantee its expression.
      • Dominant allele: Always expressed (represented with a capital letter, e.g., P).
      • Recessive allele: Only expressed when two copies are present (represented with a lowercase letter, e.g., p).

    Testcross

    • Testing a suspected homozygous or heterozygous individual's genotype.
    • A testcross involves crossing the suspected individual with a homozygous recessive individual. This produces predictable offspring ratios, making it possible to determine if the mystery parent is homozygous or heterozygous.

    Punnett Squares

    • Diagram used to predict possible genotypes of offspring from a genetic cross.
    • Helps visualize allele combinations and resulting phenotypes. Punnett squares show probabilities of specific genotypes and phenotypes from parental crosses.

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    Description

    This quiz explores the fundamentals of genetics as introduced in General Biology 1. Focus on Mendel's principles and experiments using garden peas to understand patterns of inheritance. Gain insight into true-breeding strains and hybridization processes central to Mendelian genetics.

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