What time is it? LAB TIME!

 This week in AP Biology we did the mitosis and meiosis lab. As I previously discussed in my last blogs, mitosis which is when two genetically identical diploid daughter cells are produced and meiosis is the process which produces four genetically different haploid daughter cells. To began this lab we modeled mitosis and meiosis. We then prepared garlic for another activity. After following that we looked at onion root and fish egg cells to locate cells in the various stages of mitosis. We then proceeded to prepare the garlic root tip squash lab. In this part of the lab we took the garlic we had previously prepared by putting it into a sand and water mixture and placing it into a dark drawer, and cut off around 2 mm of the root tip. After that we put the root tip and hydrochloric acid on a slide  and passed it through an open flame for five seconds. Then we put a chemical that was bright pink and fuchsia in the name on the slide and passed it over an open flame for 2 minutes. We then squished the root tip and put it under a microscope to see if we could locate cells in the various stage of mitosis, but unfortunately we were unable to. That then concluded the lab.


(I will publish pictures separately.)

Meiosis

 This week in AP Biology we went over meiosis. Meiosis is divided into 2 different parts, meiosis 1 and meiosis 2. Meiosis 2 is the most similar to mitosis. In meiosis 1 there are four stages prophase 1, metaphase 1, anaphase 1, and telophase 1. In prophase 1 chromosomes condense, homologous chromosomes attach, crossing over between chromosomes, and centrioles move to opposite ends. In metaphase 1 the tetras line up at the metaphase plate. During anaphase 1 the homologous chromosomes are separated and taken to opposite poles. After anaphase 1, telophase occurs and the sister chromosomes continued to be pulled. Cytokinesis then takes place. After that meiosis 2 takes place which is very similar to mitosis. 

 Mitosis and meiosis differ greatly in their end products; mitosis results in 2 genetically identical diploid cell and meiosis results in 4 genetically different haploid cells. 

Message Passing and Reproducing in Cells

 This week in AP Biology we reviewed cell to cell communication and the cell cycle. 

 There are three types of cell to cell communication no distance, short distance, and long distance. In no distance communication the cells are touching and can send messages to one another. Plants have holes in there cell wall that allows the message to pass. When there is a short distance in cell to cell communication a local regulator is used to pass on the message, neurotransmitters are an example. When there is a long distance to pass on a message a hormone is used. The hormone is sent all around but only passes the message on to the right cells. 

After we went over cell to cell communication we then went to the cell cycle. The cell cycle is made up of the G1 phase, S phase, G2 phase, mitosis, and cytokinesis. There is also a G0 phase that some cells go into. G1, S, and G2 phase all make up interphase. In G1 phase the cell is working normally as the cell progresses into G2 it starts copying its DNA. When the cell starts S phase it again goes through its normal process. Then the cell gets to mitosis.  When mitosis and cytokinesis are combined it is called the mitosis (m) cycle the first phase is prophase. In prophase the chromatin becomes more clear and thicker and the centrioles become visible. Metaphase follows prophase in which the chromatin which has turned into sister chromatids are lined up in the middle of the cells with the centrioles at opposite ends and the mitotic spindle is forming. Anaphase which is the third phase is when the sister chromatids are pulled apart by kinectchores and nonkinectchores elongate the cell. The fourth and finall stage of mitosis (m) cycle is telophase and cytokinesis which is when the nucleus splits apart and start to reform the nuclear wall. And the cytoplasm splits thus creating another cell identical to its self. 

 To help control mitosis and prevent uncontrollable division there are checkpoints that the cell must pass before it can proceed into different phases. The are also internal and external  mechanisms that help to control uncontrollable division which can lead to cancer.