Biology: Key Questions Essay

How many electrons does MGM+ have? Answer: MGM+ has 10 electrons. A Magnesium atom has 12 electrons, 2 of which are valence electrons. The atom will lose the 2 outermost electrons in order to stabilize its electron shell. The nucleus maintains its 12 protons and becomes a MGM+ ion. 2. Given that the half-life of the radioisotope carbon-14 is 5730 years, how useful do you think this isotope would be for dating bones that are over a million years old? Answer: Carbon-14 is incorporated in the tissues of plants and animals through their environment.

When they die the incorporation of carbon-14 ends, and what remains in the specimen decays at a constant rate, with a half-life of 5730 years. That is, after 5730 years only half of Carbon-14 remains in the sample. (Measuring the ratio between C-14 & C-12 can give us a good idea about when an organism died. ) This exponential decay continues and continues; however after about 40 000 years, less than 1% of Carbon-14 remains in the sample, so it is not useful for dating material much older than that. Thus, given the half-life of the radioisotope Carbon-14, it loud not be useful in dating a bone over a million years old. . Summarize the four major types of biochemical reactions studied in this lesson. For each type give its name, a word summary of what happens during the reaction, and an example of where the reaction might be biologically important. Hydrolysis: Hydrolysis uses water (and various enzymes) to break down molecules into smaller, simpler molecules. This occurs by breaking a bond on the reactant and adding a hydrogen atom to one part, and a hydroxyl (-AH) to the other. The result is 2 simpler molecules. Macromolecule + Water 0 molecule + molecule

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This process aids us in controlling blood sugar, by the hydrolysis of glycogen to glucose. Glycogen + Water + (Enzymes) 0 Glucose + Condensation: Glucose Condensation reactions occur when two molecules combine to form one molecule; they are the opposite of hydrolysis reactions. When the two smaller reactants Join together, water is produced and removed during the synthesis of the larger molecule. This is also called Dehydration Synthesis. For example, molecules with projecting Hydrogen atoms bond with molecules with projecting Hydroxyl groups (- OH), forming water.

The water molecule then leaves the reactants, allowing them to nod to form a larger, more complex molecule. This type of reaction occurs continuously throughout the body in the Joining of amino acids to form protein. Amino acid + Amino acid 0 Protein + Water Oxidation and Reduction (Redo) A chemical reaction involving the transfer of electrons rather than molecules is classified as a Redo reaction. A reaction involving the loss of electrons is called Oxidation, and a reaction involving the gain of electrons is called Reduction. Oxidation and Reduction always occur together, as one reactant loses electrons, and the other gains them.

This exchange often effects the physical states of molecules, as their solubility is changed with their charge. + cue+ O cue(S) + Zen+(as) Cellular respiration is a redo reaction that combines glucose & oxygen to produce carbon dioxide, water, and energy. Naturalization: Naturalization reactions are those that involve the reaction of an acid and a base to form water and salt. A solution with a high hydrogen ion concentration is acidic, and a solution with a high concentration of hydroxide ions is basic. When an acid reacts with a base, the H+ ion bonds with the OH – ions, producing water, and what remains arms salt.

H2O + CA WHICH

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