The nuclear envelope and nucleolus also start to break up. The second phase of mitosis is Metaphase, during methaphse chromosomes composed of sister chromatids move toward the centre of the cell. Furthermore cells travel to Anaphase, the spindle fibers attached to the two sister chromatids of each chromosome contract and separate chromosomes which move to opposite poles of
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.
There are 3 stages of interphase: Growth 1 (G1) G1, in which the cell grows and functions normally. During this time, a lot of protein synthesis occurs and the cell "grows" - more organelles are produced and increasing the volume of the cytoplasm. If the cell is not to divide again, it will remain in this phase. Synthesis (S) Synthesis is where the cell duplicates its DNA (via semi-conservative replication). Growth 2 (G2) G2, in which the cell ensures that its chromosomes and organelles are ready for 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.
The new viral RNA serves as blueprint. Other enzymes use it to produce proteins that will become new virus capsules. (5) An enzyme called protease cuts the long, unmilled proteins into shorter piece, which clip together to form new capsule. (6) The completed capsule bud from the surface of the cell. AIDS AS A CONCERN FOR
This energy is then in turn used by the cell to carry out various functions. Nucleus- The main function of the cell nucleus is to control gene expression and mediate the replication of DNA during the cell cycle. Nucleolus- This takes up around 25% of the volume of the nucleus. This structure is made up of proteins and ribonucleic acids (RNA). Its main function is to rewrite ribosomal RNA (rRNA) and combine it with proteins.
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.
The DNA is linear and forms into chromosomes before cell division. In eukaryotes the normal process of cell division is called mitosis, with exception of gamates. In mitosis the chromosomes are copied and divided equally
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.
Their nuclear envelopes disintegrate. A spindle is formed following replication of the sperm's centriole, and a full set of dyads assembles on it. The fertilized ovum now known as the zygote is now ready for its first mitosis. When this is done, 2 cells each with a diploid set of chromosomes are formed. Cleavage now happens which is a series of rapid mitotic divisions that subdivides the cytoplasm of the zygote into smaller, essentially equipotential cells called blastomeres contained