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SAT Biology - Chapter 6 - Cell Division - Mitosis and Meiosis - Barron's

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celine's version from 2018-01-30 23:33

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2 types of cell divisionMitosis & Meiosis
Functions in the growth and repair of body cells, produces two genetically identical daughter cells with the same chromosome number as the parent cell, and each daughter cell is diploid (2n), just like its parent cellMitosis
Occurs only in sexually reproducing organisms, produces gametes (sperm and ova) with half the chromosome number of the parent cell, and each resulting cell is haploid (n) Meiosis
A replicated chromosome consists of two of these, where one is an exact copy of the otherSister chromatids
A specialized region that holds the two sister chromatids together. Spindle fibers connect the centromere to the centrosome during cell divisionCentromere
Living and dividing cells pass through a regular sequence of growth and division called theCell cycle
5 major stages of the cell cycleG1, S, G2, Mitosis & Cytokinesis
G1, S, & G2 together make up ———————Interphase
More than 90% of the life of a cell is spent in ———————Interphase
——————— is the actual division of the nucleusMitosis
Mitosis is divided into four phases:Prophase, Metaphase, Anaphase, & Telophase
Longest phase of mitosisProphase
Steps take place in Prophase1. Strands of chromosomes begin to condense and become visible 2. The nucleoli disappear 3. Spindle fibers begin to form in the cytoplasm, extending from one centrosome to the other 4. Centrioles begin to migrate to the poles 5. The nuclear membrane begins to disintegrate
Steps take place in Metaphase1. Chromosomes line up single file located on the equator or metaphase plate 2. Centrosomes are at opposite poles of the cell 3. Spindle fibers run from centrosomes to the centromeres of the chromosomes
Steps take place in Anaphase1. The centromeres of each chromosome separate, and spindle fibers begin to pull the sister chromosomes apart 2. Anaphase is the shortest phase of mitosis
Steps take place in Telophase1. Chromosomes cluster at opposite ends of the cell, and the nuclear membrane re-forms 2. Supercoiled chromosomes begin to unravel and to return to their pre-cell division condition as long, threadlike strand 3. The nuclear membrane re-forms
——————— is division of the cytoplasmCytokinesis
In animal cells, during cytokinesis, a ——————— forms down the middle of the cell as the cytoplasm pinches inward and the two daughter cells separate from each otherCleavage Furrow
In plantl cells, during cytokinesis, a ——————— forms down the middle of the cell and daughter cells do not separate from each other. Instead, a sticky ——————— cements adjacent cells together.Cell plate, Middle lamella
——————— is a form of a cell division in which the cells having the diploid chromosome number (2n) produce gametes (sex cells) with the haploid chromosome number (n)Meiosis
Stages of meiosisMeiosis I and Meiosis II
——————— is also called reduction divisionMeiosis I
Steps take place in Meiosis I1. Synapsis and crossing over occur 2. Homologous chromosomes then separate 3. Chromosomes line up randomly on the equatorial plate and separate independently. This means that how one pair of chromosomes lines up and separates has no effect on how any other pair of chromosomes lines up and separates 4. Each resulting gamete is genetically unique.
The process in which the homologous chromosomes pair upSynapsis
The process in which homologous chromatids exchange genetic materialCrossing-over
Steps take place in Meiosis II1. Sister chromatids separate 2. This division maintains the haploid number of chromosomes 3. This phase completes the goal of meiosis--producing four genetically unique cells from one original mother cell
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