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Questions and Answers
What is one effect of genetic mutations on individuals?
What is one effect of genetic mutations on individuals?
- They are only caused by viral infections.
- They always lead to negative traits.
- They have no impact on the species.
- They can introduce new characteristics. (correct)
What occurs when nondisjunction happens during meiosis?
What occurs when nondisjunction happens during meiosis?
- Germ cells are unaffected.
- The number of chromosomes increases.
- The chromosomes divide evenly.
- Aneuploidy results. (correct)
Which of the following statements about meiosis is true?
Which of the following statements about meiosis is true?
- Meiosis occurs in all cell types.
- Mitosis and meiosis can occur simultaneously.
- Only somatic cells undergo meiosis.
- Meiosis is necessary for sexual reproduction. (correct)
How do mutations predominantly occur in organisms?
How do mutations predominantly occur in organisms?
What is the ploidy level of strawberries?
What is the ploidy level of strawberries?
What does 'n' represent in the context of chromosomes?
What does 'n' represent in the context of chromosomes?
During which phase of the cell cycle is a 4n cell present?
During which phase of the cell cycle is a 4n cell present?
Which process leads to the formation of unique haploid cells in meiosis?
Which process leads to the formation of unique haploid cells in meiosis?
What characterizes homologous chromosomes?
What characterizes homologous chromosomes?
In which part of meiosis is synapsis important?
In which part of meiosis is synapsis important?
Which of the following events is unique to Meiosis I?
Which of the following events is unique to Meiosis I?
What is the result of crossing over during meiosis?
What is the result of crossing over during meiosis?
Which phase of meiosis is more similar to mitosis?
Which phase of meiosis is more similar to mitosis?
Flashcards
What is n?
What is n?
The number of chromosomes present in a set within a cell. It is determined by counting the number of centromeres.
Based on the number of chromosome sets, what phase is the cell in?
Based on the number of chromosome sets, what phase is the cell in?
The stage of cell division where a cell has duplicated its chromosomes but has not yet divided into two cells. It is characterized by having four copies of each chromosome present.
What is a homolog?
What is a homolog?
Chromosomes that have the same genes but come from different parents. They pair up during meiosis.
What are Spermatogenesis and Oogenesis?
What are Spermatogenesis and Oogenesis?
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What is a tetrad?
What is a tetrad?
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What is crossing over?
What is crossing over?
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What is Independent Assortment?
What is Independent Assortment?
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What is Genetic Variation?
What is Genetic Variation?
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Genetic Mutation
Genetic Mutation
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Nondisjunction
Nondisjunction
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Aneuploidy
Aneuploidy
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Meiosis
Meiosis
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Ploidy
Ploidy
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Study Notes
Meiosis and Mitosis
- Meiosis produces 4 haploid cells, different from each other.
- Mitosis produces 2 diploid cells, identical to each other.
Homologous Chromosomes
- Chromosomes that carry the same genes, but may have different alleles.
- Come from different parental sources.
- Contain the same genes, but possibly different alleles (versions of a gene).
- Humans have 22 pairs of autosomes (non-sex chromosomes) and one pair of sex chromosomes.
Genetic Variation
- Variation in traits between members of the same species increases species survival ability.
- Sources of variation during meiosis include crossing over (during Prophase I), random assortment (during Metaphase I), and random mating.
- Mutations in DNA sequence can cause variation, which can be passed down to offspring if the mutation occurs in germ cells.
- Other sources of variation in sexual reproduction include the random selection of an egg and sperm during fertilization.
Meiosis I
- Separation of homologous chromosomes (occurs in Anaphase I)
- Synapsis and crossing over during Prophase I.
- Production of haploid cells (occurs in the end of Meiosis I)
Meiosis II
- Separation of sister chromatids occurs in Anaphase II.
- The result of meiosis II is 4 haploid cells with unduplicated chromosomes
Nondisjunction
- Incorrect chromosome number in gametes.
- Can occur in Meiosis I or Meiosis II.
- Can lead to aneuploidy, which is often lethal.
- Examples of syndromes caused by nondisjunction include Klinefelter syndrome (XXY).
Ploidy
- Different number of sets of chromosomes in organisms.
- Strawberries are octoploidy (8n).
- Cats have 2 sets of 19 chromosomes (2n=38).
Cell Cycle
- Interphase still happens whether the cell divides by meiosis or mitosis.
- Only germ cells undergo meiosis (gamete formation).
- Asexual reproduction uses mitosis.
Terms
- Gene: A unit of heredity (e.g., eye color gene)
- Allele: Different types or versions of a gene (e.g., blue eye color allele)
- Trait: Characteristic determined by a gene (e.g., blue eyes)
- Locus (loci): Location of a gene on a chromosome
Additional Notes
- Chiasmata: Point where homologous chromosomes attach during crossing over.
- Synaptonemal complex: Structure where homologous chromosomes are held close together for crossing over.
- Tetrad: Structure containing 4 chromosomes that are held close together.
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Description
This quiz covers the key differences between meiosis and mitosis, including their processes and outcomes. It explores the role of homologous chromosomes and genetic variation in species survival. Test your understanding of these fundamental biological concepts.
