BIOL 111 LAB PRACTICAL review

BIOL 111 LAB PRACTICAL REVIEW BIOL 111 LAB PRACTICAL REVIEW Microscope= an important tool used by biologists to magnify small objects. Types of Microscopes- (A) Dissecting Microscope- Allows us to see objects in 3 dimensions (3D). Utilizes 2 types of light- transmitted (passes through the specimen) and reflected light (bounces off the specimen). (B) Compound Microscope- For examining smaller details and specimens. Utilizes transmitted light. Can view specimens under several magnifications aided by the objectives.  Total magnification = ocular power x objective power  The Cell Theory: all organisms are composed of cells that contain DNA, or hereditary information  The Gene Theory: Genes determine characters; the sequence of DNA can be changed through mutation (changing the sequence), crossing over (swapping DNA) or segregation during meiosis  The Theory of Heredity: Genes (characters ) are passed from one generation to the next (heredity)  The Theory of Evolution: Changes in the genes over long period of time – evolution; An organism can undergo so many changes that they become a new species Experiment 1- termites • Draw basic geometric shapes and lines, colors, etc. • They were attracted based on scent/ chemical makeup of ink o i.e. they did not like the sharpie because of the strong scent LAB 2 • Polar Molecule- a molecule with opposite charges on opposite sides o Overall charge is neutral o Water can weakly bind with other water molecules due to its polar nature • Water o universal solvent o Adhesion= when water molcules are attracted to other materials  Capillary action o Cohesion= water molecules are attracted to other water molecules o Viscocity= resistance offered by a liquid to flow  Water has a low viscocity o Water has a high thermal capacity and surface tension o Water= less dense as a solid • pH o [H+] x [OH-] = 10-14 o relative hydrogen ion concentration [H+] in solution o pH = –log [H+] o pH ranges in value from 0 to 14  So, if the [H+] is 10-6 the pH is 6 o A solution is considered neutral at a pH of 7 o A solution is considered acidic at a pH below 7 o A solution is considered basic (alkaline) at a pH above 7 o Estimation  with pH paper  With colorimetric indicator (anthocyanins) o Quantitative  A more accurate and precise way to measure pH is with an electronic pH meter plasma membrane: • Is made up of a phospholipid bilayer – phospho part is hydrophilic and the lipid part is hydrophobic • It is selectively permeable- selectivity depends on size and nature of the molecule • Active Transport • Requires energy (ATP) – molecules move from area of low solute concentration to high solute concentration (against the concentration gradient) • Passive transport (diffusion, osmosis and facilitated diffusion) • Molecules move from area of high solute concentration to low solute concentration (down the concentration gradient) • Osmosis is a special case of diffusion. The diffusion of water molecules. Water moves down its concentration gradient • Water potential is the free energy available to move water molecules. • Water moves from an area of higher water potential to an area of lower water potential. • Water potential is dependent on Concentration gradient (osmotic potential) Pressure potential- amount of pressure on a solution Gravity and temperature • Water potential = Osmotic potential + Pressure potential The osmotic potential of pure water = zero. • The solute lowers the osmotic potential of a solution. Higher concentration of solute ® Lower(more negative) osmotic potential • Hypertonic = Higher solute concentration than other solutions Lower osmotic potential • Hypotonic= Lower solute concentration than other solutions Higher osmotic potential • Isotonic= Same solute concentration with other solutions Equal osmotic potential