Ch 13 - Meiosis and sexual life cycles
Terms
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- How do offspring acquire genes from their parents?
- By inheriting chromosomes
- What does evolutionary adaptation depend on?
- Genetic variation
- What describes the transmission of traits from one generation to the next?
- Hereditary
- What describes the difference in appearance between parents and siblings?
- Genetic Variation
- What it the scientific study of heredity and hereditary variation?
- Genetics
- What are the hereditary units that offspring receive from their parents?
- Genes
- These things are segments of DNA.
- Genes
- What is DNA a polymer of?
-
Nucleotides
(4 different kinds of monomers) - What cellular vehicles transmit genes from one generation to the next?
- Sperm and Ova
- What does each chromosome consist of?
- A single long DNA molecule and various proteins.
- What is the name of the specific location on a chromosome where a gene is positioned?
- Locus
- What kind of cell division is used in asexual reproduction?
- Mitotic
- What is the name of the offspring that is produced through asexual reproduction?
- Clone
- What is the cause of genetic differences in asexual reproduction?
- Mutations
- What mechanism generates genetic variation?
- The behavior of chromosomes during the sexual life cycle.
- What is the generation-to-generation sequence of stages in the reproductive history of an organism?
- Life Cycle
- How are chromosomes arranged?
- In pairs starting with the longest.
- What 3 characteristics do homologous chromosomes have in common?
-
1. Length
2. Centromere position
3. Staining patter. - What 2 types of chromosomes does each individual have?
- Sex chromosomes and Autosomes
- What number of chromosomes do gametes have?
- 23
- What is the union of gametes?
- Fertilization
- How many sets of chromosomes does a zygote have?
- 2; 1 maternal and 1 paternal
- Is a zygote a diploid or haploid cell?
- Diploid 2n=46 chromosomes = 2 sets
- What is an ordered display of an individual's chromosomes?
- Karyotype
- Is a zygote a somatic cell or a gamete?
- Somatic; diploid
- What are the only cells of the human body not produced by mitosis?
- Gametes
- Where does meiosis occur in animals?
- Ovaries and testes
- Which type of cell division conserves the chromosome number?
- Mitosis
- What 2 things alternate in the sexual life cycles?
- Fertilization and meiosis
- Are the cells that divide by mitosis haploid or diploid?
- They can be both
- Are the cells that divide by meiosis haploid or diploid?
- Diploid only
- What is the name of the life cycle for plants and some algae?
- Alternation of generation
- What are the names of the diploid and haploid cells in alternation of generation?
-
Diploid = Sporophyte
Haploid = Spore - What is the name of the 2 individual chromosomes inherited from different parents?
- Homologous Chromosomes
- What does Meiosis I begin with?
- 1 diploid parent cell containing 1 pair of Homologous chromosomes.
- What does Meiosis I end with?
- 2 haploid daughter cells containing non-sister chromosomes.
- What does Meiosis II begin with?
- 2 haploid daughter cells each containing non-sister chromatids.
- What does Meiosis II end with?
- 4 haploid daughter cells
- When in the cell cycle do the homologous pair of chromosomes replicate?
- Interphase I of Meiosis
- In what phase does synapsis occur?
- Prophase I of Meiosis
- What process attaches the homologous chromosomes tightly together all along their lengths?
- Synapsis
- In what phase of the cell cycle does a tetrad appear?
- Prophase I of Meiosis
- This is the cluster of 4 chromatids.
- Tetrad
- At what location do chromosomes change segments?
- Chiasmata
- What is crossed at the chiasmata?
- Chromatids of homologous chromosomes.
- Which phase of the Meiosis occupies the most time?
- Prophase I
- Where are the chromosomes aligned in Metaphase I?
- Metaphase plate
- What guides the movement of the chromosomes toward the poles?
- Spindle Apparatus
- What is positioned at opposite poles during Anaphase and Anaphase I?
-
Anaphase: Individual chromosomes
Anaphase I: Sister chromatids - What type of cells form during telophase I/cytokinesis?
- 2 haploid daughter cells where the chromosomes are still doubled.
- How many times does interphase occur during Meiosis?
- Once before Prophase I
- What is the process by which duplicated chromosomes pair with their homologues?
- Synapsis
- What type of cell division enables multicellular adult to arise from zygote?
- Mitosis
- What type of cell division produces cells for growth and tissue repair?
- Mitosis
- What type of cell division produces gametes?
- Meiosis
- What type of cell division reduces chromosome number by half and introduces genetic variability among the gametes?
- Meiosis
- What 3 mechanisms contribute to genetic variation arising from sexual reproduction?
-
1. Independent Assortment of Chromosomes
2. Crossing Over
3. Random Fertilization - This contains all the nucleotides in DNA.
- Genome
- This is a sequence of DNA nucleotides that code for a specific protein.
- Gene
- This is a different form of the same gene.
- Allele
- During what phase does the cell grow?
- Interphase
- What separates the homologues?
- Microtubules
- At what phases does genetic variation occur in Meiosis?
-
Prophase I = Crossing over
Metaphase I = Random Alignment - These are genes we inherit that are a combination of the our 2 parents.
- Recombinant Chromosomes
- What type of chromosomes does crossing over produce?
- Recombinant Chromosomes
- When during the cell cycle does crossing over begin?
- Prophase I
- How do homologues align?
- Gene by gene
- On average, what number of cross overs occur per chromosome pair?
- 2 or 3
- What phase is the cell in when it enters the G1 phase?
- GO
- What number of chromosomes enter the G1 phase?
- 46
- What is the division of cells to create germ cells?
- Meiosis
- What has the same traits with different information?
- Homologues
- What does Meiosis divide one diploid cell into?
- 4 haploid cells
- What are our traits determined by?
- Our chromosomes
- What phase of the cell cycle provides the greatest difference between mitosis and meiosis?
- Anaphase I = Genetic variation = greater diversity in gametes
- Meiosis II does what to the number of chromosomes in a parent cell?
- Reduces
- How many pairs of chromosomes do the resulting cells have after Meiosis?
- 23 pairs
- Which is the last phase of Meiosis?
- Telophase II