LAB 3 v2 - LAB 3 NOTE: These labs are known for high...

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

View Full Document Right Arrow Icon
LAB 3 NOTE: These labs are known for high failure rates. Therefore, if I show an example using data, a graph, etc… yours may be totally different depending upon mine and yours success with the lab. So don’t freak if your data is completely different from mine. And therefore the analysis of results sometimes may need to be answered differently since you base your analysis off your data and not mine. DISCLAMIER: DO NOT CHEAT! Introduction There are two types of nuclear division, mitosis and meiosis. Mitosis is usually used for the growth and replacement of somatic cells, while meiosis produces the gametes or spores used in an organism’s reproduction. Mitosis is the first of these studied in this lab. It is easily observed in cells that are growing at a rapid pace such as whitefish blastula or onion root tips, which are used in this lab. The root tips contain an area called the apical meristem that has the highest percentage of cells undergoing mitosis. The whitefish blastula is formed directly after the egg is fertilized. This is a period of rapid growth and numerous cellular divisions where mitosis can be observed. Just before mitosis the cell is in interphase. In this part of the cell cycle the cell will have a distinct nucleus and nucleoli where the thin threads of chromatin are duplicated. After duplication the cell is ready to begin mitosis and its starts with a step called prophase. In prophase, the chromatin thicken into distinct chromosomes and the nuclear envelope breaks open releasing them into the cytoplasm. The first signs of the spindle begin to appear. Next the cell begins metaphase, where the spindle attaches to the centromere of each chromosome and moves them to the same level in the middle of the cell. This level position is called the metaphase plate. Anaphase begins when the chromatids are separated and pulled to opposite poles. Then, the final stage is telophase. The nuclear envelope is reformed and the chromosomes gradually uncoil. Cytokinesis may occur, in which case, a cleavage furrow will form and the two daughter cells will separate. Meiosis is more complex and involves two nuclear divisions. The two divisions are called Meiosis I and Meiosis II and they result in the production of four haploid gametes. This process allows increased genetic variation due to crossing over where genes can be exchanged. The process, like mitosis, depends on interphase to replicate the DNA. Meiosis begins with Prophase I. In this stage, homologous chromosomes move together
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 08/23/2010 for the course CS 1371 taught by Professor Stallworth during the Spring '08 term at Georgia Institute of Technology.

Page1 / 7

LAB 3 v2 - LAB 3 NOTE: These labs are known for high...

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