BIO 311C Exam 2 Latest Exam Questions And Answers Updated .
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Course
BIO 311C
Institution
BIO 311C
How long ago did life start on Earth? What does the timeline look like? - Answer -Life started 500 million years after Earth's formation
Bacteria -> Archaea -> Protists (unicellular) -> Protists (unicellular) -> Plantae -> Fungi -> Animalia
Miller and Urey's experiment a...
BIO 311C Exam 2 Latest Exam
Questions And Answers Updated .
How long ago did life start on Earth? What does the timeline look like? - Answer -Life started 500
million years after Earth's formation
Miller and Urey's experiment and basic results... - Answer -Experiment: used basic molecules (H, H2O,
methane, ammonia) in a setup w/ high power electrodes to stimulate energy. Noticed that simple
sugars, amino acids, and organic acids were formed.
-Results: showed that monomers of complex molecules could have formed under the reducing
atmosphere present in the early periods of Earth's history.
Predict the logical process by which simple monomers were formed and led to polymers and the early
forms of cells - Answer Atoms (natural) -> Molecules (reducing conditions) -> Monomers
(polymerization on solid support) -> Macromolecules (self-assembly) -> Protobionts
-Molecules are in reducing conditions (ex: shallow water beds) then turn into monomers. Monomers can
aggregate to form simple structures called protobionts. The protobionts can incorporate other
macromolecules. Simple liposomes have been shown to be formed by the aggregation of lipids in an
aqueous solution and would provide a structure for complexity to evolve.
Explain why the first possible macromolecule could be RNA to store genetic information and be able to
catalyze reactions - Answer -RNA could catalyze reactions and form a variety of secondary structures
similar to proteins, which may have allowed the formation of a self-replicating cell. RNA can form
spontaneously in prebiotic conditions. Once proteins are made they can make carbohydrates and lipids.
DNA cam elater and only helped proteins evolve to be more efficient enzymes
Different methods of microscopy - Answer -Light Microscope: light is refracted. Observe live specimens
in their natural colors with stains
, -Transmission Electron Microscope: electrons are aimed at a thin section of specimen. Study internal
ultrastructures and cross-sections of cells or structures
-Scanning Electron Microscope: electron beams scan the surface of a specimen coated with gold. Used to
view the surface features and the 3-D shape of ultrastructures.
Different methods of centrifugation - Answer -Mircofuge: SMALL 0.1-2.0 mL tubes. Used for molecular
biology experiments
-Clinical: 5-15 mL. Used in clinical labs
-Floor Model or Tabletop: LARGE 1-50 mL. Used in most cell and molecular biology labs
-Ultracentrifuge: LARGE 1-50 mL. Most expensive and used only in some labs
Gel Electrophoresis - Answer -Used to fractionate DNA, RNA, or protein molecules based on their size.
Molecules migrate depending on their size and electric voltage. Negative charges on DNA and RNA make
them migrate towards the anode (+). Large molecules move slow while small move faster.
Understand the logical sequence of events in a cell fractionation and analysis experiment - Answer Cell
fractionation provides information about the composition of an organelle.
1. Harvest tissues that are fresh
2. Grind cells with liquid N2 or in a suitable buffer
3. Homogenize the cells in a suitable buffer
4. Centrifuge at various speeds for various durations to isolate the components
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