TAMU BIO 111 LAB PRACTICAL 1 (LABS 1-6) WITH VERIFIED SOLUTIONS ALREADY GRADED A+

What is a theory? A unifying explanation that has withstood many attempts to falsify it through scientific investigation over a prolonged period of time What are the 4 unifying theories in biology? - The Cell Theory - The Gene Theory - The Theory of Heredity - The Theory of Evolution Explain cell theory All organisms are made of cells that store hereditary information in DNA Explain gene theory DNA sequences may be altered by mutation or by crossing over and segregation during meiosis Explain the theory of heredity Changes in DNA sequences produce individual, heritable variation. Some of these changes result in individuals with physical characteristics that allow them to leave more offspring to the next generation than do other individuals. These individuals are considered to be more fit than those who have fewer offspring that survive to adulthood. Explain the theory of evolution Since the variations in genes possessed by more fit individuals are passed in greater numbers to the next generation, over time, this differential reproductive success may result in a population of individuals that has accumulated enough changes in DNA to develop into a new species. Evolution is simply genetic change over time. Its history can be traced in the fossil record and the result is exemplified by the biodiversity of the planet What are the steps of scientific method? 1) Observe and formulate questions 2) Propose a hypothesis 3) Test the hypothesis 4) Analyze the results 5) Support, reject or modify the hypothesis What is the hypothesis countered by The null hypothesis What is the treatment variable? The independent variable What is the dissecting microscope best for viewing? Larger, three-dimensional, or opaque specimens i.e. live Termites What kind of light do dissecting microscopes use? Transmitted and reflected What kind of light do compound microscopes use? Only transmitted When viewing through a compound scope, what is the first step? Set the scope on it's lowest objective (4x) so you don't damage the slide. ______ Microscopes have lower magnification, but greater resolution Dissecting What does transmitted light do? Passes through a specimen What does reflected light do? Bounces off the surface of a specimen Working distance The space between the objective and slide Field of View the visible area magnification ocular power x objective power Parfocal a specimen that is in focus with a low power objective remains roughly focused when a higher power objective is used Parcentric a specimen centered over the condenser using a low power objective remains centered when a higher power objective is rotated into place depth of field The depth the microscope focuses Resolution The ability to discern close objects. (although resolution increases with magnification, the relationship is not linear) What charge do water molecules have? Neutral Cohesion When water molecules are attracted to other water molecules Adhesion when water molecules are attracted to other materials What is a covalent bond a bond that occurs when two atoms share two electrons within a molecule Are covalent bonds strong or weak? Very strong What is a hydrogen bond a bond that occurs between two molecules when a positively charged hydrogen atom bonds with a negatively charged oxygen, fluorine, or nitrogen atom. what is surface tension The cohesion of water molecules in the absence of other attraction What causes water to pull itself into the shape with the smallest surface area? Surface Tension What is capillary action the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity Why do plants rely on capillary action? Because they need it to pull water (and its dissolved minerals) from the soil into the roots. What process do plants use to transport water from the roots through the rest of the plant? Transpiration Is water a solution or a solvent? Solvent. What is a solution? A homogeneous mixture of a solute dissolved in a solvent What is a solute? The minor component in a solution, dissolved in the solvent. What is a solvent? The liquid in which a solute is dissolved to form a solution What is a polar Solvent Water Explain ionic bonds Ionic bonds result from the electrostatic attraction between oppositely charged ions What is a cation An atom that loses one or more electrons is a positively charged cation What is an anion? An atom that gains one or more electrons is a negatively charged anion What is chromatography? The process by which the components of a mixed solution are separated along a matrix What does the chromatography paper separate by? Color (polarity for lipid test) Why is water able to float? Because it is less dense in the frozen state What are the pH values of Acid solutions? less than 7 What are the pH values of Basic, Alkaline solutions? more than 7