Fq 1. Explain the stages of mitosis
They're are 5 main stages in Mitosis, Interphase, Prophase, Metaphase, Anaphase and Telophase.
Interphase
-Interphase is the longest stage of mitosis
-Proteins are produced
Prophase
-prepares to split by duplicating certain DNA
-nucleus fades
-chromatin condenses into chromosomes
Metaphase
-nucleus completely breaks down so it is unnoticeable
-spindle fibers elongate and stretch to connect chromosomes
-connected at the centre by a centromere
Anaphase
-The cell begins to split
-Pressure is applied to align everything together
Telophase
-Cell membrane is completely split and closes up
-2 cells are created with half DNA
Interphase
-Interphase is the longest stage of mitosis
-Proteins are produced
Prophase
-prepares to split by duplicating certain DNA
-nucleus fades
-chromatin condenses into chromosomes
Metaphase
-nucleus completely breaks down so it is unnoticeable
-spindle fibers elongate and stretch to connect chromosomes
-connected at the centre by a centromere
Anaphase
-The cell begins to split
-Pressure is applied to align everything together
Telophase
-Cell membrane is completely split and closes up
-2 cells are created with half DNA
http://www.cellsalive.com/mitosis.htm
http://www.biology4kids.com/files/cell2_mitosis.html
http://www.biology4kids.com/files/cell2_mitosis.html
Fq 2 What is the cell cycle?
The cell cycle is made up of 4 main parts, G1, S, G2 and M. G1 - The cell grows in preparation for replication - cells Increase in size - cell produce protein S - cell completely duplicates - DNA replicates - creates 2 daughter cells G2 - cell continues to grow - produces new proteins - determines if the cell can proceed into mitosis M - the last stage is Mitosis - all the cells energy is dedicated to separating http://www.cellsalive.com/cell_cycle.htm Fq 3 Explain the stages of meiosisMeiosis occurs in organisms that reproduce sexually e.g humans plants and animals. Meiosis is a two part processes in which sex cells are made with half the number of chromosomes, this means when 2 of these sex cells meet and combine they have the right amount of chromosomes to create a baby. At the end of the process 4 daughter cells are produced. Meiosis I has two main purposes It is the reduction division, so it reduces the number of chromosomes in half, making the daughter cells haploid It is during meiosis I that most of the genetic recombination occurs. The main difference between stage 1 and stage 2 is that in stage 2 the DNA does not replicate. Prophase II Chromosomes condense and the nucleus disappears, spindle network begins Metaphase II Tension from the spindles forces the chromosomes to line up at the equator (cells centre) The kinetochore fibers point toward opposite poles. Anaphase II Chromosomes split with one head going toward each pole, Fibres elongate the cell. The two poles move further apart Telophase II 4 daughter cells are produced and they all have the right amount of DNA http://www.cellsalive.com/meiosis.htmhttp://faculty.stcc.edu/BIOL102/Lectures/lesson9/stepbystep.htm http://biology.about.com/od/meiosis/ss/meiosisstep_9.htm |