BIOLOGY LABORATORY FROM METRIC SYSTEM TO DNA TECHNOLOGY
... the use of several methods of measuring pH, learn about the effects of buffers on pH change, and learned how to test for various macromolecules in solutions. pH is measure of the proton concentration of a certain solution. It is important to remember that the values fo pH and proton concentration go in opposite directions. In other words if the molar concentration of protons is high, then pH is low. A solution with low pH<7 is described as acidic, and a solution with a high pH >7 is described as basic. A solution with a pH 7 like pure water is neutral. We learned methods for measuring pH, learned about buffers, and the chemical composition of cells. During the experiment we used Litmus test, pHydrion color/pH, and the pH meter on the solutions of ammonia, antacid, aspirin, cola, and lemon juice. Then we added the buffers to the solutions and we graphed them. We performed the benedict’s test for reducing sugars in the solutions of glucose, water onion extract, potato extract, and milk. We also performed the iodine test for polysacchiredes, the Sudan IV test for lipids, and the Biuret test for proteins. We learned that the blood of humans remains constant due to the help of the buffers that stabilize our blood, a slight change on pH can be fatal. Buffers are important in the homeostasis of living organisms, without it survival will not be possible. TOPIC 5 ENZYMES We became familiarized with the enzyme function, the effects of pH, temperature and inhibitors on enzyme function, and also with the use of a spectrophotometer. To maintain life, the chemical reactions of cellular metabolism must occur at rapid rates. However, the reactants involved in metabolism in cells are present at relatively low concentrations and at temperatures usually below 40̊C. Enzymes are proteins with one or more locations called active sites. The specific shape of the enzyme, particularly its active site, determines the catalytic effect of that enzyme. The substrate, that is the substance acted upon by the enzyme, attaches to the active site. As the result of this interaction between substrate and enzyme, the substrate is chemically modified and converted into one or more products. Enzymes are quite specific for their substrate and will not often not react with molecules of a slightly different shape; for example, a particular enzyme may react with glucose but not with its isomer, galactose. We analyze the factors effecting enzyme activity such as inhibitors and their effects. We were introduced to spectrophotometry, a spectrophotometer is an instrument designed to detect the amount of light absorbed by the molecules in a solution. We acquired data on the enzyme activity, temperature experiment, temperature effects on peroxidase, effects of pH on peroxidase, effects of boiling on peroxidase activity, and the effects of boiling on peroxidase. TOPIC 6 EXCHANGE MECHANISMS BETWEEN CELLS AND THEIR ENVIRONMENT We became familiarized with the concepts of diffusion, osmosis, and other types of solute transport mechanisms, illustrate the effects of molecule size on diffusion, illustrate the diffusion of a gas, and illustrate osmosis in living and non-living systems. The plasma membrane serves as a exchange mechanism between cells. Materials that cross the outer cell boundary are either engulfed in the membrane, forming a vesicle or vacuole that can pass into or out of the cell, or else they interact with the membrane lipids and proteins or th spaces between these molecules. We studied the plasma membrane, diffusion, osmosis, and other transport mechanisms such as: facilitated defusion, active transport, and pumping. Molecules will diffuse proportionally to their molecular weight. We collected data from the agar plate, we used the data to observe distance, and obtained relative rate. The purpose of this experiment was to give a precipitate to examine the diffusion of the substances. We studied as well the diffusion of a gas through a membrane. The molecules of the gas moved into the solution because of the concentration gradient from high to low. This movement of the molecules is described as passive transport. We studied osmosis which is the diffusion of water through a selectively permeable membrane. We found out that the bag used changed shape (bigger) because it got bigger. We did the same thing with osmosis in plants with water, distilled water, and 3% NaCl. TOPIC 7 CELLULAR RESPIRATION We became familiarized with the process of cellular respiration, we learned about yeast cell preferences for cellular respiration substrates, and learn how various inhibitors affect cellular respiration. The purpose of cellular respiration is to extract the energy from the small molecules from food and use it to make ATP. Cellular respiration uses oxygen and gives carbon dioxide. The relationship between respiration and cellular respiration is that oxygen taken in when we inhale is used in cellular respiration and the Co² that is produced during cellular respiration. The three stages of cellular respiration include glycolysis, connecting with Kreb’s cycle, and Kreb’s cycle. During the process of kreb’s cycle, there are 8 reactions that take place for the purpose of producing carbon dioxide. We studied the three stages of cellular respiration, various sugars as respiratory substrates, and cellular respiration inhibitors. We did respiration experiments in tubes with different contents. We got data from the accumulation of carbon dioxide under various yeast culture conditions, which gave us numbers in height of gas column of the fermentation tube, volume of gas column of tube, and gas accumulation. We found out that cells typically don’t contain enzymes that is the reason why yeast cells lack enzymes for metabolizing certain sugars. TOPIC 8 PHOTOSYNTHESIS We became familiarized with the structure of leaves, learn about pigments involved in collecting light energy for photosynthesis, and learn about the components required for photosynthesis. The purpose of photosynthesis is to collect energy. Energy is needed for processes such as driving endergonic chemical reactions, active transport of molecules across membranes, movement of organelles within cells, and movement of muscles. Plants also need energy in the form of ATP, bit since plants typically don’t eat or even absorb organic nutrients, they must get their starting material for cellular respiration (like glucose) some other way. Plants get their nutrition by making their own food. Plants make their food during the process of photosynthesis. Photosynthesis consists of two stages: the light dependent reactions and the Calvin cycle. In this experiment we separated the various pigments by the process of chromatography. We found that it is beneficial that plants have several different types of pigments because that means that they can use different pigment to carry out photosynthesis. We studied the cross section of a dicot privet leaf.. We also studied the storage sites of starch in plant tissues and in potato cells. TOPIC 9 CELL DIVISION We observed the cell nuclei from several different cell types, became familiarized with mitosis and meiosis, became familiarized with the process of kariotyping. Two types of nuclear division are recognized: mitosis and meiosis. The terms mitosis and meiosis may also be loosely applied to the entire process of cell division. We examine the cell nuclei of an onion and a human cheek cell nuclei. Also we did mitosis and the cell cycle, it consists of interphase, prophase, metaphase, anaphase, and telophase. We studied mitosis in allium root tip, we got the length of each stage in the cell cycle of Allium. We also compared the plant mitosis vs. animal mitosis. We learned that cancer is a cell division out of control. The second type of cell division that some cell might undergo is meiosis. This type of cells are only in sexually reproducing organisms. Meiosis I divided in stages within meiosis 1 and meiosis 2. The stages are as follows: metaphase 1, anaphase 1, telophase1, interkinesis, prophase 2, metaphase2, anaphase2, telophase2, and gametes are formed. We did a kariotyping exercise. Karyotype is an analysis of chromosomes developed from a photograph of the chromosomes in a cell undergoing mitosis. This photograph is use to detect abnormalities. We learned some chromosome abnormalities and their effects. TOPIC 10 ELEMENTS OF GENETICS We became familiarized with some of ...