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Questions and Answers
What is the term for the physical characteristics of an organism?
What is the term for the physical characteristics of an organism?
What process refers to the separation of alleles during gamete formation?
What process refers to the separation of alleles during gamete formation?
An organism with two different alleles for a trait is considered:
An organism with two different alleles for a trait is considered:
Which of the following describes the situation in which one gene affects the expression of another gene?
Which of the following describes the situation in which one gene affects the expression of another gene?
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What do we call a specific characteristic that varies from one individual to another?
What do we call a specific characteristic that varies from one individual to another?
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What is the term for when both alleles of a gene contribute to the phenotype of an organism?
What is the term for when both alleles of a gene contribute to the phenotype of an organism?
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A single phenotype character is affected by two or more genes, this is known as:
A single phenotype character is affected by two or more genes, this is known as:
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What is the term for a sequence of DNA that codes for a protein?
What is the term for a sequence of DNA that codes for a protein?
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What is the term for the range of possible phenotypes for a given genotype due to environmental factors?
What is the term for the range of possible phenotypes for a given genotype due to environmental factors?
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Which process results in daughter cells with half the number of chromosomes as the parent cell?
Which process results in daughter cells with half the number of chromosomes as the parent cell?
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What are chromosomes that have corresponding chromosomes from the opposite-sex parent considered?
What are chromosomes that have corresponding chromosomes from the opposite-sex parent considered?
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During meiosis, at what location does the exchange of genetic material between homologous chromosomes occur?
During meiosis, at what location does the exchange of genetic material between homologous chromosomes occur?
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Why is Mendel's law of independent assortment not entirely correct?
Why is Mendel's law of independent assortment not entirely correct?
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In humans, which of the following terms best describes a cell that contains 23 chromosomes?
In humans, which of the following terms best describes a cell that contains 23 chromosomes?
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In a cross between a white-eyed male fruit fly and a red-eyed female, where all F1 offspring have red eyes what can be concluded about the white-eyed trait?
In a cross between a white-eyed male fruit fly and a red-eyed female, where all F1 offspring have red eyes what can be concluded about the white-eyed trait?
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What is the term for the new combinations of traits that are not present in either parent?
What is the term for the new combinations of traits that are not present in either parent?
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Flashcards
Segregation
Segregation
Separation of alleles during gamete formation.
Independent Assortment
Independent Assortment
Genes for different traits segregate independently during gamete formation.
Hybrid
Hybrid
Offspring from parents with different traits.
Homozygous
Homozygous
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Heterozygous
Heterozygous
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Phenotype
Phenotype
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Genotype
Genotype
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Codominance
Codominance
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Norm of Reaction
Norm of Reaction
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Asexual Reproduction
Asexual Reproduction
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Sexual Reproduction
Sexual Reproduction
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Meiosis
Meiosis
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Homologous Chromosomes
Homologous Chromosomes
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Crossing Over
Crossing Over
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Chiasmata
Chiasmata
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Dihybrid Crosses
Dihybrid Crosses
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Study Notes
Mendelian Genetics
- Inheritance: Biological characteristics are determined by genes passed from parents to offspring.
- Alleles: Genes can exist in different forms called alleles. Some are dominant, others recessive.
- Dominant/Recessive Alleles: A dominant allele masks the effect of a recessive allele when both are present in a heterozygous organism.
- Homozygous/Heterozygous: Homozygous organisms have two identical alleles, while heterozygous organisms have two different alleles.
- Phenotype/Genotype: Phenotype refers to observable traits, genotype to genetic makeup.
Gene Segregation and Independent Assortment
- Segregation: Alleles separate during gamete formation.
- Independent Assortment: Genes for different traits segregate independently during gamete formation. Critically, this is not always true. Mendelian's independent assortment concept is only accurate for chromosomes that are NOT linked on the same chromosome.
- Chromosomes, NOT Genes, segregate independently.
Non-Mendelian Inheritance Patterns
- Incomplete Dominance: Neither allele is completely dominant, resulting in an intermediate phenotype (e.g., pink flowers from red and white parents).
- Codominance: Both alleles contribute equally to the phenotype (e.g., blood type AB).
- Multiple Alleles: Three or more alleles exist for a single gene (e.g., human blood type).
- Polygenic Inheritance: Multiple genes influence a single trait (e.g., human height).
- Epistasis: One gene affects the expression of another gene.
- Pleiotropy: A single gene can have multiple effects on an organism's phenotype.
- Norm of Reaction: The range of phenotypes a genotype can produce in different environments.
Sex-Linked Traits
- Sex Chromosomes: Humans have XY sex chromosomes.
- X-Linked Traits: Males are more likely to express recessive X-linked traits because they possess only one X chromosome.
- Examples: Hemophilia.
- Wild Type/Mutant: Wild type refers to normal traits, mutants are alternate phenotypes.
Chromosomal Basis of Inheritance
- Crossing Over: Homologous chromosomes exchange segments during meiosis.
- Synapsis/Tetrad: Homologous chromosomes pair up; the resulting structure contains four chromatids. Chiasmata are the points of exchange.
- Linked Genes: Genes located close together on the same chromosome tend to be inherited together.
- Recombination Frequency: Measures the likelihood that linked genes will separate during meiosis, used to map gene order on chromosomes.
Reproduction
- Asexual/Sexual Reproduction: Asexual reproduction (mitosis, binary fission) results in offspring identical to parents; sexual reproduction (meiosis) leads to greater variation due to alleles’ recombination.
- Gamete Formation: Sperm and eggs (gametes) are haploid (containing half the chromosome number of somatic cells (body cells)). Humans have 46 chromosomes 23 pairs. One allele inherited from each parent.
- Meiosis: A reductional division that creates gametes.
Additional Concepts
- Homologous Chromosomes: Chromosome pairs with similar gene sequences, but not necessarily the same alleles.
- Diploid/Haploid Cells: Diploid cells have two sets of chromosomes (2n); haploid cells have one set (n).
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Description
This quiz covers essential concepts of Mendelian Genetics, including inheritance patterns, the concepts of dominant and recessive alleles, and the distinction between homozygous and heterozygous genotypes. It also explores the principles of gene segregation and independent assortment, crucial for understanding genetic variation.
