Chap.13-Meiosis-2008 - Cell and Mol Biol Course Guide Sathasivan 2006 Chapter 9 Part B MEIOSIS Meiosis occurs in sex cells to generate reproductive

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Cell and Mol. Biol. Course Guide Sathasivan, 2006 Chap. 9Part B Meiosis 1 Chapter 9. Part B. MEIOSIS Meiosis occurs in sex cells to generate reproductive cells (gametes) with half the number of chromosomes that are different, but derived from both the parent chromosomes. Meiosis is also known as reduction division. This is important for sexual reproduction where individual gametes from two parents (male and female) combine to form a new zygote cell developing into a new organism. Ploidy level indicates how many sets of chromosomes (N) are present in a cell as mentioned below. Haploid (1N) single set of chromosomes. e.g. sperm cell, egg cell. Diploid (2N) two sets of chromosomes. e.g. body cells Tetraploid (4N) four sets of chromosomes. e.g. plants, tobacco. Polyploid (manyN) several sets of chromosomes. e.g. sugarcane. The basic differences between sexual and asexual reproduction are shown below. Sexual Reproduction Asexual Reproduction Involves gametes or reproductive cells. Involves somatic or vegetative cells. Needs both meiosis and mitosis. Mitosis is enough to reproduce. Two parents/cells needed. Single parent or cell is enough. Chromosome number is reduced to half in gametes and then regained after fertilization. Chromosomes numbers and DNA sequence remains same. Greater variation among offsprings due to recombination. e.g. animals, most plants Highly homogeneous population due to identical progenies. E.g. potato, sugarcane. Example of a diploid cell: Human cells contain 46 chromosomes or 23 pairs or two sets as in any other diploid organism. Among these 22 pairs are called autosomes and two (X and Y) are sex chromosomes. The 23 pairs come from two parents. So in each pair of chromosome, one is paternal (from father) and another
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/31/2010 for the course BIO 49810 taught by Professor Satasivan during the Spring '10 term at University of Texas at Austin.

Page1 / 4

Chap.13-Meiosis-2008 - Cell and Mol Biol Course Guide Sathasivan 2006 Chapter 9 Part B MEIOSIS Meiosis occurs in sex cells to generate reproductive

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online