Questions and Answers
What does the chromosome theory of inheritance state?
What is a wild type?
The phenotype for a character most commonly observed in populations.
What is a sex-linked gene?
A gene located on either sex chromosome.
What is Duchenne muscular dystrophy?
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What is hemophilia?
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What is a Barr body?
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What are linked genes?
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What is genetic recombination?
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What are parental types?
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What are recombinant types?
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What is crossing over?
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What is a genetic map?
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What is a linkage map?
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What are map units?
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What are cytogenetic maps?
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What is nondisjunction?
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What is aneuploidy?
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What is monosomic?
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What is trisomic?
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What is polyploidy?
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What is deletion?
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What is duplication?
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What is inversion?
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What is translocation?
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What is Down syndrome?
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What is genomic imprinting?
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Study Notes
Chromosome Theory and Genes
- Chromosome theory of inheritance states that genes reside at specific locations (loci) on chromosomes, which segregate and assort independently during gamete formation.
Genetic Terminology
- Wild type refers to the most commonly observed phenotype in a given population for a specific trait.
- Sex-linked genes are located on sex chromosomes, influencing inheritance patterns associated with gender.
Genetic Disorders
- Duchenne muscular dystrophy is a sex-linked disorder marked by muscle weakness and coordination loss.
- Hemophilia is a sex-linked recessive disorder characterized by the deficiency of blood clotting proteins.
Cellular Structures
- Barr bodies are inactive X chromosomes in female cells, condensed and lying along the nuclear envelope.
Genetic Inheritance
- Linked genes are those located on the same chromosome and typically inherited together during genetic crosses.
- Genetic recombination results in offspring with allele combinations that differ from either parent.
Offspring Types
- Parental types exhibit phenotypes that match one of their parents.
- Recombinant types display phenotypes that differ from both parents.
Meiotic Processes
- Crossing over involves the exchange of genetic material between nonsister chromatids during prophase I of meiosis, increasing genetic variation.
Genetic Mapping
- Genetic maps detail the ordered loci along chromosomes, while linkage maps are based on recombination frequencies.
- Map units, defined as a 1% recombination frequency, serve as a measure in genetic mapping.
- Cytogenetic maps locate genes in relation to chromosomal structures.
Aberrations and Variations
- Nondisjunction occurs when homologous chromosomes or sister chromatids fail to separate during meiosis, leading to gametes with abnormal chromosome numbers.
- Aneuploidy involves presence of extra or missing chromosomes, resulting in conditions like monosomy (one copy) or trisomy (three copies).
- Polyploidy refers to organisms with more than two complete sets of chromosomes.
Chromosomal Alterations
- Deletion entails the loss of a chromosomal fragment.
- Duplication arises when a deleted segment is added to a sister chromatid.
- Inversion is the reattachment of a chromosomal fragment in the reverse orientation.
- Translocation involves a chromosomal fragment joining a non-homologous chromosome, altering genetic layout.
Down Syndrome and Imprinting
- Down syndrome is an aneuploid condition caused by an extra chromosome 21, resulting in 47 chromosomes total in each cell.
- Genomic imprinting leads to phenotypic differences based on the parental origin of an allele.
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Description
Test your knowledge of key concepts from AP Biology Chapter 15 with these flashcards. Topics include the chromosome theory of inheritance, wild type phenotypes, and sex-linked genes. Perfect for quick reviews and reinforcing your understanding of genetics.