Lab Practical Biology 1107
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This 9 page Study Guide was uploaded by Hunter McElmurray on Monday April 11, 2016. The Study Guide belongs to Biology 1107 at East Georgia State College taught by Dr. Silva in Winter 2016. Since its upload, it has received 21 views. For similar materials see General Biology in Biological Sciences at East Georgia State College.
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Date Created: 04/11/16
Lab Practical: Study Guide: The scientific method - What are the steps in the scientific method? o Observation and stating the problem o Ask a question o Do background research o Construct a hypothesis o Make a prediction o Test the hypothesis by doing an experiment o Analyze the data and draw a conclusion o Communicate the results - Define and explain dependent and independent variables, experimental error, and purpose of controls o Dependent variables (y) Value depends on that of the other o Independent variables (x) Stands alone and is not changed by another o Experimental error Difference between the measurement and the true value or between two measured values o Purpose of controls To have something to compare the results of the effect of the Independent and Dependent variables on Receives no treatment - Be able to formulate a hypothesis, plot data, and explain how scientific data are presented. o Hypothesis A hypothesis is an educated guess about how things work. Most of the time a hypothesis is written like this: "If _____[I do this] _____, then _____[this]_____ will happen." ... Your hypothesis should be something that you can actually test, what's called a testable hypothesis. o Plot Data Review your data. Try to look at the results of your experiment with a critical eye. Ask yourself these questions: Is it complete, or did you forget something? Do you need to collect more data? Did you make any mistakes? Calculate an average for the different trials of your experiment, if appropriate. Make sure to clearly label all tables and graphs. And, include the units of measurement (volts, inches, grams, etc.). Place your independent variable on the x-axis of your graph and the dependent variable on the y-axis. o Explain how scientific data are presented Explain data in graph The Biological Molecules and Enzymes - What are the four groups of biological molecules? o Carbohydrates o Lipids o Nucleic Acids o Proteins - What are Monomers? What are Polymers? o Monomer is a molecule that can be bonded to other identical molecules to form a polymer o Polymer is a substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together - How are polymers synthesized? o Is the process by which monomers (small molecules) are covalently bonded to form a (usually long) polymer chain or network - How are they broken down into monomers? o In a process known as hydrolysis, which means, "to split water," a reaction in which a water molecule is used during the breakdown. During these reactions, the polymer is broken into two components. - Be able to name the monomers and polymers of the four biological molecules. How did we test for each when analyzing foods? o Monomers of the four biological molecules Carbohydrates; Simple Sugars or monosaccharides. Lipids; Fatty Acids. Protein; Amino Acids. Nucleic Acid; Nucleotides. o Polymers of the four biological molecules Proteins Carbohydrates Nucleic Acids o Test each when analyzing food Testing for carbohydrates Testing for the presence of starch (complex sugar) Lugol's reagent (iodine solution) changes from yellowish- brown to dark purple/black. Testing for simple carbohydrates (monosaccharides and some disaccharides) Benedict's solution is used to test for simple carbohydrates. Benedict's solution is a blue colored liquid that contains copper ions. When Benedict's solution and simple carbohydrates are heated, the solution changes to orange red/ brick red. This reaction is caused by the reducing property of simple carbohydrates. The copper (II) ions in the Benedict's solution are reduced to Copper (I) ions, which causes the color change. Sometimes a brick red solid, copper oxide, precipitates out of the solution and collects at the bottom of the test tube. Complex carbohydrates such as starches DO NOT react positive with the Benedict's test unless they are broken down through heating or digestion (try chewing crackers and then doing the test). Table sugar (disaccharide) is a non- reducing sugar and does also not react with the iodine or with the Benedict Reagent. Sugar needs to be decomposed into its components glucose and fructose then the glucose test would be positive but the starch test would still be negative. Testing for lipids Grease spot test/Brown paper test As we all know from experience, lipids leave translucent spots (grease spots) on unglazed brown paper bags. Sudan Red test o Sudan red is a fat-soluble dye that stains lipids red. Using Sudan red can show the amount and the location of lipids. Testing for proteins Buiret test Buiret solution is a blue liquid that changes to purple when proteins are present and to pink in the presence of short chains of polypeptides. The copper atom of the biuret solution reacts with the peptide bonds to cause the color change. - What is an enzyme? o Enzyme is a substance produced by a living organism that acts as a catalyst to bring about a specific biochemical reaction. - What is the name of the enzyme studied in the enzyme lab? o Catalase in yeast - How does temperature and pH affect enzyme reaction rates? o At extreme temperatures, pH, or ionic strength, enzymes may lose their shape permanently: a process called Denaturation. As a result, the enzyme will no longer function. - What is the equation for the enzymes reaction you performed? o 2H2O2 → 2H2O + O2 - What was the source of enzyme? What gas was produced by the reaction? o Source of enzyme Catalase o Gas produced Oxygen - What were your predicted results? How did your results compare with your predictions? o I predicted that the enzyme would speed up the chemical reaction and that temperature would affect how catalase works. My prediction compared with the results in the way of temperature and pressure directly affecting the rate in which catalase works. - Make sure to review your worksheets from both labs Cell Biology and the Microscope - You should know the parts of the microscope as well as understand magnification, diameter of field, brightness, resolution, and depth of field o Study microscope vocabulary - Remember the relationships between magnification and light requirements o To magnify (enlarge) the image, light rays have to be spread further apart - therefore, the image becomes dimmer, or light intensity decreases - You looked at several slides including onion and your cheek cells. Why were dyes needed to see the cells? o To make the cells’ nuclei more visible - What are the differences between prokaryotic and eukaryotic cells? o Prokaryotic No nucleus DNA in an unbound region called the nucleoid No membrane-bound organelles Cytoplasm bound by the plasma membrane o Eukaryotic DNA in a nucleus that is bounded by a membranous nuclear envelope Membrane-bound organelles Cytoplasm in the region between the plasma membrane and nucleus Generally larger than prokaryotic cells - What are examples of prokaryotic cells? What are the organelles found in eukaryotic cells? Can you describe the function of each organelle? What are the differences between plant and animal? Be able to identify a picture of the plant and animal cells o Prokaryotic cell examples Bacteria and Archaea o Organelles in eukaryotic cells and function Organelle Function Nucleus: The “brains” of the cell, the nucleus directs cell activities and contains genetic material called chromosomes made of DNA. Mitochondria: Make energy out of food Ribosomes: Make protein Golgi Apparatus: Make, process and package proteins Lysosome Contains digestive enzymes to help break food down Endoplasmic Reticulum: Called the "intracellular highway" because it is for transporting all sorts of items around the cell. Vacuole: Used for storage, vacuoles usually contain water or food. (Are you are thirsty? Perhaps your vacuoles need some water!) Plant cells also have: Chloroplasts:Use sunlight to create food by photosynthesis Cell Wall: For support o Differences between plant and animal cells Chloroplasts Plants are autotrophs; they produce energy from sunlight through the process of photosynthesis, for which they use cell organelles called chloroplasts. Animal cells do not have chloroplasts. In animal cells, energy is produced from food (glucose) via the process of cellular respiration. Cellular respiration occurs in mitochondria on animal cells, which are structurally somewhat analogous to chloroplasts, and also perform the function of producing energy. However, plant cells also contain mitochondria. Shape Another difference between plant cells and animal cells is that animal cells are round whereas plant cells are rectangular. Further, all animal cells have centrioles whereas only some lower plant forms have centrioles in their cells. Cell Wall Plant cells have a rigid cell wall that surrounds the cell membrane. Animal cells do not have a cell wall. When looking under a microscope, the cell wall is an easy way to distinguish plant cells. Vacuoles Shape and size of vacuoles Animal cells have one or more small vacuoles whereas plant cells have one large central vacuole that can take up to 90% of cell volume. Difference in function of vacuoles In plant cells, the function of vacuoles is to store water and maintain turgidity of the cell. Vacuoles in animal cells store water, ions and waste. Osmosis and Diffusion - What is diffusion? o The tendency of particles to spread out evenly in a given space - What is osmosis? o The diffusion of water molecules across a membrane - What is Brownian motion? o is the random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the quick atoms or molecules in the gas or liquid. Wiener Process refers to the mathematical model used to describe such Brownian Motion, which is often called a particle theory - What is a selectively permeable membrane? o is a type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by diffusion—or occasionally by more specialized processes of facilitated diffusion, or passive or active transport - What do the terms hypertonic, hypotonic, and isotonic mean? An isotonic solution is one that has an equal concentration of solute as compared to the inside of a cell A hypertonic solution is one that has a higher concentration of solute molecules and a lower concentration of solvent molecules A hypotonic solution is a solution that has a lower solute concentration and a greater solvent concentration than intracellular fluids - How did you set up the osmosis and diffusion experiment? o Cut very thin slices of potato o Set up sugar solutions - What solutes were used? What solvents were used? o Solutes Sugar solutions o Solvents Distilled water - What did positive and negative results look like? o Gained weigh at 0%, Lost weight at 10%, and remained the same at 5% - What solutions did you use? o 0%, 5%, 10%, 20% - Why did you use them? o They were all different percentages from each other, so they produce different results - What were the predicted results? How did the predicted results compare to yours? o It was predicted for 20% to cause the potato to gain the most weight, but 0% was the only one to gain weight - What are possible sources of variation? What is plasmolysis? What organelle is responsible for the effects seen after plasmolysis? Do plant cells lyse? Why or why not? o Possible sources of variation were the percentages of sugar o Plasmolysis is the shrinking of the cytoplasm of a plant cell due to the diffusion of water out of the cell into a hypertonic solution o The organelle responsible for plasmolysis is the vacuole o Plant cells do not lyse, but it causes them to turgor but not bust. They have cell walls to keep them from busting. Respiration and Photosynthesis - What are the general equations for cellular respiration and photosynthesis? o C6H12O6 + O2 → CO2 + H2O + Energy – cellular respiration o CO2 + H2O + Energy(light) → C6H12O6 + O2 – photosynthesis - Where does each process take place? o Cellular respiration Mitochondria o Photosynthesis Chloroplasts - What are the reactants and products for each pathway? o Carbon dioxide is product of cellular respiration o Oxygen is product of photosynthesis o Vice versa for reactants - What was being produced in the yeast experiment that you were measuring? o Carbon dioxide - How did you set up the photosynthesis experiment? What substance did you use to provide carbon dioxide? o Control had water and light o Bicarbonate and light o Bicarbonate and light and nail polish o Bicarbonate and dark o The substance used to provide carbon dioxide was baking soda mixed with water - What waste product of photosynthesis was measured by floating disks? o Oxygen - Under what conditions did you observe an increase in photosynthesis? When would you not expect to see photosynthesis in a leaf? Review stomata structure and function o Water and light is when there was the most increase in photosynthesis o I would not expect to see photosynthesis in a leaf when there is no light Cell Reproduction – mitosis, meiosis, and karyotype - What are the phases of the cell cycle? o Interphase o Mitosis o Cytokinesis - What happens in each phase? o Interphase: G1: period of cell growth before the dna is duplicated (interphase begins in daughter cells) S: period when the dna is duplicated (that is, when chromosomes are duplicated) G2: period after dna is duplicated. Cell prepares for division (interphase ends in parent cell) o Mitosis: Prophase Metaphase Anaphase TelophasE o Cytokinesis: C: Cytoplasm divided - What are the stages of mitosis? o Prophase o Prometaphase o Metaphase o Anaphase o Telophase - What are the stages of meiosis? o Prophase 1 o Metaphase 1 o Anaphase 1 o Telophase 1 o Prophase 2 o Metaphase 2 o Anaphase 2 o Telophase 2 - What types of cells undergo meiosis? o Gametes (sex cells) - Pay particular attention to the terminology such as chromosome, chromatin, centromere, chromatid, haploid, diploid, “N”, and centromeres - How is mitosis in a plant cell different from mitosis in an animal cell? o The only difference between their divisions is cytokinesis. In animal cell, cytokinesis occurs by a process known as cleavage. On the other hand, cytokinesis is different in plant cells, which process a cell wall. During telophase, membranous vesicles containing cell wall collect a middle of the parent cell. The vesicles fuse, forming a membranous disk called the cell plate. - How is meiosis in a male and female different from each other? What is nondisjunction? o Meiosis occurs in two different and opposite stages. In human males, meiosis occurs in the seminiferous tubules of the testicles while in females, it occurs in cells called as oogonia.in males, it occurs at puberty and in females it generates right after the time of the birth o Nondisjunction is the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei - What disorders are caused by nondisjunction, give examples? What is a karyotype? o William’s disorder, trisomy 21, klinefelter’s syndrome, and turner syndrome o A karyotype is the number and visual appearance of the chromosomes in the cell nuclei of an organism or species Mendelian Genetics Problems - Be able to solve mendelian genetics problems that include monohybrid and dihybrid crosses, incomplete dominance, codominance, sex-linked genes, and pedigree analysis. - Be able to define and analyze a pedigree. Review all lab activities and notes for each lab
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