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Questions and Answers
What is the result of genetic recombination during meiosis?
What is the result of genetic recombination during meiosis?
- Genetic variation is reduced
- Mutations occur in DNA sequence
- New combinations of alleles are generated (correct)
- Alleles for different genes are sorted independently
What is the function of the centromere?
What is the function of the centromere?
- Sites for DNA replication initiation
- Specialized region for chromosome segregation (correct)
- Initiates DNA replication
- Repetitive DNA sequences at chromosome ends
What occurs during the anaphase stage of mitosis?
What occurs during the anaphase stage of mitosis?
- Chromatin condenses, spindle fibers form
- Sister chromatids separate (correct)
- Nuclear envelope breaks down
- Chromosomes align at cell equator
What is the term for the movement of genes between populations?
What is the term for the movement of genes between populations?
What is the term for the different forms of a gene?
What is the term for the different forms of a gene?
What is the term for the chemical modifications to DNA or histone proteins?
What is the term for the chemical modifications to DNA or histone proteins?
What is the main importance of somatic cell division?
What is the main importance of somatic cell division?
What is the result of meiosis in terms of genetic variation?
What is the result of meiosis in terms of genetic variation?
What is the main difference between mitosis and meiosis?
What is the main difference between mitosis and meiosis?
During which stage of meiosis do homologous chromosomes pair?
During which stage of meiosis do homologous chromosomes pair?
What occurs during anaphase II of meiosis?
What occurs during anaphase II of meiosis?
Which type of reproduction involves mitosis?
Which type of reproduction involves mitosis?
Flashcards
Sources of genetic variation
Sources of genetic variation
Sources include mutations, recombination, and gene flow.
Mutations
Mutations
Changes in the DNA sequence that create variation.
Genetic recombination
Genetic recombination
Mixing of parental genes during meiosis through crossing over.
Gene flow
Gene flow
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Allelic variation
Allelic variation
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Mendel's Law of Segregation
Mendel's Law of Segregation
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Law of Independent Assortment
Law of Independent Assortment
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Mitosis
Mitosis
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Meiosis
Meiosis
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Chromatin
Chromatin
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Sexual reproduction
Sexual reproduction
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Study Notes
Genetic Variation
-
Sources of genetic variation:
- Mutations: changes in DNA sequence
- Genetic recombination: crossing over and independent assortment during meiosis
- Gene flow: movement of genes between populations
-
Types of genetic variation:
- Allelic variation: different forms of a gene, resulting in varying expressions of a single trait, such as different flower colors or blood types, which can provide a selective advantage or disadvantage in certain environments.
: Allelic variation: multiple forms of a gene, such as different alleles of the ABO gene that determine an individual's ABO blood type, leading to variations in the expression of a single trait.
- Genomic variation: differences in DNA sequence and structure
- Epigenetic variation: chemical modifications to DNA or histone proteins
Genetic Inheritance
- Mendel's Laws:
- Law of Segregation: each pair of alleles separates during gamete formation
- Law of Independent Assortment: alleles for different genes are sorted independently
- Law of Dominance: dominant alleles mask recessive alleles
- Patterns of inheritance:
- Autosomal dominant/recessive traits
- X-linked traits
- Incomplete dominance and codominance
Chromosome Structure
- Chromatin:
- DNA wrapped around histone proteins to form nucleosomes
- Higher-order chromatin structures: chromatin fibers and chromonema
- Chromosome components:
- Centromere: specialized region for chromosome segregation
- Telomere: repetitive DNA sequences at chromosome ends
- Origins of replication: sites for DNA replication initiation
Mitosis
- Stages:
- Interphase: chromatin condenses, spindle fibers form
- Prophase: chromatin condenses, nuclear envelope breaks down
- Metaphase: chromosomes align at cell equator
- Anaphase: sister chromatids separate
- Telophase: nuclear envelope reforms, chromatin decondenses
- Cytokinesis: cytoplasm divides, cell splits
- Importance:
- Somatic cell division: replacement and growth
- Produces genetically identical daughter cells
Meiosis
- Stages:
- Interphase: chromatin condenses, spindle fibers form
- Prophase I: chromatin condenses, homologous chromosomes pair
- Metaphase I: paired chromosomes align at cell equator
- Anaphase I: homologous chromosomes separate
- Telophase I: nuclear envelope reforms, chromatin decondenses
- Prophase II: chromatin condenses, spindle fibers form
- Metaphase II: sister chromatids align at cell equator
- Anaphase II: sister chromatids separate
- Telophase II: nuclear envelope reforms, chromatin decondenses
- Cytokinesis: cytoplasm divides, cell splits
- Importance:
- Gamete formation: diversity and genetic variation
Sexual and Asexual Reproduction
- Sexual reproduction:
- Involves meiosis and fertilization
- Increases genetic variation
- Examples: humans, animals, plants
- Asexual reproduction:
- Involves mitosis
- Produces genetically identical offspring
- Examples: bacteria, some plants and animals
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