NCERT - PRINCIPLES OF INHERITANCE & VARIATION - 24-25
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Questions and Answers

What is the term for genes that code for contrasting traits?

  • Chromosomes
  • Phenotypes
  • Alleles (correct)
  • Genotypes

    • The phenotype of a plant with a genotype Tt will be dwarf.

    False

    What represents the alleles for height in pea plants?

    T and t

    In true breeding plants, the allelic pairs are said to be _____ for height.

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

    Match the genotype with its corresponding phenotype:

    <p>TT = Tall tt = Dwarf Tt = Dwarf</p> Signup and view all the answers

    Which of the following represents a homozygous genotype for height?

    <p>Both B and C</p> Signup and view all the answers

    Mendel found that in a pair of dissimilar traits, one trait can dominate the other.

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

    What is the result when alleles IA and IB are present together?

    <p>Both IA and IB express their types of sugars</p> Signup and view all the answers

    What is the phenotype of a plant with the genotype Tt?

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

    Allele i produces a form of sugar.

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

    How many phenotypes are possible for the ABO blood types?

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

    What was one of the contrasting traits studied by Mendel in pea plants?

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

    Mendel's experiments used a small sampling size to increase the credibility of his data.

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

    The phenomenon where two different alleles express themselves equally is called ______.

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

    Match the allele with its corresponding blood type:

    <p>IA = Type A IB = Type B IAIB = Type AB ii = Type O</p> Signup and view all the answers

    What is a true-breeding plant?

    <p>A plant that shows stable trait inheritance and expression for several generations through self-pollination.</p> Signup and view all the answers

    What type of inheritance is shown in the example of starch synthesis in pea seeds?

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

    Mendel conducted _____ experiments using several true-breeding pea lines.

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

    Match the following virtues with their corresponding contrasting traits studied by Mendel:

    <p>Tall = Dwarf Yellow seeds = Green seeds Inflated pods = Constricted pods Smooth seeds = Wrinkled seeds</p> Signup and view all the answers

    An individual can possess more than two alleles for a single gene at one time.

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

    Which of these traits is NOT one of the contrasting traits that Mendel studied?

    <p>Yellow or blue flowers</p> Signup and view all the answers

    What are the genotypes of blood type O?

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

    Mendel's findings were based solely on theories without any experimental support.

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

    What did Mendel's experiments contribute to the understanding of genetics?

    <p>They pointed to general rules of inheritance.</p> Signup and view all the answers

    What is the phenotypic ratio among the plants in the F2 generation?

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

    All F1 plants have the same genotype of Tt.

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

    What are the genotypes produced from the self-pollination of F1 plants?

    <p>TT, Tt, tt</p> Signup and view all the answers

    The dominant phenotype expressed in the F1 generation is ______.

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

    What is the genotypic ratio in the F2 generation?

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

    The F2 generation contains only dominant tall plants.

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

    What conclusion did Mendel draw about the genotype of the dwarf plants?

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

    Which type of allele is usually associated with producing a non-functional enzyme?

    <p>Recessive allele</p> Signup and view all the answers

    The F1 generation in co-dominance resembles only one parent.

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

    What type of inheritance involves multiple genes controlling a trait?

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

    What are the three alleles that control the ABO blood grouping in human beings?

    <p>IA, IB, i</p> Signup and view all the answers

    Pleiotropic genes can cause multiple phenotypic expressions from a single gene.

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

    Name a classic example of a polygenic trait in humans.

    <p>Skin color</p> Signup and view all the answers

    In a monohybrid cross, the presence of __________ determines the phenotype when paired with a recessive allele.

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

    Match the allele types with their characteristics:

    <p>Dominant allele = Produces the expressed trait Recessive allele = May lead to non-functional traits Modified allele = Can be equivalent to dominant allele Co-dominant allele = Expresses traits from both parents</p> Signup and view all the answers

    The genotype with all dominant alleles for skin color is represented as ______.

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

    Which of the following traits in humans is considered a result of pleiotropy?

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

    What happens when a modified allele produces a normal enzyme?

    <p>It is equivalent to the unmodified allele</p> Signup and view all the answers

    In incomplete dominance, the F1 generation presents traits that are a mix of both parents.

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

    Match the following terms with their definitions:

    <p>Polygenic inheritance = Trait controlled by multiple genes Pleiotropy = Single gene affects multiple traits Dominant allele = Allele that expresses when present Recessive allele = Requires two copies for expression</p> Signup and view all the answers

    The height of individuals is an example of monogenic inheritance.

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

    What is the result when the recessive trait is expressed due to a non-functional enzyme?

    <p>The phenotype displays the recessive attribute.</p> Signup and view all the answers

    What is the role of the gene that causes phenylketonuria?

    <p>It codes for the enzyme phenyl alanine hydroxylase.</p> Signup and view all the answers

    What discovery allowed scientists to observe cell division more clearly in the early 1900s?

    <p>Microscopic technology improvements</p> Signup and view all the answers

    Mendel's work was recognized immediately after he published his findings in 1865.

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

    What parallel did Walter Sutton and Theodore Boveri observe between chromosomes and genes?

    <p>The behavior of chromosomes is parallel to the behavior of genes.</p> Signup and view all the answers

    Mendel's concept of genes as stable and discrete units that controlled traits was initially _____ by many biologists.

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

    Match the following scientists with their contributions related to Mendel's work:

    <p>Mendel = Established the laws of inheritance de Vries = Rediscovered Mendel's principles independently Sutton = Noted the parallel between chromosomes and genes Boveri = Contributed to the chromosome theory of inheritance</p> Signup and view all the answers

    Which of the following best describes chromosomes?

    <p>Discreet units of inheritance visible during cell division</p> Signup and view all the answers

    Mendel's mathematical approach helped clarify biological phenomena in his time.

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

    What chromosomes determine female characteristics in birds?

    <p>ZW chromosomes</p> Signup and view all the answers

    What important concept did Mendel devise about alleles?

    <p>Alleles do not blend with each other.</p> Signup and view all the answers

    Human males produce only one type of gamete carrying either an X or Y chromosome.

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

    What is the genetic composition of the zygote if the ovum fertilizes with a sperm carrying an X chromosome?

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

    In human beings, the sex determining mechanism is of the _____ type.

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

    Match the type of gamete production with their respective sex determination mechanism:

    <p>Males (humans) = Produces X and Y gametes Females (birds) = Produces Z and W gametes Males (birds) = Produces Z gametes Females (humans) = Produces X gametes</p> Signup and view all the answers

    What is the probability of having a female child during each pregnancy in humans?

    <p>50%</p> Signup and view all the answers

    Females in humans can produce two types of gametes.

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

    What degree did James Dewey Watson obtain in 1947?

    <p>B.Sc. in Zoology</p> Signup and view all the answers

    What are the sex chromosomes present in human males?

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

    Francis Crick was born in Chicago, Illinois.

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

    What significant discovery did Watson and Crick propose in March 1953?

    <p>The double-helical structure of DNA</p> Signup and view all the answers

    Crick completed his Ph.D. in _____ on a thesis about X-ray diffraction.

    <p>1954</p> Signup and view all the answers

    Match the scientist to their contribution:

    <p>James Watson = Discovered the DNA double helix Francis Crick = Ph.D. on X-ray diffraction Mendel = Principles of inheritance Hershey and Chase = Confirmed DNA as the genetic material</p> Signup and view all the answers

    What influenced Francis Crick's career significantly?

    <p>His friendship with Watson</p> Signup and view all the answers

    James Watson and Francis Crick received the Nobel Prize for their work on the DNA structure in 1962.

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

    What field of science addresses questions related to inheritance and variation in organisms?

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

    Which genotype results from self-pollination of F1 plants of genotype Tt?

    <p>All of the above</p> Signup and view all the answers

    The phenotype of a plant with the genotype TT can be distinguished from that of a plant with the genotype Tt.

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

    What is the phenotypic ratio of tall to dwarf plants in the F2 generation?

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

    The dominant allele for height in pea plants is represented by the letter _____.

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

    Match the genotype with its corresponding phenotypic expression:

    <p>TT = Tall Tt = Tall tt = Dwarf</p> Signup and view all the answers

    What conclusion can be drawn about the genotype of dwarf plants?

    <p>They are homozygous.</p> Signup and view all the answers

    All F1 plants from the Tt genotype are dwarf.

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

    How did Mendel determine the genotype of dwarf plants from his experiments?

    <p>He observed that dwarf F2 plants produced only dwarf offspring.</p> Signup and view all the answers

    Which column in the comparison represents chromosomes?

    <p>Column A</p> Signup and view all the answers

    Independent assortment allows chromosome pairs to segregate in a way that one pair affects the segregation of another pair.

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

    What is the significance of the chromosomal theory of inheritance?

    <p>It unites the principles of chromosomal segregation with Mendelian inheritance.</p> Signup and view all the answers

    During Anaphase of meiosis I, genetic variation is introduced through __________ of chromosome pairs.

    <p>independent assortment</p> Signup and view all the answers

    Match the following concepts with their descriptions:

    <p>Chromosomal Segregation = Process during meiosis that involves the separation of chromosomes. Independent Assortment = Random distribution of chromosome pairs during gamete formation. Mendelian Principles = Fundamental rules that govern inheritance patterns. Drosophila melanogaster = Common model organism for genetic studies.</p> Signup and view all the answers

    Which of the following best describes Drosophila melanogaster?

    <p>A tiny fruit fly suitable for genetic experiments</p> Signup and view all the answers

    The life cycle of Drosophila melanogaster can be completed in approximately __________.

    <p>two weeks</p> Signup and view all the answers

    Thomas Hunt Morgan was instrumental in experimentally verifying the chromosomal theory of inheritance.

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

    What phenotype does the F1 generation exhibit in the case of incomplete dominance with red and white flowered plants?

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

    In incomplete dominance, the F2 generation shows a 3:1 ratio of phenotypes.

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

    What is the genotypic ratio of the F2 generation from the self-pollination of the F1 generation in the example of incomplete dominance?

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

    In the case of Antirrhinum sp., true-breeding red flowers have the genotype _____ and true-breeding white flowers have the genotype _____.

    <p>RR, rr</p> Signup and view all the answers

    Match the genotype with the corresponding phenotype in the context of incomplete dominance.

    <p>RR = Red flower Rr = Pink flower rr = White flower</p> Signup and view all the answers

    How are alleles expressed in a heterozygote in the case of incomplete dominance?

    <p>Both alleles are expressed equally.</p> Signup and view all the answers

    Alleles can be completely dominant, recessive, or incompletely dominant.

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

    Define incomplete dominance.

    <p>A genetic phenomenon where the heterozygous phenotype is a blend of both alleles.</p> Signup and view all the answers

    What is the phenotype of a plant with a genotype of TT?

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

    Alleles are identical forms of a gene.

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

    What does the term 'homozygous' refer to in relation to alleles?

    <p>Having two identical alleles for a particular gene.</p> Signup and view all the answers

    In a monohybrid cross, the genotype of the F1 generation is typically represented as _____ when one allele is dominant.

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

    Match the genotype with its corresponding description:

    <p>TT = Homozygous dominant tt = Homozygous recessive Tt = Heterozygous T = Dominant allele</p> Signup and view all the answers

    Which statement best describes the relationship between dominant and recessive traits?

    <p>In a heterozygote, the dominant trait will mask the recessive trait.</p> Signup and view all the answers

    The phenotype of the F1 generation will always reflect the recessive trait.

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

    What allele represents the recessive trait for height in pea plants?

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

    What is the karyotype of an individual with Klinefelter’s Syndrome?

    <p>47, XXY</p> Signup and view all the answers

    Individuals with Turner’s Syndrome have normal ovaries.

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

    What term describes the phenomenon where one trait is completely dominant over another?

    <p>Law of Dominance</p> Signup and view all the answers

    A female with Turner’s Syndrome has a karyotype of _____ with X0.

    <p>45</p> Signup and view all the answers

    Match the genetic disorders with their characteristics:

    <p>Klinefelter’s Syndrome = 47, XXY, sterile males with feminine traits Turner’s Syndrome = 45, X0, sterile females with rudimentary ovaries</p> Signup and view all the answers

    Which of the following statements about Mendel's work is correct?

    <p>Mendel's laws include the Law of Segregation.</p> Signup and view all the answers

    All individuals with Klinefelter’s Syndrome express exclusively feminine traits.

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

    What is a common characteristic of individuals with Klinefelter’s Syndrome?

    <p>They are sterile.</p> Signup and view all the answers

    What determines the sex of honey bees?

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

    Honey bee males have the same number of chromosomes as females.

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

    What is the total number of chromosomes for a female honey bee?

    <p>32</p> Signup and view all the answers

    Males develop from ______ eggs in honey bees.

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

    What type of mutation results in the alteration of a single base pair of DNA?

    <p>Point mutation</p> Signup and view all the answers

    Match the type of mutation with its description:

    <p>Point mutation = Alteration of a single base pair Frame-shift mutation = Caused by deletions or insertions Chromosomal aberration = Commonly observed in cancer cells Duplication = Increase in the number of DNA segments</p> Signup and view all the answers

    Males in honey bees do not have a father.

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

    Name a classical example of a mutation affecting phenotype.

    <p>Sickle cell anemia</p> Signup and view all the answers

    In XO type of sex determination, which of the following statements is true?

    <p>Males have one X-chromosome and no Y-chromosome.</p> Signup and view all the answers

    In humans, males have a pair of XX chromosomes.

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

    What is the sex determination mechanism present in many birds?

    <p>ZW mechanism</p> Signup and view all the answers

    In the XX-XY sex determination system, the male is referred to as ______.

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

    Match the following species with their corresponding sex determination system:

    <p>Grasshopper = XO type Human = XY type Bird = ZW type Drosophila = XY type</p> Signup and view all the answers

    Which sex chromosome pair do females possess in both humans and Drosophila?

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

    All male birds have the same chromosomes as female birds.

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

    In sex determination systems, chromosomes that are not involved in sex determination are termed ______.

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

    What is the term used to describe agents that induce mutations?

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

    UV radiation is considered a mutagen.

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

    What process is used to analyze the inheritance pattern of traits in humans?

    <p>Pedigree analysis</p> Signup and view all the answers

    An alteration in the genetic material is referred to as a _____.

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

    Which of the following best describes the purpose of pedigree analysis?

    <p>To trace the inheritance of traits across generations</p> Signup and view all the answers

    Changes in DNA are always harmful to the organism.

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

    What role does DNA play in genetics?

    <p>DNA carries genetic information from one generation to the next.</p> Signup and view all the answers

    Which of the following disorders is an example of a Mendelian disorder?

    <p>Cystic fibrosis</p> Signup and view all the answers

    Colour blindness is transmitted from father to daughter.

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

    What is the pattern of inheritance observed for Haemophilia?

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

    The chance of a son being color blind if his mother is a carrier is ______ percent.

    <p>50</p> Signup and view all the answers

    Match the following Mendelian disorders with their characteristics:

    <p>Haemophilia = X-linked recessive disorder affecting blood clotting Sickle-cell anaemia = Autosomal recessive disorder affecting red blood cells Phenylketonuria = Autosomal recessive disorder resulting in the inability to process phenylalanine Thalassemia = Autosomal recessive disorder affecting hemoglobin production</p> Signup and view all the answers

    Which statement is true about the inheritance of Mendelian disorders?

    <p>They may be dominant or recessive in inheritance.</p> Signup and view all the answers

    Mendelian disorders can be identified using pedigree analysis.

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

    Name a common Mendelian disorder that affects the ability to clot blood.

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

    Which of the following statements best describes the Law of Independent Assortment?

    <p>Gametes combine in random permutations.</p> Signup and view all the answers

    Linked genes are genes that assort independently from one another.

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

    What are the male and female sex chromosomes in humans?

    <p>Male: XY; Female: XX</p> Signup and view all the answers

    Down’s syndrome is caused by _____ of chromosome 21.

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

    Which type of mutation involves a change in a single base pair?

    <p>Point mutation</p> Signup and view all the answers

    Match the following genetic disorders with their descriptions:

    <p>Down's syndrome = Trisomy of chromosome 21 Turner's syndrome = XO sex chromosome configuration Klinefelter's syndrome = XXY sex chromosome configuration</p> Signup and view all the answers

    What is the chromosomal configuration in females in chickens?

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

    Phenotypes express genetic traits regardless of the underlying genotype.

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

    What does the Law of Dominance state?

    <p>Only one member of a dissimilar pair of factors dominates the other.</p> Signup and view all the answers

    In a test cross, a dominant phenotype is crossed with a homozygous dominant parent.

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

    What did Morgan observe about the F2 ratio in his dihybrid crosses?

    <p>It deviated significantly from the expected ratio</p> Signup and view all the answers

    All genes located on the same chromosome show tight linkage and minimal recombination.

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

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

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

    The process of determining the genotype of an organism by crossing it with a recessive organism is known as a _____ cross.

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

    What term did Morgan use to describe the physical association of genes on a chromosome?

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

    Match the components of Mendel's Laws with their descriptions:

    <p>First Law (Law of Dominance) = One trait dominates the expression of another. Second Law (Law of Segregation) = Alleles segregate during gamete formation. Factors = Discrete units controlling characters. Homozygous = Two identical alleles for a trait.</p> Signup and view all the answers

    The genes white and yellow in Drosophila showed only _____ percent recombination.

    <p>1.3</p> Signup and view all the answers

    Match the following pairs of genes with their recombination percentages:

    <p>White and Yellow = 1.3% White and Miniature Wing = 37.2% Yellow and Brown = Varies Red and Brown = Low</p> Signup and view all the answers

    Which statement correctly describes an allele?

    <p>Alleles are forms of genes that control specific traits.</p> Signup and view all the answers

    The Law of Segregation states that both alleles of a gene blend together in gametes.

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

    Which of the following statements about the dihybrid crosses in Drosophila is true?

    <p>Two genes can show much higher parental combinations.</p> Signup and view all the answers

    Alfred Sturtevant used recombination frequency to map gene positions on chromosomes.

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

    In a monohybrid cross involving tall (T) and dwarf (t) plants, what are the possible gametes produced by a heterozygous plant?

    <p>T, t</p> Signup and view all the answers

    What was the primary method Morgan used to study sex-linked genes in Drosophila?

    <p>dihybrid crosses</p> Signup and view all the answers

    All F1 generation plants exhibit dwarf characteristics.

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

    What genotype represents a true-breeding dwarf plant?

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

    The ratio of genotypes TT, Tt, and tt obtained from self-pollination is _____ : _____ : _____

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

    Match the genotype with its phenotypic expression:

    <p>TT = Tall Tt = Tall tt = Dwarf</p> Signup and view all the answers

    What would Mendel expect to occur if he self-pollinated a tall F2 plant?

    <p>There would be a mixture of tall and dwarf offspring.</p> Signup and view all the answers

    The F2 generation contains only genotype Tt.

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

    What does the symbol 'T' represent in the context of plant height?

    <p>Tall allele</p> Signup and view all the answers

    Which of the following disorders is primarily an X-linked recessive disorder?

    <p>Colour blindness</p> Signup and view all the answers

    Mendelian disorders can only be dominant traits.

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

    What type of genetic analysis is used to trace the inheritance of Mendelian disorders in families?

    <p>pedigree analysis</p> Signup and view all the answers

    Haemophilia is an example of a _____ disorder.

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

    What is the chance of a son of a carrier mother being colour blind?

    <p>50%</p> Signup and view all the answers

    Males have two X chromosomes, which increases the likelihood of being affected by X-linked disorders.

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

    Name one common Mendelian disorder that affects the blood's ability to clot.

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

    What karyotype is associated with Klinefelter's Syndrome?

    <p>47, XXY</p> Signup and view all the answers

    Individuals with Turner’s Syndrome have normally developed ovaries.

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

    List one primary feature of individuals diagnosed with Klinefelter's Syndrome.

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

    The presence of an additional copy of the X chromosome results in _____ development in Klinefelter's Syndrome.

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

    Which of the following statements describes Mendel's Law of Segregation?

    <p>Alleles segregate when gametes are formed.</p> Signup and view all the answers

    Match the following syndromes with their characteristics:

    <p>Klinefelter's Syndrome = 47, XXY, Gynaecomastia Turner's Syndrome = 45, X0, Rudimentary ovaries</p> Signup and view all the answers

    Mendel's principles of inheritance are applicable to both plants and animals.

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

    What phenomenon results in some characters being expressed in homozygous conditions but not in heterozygous conditions?

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

    What type of plants did Mendel primarily use for his experiments?

    <p>Garden pea plants</p> Signup and view all the answers

    Mendel's experiments had a small sampling size which decreased the credibility of the data he collected.

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

    Mendel selected ___ true-breeding pea plant varieties for his studies.

    <p>14</p> Signup and view all the answers

    Which of the following is one of the contrasting traits studied by Mendel?

    <p>Height - Tall/Dwarf</p> Signup and view all the answers

    Match the following traits with their contrasting characteristics:

    <p>Stem height = Tall/Dwarf Seed color = Yellow/Green Pod shape = Inflated/Constricted Seed texture = Smooth/Wrinkled</p> Signup and view all the answers

    What general rules did Mendel's results come to point towards?

    <p>General rules of inheritance.</p> Signup and view all the answers

    Mendel's work had no experimental support before being acknowledged in genetics.

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

    What theory did Sutton unite with Mendelian principles regarding inheritance?

    <p>Chromosomal theory of inheritance</p> Signup and view all the answers

    Independent assortment of chromosomes occurs during metaphase II of meiosis.

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

    What organism did Thomas Hunt Morgan use in his genetics experiments?

    <p>Drosophila melanogaster</p> Signup and view all the answers

    During gamete formation, chromosomes from each pair are __________ to gametes.

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

    Match the following aspects of chromosomes and genes:

    <p>Occur in pairs = Chromosomes Independent pairs segregate = Genes Segregate at gamete formation = Both One of each pair transmitted to gamete = Chromosomes</p> Signup and view all the answers

    What is the primary purpose of a test cross?

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

    What advantage does Drosophila melanogaster present in genetic research?

    <p>Large number of offspring</p> Signup and view all the answers

    The Law of Segregation states that alleles blend together during gamete formation.

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

    What flower color in pea plants is dominant according to Mendel's findings?

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

    Mendel's experiments with pea plants were conducted in a natural environment without control.

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

    What process leads to the variation produced by sexual reproduction according to the chromosomal theory of inheritance?

    <p>Segregation and independent assortment of chromosomes</p> Signup and view all the answers

    The expression of only one parental character in the F1 generation can be explained by the __________.

    <p>Law of Dominance</p> Signup and view all the answers

    Match the following laws of inheritance with their descriptions:

    <p>Law of Dominance = Explains dominant and recessive traits Law of Segregation = Describes how alleles segregate during gamete formation</p> Signup and view all the answers

    What phenotypic ratio is expected in the F2 generation of a monohybrid cross?

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

    A homozygous parent produces two different types of gametes.

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

    Define a test cross in your own words.

    <p>A test cross is a breeding experiment used to determine the genotype of an organism with a dominant phenotype by crossing it with a recessive organism.</p> Signup and view all the answers

    Which mechanism describes males producing two different types of gametes, either with or without an X-chromosome?

    <p>Male heterogamety</p> Signup and view all the answers

    In humans, females have two X-chromosomes and males have one X and one Y chromosome.

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

    What are the two types of gametes produced by males during spermatogenesis?

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

    In birds, females have one Z and one _____ chromosome.

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

    What is the probability of having a male or female offspring in humans?

    <p>50%</p> Signup and view all the answers

    Match the sex determination mechanisms with the correct descriptions:

    <p>Male heterogamety = Males produce gametes with X and Y chromosomes Female heterogamety = Females produce gametes with Z and W chromosomes Human sex determination = Males have X and Y, females have two X chromosomes Bird sex determination = Same chromosome number but different sex chromosomes for females</p> Signup and view all the answers

    The genetic makeup of the ovum determines the sex of the child in humans.

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

    What are the sex chromosomes present in female birds?

    <p>Z and W</p> Signup and view all the answers

    What is the chromosome number in male honey bees?

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

    Honey bee males develop from fertilized eggs.

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

    What type of sex-determination system do honey bees exhibit?

    <p>Haplodiploid sex-determination system</p> Signup and view all the answers

    Honey bees have ____ chromosomes, while drones have ____ chromosomes.

    <p>32, 16</p> Signup and view all the answers

    Which of the following mutations is caused by a change in a single base pair of DNA?

    <p>Point mutation</p> Signup and view all the answers

    Chromosomal aberrations are often found in healthy, non-cancerous cells.

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

    Match the following types of mutations with their descriptions:

    <p>Point mutation = Change in a single base pair Frame-shift mutation = Involves deletions or insertions causing shifts in reading frame Deletion mutation = Loss of a segment of DNA Insertion mutation = Gain of a segment of DNA</p> Signup and view all the answers

    What is one classical example of a point mutation?

    <p>Sickle cell anemia</p> Signup and view all the answers

    Haemophilia is a recessive disorder linked to the X chromosome.

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

    What is the typical inheritance pattern of colour blindness in males?

    <p>Males inherit colour blindness from carrier females, having a 50% chance of being affected.</p> Signup and view all the answers

    The disorder resulting in the inability to properly metabolize phenylalanine is called _____

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

    What percentage of males is affected by colour blindness?

    <p>8%</p> Signup and view all the answers

    A daughter of a carrier mother for colour blindness will always be colour blind.

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

    What type of genetic traits can be determined through pedigree analysis?

    <p>Mendelian traits and their inheritance patterns.</p> Signup and view all the answers

    In Mendel's experiments, what was the observed phenotypic ratio among the F2 generation plants?

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

    All F1 progeny plants in Mendel's crosses were a blend of their parental traits.

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

    What term did Mendel use to refer to the units of inheritance?

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

    The two contrasting traits of pea plants that Mendel studied included tall and _____ plants.

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

    Match the following traits with their respective options:

    <p>Flower Colour = Violet/White Pod Shape = Inflated/Constricted Seed Colour = Yellow/Green Seed Shape = Round/Wrinkled</p> Signup and view all the answers

    During self-pollination of the tall F1 plants, what unexpected result did Mendel find in the F2 generation?

    <p>Some plants were dwarf</p> Signup and view all the answers

    Mendel's studies concluded that traits could blend in offspring.

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

    What does the term 'Filial1' refer to in Mendel's experiments?

    <p>First hybrid generation</p> Signup and view all the answers

    What type of gametes do males produce in male heterogamety?

    <p>Either X-chromosome or Y-chromosome gametes</p> Signup and view all the answers

    In birds, males have a pair of Z-chromosomes while females have one Z and one W chromosome.

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

    What chromosome pair is present in females in the XY sex determination system?

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

    The sex of a child in humans is determined by the genetic makeup of the _____.

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

    Match the following organisms with their sex determination mechanisms:

    <p>Males = Male heterogamety Females (Birds) = Female heterogamety Humans = XY sex determination Birds = ZW sex determination</p> Signup and view all the answers

    What is the probability of having a male child if an ovum fertilizes with a Y-chromosome carrying sperm?

    <p>50%</p> Signup and view all the answers

    Women are solely responsible for the sex of the child, where female children are the result of their genetic contribution.

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

    What type of chromosomes are present in male birds according to their sex determination mechanism?

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

    What is the dominant allele for seed shape in the described pea plant crosses?

    <p>Round (R)</p> Signup and view all the answers

    The phenotype of the heterozygous Bb seeds is larger than the phenotype of the homozygous BB seeds.

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

    What phenotypic ratio is observed for yellow to green seeds in the F2 generation?

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

    In Mendel's pea plant experiments, the allele for yellow seeds is designated as _____ and the allele for green seeds is designated as _____.

    <p>Y, y</p> Signup and view all the answers

    Match the following seed traits with their dominant or recessive status:

    <p>Yellow seed color = Dominant Green seed color = Recessive Round seed shape = Dominant Wrinkled seed shape = Recessive</p> Signup and view all the answers

    What type of inheritance is illustrated by the starch grain sizes in homozygous and heterozygous pea seeds?

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

    Which column represents chromosomes and which represents genes?

    <p>Column A represents chromosomes and Column B represents genes</p> Signup and view all the answers

    Sutton and Boveri proposed that the segregation of chromosomes leads to the segregation of genes.

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

    What does the cross between genotype RRYY and rryy produce in the F1 generation?

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

    What is the main organism used by Thomas Hunt Morgan to study inheritance?

    <p>Drosophila melanogaster</p> Signup and view all the answers

    Heterozygous Bb seeds produce the largest starch grains compared to other genotypes.

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

    During ______, chromosome pairs can align independently at the metaphase plate.

    <p>Anaphase I</p> Signup and view all the answers

    What is a key characteristic of independent assortment observed during meiosis?

    <p>The segregation of one pair does not affect the other pairs</p> Signup and view all the answers

    The life cycle of Drosophila melanogaster takes about two months to complete.

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

    Who experimentally verified the chromosomal theory of inheritance?

    <p>Thomas Hunt Morgan</p> Signup and view all the answers

    What are mutagens?

    <p>Factors that induce mutations</p> Signup and view all the answers

    Pedigree analysis is used to study the inheritance of traits in plants only.

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

    What is DNA's role in genetics?

    <p>DNA serves as the carrier of genetic information.</p> Signup and view all the answers

    An alteration in the genetic material is known as a _____ .

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

    Which of the following can cause mutations?

    <p>UV radiation</p> Signup and view all the answers

    Each feature in an organism is controlled by multiple genes located throughout the DNA.

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

    What is represented in a pedigree analysis?

    <p>The inheritance of a particular trait over generations in a family.</p> Signup and view all the answers

    What is the total number of chromosomes in a normal human cell?

    <p>46</p> Signup and view all the answers

    Down's syndrome is caused by having an extra copy of chromosome 21.

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

    What is the term for the situation where an individual has an additional chromosome?

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

    Individuals with __________ syndrome may have short stature and other physical anomalies.

    <p>Turner’s</p> Signup and view all the answers

    Which of the following is a common characteristic of Down's syndrome?

    <p>Short stature with a broad flat face</p> Signup and view all the answers

    Match the following chromosomal disorders with their characteristics:

    <p>Down’s syndrome = Trisomy of chromosome 21 Turner’s syndrome = Missing an X chromosome Klinefelter’s syndrome = Extra X chromosome in males Monosomy = Lack of one chromosome from a pair</p> Signup and view all the answers

    Monosomy refers to the presence of an additional chromosome.

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

    What genetic feature is typically observed in individuals with Down's syndrome?

    <p>Broad palm with characteristic palm crease</p> Signup and view all the answers

    What structure did Henking name after tracing it during spermatogenesis in insects?

    <p>X body</p> Signup and view all the answers

    In the XO system of sex determination, males have an additional chromosome compared to females.

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

    What happens to eggs fertilised by sperm that do not carry an X-chromosome?

    <p>They become males.</p> Signup and view all the answers

    Henking's observations led to the understanding of the _______ basis of sex-determination in insects.

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

    What does the capital letter in gene representation signify?

    <p>The dominant trait expressed at the F1 stage</p> Signup and view all the answers

    Tallness is dominant over dwarfness in pea plants.

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

    What is the genotype of a true-breeding dwarf pea plant?

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

    In genetics, two different forms of the same gene are known as _____ .

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

    Match the genotype with its description:

    <p>TT = Homozygous dominant tt = Homozygous recessive Tt = Heterozygous T = Allele for tallness</p> Signup and view all the answers

    Which phenotype would a Tt plant exhibit?

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

    Mendel's studies indicated that the genotype is the visible expression of a trait.

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

    What term describes the physical expression of a genotype?

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

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

    <p>The physical association of genes on the same chromosome</p> Signup and view all the answers

    Which statement describes how chromosomes behave during gamete formation?

    <p>Only one member of each chromosome pair is transmitted to a gamete.</p> Signup and view all the answers

    Sutton and Boveri proposed that the pairing and separation of chromosomes leads to the segregation of alleles.

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

    Morgan discovered that the F2 ratio in dihybrid crosses deviated significantly from the expected 9:3:3:1 ratio due to independent assortment.

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

    What percentage of recombination was observed between the tightly linked genes white and yellow?

    <p>1.3 percent</p> Signup and view all the answers

    What type of organism did Thomas Hunt Morgan use for his experiments on inheritance?

    <p>Drosophila melanogaster</p> Signup and view all the answers

    The chromosomal theory of inheritance was based on the work of __________ and Boveri.

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

    The term _____ refers to the generation of non-parental gene combinations.

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

    Which of the following was a method used by Morgan to study sex-linked genes?

    <p>Dihybrid crosses in Drosophila</p> Signup and view all the answers

    During which phase of meiosis do chromosomes align at the metaphase plate independently?

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

    What is the primary reason for higher proportions of parental gene combinations in linked genes?

    <p>Physical proximity on the same chromosome</p> Signup and view all the answers

    Genes and chromosomes behave in exactly the same way during inheritance.

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

    What is the significance of independent assortment in genetics?

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

    Who was the student of Morgan that contributed to genetic mapping?

    <p>Alfred Sturtevant</p> Signup and view all the answers

    Which of the following traits is an example of polygenic inheritance?

    <p>Human height</p> Signup and view all the answers

    Pleiotropic genes can only affect a single phenotype.

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

    What is the dominant genotype for skin color according to the described polygenic trait?

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

    Phenylketonuria is an example of a disorder caused by a mutation in a gene that codes for ______.

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

    Match the following traits with their descriptions:

    <p>Height = Polygenic trait Phenylketonuria = Pleiotropic condition Skin color = Affected by multiple genes Male/Female = Determined by sex chromosomes</p> Signup and view all the answers

    Which of the following best describes how polygenic traits function?

    <p>They involve multiple genes and exhibit additive effects.</p> Signup and view all the answers

    The phenotype of an individual with the genotype aabbcc will have the darkest skin color.

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

    Identify one trait in humans that exhibits pleiotropy.

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

    What is the main result of the accumulation of phenylalanine in individuals with phenylketonuria?

    <p>Mental retardation</p> Signup and view all the answers

    Thalassemia is caused by the overproduction of hemoglobin chains.

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

    What genetic mechanism causes phenylketonuria?

    <p>Autosomal recessive inheritance</p> Signup and view all the answers

    Down’s syndrome is caused by the gain of an extra copy of chromosome ______.

    <p>21</p> Signup and view all the answers

    Match the following conditions with their descriptions:

    <p>Phenylketonuria = Lacks an enzyme converting phenylalanine to tyrosine Thalassemia = Reduced synthesis of globin chains Down's syndrome = Gain of an extra chromosome 21 Turner's syndrome = Loss of an X chromosome in females</p> Signup and view all the answers

    Which type of thalassemia is associated with a defect in the alpha globin chain?

    <p>Alpha Thalassemia</p> Signup and view all the answers

    Polyploidy occurs due to the gain of a chromosome.

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

    What is the primary cause of Turner’s syndrome?

    <p>Loss of an X chromosome</p> Signup and view all the answers

    What is the primary field of study that deals with the questions related to inheritance and variation?

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

    James Watson was awarded the Nobel Prize in 1960.

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

    Who were the two scientists credited with proposing the double-helical structure of DNA?

    <p>James Watson and Francis Crick</p> Signup and view all the answers

    Francis Crick completed his Ph.D. in ____ on a thesis about X-ray Diffraction.

    <p>1954</p> Signup and view all the answers

    Match the following scientists with their corresponding achievements:

    <p>James Watson = Proposed the DNA structure in 1953 Francis Crick = Completed Ph.D. in X-ray Diffraction J.D. Watson = Known for bird-watching and genetics</p> Signup and view all the answers

    In what year did Watson receive his B.Sc. degree?

    <p>1947</p> Signup and view all the answers

    The study of genetics only covers questions about human inheritance.

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

    What method did Watson and Crick utilize to arrive at their proposal for DNA structure?

    <p>Experimental evidence and nucleic acid literature</p> Signup and view all the answers

    In Mendel's experiments with pea plants, what does the capital letter represent when coding for traits?

    <p>The dominant trait</p> Signup and view all the answers

    In a monohybrid cross, Tt genotype will result in a dwarf phenotype.

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

    What is the phenotypic outcome when a homozygous tall plant (TT) is crossed with a homozygous dwarf plant (tt)?

    <p>All offspring will be tall (Tt).</p> Signup and view all the answers

    In genetics, a pair of dissimilar alleles is referred to as _____.

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

    Which term is used to describe the physical appearance of an organism regarding a specific trait?

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

    Alleles are identical forms of a gene found at the same locus on homologous chromosomes.

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

    What was the key finding of Mendel regarding dominant and recessive traits?

    <p>In a pair of dissimilar factors, one factor is dominant and masks the expression of the other recessive factor.</p> Signup and view all the answers

    What term refers to the physical association of genes on a chromosome?

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

    Alfred Sturtevant determined the distance between genes based on recombination frequencies.

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

    What fruit fly species did Morgan use for his dihybrid crosses?

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

    Match the following terms with their corresponding definitions:

    <p>Linkage = Physical association of genes on the same chromosome Recombination = Generation of non-parental gene combinations Dihybrid Cross = Cross involving two traits Sex-linked genes = Genes located on the sex chromosomes</p> Signup and view all the answers

    What observed ratio deviated from the expected 9:3:3:1 ratio in Morgan's experiments?

    <p>Not applicable</p> Signup and view all the answers

    Morgan's crosses indicated that genes on different chromosomes segregate independently.

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

    What was the main observation made by Morgan regarding parental gene combinations?

    <p>Parental gene combinations were much higher than non-parental combinations.</p> Signup and view all the answers

    What determines the sex of the child in humans?

    <p>The genetic makeup of the sperm</p> Signup and view all the answers

    Females produce two different types of gametes in humans.

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

    In humans, males possess one _____ chromosome and one _____ chromosome.

    <p>X, Y</p> Signup and view all the answers

    Match the sex determination mechanisms with their descriptions:

    <p>Male heterogamety = Males produce gametes with X or Y chromosomes Female heterogamety = Females produce gametes with Z or W chromosomes XY sex determination = Humans having X and Y chromosomes ZW sex determination = Birds having Z and W chromosomes</p> Signup and view all the answers

    What percentage of sperm produced by males carries the Y chromosome?

    <p>50%</p> Signup and view all the answers

    There is an equal probability of fertilization resulting in male or female offspring.

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

    Which chromosomes do female humans have?

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

    Pleiotropic genes can affect multiple traits based on a single genetic mutation.

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

    What are the dominant alleles for skin color as described in the content?

    <p>A, B, C</p> Signup and view all the answers

    The condition caused by a mutation in the gene coding for phenyl alanine hydroxylase is known as ______.

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

    Match the following examples with their type of inheritance:

    <p>Height in humans = Polygenic inheritance Phenylketonuria = Pleiotropy ABO blood type = Multiple alleles Skin color = Polygenic inheritance</p> Signup and view all the answers

    In polygenic inheritance, how does the contribution of each allele affect the phenotype?

    <p>It is additive.</p> Signup and view all the answers

    Human skin color is determined by a single gene.

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

    What range of skin colors is seen in humans, and what factors influence this range?

    <p>A gradient of skin colors influenced by multiple genes and environmental factors.</p> Signup and view all the answers

    What is the karyotype associated with Klinefelter's Syndrome?

    <p>47, XXY</p> Signup and view all the answers

    Individuals with Turner’s Syndrome have a normal number of X chromosomes.

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

    What is a notable physical characteristic of individuals with Klinefelter’s Syndrome?

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

    Mendel proposed the principles of inheritance known as _______.

    <p>Mendel’s Laws of Inheritance</p> Signup and view all the answers

    Match the following genetic terms with their descriptions:

    <p>Dominant alleles = Expressed in heterozygous condition Recessive alleles = Expressed in homozygous condition Homozygous condition = Two identical alleles Heterozygous condition = Two different alleles</p> Signup and view all the answers

    Which of the following best describes the Law of Segregation?

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

    Incomplete dominance occurs when one allele fully masks the expression of another.

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

    What condition leads to the development of rudimentary ovaries in Turner’s Syndrome?

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

    What structure did Henking trace during spermatogenesis in insects?

    <p>X body</p> Signup and view all the answers

    Sperms fertilized by eggs with no X-chromosome will result in males.

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

    What type of sex determination mechanism is observed in a large number of insects?

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

    Henking's observations contributed to the understanding of the ____-chromosome's role in sex determination.

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

    Which of the following statements about alleles is true?

    <p>Alleles can be dominant or recessive.</p> Signup and view all the answers

    In Mendel's experiments, the phenotype of the Tt genotype was not different from that of the TT genotype.

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

    What does the term 'phenotype' refer to in the context of genetics?

    <p>The observable traits of an organism.</p> Signup and view all the answers

    The alleles TT and tt represent _____ genotypes for height in pea plants.

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

    Match the following genotypes with their corresponding characteristics:

    <p>TT = Homozygous dominant Tt = Heterozygous tt = Homozygous recessive T = Dominant allele</p> Signup and view all the answers

    Which of the following accurately describes Mendel's dominant and recessive factors?

    <p>The dominant factor masks the effect of the recessive factor.</p> Signup and view all the answers

    Individuals with the genotype Tt are considered homozygous for height.

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

    What is the genotype of a true-breeding dwarf pea plant for height?

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

    What was one reason Mendel's work on inheritance went unrecognized until 1900?

    <p>The scientific community did not recognize genetic principles.</p> Signup and view all the answers

    Mendel's theory of inheritance included the concept that alleles blend together to form new traits.

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

    Name one advancement that helped rediscover Mendel's results in the early 1900s.

    <p>Advancements in microscopy</p> Signup and view all the answers

    Mendel's experiments suggested that factors, which we now call _____, were discrete units controlling traits.

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

    Match the following scientists with their contributions:

    <p>Mendel = Proposed the laws of inheritance Sutton = Established the chromosome theory of inheritance Boveri = Behavior of chromosomes during meiosis de Vries = Rediscovered Mendel's work</p> Signup and view all the answers

    In which year did Mendel publish his work on inheritance?

    <p>1865</p> Signup and view all the answers

    Chromosomes are observed to double and divide just before cell division.

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

    What did Walter Sutton and Theodore Boveri note about the behavior of chromosomes?

    <p>The behavior of chromosomes is parallel to the behavior of genes.</p> Signup and view all the answers

    What phenotypic ratio is commonly derived from a dihybrid cross involving seed color and seed shape?

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

    Mendel's Law of Independent Assortment states that the segregation of one pair of alleles is dependent on the segregation of another pair.

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

    How many different types of gametes are produced in a dihybrid cross involving RrYy?

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

    Based on Mendel's cross, the genotypes of the gametes can be expressed as ______.

    <p>RY, Ry, rY, ry</p> Signup and view all the answers

    Match the following genotype with its phenotype:

    <p>RrYy = Round and yellow seeds RRYy = Round and yellow seeds rryy = Wrinkled and green seeds</p> Signup and view all the answers

    Which of these statements correctly defines a dihybrid cross?

    <p>A cross that studies two pairs of contrasting traits.</p> Signup and view all the answers

    Punnett squares can illustrate the segregation of alleles during meiosis.

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

    What is the genotypic ratio in the F2 generation for a dihybrid cross?

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

    What does the Law of Independent Assortment state regarding gene inheritance?

    <p>Different genes assort independently of one another.</p> Signup and view all the answers

    What is the primary purpose of a test cross in genetics?

    <p>To identify the genotype of a plant showing dominant traits</p> Signup and view all the answers

    Sex-linked genes are located on autosomes.

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

    What condition is caused by trisomy of chromosome 21?

    <p>Down's syndrome</p> Signup and view all the answers

    The Law of Segregation explains that alleles blend together during gamete formation.

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

    In humans, a normal male has _____ pairs of autosomes and one pair of sex chromosomes.

    <p>22</p> Signup and view all the answers

    What ratio is typically observed among phenotypes in the F2 generation of a monohybrid cross?

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

    In a monohybrid cross, the traits of the ______ generation can express both parental traits.

    <p>F2</p> Signup and view all the answers

    Match the syndrome with its corresponding chromosomal condition:

    <p>Down's syndrome = Trisomy 21 Turner's syndrome = XO genotype Klinefelter's syndrome = XXY genotype Sickle-cell anemia = Point mutation in hemoglobin gene</p> Signup and view all the answers

    Which of the following describes point mutation?

    <p>A change of a single base pair in DNA.</p> Signup and view all the answers

    Match each Law of Inheritance with its main principle:

    <p>Law of Dominance = One trait will dominate another in a pair. Law of Segregation = Alleles segregate during gamete formation. Law of Independent Assortment = Different traits are passed independently. Law of Genetics = Inheritance occurs through discrete units called factors.</p> Signup and view all the answers

    Linked genes assort independently during meiosis.

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

    What is the outcome of a test cross between a tall plant (unknown genotype) and a dwarf plant?

    <p>The offspring phenotype ratio indicates the genotype of the tall parent.</p> Signup and view all the answers

    According to Mendel's first law, the recessive trait is observed only in the F1 generation.

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

    What is the primary method used to study inheritable mutations within families?

    <p>Pedigree analysis</p> Signup and view all the answers

    Study Notes

    Summary of Genetics

    • Genetics is the study of inheritance and variation of traits.
    • Traits are characteristics passed from parents to offspring.
    • Variation describes how offspring differ from their parents.

    Mendel's Laws of Inheritance

    • Inheritance patterns were studied using pea plants.
    • Dominant traits mask recessive traits in the first filial generation (F1).
    • Recessive traits reappear in the second filial generation (F2).
    • Law of Dominance: One trait masks the other in the F1, for example, the tall trait masks the short trait.
    • Law of Segregation: Alleles separate during gamete formation.
    • Law of Independent Assortment: Alleles of different traits segregate independently, for example, seed color and seed shape independently segregate.

    Incomplete Dominance

    • The F1 generation exhibits a blending of traits, for example, crossing a red flower with a white flower results in pink flowers.
    • The resulting phenotypes blend, the blended traits are intermediate in characteristics, for example, in snapdragon.
    • The heterozygous phenotype is not identical to either homozygous phenotype.
    • Example of incomplete dominance: Snapdragon flower color.

    Co-dominance

    • Both traits are expressed in the F1 generation, for example, ABO blood groups; A and B alleles are both expressed if present, resulting in the AB blood type.
    • Example: ABO blood groups.
    • Co-dominance: Both alleles are fully expressed in the phenotype.

    Sex Determination

    • Humans have 23 pairs of chromosomes, 22 pairs are autosomes, one pair are sex chromosomes.
    • Males have XY chromosomes.
    • Females have XX chromosomes.
    • In some organisms like birds, the female has ZW chromosomes, and males have ZZ chromosomes.
    • Gene products influence the expression of traits.
    • Sex determination mechanisms exist in different species (e.g., XO, XY, ZW).
    • In Honeybees, sex is determined by whether the egg is fertilized.
    • Example of sex determination: Honey bee; diploid females, haploid males.

    Mutations

    • Mutations are changes in DNA sequence that can alter traits.
    • They can be caused by environmental factors or errors in DNA replication.
    • There are many types of mutations, including substitutions, insertions, and deletions.

    Genetic Disorders

    • Genetic disorders arise from mutations altering DNA.
    • Examples include:
      • Down Syndrome (trisomy 21).
      • Sickle-cell anemia (caused by a substitution of an amino acid in the hemoglobin protein).
      • Haemophilia (sex-linked recessive trait).
      • Phenylketonuria (lack of an enzyme that converts phenylalanine into tyrosine).
      • Thalassemia (deficient globin production leading to abnormal hemoglobin resulting in anemia).
    • These can result from abnormalities in chromosome number or structure (e.g., an extra chromosome, missing chromosome).
    • Examples of chromosomal disorders include Klinefelter's syndrome (XXY) and Turner's syndrome (XO).
    • Other examples include phenylketonuria, thalassemia, and color blindness (sex-linked, recessive).
    • Mutations can lead to altered gene products, which causes various disorders.
    • Genetic disorders can be caused by mutations in a single gene or multiple genes, or by changes in chromosome structure or number.
    • Pedigree analysis is used to study patterns of inheritance of genetic traits in families.
    • Examples of Genetic Disorders based on their inheritance patterns:
      • Autosomal dominant disorders; Myotonic dystrophy.
      • Autosomal recessive disorders; Sickle-cell anemia.
      • Sex-linked recessive disorders; Colour blindness, haemophilia.
    • Other disorders include Klinefelter syndrome, Turner syndrome.
    • Genetic disorders can be caused by mutations in a single gene or multiple genes, or by changes in chromosome structure or number.

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    Principles of Inheritance (PDF)

    Description

    Test your knowledge of genetics and Mendelian traits with this quiz. Covering topics from allele interactions to phenotypic expressions, this quiz engages learners at all levels. Prepare to challenge your understanding of key genetic concepts related to pea plants and blood types.

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