Usually, this occurs during mitosis, when genetic material is duplicated, and one copy is passed onto each daughter cell. Mitosis is generally followed by cytokinesis, or cytoplasmic division, in which the rest of thecell divides in half forming two new cells. Most of the life of a cell is spent in a non-dividing phase called Interphase. In this phase of the cell cycle, cells are not actively dividing. Interpahse includes the G1, S, and G2 phases of the cell cycle.
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.
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.
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.
Additionally, the DNA of mitochondria and chloroplasts are different from that of the eukaryotic cell in which they are found. As Margulis predicted, both types of organelles include DNA that is like that of prokaryotes- circular, not linear. The DNA of these organelles evolves independently and at a different rate from the nuclear DNA of the eukaryotic cell. Mitochondria arise from pre-existing mitochondria and chloroplasts arise from pre-existing chloroplasts (not manufactures through the direction of nuclear genes). A fairly simple piece of evidence for the endosymbiotic hypothesis is the fact that both mitochondria and chloroplasts have double phospholipid bilayers.
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.
4 – Dismantles debris B. 6 – Protein synthesis C. 2 – Houses DNA D. 1 – Lipid synthesis E. 7 – Processes secretions F. 3 – Energy extraction G. 5 – Detoxification 2) Explain the functions of the following proteins: A. Tubulin and Actin – Tubulin forms microtubules, while actin forms microfilaments. B. Caspases – Caspases are responsible for apoptosis. C. Cyclins and kinases – The interaction of cyclins and kinases trigger mitosis from the inside. D. Checkpoint proteins – Checkpoint proteins are responsible for regulating the cell cycle.
The Nuclear Envelope is made up of two layers, each is made of lipids. It is a membrane that covers the nucleus in the eukaryote cell. These cells generally have nuclei in which the genetic material is separated from the rest of the cell. The envelope separates the contents in the nucleus from the cytoplasm which contains the organelles. The nuclear envelope is marked with tiny holes called the complex nuclear pores; these keep the moving in and out of things like RNA and proteins between the cytoplasm and the nucleus running smoothly.