BIO 311C QUESTIONS AND ANSWERS A+ GRADED
Reconstruct the major timelines in the origin and evolution of life on earth in a logical sequence but no need to memorize the specific times.
earth formation (4.5 bya) - bacterial fossils (4.0 - 3.5 bya) - cyanobacteria (2.5 bya) - unicellular eukaryot...
BIO 311C QUESTIONS AND ANSWERS A+ GRADED
Reconstruct the major timelines in the origin and evolution of life on earth in a
logical sequence but no need to memorize the specific times.
earth formation (4.5 bya) - bacterial fossils (4.0 - 3.5 bya) - cyanobacteria (2.5 bya) -
unicellular eukaryotes (1.5 bya) - multicellular eukaryotes (1.0 bya) - humans
Interpret Miller and Urey's experimental setup
They used H. H20, methane, and NH4+ in a setup with high power electrodes to
simulate lightning conditions to provide energy for further reactions. After cooling the
reaction products, they noticed that simple organic molecules including urea, organic
acids, simple sugars and amino acids were formed from this set up.
Basic results of Miller and Urey's experiment to make logical connections to the
possible origin of life on earth.
This proved the point that monomers of complex molecules can be formed under the
reducing atmosphere present in the early periods of the earth.
Predict the logical process by which simple monomers were formed and led to
polymers and the early forms of cells.
atoms - molecules - monomers - macromolecules - protobionists
Explain why the first possible macromolecule could be RNA to store genetic
information and be able to catalyze reactions
It is proposed that DNA evolved later to be a more stable molecule than RNA and
proteins evolved to be more efficient enzymes, RNA with catalytic activity is referred to
as ribozyme. The concept of catalytic RNA provides the possibility of abiotic synthesis
of short strands of RNA molecules and their replication. This idea paved the way that all
other molecules could have originated along with or after RNA
What is the sequence of various biological processes evolved based on the
organisms that performs such processes?
RNA replication - DNA replication - mitosis - photosynthesis - meiosis - cellular
respiration
Light Microscope
- Light is focused on the specimen through condenser lens.
- Light passing through the specimen is refracted through the objective lens and ocular
lens to magnify the subject.
- um resolution
- paramecium, human egg, human red blood cell, bacterium
Transmission Electron Microscope (TEM)
- Electron beams are aimed at a thin section of a specimen stained with metal to absorb
electrons and enhance the contrast.
- Electrons transmitted through the specimen are focused and the image is magnified by
electromagnetic lenses.
- Used to study internal ultrastructure and cross-sections of cells or structures.
- paramecium, human egg, human red blood cell, bacterium, large virus, ribosome,
protein, amino acid, hydrogen atom
- The magnified image in both TEM and SEM is viewed on a screen and can be
recorded on a photogenic film.
Scanning Electron Microscope (SEM)
, - Electron beams scan the surface of a specimen coated with gold.
- Scanning beams excite the secondary electrons on the sample surface.
- The secondary electrons are collected and focused by the electromagnetic lens.
- Used to view the surface features and the 3-D shape of ultrastructure
- The magnified image in both TEM and SEM is viewed on a screen and can be
recorded on a photogenic film.
- paramecium, human egg, human red blood cell, bacterium, large virus, ribosome,
protein, amino acid, hydrogen atom
Microfuge
Small centrifuge that can spin up to 114 k rpm and hold small tubes (0.1 - 2 ml). It is
commonly used for molecular biology experiments
Clinical Centrifuge
Can hold 5 to 15 ml tubes and centrifuge the, at 1-5 K rpm. This is used mostly in
clinical labs
Floor model or tabletop centrifuge
Up to 20 - 30 K rpm, large tubes (1-50 ml). Present in most cell and molecular biology
labs.
Ultracentrifuge
Up to 80 K rpm, large tubes (1-50 ml). Most of them are refrigerated and some are
equipped with a vacuum pump. This is the most expensive one and it is used in some
labs.
Gel electrophoresis
Used to fractionate DNA, RNA, or protein molecules based on their size. The negative
charges on the DNA or RNA (phosphate groups) make them migrate toward the anode
(+) through tiny pores in the gel, made of agarose or polyacrylamide. Large molecules =
slow. Small molecules = fast. If voltage is increased, the molecules move faster.
Agarose gels are used to fractionate DNA or RNA.
Chromotography
The separation of a mixture by passing it in solution or suspension or as a vapor
through a medium in which the components move at different rates.
Separation of Carbohydrates
Since carbs do not have any charges they cannot be separated by gel electrophoresis.
Carbs can be initially purified by centrifugation and then various techniques such as
calorimetric identification of simple vs complex carbohydrates and spectroscopic
analysis will give approx. results. For further identification, mass spectrometry (MS) and
gas chromatography (GC) are used.
Separation of Lipids
Lipids include both polar (phospholipids) and mostly neutral lipids (fats, steroids, and
carotenoids). Initial separation can be done with Thin Layer Chromatography (TLC) and
the detailed analysis is done by High Performance Liquid Chromatography (HPLC),
mass spectrometry (MS) and gas chromatography (GC).
Prokaryotic cells
- NO nucleus
- DNA in the nucleoid region
- No proteins attached to DNA
- NO endomembrane system
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