Variation in Population and Species
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Questions and Answers

Which statement best describes the relationship between genotype and phenotype?

  • Genotype remains the same throughout life while phenotype can change based on environmental conditions.
  • Genotype is inherited from the parent while phenotype is determined by scientific methods.
  • Genotype is the hereditary information while phenotype is the external appearance. (correct)
  • Genotype is influenced by environmental factors while phenotype is affected by genes.

    • What defines homozygosity?

  • Homozygosity refers to the linear arrangement of genes on chromosomes.
  • Homozygosity is determined by observing the external appearance of an organism.
  • Homozygosity describes having two identical alleles at a specific locus. (correct)
  • Homozygosity occurs when a single gene has two different alleles.

    • What does heterozygosity refer to?

  • Heterozygosity describes a single gene having two different alleles. (correct)
  • Heterozygosity describes having two identical alleles at a specific locus.
  • Heterozygosity is the same as homozygosity in genetic terms.
  • Heterozygosity occurs when genotype remains constant throughout life.

    • How are alleles, genes, and chromosomes related?

    <p>Alleles are different forms of the same gene, and genes are linearly arranged on chromosomes.</p> Signup and view all the answers

    Which factor affects both genotype and phenotype?

    <p>Environmental conditions</p> Signup and view all the answers

    What determines the external appearance of an organism?

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

    How do genotype and phenotype differ in terms of inheritance?

    <p>Phenotype is inherited from parents while genotype can change based on environmental factors.</p> Signup and view all the answers

    What distinguishes chromosomes from genes?

    <p>'Chromosomes contain DNA,' but 'Gene are the physical traits.'</p> Signup and view all the answers

    What is the main characteristic of continuous variation?

    <p>It smoothly grades between two extremes</p> Signup and view all the answers

    Which of the following best describes discontinuous variation?

    <p>It is composed of well-defined classes</p> Signup and view all the answers

    What type of variation does human height exemplify?

    <p>Continuous variation</p> Signup and view all the answers

    Which type of variation can be influenced by factors like scars and tattoos?

    <p>Environmental variation</p> Signup and view all the answers

    In continuous variation, what is the range of possibilities?

    <p>Any value within a range is possible</p> Signup and view all the answers

    What distinguishes genetic variation from environmental variation?

    <p>Genetic variation involves differences inherited from parents</p> Signup and view all the answers

    Which type of variation can be directly affected by an individual's living conditions?

    <p>Environmental variation</p> Signup and view all the answers

    What factor contributes to the existence of both genetic and environmental variation in individuals?

    <p>Both genetic and environmental factors</p> Signup and view all the answers

    What is the term used to describe an individual with two identical alleles for a trait?

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

    In an organism that is homozygous for the recessive allele, what type of traits are expressed?

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

    What term is used to describe an individual with two different alleles for a trait?

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

    Which allele is expressed exclusively in a heterozygote?

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

    What type of variation results in an organism expressing different traits depending on whether it is homozygous or heterozygous for a gene?

    <p>Discontinuous variation</p> Signup and view all the answers

    What kind of relationship between alleles is described where one allele masks the expression of another allele at the same locus?

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

    What term is used to describe the characteristics coded for by alleles?

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

    'Allele' refers to what on a chromosome?

    <p>Different types of the same gene</p> Signup and view all the answers

    What type of plant did Mendel conduct his experiments on?

    <p>Pea plant</p> Signup and view all the answers

    Which of the following best describes the F1 progeny in Mendel's monohybrid cross experiment?

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

    What were the contrasting traits Mendel considered in his experiments?

    <p>Green peas vs. yellow peas, round vs. wrinkled</p> Signup and view all the answers

    What term did Mendel use to describe the first generation offspring in his monohybrid cross experiment?

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

    What is the term used for the units of inheritance that Mendel identified in his experiments?

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

    In a dihybrid cross experiment, how many traits did Mendel consider?

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

    Which of the following laws did Mendel formulate based on his monohybrid cross experiments?

    <p>Laws of Segregation And Dominance</p> Signup and view all the answers

    Why did Mendel choose pea plants for his experiments?

    <p>Because they are self-pollinating and easy to cross-pollinate.</p> Signup and view all the answers

    What term is used to describe different versions of a gene?

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

    Which type of allele is represented by an uppercase letter?

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

    In order for a person to exhibit a dominant trait, what must be present?

    <p>At least one parent must have the trait</p> Signup and view all the answers

    What is the term for having two different alleles for a gene?

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

    What is the term used when both alleles are expressed equally in a heterozygous individual?

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

    If an individual has two lowercase alleles for a gene, what will be their phenotype?

    <p>They will exhibit the recessive trait</p> Signup and view all the answers

    'Brown eye allele' is an example of which type of allele?

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

    'Codominance' occurs when:

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

    The absence of a line of best fit in the graph is due to the fact that the values on the x-axis (blood groups) can be arranged in any order.

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

    Heredity is solely dependent on inheritance, leading to offspring having similar characteristics to their parents.

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

    Gregor Mendel developed Mendel's Laws of Inheritance in the early 20th century.

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

    Pea plants were chosen by Mendel for his experiments as they were difficult to grow and maintain.

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

    Continuous variation in genetics refers to characteristics that fall into distinct categories with no intermediate forms.

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

    Discontinuous variation in genetics involves traits that exhibit a smooth and uninterrupted range of possibilities.

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

    A bar chart is commonly used to display the frequency of different blood groups in a population.

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

    In Mendel's experiments, pea plants were selected due to their complexity in growth and maintenance.

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

    Mendel conducted 3 main experiments to determine the laws of inheritance.

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

    Mendel found that genes can be called the molecules of inheritance.

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

    In Mendel's monohybrid cross experiment, he only considered contrasting traits related to plant height.

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

    Dihybrid Cross was one of Mendel's main experiments in determining the laws of inheritance.

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

    Mendel's experiments on pea plants included consideration of 5 main contrasting traits.

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

    In all cases, Mendel found different results when conducting experiments with other contrasting traits like green peas vs yellow peas.

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

    Mendel formulated the laws of Segregation And Dominance based on his Dihybrid Cross experiment findings.

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

    In the F1 progeny obtained from Mendel's Monohybrid Cross experiment, all plants were short in height.

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

    Continuous variation is characterized by results that come in a range, such as human height.

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

    Discontinuous variation is composed of smoothly grading differences between individuals.

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

    Genetic variation is caused by environmental factors that influence an organism's traits.

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

    Environmental variation includes traits like eye color, hair color, and skin tone.

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

    Continuous variation allows for any value within a range, while discontinuous variation has fixed categories.

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

    In continuous variation, it is possible to find values between the extremes.

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

    Genetic and environmental factors never interact to create variations in individuals.

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

    Variation within a population of the same species is solely caused by genetic factors.

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

    Mendel's F1 progeny from crossing wrinkled green seed and round yellow seeds were all wrinkled-yellow.

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

    In Mendel's experiments, the F1 progeny were self-pollinated to obtain 4 different traits in the ratio 9:3:3:1.

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

    Mendel's second law of inheritance is known as the Law of Dominance.

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

    Genotype refers to the physical appearance of an organism.

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

    Homozygous alleles have two different forms of a gene.

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

    In Mendel's experiments, the two laws of inheritance formulated were the Law of Dominance and the Law of Segregation.

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

    Alleles are transferred from offspring to parents in pairs.

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

    The Law of Independent Assortment refers to the random distribution of alleles during gametogenesis.

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

    If a person has two copies of the red and white dominant traits, the flower will have a mix of red and white petals.

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

    A person carrying two copies of the brown eye allele will have blue eyes due to codominance.

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

    Recessive alleles always show the traits visibly.

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

    A person with one copy of the brown eye allele and one copy of the blue eye allele is considered a carrier of the blue eye trait.

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

    Homozygous individuals have different copies of alleles for a trait.

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

    Sex-linked genes are inherited through the Y chromosome in males.

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

    A biological male carries two sets of X chromosomes (XX).

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

    The external appearance of an organism is determined solely by genetic factors.

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

    What is the term used to describe alleles that are considered dominant and are observed or shown?

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

    How many sets of alleles can be dominant or recessive in an individual?

    <p>2 sets of alleles</p> Signup and view all the answers

    What do you call a set of alleles where both uppercase and lowercase letters of the gene are present?

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

    What is the term for having at least one copy of the brown eye allele to have brown eyes?

    <p>Brown eye allele (B)</p> Signup and view all the answers

    What do you call it when an individual has two copies of alleles that are both dominant?

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

    What type of variation involves traits that exhibit a smooth and uninterrupted range of possibilities?

    <p>Continuous variation</p> Signup and view all the answers

    How many main contrasting traits did Mendel consider in his experiments on pea plants?

    <p>5 main contrasting traits</p> Signup and view all the answers

    What term is used to describe the first generation offspring in Mendel's monohybrid cross experiment?

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

    What is the significance of Mendel's laws of inheritance?

    <p>Mendel's laws of inheritance helped in understanding how genetic information is passed from parents to offspring.</p> Signup and view all the answers

    Why did Gregor Mendel choose pea plants for his experiments?

    <p>Mendel chose pea plants because they are easy to grow and maintain.</p> Signup and view all the answers

    Explain the concept of continuous variation in genetics.

    <p>Continuous variation in genetics refers to traits that can vary along a spectrum with no distinct categories.</p> Signup and view all the answers

    Describe discontinuous variation in genetics.

    <p>Discontinuous variation involves traits that fall into distinct categories with no intermediate forms.</p> Signup and view all the answers

    What is the relationship between heredity and inheritance?

    <p>Heredity is dependent on inheritance, which is the process of passing genetic information from parents to offspring.</p> Signup and view all the answers

    What was the main contribution of Gregor Mendel to genetics?

    <p>Gregor Mendel's main contribution was formulating Mendel's laws of inheritance to explain genetic inheritance patterns.</p> Signup and view all the answers

    Explain why continuous variation is important in genetics.

    <p>Continuous variation is important as it allows for a wide range of traits within a population.</p> Signup and view all the answers

    How did Mendel's experiments on pea plants impact the field of genetics?

    <p>Mendel's experiments provided key insights into how traits are inherited and led to the development of modern genetics.</p> Signup and view all the answers

    What does it mean when a person is considered a carrier of an allele?

    <p>The person carries one copy of the allele but does not express the associated trait.</p> Signup and view all the answers

    Explain the difference between continuous and discontinuous variation in genetics.

    <p>Continuous variation allows for a range of possibilities within a trait, while discontinuous variation has fixed categories with no intermediates.</p> Signup and view all the answers

    What is the relationship between genotype and phenotype?

    <p>Genotype refers to the genetic makeup of an organism, while phenotype refers to its physical characteristics resulting from the genotype.</p> Signup and view all the answers

    What is the term for an individual with two different alleles for a gene?

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

    How are sex-linked genes inherited differently in biological males and females?

    <p>Biological females inherit sex-linked genes through two sets of X chromosomes (XX), while biological males inherit them through one X and one Y chromosome (XY).</p> Signup and view all the answers

    What type of traits are expressed in an organism that is homozygous for the recessive allele?

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

    How do codominant alleles interact in terms of trait expression?

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

    How many copies of a recessive allele must a person have to exhibit the associated trait?

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

    Explain the difference between genotype and phenotype.

    <p>Genotype refers to the hereditary information in the form of genes in DNA, while phenotype refers to the visible characteristics of an organism.</p> Signup and view all the answers

    What is the relationship between alleles, genes, and chromosomes?

    <p>Alleles are different forms of the same gene, genes are linearly arranged on chromosomes, and chromosomes contain genetic material (DNA).</p> Signup and view all the answers

    Define homozygosity and heterozygosity.

    <p>Homozygosity is having two identical alleles at a locus, while heterozygosity is when a single gene has two different alleles.</p> Signup and view all the answers

    How is phenotype determined?

    <p>Phenotype is determined by observing the organism.</p> Signup and view all the answers

    What type of information does genotype hold?

    <p>Genotype holds the hereditary information of the organism in the form of genes in DNA.</p> Signup and view all the answers

    Explain the concept of alleles.

    <p>Alleles are different forms of the same gene, representing variations in a specific trait.</p> Signup and view all the answers

    Describe the difference between homozygosity and heterozygosity.

    <p>Homozygosity is when an individual has two identical alleles at a locus, while heterozygosity is when a single gene has two different alleles.</p> Signup and view all the answers

    How do alleles, genes, and chromosomes relate to each other?

    <p>Alleles are different forms of the same gene, genes are arranged on chromosomes, and chromosomes contain DNA, which carries genetic material.</p> Signup and view all the answers

    What determines the biological sex of an individual in humans?

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

    What term is used to describe characteristics influenced by genes carried on the sex chromosomes in humans?

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

    Why are males more likely to be affected by a sex-linked disorder than females?

    <p>Males have only a single copy of the X chromosome</p> Signup and view all the answers

    What do the X and Y chromosomes contain in humans?

    <p>Genes necessary to determine biological sex</p> Signup and view all the answers

    How many pairs of chromosomes are found in the human genome?

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

    What is the term used to describe traits that are influenced by genes on the sex chromosomes?

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

    In humans, what determines whether an individual develops as male or female?

    <p>Presence or absence of the Y chromosome</p> Signup and view all the answers

    Why is the presence of the Y chromosome critical in human development?

    <p>It contains genes necessary to cause male development</p> Signup and view all the answers

    A person’s genotype is their unique sequence of ______

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

    Phenotype is the observable expression of this genotype – a person's ______

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

    The genotype is a set of genes in DNA responsible for unique traits or characteristics, while the phenotype is the physical appearance or characteristic of an ______

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

    The human genetic code could be found by their ______

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

    The phenotype is determined by an individual’s genotype and expressed genes or by visible traits, for instance, hair colour or type, eye colour, body shape, and ______

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

    Organisms that look the same do not have the same ______

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

    Biological tests can determine ______

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

    Both the genotype and phenotype sound similar but have ______

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

    The coloring of the blue and brown eyes is an example of different versions of a ______.

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

    Different versions of a gene are called ______.

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

    Alleles can be considered dominant or ______, with dominant being the trait that is observed or shown.

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

    Dominant alleles are seen as an uppercase of a letter; for example, _____.

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

    In order for a person to show the dominant trait, one of the person’s parents must have the dominant trait (which is an uppercase letter). Remember that human cells carry 2 copies of each chromosome, one from the biological mother’s genes and one from the biological father’s genes. With that being said, there are 2 sets of alleles that can be dominant or recessive. If a person carries a heterozygous set of alleles (both uppercase and lower case letter of the gene) then the person will show the dominant trait (being that there is an uppercase letter present).

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

    For example, the brown eye allele is dominant, _____.

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

    When you have two copies of the alleles that are both dominant, this is called ______.

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

    If a person carries two copies of the red and white dominant traits, the flower will have a mix of red and white ______.

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

    If a person has one copy of the brown eye allele (dominant) and one copy of the blue eye allele (recessive) then that person is considered to be a carrier of the ______ eye allele

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

    Recessive alleles only show the traits if the person has 2 copies of the same ______

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

    Sex-linked genes are genes that are inherited through the X ______

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

    If the offspring is a boy, the X chromosome comes from the mother and the Y comes from the ______

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

    A biological female carries 2 sets of X chromosomes (XX) and a biological male carries one set of the X and one set of Y chromosomes (XY). Remember that a biological female carries 2 sets of X chromosomes (XX) and a biological male carries one set of the X and one set of Y chromosomes (XY). If the offspring is a ______, the X chromosome comes from the mother and the Y comes from the father.

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

    Recessive alleles are the genes that do not show the ______

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

    Codominance occurs when both dominant traits are expressed ______

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

    In continuous variation, it is possible to find values between the ______

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

    In X-linked gene inheritance, the expression of recessive genes is more common in ______ who only have one X gene.

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

    Autosomes determine somatic characters such as body weight and length, while Sex Chromosomes determine sex and sex-related hormonal traits. Autosomes follow ______ Inheritance.

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

    In humans, 22 pairs of ______ are present.

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

    Determining the gender and sex-related traits is the role of ______.

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

    All chromosomes are of the same ______, that is, homologous.

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

    With females, there is a lower chance of getting a diseased trait as it depends on what chromosome she inherited from the mother whether it's dominant or recessive and what X chromosome she inherited from her ______.

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

    In autosomes, determining somatic characters mainly involves the growth of an organism and all chromosomes are ______.

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

    Determines the gender and sex-related traits: Sex ______.

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

    The human genome is organized into __ pairs of chromosomes

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

    In humans, only one pair of chromosomes is present, which is the pair of __ chromosomes

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

    Males inherit a __ chromosome from the father for an XY genotype

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

    Sex-linked traits are influenced by genes carried on the __ chromosomes

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

    Females inherit an X chromosome from the father for a __ genotype

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

    The X and Y chromosomes determine the biological __ of an individual

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

    Males, who have only a single copy of the X chromosome, are more likely to be affected by a sex-linked disorder than __

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

    The presence or absence of the Y chromosome is critical because it contains the genes necessary to override the biological default - __ development

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

    Match the following terms with their correct definitions:

    <p>Continuous variation = Characteristic that changes gradually over a range of values Discontinuous variation = Values that come in groups rather than a range</p> Signup and view all the answers

    Match the following genetic concepts with their descriptions:

    <p>Normal distribution = Characteristic shape seen in surveys of continuous variation ABO blood group system = Example of discontinuous variation</p> Signup and view all the answers

    Match the following examples with the correct type of variation:

    <p>Height recorded in a group of people = Continuous variation Human blood groups = Discontinuous variation</p> Signup and view all the answers

    Match the following chromosome-related terms with their correct descriptions:

    <p>Autosomes = Chromosomes responsible for somatic characters Homologous chromosomes = Chromosomes of the same type</p> Signup and view all the answers

    Match the following traits with their corresponding terms:

    <p>Round shape and yellow color = Dominant traits Genetic makeup of the plant = Genotype Physical appearance of the plant = Phenotype Transferred genes from parents to offspring = Alleles</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Homozygous alleles = Same alleles for a trait Heterozygous alleles = Different alleles for a trait Law of Dominance = Trait that is observed or shown Law of Segregation = Genes transferred in pairs</p> Signup and view all the answers

    Match the following pairs with their descriptions:

    <p>Law of Independent Assortment = Mendel's second law of inheritance Law of Dominance = First law of Mendel's laws of inheritance Law of Segregation = Second law of Mendel's laws of inheritance Law of Inheritance = Formulated from Mendel's experiments</p> Signup and view all the answers

    Match the following terms with their characteristics:

    <p>Continuous variation = Results in a range Discontinuous variation = Fixed categories Codominance = Both dominant traits expressed Genetic variation = Caused by genetic factors</p> Signup and view all the answers

    Match the following terms with their correct descriptions:

    <p>Autosomes = Chromosomes determining somatic characters such as body weight and length Sex Chromosomes = Chromosomes determining sex and sex-related hormonal traits</p> Signup and view all the answers

    Match the following statements with the correct type of gene inheritance:

    <p>X-linked gene inheritance = Expression more common in boys who only have one X gene Autosomal Inheritance = Follows Mendelian Inheritance</p> Signup and view all the answers

    Match the following genetic concepts with their appropriate descriptions:

    <p>Recessive allele = Trait shows only if person has 2 copies of the same allele Codominance = Both dominant traits are expressed equally</p> Signup and view all the answers

    Match the following factors with their impact on genetic variation:

    <p>Genetic factors = Contribute to variations in individuals Environmental factors = Influence organism's traits</p> Signup and view all the answers

    Match the type of variation with its description:

    <p>Continuous variation = Important in genetics, shows a range of possibilities Discontinuous variation = Distinct categories, no intermediates</p> Signup and view all the answers

    Match the genotype-related statements with their correct descriptions:

    <p>Genotype = Set of alleles present in an organism Phenotype = Observable expression of genotype</p> Signup and view all the answers

    Match the following chromosome-related terms with their functions:

    <p>XX and XY chromosomes = Determine whether an individual develops as male or female Y chromosome = Critical for male development, overrides biological default</p> Signup and view all the answers

    Match the inheritance laws with their corresponding experimental findings by Gregor Mendel:

    <p>Law of Dominance = Based on Dihybrid Cross experiment findings Law of Segregation = Formulated based on monohybrid cross experiments</p> Signup and view all the answers

    Match the following terms with their correct definitions:

    <p>Continuous variation = Variation that shows a range of phenotypes with no distinct categories Discontinuous variation = Variation that shows distinct, separate phenotypes with no intermediates Genotype = The genetic makeup of an individual Phenotype = The physical traits or characteristics of an individual</p> Signup and view all the answers

    Match the following scientists with their contributions to genetics:

    <p>Gregor Mendel = Formulated Mendel's laws of inheritance Charles Darwin = Proposed the theory of evolution by natural selection Francis Crick = Discovered the structure of DNA James Watson = Worked with Francis Crick on the structure of DNA</p> Signup and view all the answers

    Match the following genetic terms with their correct characteristics:

    <p>Homozygous = Having two identical alleles for a particular gene Heterozygous = Having two different alleles for a particular gene Codominance = Both dominant alleles are expressed in the phenotype Incomplete dominance = A blending of traits where neither allele is fully dominant</p> Signup and view all the answers

    Match the following inheritance patterns with their descriptions:

    <p>Autosomal inheritance = Inheritance pattern of genes located on autosomes (non-sex chromosomes) X-linked inheritance = Inheritance pattern of genes located on the X chromosome Y-linked inheritance = Inheritance pattern of genes located on the Y chromosome Mitochondrial inheritance = Inheritance pattern of genes located in the mitochondria</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Homozygosity = Having two identical alleles for a gene Phenotype = Physical appearance or characteristic of an organism Genotype = Set of genes in DNA responsible for unique traits or characteristics Dominant allele = An allele that is always expressed when present</p> Signup and view all the answers

    Match the following genetics concepts with their descriptions:

    <p>Sex-linked genes = Inherited through the X chromosome in males and females Continuous variation = Trait variation with values between the extremes Recessive allele = A gene that is not expressed in the presence of a dominant allele Mendel's Laws of Inheritance = Formulated based on dihybrid cross experiments</p> Signup and view all the answers

    Match the following genetic terms with their roles:

    <p>X chromosome = Carries sex-linked disease-causing mutations in males Y chromosome = Determines biological sex in humans Genes on sex chromosomes = Influence characteristics related to an organism's sex Alleles = Different versions of a gene</p> Signup and view all the answers

    Match the following genetics principles with their implications:

    <p>Presence of second X chromosome (females) = May cause milder symptoms of sex-linked disorders Single X chromosome (males) = More likely to be affected by X-linked diseases Pair of sex chromosomes inheritance = One from each parent determines sex-linked traits Random allele distribution during gametogenesis = Law of Independent Assortment</p> Signup and view all the answers

    Study Notes

    Genotype and Phenotype

    • Genotype: the hereditary information of an organism, encoded in the genes in the DNA, and remains the same throughout life
    • Phenotype: the characteristics of an organism that are visible, resulting from the expression of genes
    • Same genotype can produce same phenotype, but same phenotype may not belong to same genotype
    • Genotype is inherited from parents, while phenotype is not
    • Genotype can be determined by scientific methods (e.g., polymerase chain reaction), while phenotype can be observed

    Chromosomes, Genes, and Alleles

    • Alleles: different forms of the same gene
    • Genes: linearly arranged on chromosomes
    • Chromosomes: contain genetic material of the cell (DNA)
    • All three are chemically composed of DNA

    Homozygosity and Heterozygosity

    • Homozygosity: having two identical alleles at a locus (e.g., AA or aa)
    • Heterozygosity: having two different alleles at a locus (e.g., Aa)
    • Dominant alleles are expressed exclusively in heterozygotes, while recessive alleles are only expressed if homozygous for the recessive allele

    Continuous and Discontinuous Variation

    • Continuous variation: smoothly grading between two extremes, with the majority of individuals at the centre (e.g., human height)
    • Discontinuous variation: composed of well-defined classes (e.g., blood groups)

    Inheritance

    • Inheritance: the process of a child receiving genetic information from parents
    • Mendel's laws of inheritance: formulated by Gregor Mendel to understand inheritance
    • Laws of inheritance include:
      • Law of Dominance
      • Law of Segregation
      • Law of Independent Assortment

    Mendel's Experiments

    • Mendel conducted experiments on pea plants to determine the laws of inheritance
    • He considered 7 main contrasting traits in the plants
    • Experiments included:
      • Monohybrid cross
      • Dihybrid cross
    • Results of the experiments led to the formulation of Mendel's laws of inheritance

    Dominant and Recessive Alleles

    • Dominant alleles: upper case letters (e.g., B)
    • Recessive alleles: lower case letters (e.g., b)
    • For a person to show the dominant trait, one of their parents must have the dominant trait
    • If a person has two copies of the dominant allele, they are codominant
    • Recessive alleles only show the trait if the person has two copies of the same alleles (homozygous)

    Sex-Linked Genes

    • Sex-linked genes: inherited through the X chromosome
    • Biological females: 2 sets of X chromosomes (XX)
    • Biological males: 1 set of X and 1 set of Y chromosomes (XY)
    • Offspring inherits X chromosome from mother and Y chromosome from father### Chromosomes and Sex Determination
    • Humans have 23 pairs of chromosomes, with 22 pairs of autosomes and one pair of sex chromosomes.
    • Sex chromosomes (X and Y) determine the biological sex of an individual:
      • Females inherit an X chromosome from each parent (XX genotype).
      • Males inherit a Y chromosome from the father and an X chromosome from the mother (XY genotype).
    • The presence or absence of the Y chromosome is critical for male development.

    Genotype and Phenotype

    • Genotype: the unique sequence of DNA, including the two forms inherited from each parent for a particular gene.
    • Phenotype: the observable expression of the genotype, resulting from the interaction between the genotype and the environment.

    Dominant and Recessive Traits

    • Alleles: different versions of a gene; dominant alleles are represented by an uppercase letter, while recessive alleles are represented by a lowercase letter.
    • Inheritance of dominant and recessive traits:
      • Codominance: when both alleles are expressed equally.
      • Heterozygous: having one dominant and one recessive allele.
      • Homozygous: having two identical alleles (either both dominant or both recessive).

    Sex-Linked Inheritance

    • Sex-linked genes: genes carried on the X chromosome, which influence traits or disorders.
    • X-linked inheritance:
      • Males are more likely to be affected by sex-linked disorders due to having only one X chromosome.
      • Females have a lower chance of being affected due to having two X chromosomes.

    Autosomes and Sex Chromosomes

    • Autosomes: chromosomes that determine somatic characters such as body weight and length.
    • Sex chromosomes: chromosomes that determine sex and sex-related traits.
    • Autosomes:
      • Determine somatic characters.
      • Are homologous pairs.
      • Follow Mendelian inheritance.
      • 22 pairs are present in humans.
    • Sex chromosomes:
      • Determine sex and sex-related traits.
      • Are partially homologous.
      • Show non-Mendelian inheritance.
      • One pair is present in humans.

    Mendel's Experiments

    • Mendel's laws of inheritance:
      • Law of Dominance
      • Law of Segregation
      • Law of Independent Assortment
    • Conclusions from Mendel's experiments:
      • Genotype (genetic makeup) vs. phenotype (physical appearance)
      • Genes are transferred in pairs (alleles) from parents to offspring.

    Continuous and Discontinuous Variation

    • Continuous variation: characteristics that change gradually over a range of values (e.g., height, arm span, weight).
    • Discontinuous variation: characteristics that come in distinct groups (e.g., blood groups, eye color).

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    Description

    Explore the classification of variations as continuous or discontinuous in a population. Learn about genetic variation and environmental influences on variations within a species.

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