Podcast
Questions and Answers
What does aneuploidy refer to?
What does aneuploidy refer to?
- A change in the number of chromosomes caused by nondisjunction (correct)
- A complete set of chromosomes in an organism
- The correct number of chromosomes in a species
- An increase in chromosomes due to mitosis
Which statement correctly describes monosomy?
Which statement correctly describes monosomy?
- An individual has two copies of a chromosome
- An individual lacks one copy of a specific chromosome (correct)
- An individual has the correct number of chromosomes
- An individual has an extra copy of a chromosome
How does sexual reproduction contribute to genetic variation?
How does sexual reproduction contribute to genetic variation?
- It involves only one gamete from a single parent
- It maintains the same gene combinations through asexual methods
- It creates identical offspring from one parent
- It merges genes from two parents and involves crossing over (correct)
Why is meiosis necessary for gametes but not for somatic cells?
Why is meiosis necessary for gametes but not for somatic cells?
What is the main outcome of meiosis I?
What is the main outcome of meiosis I?
Which of the following is a similarity between mitosis and meiosis I?
Which of the following is a similarity between mitosis and meiosis I?
What is a key difference between mitosis and meiosis I?
What is a key difference between mitosis and meiosis I?
Why is genetic variation important in a species?
Why is genetic variation important in a species?
What is the primary outcome of meiosis?
What is the primary outcome of meiosis?
What is a zygote?
What is a zygote?
What does crossing over achieve during meiosis?
What does crossing over achieve during meiosis?
What does independent assortment refer to in meiosis?
What does independent assortment refer to in meiosis?
Which of the following describes nondisjunction?
Which of the following describes nondisjunction?
A gamete carries which type of chromosome count?
A gamete carries which type of chromosome count?
What is the purpose of synapsis during meiosis?
What is the purpose of synapsis during meiosis?
How does meiosis differ from mitosis?
How does meiosis differ from mitosis?
Which event typically leads to aneuploidy during meiosis?
Which event typically leads to aneuploidy during meiosis?
At which stages of meiosis can chromosomal mutations such as deletions or duplications occur?
At which stages of meiosis can chromosomal mutations such as deletions or duplications occur?
How do mitosis and meiosis II differ in terms of genetic output?
How do mitosis and meiosis II differ in terms of genetic output?
What defines a diploid cell?
What defines a diploid cell?
During which phase does crossing over occur?
During which phase does crossing over occur?
What best describes the genetic composition of offspring resulting from asexual reproduction?
What best describes the genetic composition of offspring resulting from asexual reproduction?
Which of the following describes the result of a translocation mutation?
Which of the following describes the result of a translocation mutation?
Flashcards
Aneuploidy
Aneuploidy
A condition where the number of chromosomes is not the typical count due to nondisjunction.
Monosomy
Monosomy
A type of aneuploidy where one chromosome from a pair is missing.
Trisomy
Trisomy
A type of aneuploidy where an extra chromosome is present, resulting in three chromosomes of a kind.
Karyotype
Karyotype
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Meiosis
Meiosis
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Genetic Variation
Genetic Variation
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Mitosis vs Meiosis
Mitosis vs Meiosis
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Independent Assortment
Independent Assortment
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Meiosis II
Meiosis II
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Mitosis vs. Meiosis II
Mitosis vs. Meiosis II
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Crossing Over
Crossing Over
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Haploid
Haploid
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Chromosome Mutations
Chromosome Mutations
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Deletions
Deletions
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Sexual Reproduction
Sexual Reproduction
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Diploid (2n)
Diploid (2n)
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Haploid (n)
Haploid (n)
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Gamete
Gamete
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Zygote
Zygote
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Nondisjunction
Nondisjunction
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Study Notes
Meiosis and Sexual Reproduction
- Meiosis is a type of cell division that reduces the chromosome number by half, creating four unique haploid cells. This is crucial for sexual reproduction and genetic diversity.
Vocabulary
- Diploid (2n): Refers to the total number of chromosomes, where chromosomes exist in two sets.
- Haploid (n): Refers to half the total amount of chromosomes, which is a single set.
- Chromosome: A threadlike structure of nucleic acids and protein found in the nucleus of most living cells. It carries genetic information in genes.
- Chromatid: One of the two identical halves of a chromosome that has been replicated.
- Homologous chromosomes (homologues): Chromosome pairs that are similar in length, gene location, and centromere position. They carry the same genes but may have different alleles.
- Gamete: A reproductive cell (sperm or egg) that carries half of the genetic material needed to create a new organism.
- Zygote: A fertilized egg cell that results from the union of a female gamete (egg, or ovum) with a male gamete (sperm).
- Gene: The basic unit of heredity, consisting of a sequence of DNA, located in the chromosomes.
- Allele: One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
- Synapsis: The fusion of chromosome pairs at the start of meiosis.
- Crossing over: The exchange of genetic material between homologous chromosomes during meiosis. This increases genetic diversity by mixing up alleles.
- Nondisjunction: Failure of two chromosomes to separate during gamete formation, leading to aneuploidy.
- Independent assortment: The random distribution of chromosomes into gametes during meiosis. Increases genetic variation.
- Fertilization: The action or process of fertilizing an egg, female animal, or plant, involving the fusion of male and female gametes, forming a zygote.
- Aneuploidy (monosomy or trisomy): The incorrect number of chromosomes in a species. Monosomy - an individual only has one of a particular type of chromosome. Trisomy - an individual has three of a particular type of chromosome. This arises from nondisjunction.
- Karyotype: A visual display of the chromosomes arranged by size, shape, and banding pattern, which can be used to identify conditions like Down syndrome.
Meiosis I
- The first stage of meiosis, resulting in cells with half the number of chromosomes as the original cell.
- DNA replication occurs prior to meiosis I.
- Homologous chromosomes separate during meiosis I.
Meiosis II
- The second stage of meiosis that results in four haploid daughter cells.
- Sister chromatids separate during meiosis II.
Asexual vs. Sexual Reproduction
- Asexual reproduction results in offspring that are genetically identical to the parent.
- Sexual reproduction produces offspring with unique combinations of genes from two parents, increasing genetic variation.
Genetic Variation in Sexual Reproduction
- Sexual reproduction increases genetic variation through crossing over and independent assortment.
Somatic Cells vs. Gametes
- Somatic cells undergo mitosis; gametes undergo meiosis.
Mitosis vs. Meiosis
- Mitosis maintains the same chromosome number, producing two identical diploid cells from one diploid parent, while meiosis reduces the chromosome number by half, producing four genetically unique haploid cells from one diploid parent.
Chromosome Mutations
- Deletions are the loss of a segment of a chromosome.
- Duplications are the presence of a chromosomal segment more than once.
- Inversions are when a segment of a chromosome is reversed.
- Translocations are when a segment of a chromosome moves to another chromosome.
Importance of Sexual Reproduction
- Increases genetic variation, making species more resilient to environmental pressures and diseases.
- Provides the raw material for evolution.
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