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Questions and Answers
What are genes?
What are genes?
Genes are segments of DNA located on chromosomes that determine distinct traits.
What are alleles?
What are alleles?
An allele is an alternative form of a gene located at a specific position on a chromosome.
What is the purpose of mitosis?
What is the purpose of mitosis?
Mitosis produces identical cells with a complete set of DNA.
What is the purpose of meiosis?
What is the purpose of meiosis?
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What are the subphases of interphase?
What are the subphases of interphase?
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Name the subphases of mitosis.
Name the subphases of mitosis.
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What is asexual reproduction?
What is asexual reproduction?
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What is an autosome?
What is an autosome?
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What are sex chromosomes?
What are sex chromosomes?
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Who is Gregor Mendel?
Who is Gregor Mendel?
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What is the restriction point in the cell cycle?
What is the restriction point in the cell cycle?
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What is a Barr body?
What is a Barr body?
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What is a centrosome?
What is a centrosome?
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What are spindle fibers?
What are spindle fibers?
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What is polygenic trait? Give an example.
What is polygenic trait? Give an example.
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What are differences between cell plates and cleavage furrows?
What are differences between cell plates and cleavage furrows?
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In humans, the haploid number of chromosomes is ____.
In humans, the haploid number of chromosomes is ____.
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In humans, the diploid number of chromosomes is ____.
In humans, the diploid number of chromosomes is ____.
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What is the difference between phenotype and genotype?
What is the difference between phenotype and genotype?
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Match the following human disorders with their chromosome abnormalities.
Match the following human disorders with their chromosome abnormalities.
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Study Notes
Genes and Alleles
- Genes are segments of DNA on chromosomes that determine traits.
- Alleles are alternative forms of a gene located at specific positions on chromosomes.
- Traits are passed from parents to offspring through alleles, as clarified by Gregor Mendel's law of segregation.
Cell Division: Mitosis and Meiosis
- Mitosis produces identical diploid cells, functioning as body cells with one division resulting in two identical cells.
- Meiosis produces haploid gametes (sperm and eggs) through two divisions, resulting in four cells that each have half the genetic material.
Mitosis Phases
- Prophase: Chromosomes condense; centrioles move apart; spindle fibers form; nuclear membrane dissolves.
- Metaphase: Chromatids align at the metaphase plate; kinetochores face opposite poles.
- Anaphase: Chromatids separate to opposite poles, becoming individual chromosomes; cell elongates.
- Telophase: Chromosomes decondense; spindle fibers dissolve; nuclear envelope reforms; cytokinesis begins.
Chromosome and Cell Characteristics
- Autosomes are non-sex chromosomes that occur in pairs in somatic cells.
- Sex chromosomes (X and Y) determine an individual's sex; XX is female, XY is male.
- Haploid cells have 23 chromosomes; diploid cells have 46 chromosomes.
Genetic Disorders
- Aneuploidy refers to abnormal chromosome numbers, such as trisomy (e.g., Down syndrome) and monosomy (e.g., Turner syndrome).
- Disorders can arise from deletions (e.g., Smith-Magenis) and exhibit incomplete dominance (e.g., Tay-Sachs).
Concepts of Dominance
- Complete Dominance: One allele masks the expression of another.
- Incomplete Dominance: The phenotype is a blend of both alleles (e.g., red and white flowers produce pink).
- Co-dominance: Both alleles are expressed simultaneously (e.g., red and white spotted flowers).
Cell Structure and Function
- The centrosome organizes microtubules and plays a role in cell division.
- Chromatin is uncondensed DNA; chromosomes are condensed chromatin.
- Spindle fibers separate chromosomes during cell division.
Reproductive Genetics
- A monohybrid cross involves one trait, while a dihybrid cross involves two traits.
- Test crosses determine an individual's genotype based on a dominant phenotype.
Genetic Variability
- Polymorphism results from variations in genes influencing traits (e.g., skin color as a polygenic trait).
- Pleiotropic effects occur when one gene affects multiple phenotypes (e.g., Sickle Cell trait offers malaria resistance).
Regulation of Cell Division
- Cyclins and cyclin-dependent kinases (Cdks) regulate the cell cycle.
- Growth factors provide external signals to control cell division.
Tumors and Cancer
- Benign tumors are non-cancerous; malignant tumors are cancerous.
- Metastasis is the spread of cancer, while transformed cells lose anchorage dependence and density inhibition.
Genetic Phenomena
- Norm of reaction describes the environmental impact on phenotype.
- Multifactorial traits are influenced by both genetics and environment.
Inheritance Patterns
- Genomic imprinting refers to genes being expressed differently based on parental origin.
- Wildtype organisms exhibit typical phenotypes, while mutants show variations.
Human Chromosome Tolerance
- Humans can tolerate extra X and Y chromosomes due to mechanisms such as X-chromosome inactivation (Barr bodies) in females.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge with flashcards covering key concepts from Biology Chapters 13 and 14. This quiz includes essential terms such as genes and alleles, along with their definitions and significance in inheritance. Perfect for reinforcing your understanding of genetic principles!
