The Process Of Cell Division In Animals Coursework

The Process Of Cell Division In Animals - Coursework Example The cell cycle comprises of four important stages. S stage is for synthesis and DNA replication occurs in this stage. G2 comes after and S phase and is the phase of DNA repair and correction of any mistakes made during DNA replication. Only the cells with repaired DNA are allowed to enter the M phase. M phase or mitosis is when nuclear and cytoplasmic division occurs culminating in the formation of daughter cells. Cytokinesis is the cytoplasmic division of the parent cells. When a fibrin ring called actin contracts around the center of the cell, it leads to pinching of the cell into two daughter cells, each containing one nucleus. Interphase is not technically a part of mitosis as it is the phase in which the cell is metabolically prepared for mitosis. Chromosomes are not clearly distinguished and the pair of centrioles starts appearing. 5. Suppose someone presented data from their research that showed the DNA of a newly discovered species was composed of: 30% adenine, 30% guanine, 2 0% thymine, 20% cytosine. Based on what you know about DNA structure, explain why these data do not make sense. The Chargaff’s rules indicate that the amount of adenosine equals the amount of Thymine and the amount of Guanine equals the amount of Cytosine. Therefore, the total purines equal the total pyrimidines. However, the rules only apply on double-stranded DNA or double stranded RNA and single stranded nucleic acids such as in viruses do not follow the Chargaff’s rule. The data presented shows 30% adenosine and 20% thymine, and 30% guanine in comparison to 20% cytosine. This data contradicts the Chargaff’s rule, indicating that it is not a double-stranded nucleic acid and most likely represents the base pairing of single-stranded nucleic acid, maybe in viruses. 6. What are the differences between a covalent bond and an ionic bond? In a covalent bond, the atoms are bound by the sharing of electrons. The electrons are shared either equally or unequally betwee n the two atoms. If the electrons are shared equally between the two atoms, the covalent bond is said to be non-polar. If the electron is attracted more towards one atom than another, it leads to the formation of a polar covalent bond, for example the molecule of water H2O. In contrast, the ionic bond of two atoms is formed by the forces of attraction between oppositely charged ions. For example, NaCl is formed by the positively charged Sodium (Na) atom and the negatively charged Chloride (Cl) atom. 7. Water is crucial for life as we know it. One of the most important characteristics of water is its ability to act as a solvent. Explain why water is such a good solvent for polar and charged molecules. The physical and chemical composition of water makes it a very good solvent for polar and charged molecules. Water molecule is made up of positive electrical charge of Hydrogen atoms and the negative charge of Oxygen atom. This forms a very strong polar covalent bond and contributes it a property of being a good solvent, by disrupting the attractive forced between other charged molecules. The polar molecules are easily dissolved in water because the forces of attraction are disrupted between the solute. The positive charges are attracted towards the negative Oxygen pole of water and the negative charges of the solute are attracted towards the positive Hydrogen pole of water. The atoms of solute are then surrounded by water molecules, making it a good solvent for charged and polar molecules. 8. Suppose you are taking a cruise from California to Hawaii. About halfway there, the ship begins to sink. You are able to board a lifeboat, but now you are floating in the ocean waiting to be rescued. After several days, you are so thirsty that you bend over the side of the boat and drink