Bio Quiz Meiosis
Terms
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- homologous
- chromosomes that have a corresponding chromosome from the opposite sex-parent (meaning the number of chromosomes from the male parent corresponds to the number from the female parent)
- diploid
-
a cell that contains both sets of homologous chromosomes
-means "two sets"-two complete sets of chromosomes and two complete sets of genes - diploid number
-
the way the number of chromosomes in a diploid cell are represented-uses 2N
ex. fruit fly had 8 chromosomes
diploid number=
2N=8 - haploid
- cells that contain only a single set of chromosomes, and therefore only a single set of genes.
- haploid number
-
haploid # for fruit fly (8 chromosomes)
N=4 - meiosis
- a process of reduction division in which the number of chromsomes per cell is cut in half throuh the separation of homologous chromosomes in a diploid cell.
- what are the two distinct stages of meiosis and what is the result by the end of the second stage?
- Meiosis I and meiosis II- the end result is 4 haploid cells with a diploid number of 4 (2N=4)
- Interphase I
- First step, prior to meiosis I. Cells undergo a round of DNA replication, forming duplicate chromosomes.(might not be visible)
- Name steps of meiosis in order of occurance.
-
Prior to meiosis I: Interphase I
Meiosis I: Prophase I, Metaphase I, Anaphase I, Telephase I and cytokinesis
Meiosis II: Prophase II, Metaphase II, Anaphase II, Telephase II and cytokinesis - Prophase I
- each chromosome pairs with its corresponding homologous chromosomes to form a tetrad. Crossing-over can occur here.
- Tetrad
- a structure formed during Prophase I that contains 4 chromatids.
- crossing-over
- as homologous chromosomes pair up and form tetrads in meiosis I (prophase I), they may exchange portions of their chromatids. Crossing-over results in the exchange of alleles between homologous chromosomes and produces new combinations of alleles.
- Metaphase I
- Spindle fibers attach to the chromsomes
- Anaphase I
- The fibers pull the homologous chromosomes toward opposite ends of the cell
- Telephase I and cytokinesis
- Nuclear membranes form. The cell separates into two cells, each with 2 chromosomes.
- Difference between meiosis I and meiosis II
- the chromosomes in meiosis I were replicated and so there was four, but at the start of meiosis II there are two chromosomes in each cell.
- prophase II
- meiosis I results in two haploid daughter cells, each with half the number of chromosomes as the original cell
- Metaphase II
- the (two) chromosomes line up in a similar way to the metaphase stage of mitosis.
- anaphase II
- the sister chromatids separate and move toward opposite ends of the cell
- telophase II and cytokinesis
- meiosis II results in four haploid daughter cells now contain just two chromosomes each
- gametes
- specialized cells in sexual reproduction
- sperm
- haploid gametes produced by male animals
- egg/egg cell
- female gamete in aniamls and some plants
- how is the cell division in females uneven?
- the egg receives most of the cytoplasm and the 3 polar bodies receive less
- polar bodies
- the other three cells produced in the female during meiosis that usually do not participate in reproduction
- What is the one major difference between mitosis and meiosis??
- mitosis results in the production of two genetically identical diploid cells, whereas meiosis produces four genetically different haploid cells