Mallery BIL150 exam 1- ANSWERS 100% VERIFIED.
Lecture presented possible scenarios for the origin of the chemicals necessary for the
evolution of early life on Earth. The 3 major hypotheses of the origins of life and cells are?
correct answers 1 .Chemical Evolution
2. Astrobiological 3.Supreme Being (non-testable)
Radioisotope dating using 235U decay indicates that the Earth is
around______________________________old and that life originated between correct
answers 4.0 and 4.5 billion years old
life originated about 3.5 billion years ago
Conditions on the primitive Earth are thought to have favored the spontaneous formation of
organic monomers, the linking of these monomers into polymers, the development of self-
replicating molecules, and the grouping of aggregates of organic molecules into droplets
called correct answers protobionts
Consider the Stanley Miller apparatus. What was it meant to simulate correct answers early
earth-like conditions
What molecules are found in the reaction vesicle labeled A (top) correct answers methane,
ammonia, hydrogen, and water
the atmosphere inside the vessel "A." (top) is described as a chemically correct answers
reducing
Miller & Urey's atmosphere was probably more strongly reducing than the actual atmosphere
of early Earth. Volcanoes today emit CO, CO2, and N2 and it is likely they were also
abundant.
in the sample vesicle which they tested for various types of chemical made...what molecules
did they find in "B (flask on bottom) correct answers Hydrogen cyanide,f ormaldehyde, and
many organic molecules, including amino acids, nucleotides, and sugars.
At the end of one week, Miller observed that as much as 10-15% of the carbon was now in
the form of organic compounds. Two percent of the carbon had formed some of the amino
acids. Perhaps most importantly, Miller's experiment showed that organic compounds such as
amino acids, which are essential to cellular life, could be made easily under the conditions
that scientists believed to be present on the early earth. The formaldehyde can spontaneously
react to form a variety of sugars, including the five-carbon sugars fundamental to the
formation of nucleic acids and such six-carbon sugars as glucose and fructose
in 1961, Juan Oro found that correct answers Juan Oro found that amino acids could be made
from hydrogen cyanide (HCN) and ammonia in an aqueous solution. He also found that his
experiment produced an amazing amount of the nucleotide base, adenine. Adenine is of
tremendous biological significance as an organic compound because it is one of the four
bases in RNA and DNA. It is also a component of adenosine triphosphate, or ATP, which is a
major energy releasing molecule in cells. Experiments conducted later showed that the other
,RNA and DNA bases could be obtained through simulated prebiotic chemistry with a
reducing atmosphere
in miller experiment, what energy source(s) were provided, and what was it likely meant to
simulate? correct answers An electrode.
energy Sources on primitive Earth, especially electricity in the form of lightning. While it is
believed lightning storms were extremely common on the primitive Earth, they were not
continuous as the Miller/Urey experiment portrayed.Subsequent experiments have substituted
ultraviolet light or heat as the energy source On the early Earth there was much more energy
available in ultraviolet light than in lightning discharges
How might each of the molecules made in the Miller/Urey apparatus have contributed to the
formation of early cells? correct answers All of these organics are extremely common
metabolites and structural building blocks in contemporary organisms. Furthermore, the
nucleotide bases as well as porphyrins have been produced in the laboratory under simulated
primitive Earth conditions by several investigators. While there is still debate on the
generality of the experimental synthetic pathways and on the stability of the molecules
produced, most if not all of the essential building blocks of proteins, carbohydrates, and
nucleic acids can be readily produced under quite general primitive reducing conditions
What is an abiotic molecule? correct answers abiotic components Nonliving chemical and
physical factors in the environment
What is the definition of a biological macromolecule? correct answers biotic -a giant
molecule formed by the joining of smaller molecules, usually by a condensation reaction.
Polysaccharides, proteins, and nucleic acids are macromolecules that makeup living
organisms
examples of
1. nucleic acid
2. protein
3. carbohydrate
4. lipid correct answers 1. nucleic acid
a. deoxyribonucleic acid
b. ribonucleic acid
2. protein
a. albumin
b. petidase
3. carbohydrate
a. glucose, etc
b. sucrose
4. lipid
a. triglyceride
b. phospholipids
Where did the Chemicals of Life come from?
, This idea is often known as correct answers Panspermia
Pose an experimentally testable research question that might help to determine whether this
idea might be correct. Have your Learning Community critique the experiment. Is the
experiment really testable? correct answers Determine if the precursor chemicals of life on
Earth (amino acids, sugars, and nucleotides) exist on other planetary bodies in the Universe,
such as planets like Mars
Possible extraterrestrial sources of early organic molecules that may have lead to life include:
correct answers comets
meteorites
asteroids
science vs religious belief correct answers The difference between science and religious
belief is that science is experimentally testable. At present, the existence of a divine creation
is not experimentally testable and therefore is in the realm of faith.
What are the differences between a hypothesis that is scientifically verifiable and one that is
not? correct answers A hypothesis in science is a supposition, conjecture, guess, postulate,
premise, proposition, speculation, supposition, thesis, or theory made as basis for reasoning
that is testable by experiment.It is a tentative theory about the natural world; a concept that is
not yet verified but that if true would explain certain facts or phenomena.A hypothesis is an
idea or explanation for something that is based on known facts, has not yet been proved, but
is subject to experimental testing.A hypothesisis a proposed explanation for a phenomenon.
In the scientific method, a hypothesis should be falsifiable, meaning that it can be disproved
by further observation
besides an extraterrestrial possible source for early cells and life, or its molecules, there is
another terrestrial (Earth origin) source of primitive organic molecules for the chemical
evolution of life. These sources are found in the deep sea in areas referred to as _ correct
answers hydrothermal vents
The currently accepted paradigm suggests that there were at least 4-steps or stages that
contributed to the chemical evolution of life: correct answers 1. the abiotic synthesis of small
organicmonomer precursors of today's macromolecules
2. the joining of small organic monomers into polymers
3. the origin of heredity via complementary templating molecules
4. and the packaging of these molecules into membrane-like enclosed bodies called
protobionts
In 1998 Robert Hazen's lab showed that minerals such as feldspar, magnetite, clay, and
calcite may be able to play roles in allowing primitive organic molecules to react with each
other,chemically forming morecomplexmolecules. This is primarily because these minerals
provide correct answers 1. scaffolding support... minerals provides surfaces as an easy way to
assemble molecules in dilute solution by concentrating the molecules on a flat surface
