Podcast
Questions and Answers
What is the primary difference between a gene and an allele?
What is the primary difference between a gene and an allele?
- A gene is a specific sequence of DNA, while an allele is a variant of that sequence. (correct)
- A gene determines the physical trait, while an allele determines the chromosome.
- A gene is only present in homozygous individuals, while an allele is present in heterozygous individuals.
- A gene is a variant of a DNA sequence, while an allele is the complete sequence.
In Mendel's experiments, if a homozygous dominant pea plant (YY) is crossed with a homozygous recessive pea plant (yy) for seed color, what will be the genotype of the F₁ generation?
In Mendel's experiments, if a homozygous dominant pea plant (YY) is crossed with a homozygous recessive pea plant (yy) for seed color, what will be the genotype of the F₁ generation?
- Yy (correct)
- yy
- yY
- YY
Which of the following is a characteristic of incomplete dominance?
Which of the following is a characteristic of incomplete dominance?
- The dominant allele is expressed only in homozygous individuals.
- Both alleles are equally expressed in the heterozygote.
- One allele completely masks the effect of the other.
- The heterozygous phenotype is a blend of the homozygous phenotypes. (correct)
In a codominant inheritance pattern, if a black-feathered chicken (BB) is crossed with a white-feathered chicken (WW), what would be the expected phenotype of the F₁ generation?
In a codominant inheritance pattern, if a black-feathered chicken (BB) is crossed with a white-feathered chicken (WW), what would be the expected phenotype of the F₁ generation?
A woman with blood type A has a child with blood type O. The father has blood type B. What are the possible genotypes of the parents?
A woman with blood type A has a child with blood type O. The father has blood type B. What are the possible genotypes of the parents?
Why are males more frequently affected by X-linked recessive disorders than females?
Why are males more frequently affected by X-linked recessive disorders than females?
A woman, who is a carrier for a sex-linked recessive trait, has children with a man who does not have the trait. What is the probability that their son will inherit the trait?
A woman, who is a carrier for a sex-linked recessive trait, has children with a man who does not have the trait. What is the probability that their son will inherit the trait?
Incomplete dominance is observed in a particular species of flower. A homozygous plant with red flowers ($C^RC^R$) is crossed with a homozygous plant with white flowers ($C^WC^W$). What phenotypic ratio is expected in the F₂ generation?
Incomplete dominance is observed in a particular species of flower. A homozygous plant with red flowers ($C^RC^R$) is crossed with a homozygous plant with white flowers ($C^WC^W$). What phenotypic ratio is expected in the F₂ generation?
Two parents, both with blood type AB, have children. What is the probability that their child will have blood type O?
Two parents, both with blood type AB, have children. What is the probability that their child will have blood type O?
A scientist is studying a newly discovered genetic disorder that appears to affect males almost exclusively. Pedigree analysis reveals that affected males always have unaffected mothers, but affected fathers never pass the trait to their sons. However, affected fathers can pass the trait to their daughters, who then have a 50% chance of having affected sons. What mode of inheritance is MOST likely at play?
A scientist is studying a newly discovered genetic disorder that appears to affect males almost exclusively. Pedigree analysis reveals that affected males always have unaffected mothers, but affected fathers never pass the trait to their sons. However, affected fathers can pass the trait to their daughters, who then have a 50% chance of having affected sons. What mode of inheritance is MOST likely at play?
Flashcards
Heredity
Heredity
The passing of traits from parents to offspring.
Mendel's Experimental Method
Mendel's Experimental Method
Mendel's controlled process for studying inheritance using pea plants.
Gene
Gene
A segment of DNA that codes for a specific trait.
Allele
Allele
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Dominant Allele
Dominant Allele
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Recessive Allele
Recessive Allele
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Phenotype
Phenotype
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Genotype
Genotype
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Punnett Square
Punnett Square
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Homozygous Genotype
Homozygous Genotype
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Study Notes
- The exam on Genetics and Heredity is scheduled for Wednesday, February 19, 2025.
Mechanisms of Heredity
- Gregor Mendel utilized pea plants in his experiments to study heredity.
- A gene is a unit of heredity, while an allele is a variant form of a gene.
- A dominant allele masks the effect of a recessive allele when present together in an individual.
- Alleles influence both the observable traits (phenotype) and the genetic makeup (genotype) of an organism.
- A Punnett square is used to predict the possible genotypes and phenotypes of offspring from a genetic cross.
- Homozygous genotypes have two identical alleles for a trait, whereas heterozygous genotypes have two different alleles.
Complete Dominance, Incomplete Dominance, and Codominance
- Complete dominance occurs when one allele completely masks the expression of another.
- Incomplete dominance is when the heterozygous genotype results in a phenotype that is a blend of the two homozygous phenotypes.
- Codominance is when both alleles are expressed equally in the phenotype.
- Genetic crosses in the F₁ and F₂ generations can be predicted based on the type of dominance.
- Parental (P) generation genotypes can be determined from the results of F₁ or specific F₂ generations.
- Phenotypes of homozygous and heterozygous individuals vary depending on the type of dominance.
Blood Groups (An Example of Codominance)
- The four blood types (A, B, AB, and O) are determined by codominant alleles.
- The probability of a child's blood type can be predicted based on the parents' blood types, using genetic principles.
Sex-Linked Inheritance
- The X and Y chromosomes differ in size and gene content.
- Sex-linked genetic disorders are caused by genes located on the sex chromosomes, typically the X chromosome.
- The probability of offspring inheriting a sex-linked disorder can be predicted by understanding the inheritance patterns.
- Males are more frequently affected by sex-linked disorders because they have only one X chromosome.
- A carrier is an individual who has one copy of a recessive sex-linked allele but does not express the trait, while an affected individual has the phenotype associated with the sex-linked disorder.
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Description
Explore genetics and heredity, including Mendel's experiments. Understand genes, alleles, dominant and recessive traits. Learn about phenotype, genotype, and using Punnett squares. Differentiate between homozygous and heterozygous genotypes.
