Study Guide: Mitosis and Meiosis prepared by Kathleen Bartholomew Mitosis is the process of dividing the replicated chromosomes of a single cell into two identical daughter cells. It is a part of cell division and happens during division of somatic cells. Mitosis is a form of asexual reproduction. It begins with a diploid cell, and ends with two diploid daughter cells. The number of chromosomes does not change in mitosis.
After duplication the cell is ready to begin mitosis. More, cells undergo prophase, Prophase is the first phase of mitosis. The DNA and proteins start to condense. The two centrioles move toward the opposite end of the cell as the chromosomes become visible. The nuclear envelope and nucleolus also start to break up.
Meiosis consists of 2 cell divisions: Meiosis I and Meiosis II. Meiosis starts with a diploid (2n) parent cell that divides to make 4 haploid (n) cells. In sexual reproduction, haploid gametes from two different individuals combine to produce a diploid zygote. The resulting offspring is genetically different from both parents. Chromosome characteristics: Haploid (n) = one set of chromosomes Diploid (2n) = two sets of chromosomes Eggs and sperm (gametes) are haploid Diploid set for humans: 2n = 46 Interphase before Meiosis: During the interphase preceding meiosis, DNA replication takes place.
Growth 2 (G2) G2, in which the cell ensures that its chromosomes and organelles are ready for mitosis. The proteins necessary for cell division are also made. For example, the proteins needed for the microtubules to form the spindle fibres. Duration is variable and depends on the function of the cell. Some human cells divide every 24 hours; in this case interphase takes about 22 hours and mitosis the remaining 2.
This essay will explain and describe how each cell groups together to form a tissue and how the tissues form our body system. It will also describe how the body systems work and give detail and a clear understanding of these. Each cell within the human body cannot be seen by the naked eye but only under a microscope. Within a cell there are a number of parts and these have all be explained in detail in part 1.1. All cells contain some DNA which is the most common feature of a cell and go through the process of cell division, during cell division Mitosis happens and this is making new cells exactly the same.
Many crops already “clone themselves naturally to reproduce” (cloning plants) by sending a runner into the soil, the runner then grows into a genetically identical plant. Mammal cloning though began in the late 1800’s, Hans Dreisch created the first cloned animal. Dreisch wanted to prove that “genetic material is not lost during cell division” (History Of). Dreisch used a 2 celled sea urchin
Meiosis is a type of cell division required for sexual reproduction and produces gametes or spores. During Meiosis I, DNA replication occurs and chromosomes line up on the equator as a homologous pair known as chromatids. At the first stage of Meiosis, Prophase I, DNA of individual chromosomes coils more and more tightly, known as DNA condensation. Sister chromatids then attach to specific sites on the nuclear envelope to bring the homologous pair of chromosomes close together. The sister chromatids line up so they can pair up with its corresponding "sister gene" on the homologous chromosome.
Answer True or False a) A chromosome is found in the nucleus of a cell. (True) b) In ordinary cell division (Mitosis), each cell formed has the same number of chromosomes as the parent cell. (True) c) A gamete is a sex cell. (true) d) A sex cell has the same number of chromosomes as the parent cell. (false) e) Meiosis produces sex cells in humans, animals and plants.
Manipulating the DNA• The whole process of genetic modification consists of manipulating the DNA.• Manipulating the DNA= Allows certain genes to be identified, copied and brought into other organisms in more specific ways. 4. Main types of Modified Organisms• Foods• Plants• Animals• Bacteria 5. Modifying Plants & Animals• To modify plants and animals the plasmid is taken out from the bacteria and the clone gene is replaced with a restriction enzyme.• For animals this is done by injecting millions of copies of the gene into the nucleus of a fertilized egg. 6.
There has to be primers to start the synthesis at the 3’ end of the new strands. The RNA primers are later replaced with DNA. Leading & Lagging Strands DNA splits into 2 strands. The continuous strand (the leading strand), and the discontinuous strand (the lagging strand) that grows away from the replication fork. Death Cap Mushroom Transcription and Translation: mRNA is necessary to direct synthesis (transcription) of the polypeptides.