Early Earth vs. Modern Earth
Origins of Life
Viruses (General)
Viruses (Specific Examples)
Misc. Topics (Relevant to Unit)
250
What gas found in today's atmosphere was NOT present in the atmosphere of early Earth?
Oxygen (O2)
250
What molecules were created during the initial run of the Miller-Urey experiment?
Amino acids
250
Name the two structural features shared by every type of virus.
Capsid (made of proteins) and genome (nucleic acid; type varies)
250
Name the specific virus which causes the disease we call COVID-19.
SARS-CoV-2
250
This is the hypothesis which explains how early biochemistry -- including genetic information storage and metabolism -- may have been possible even without DNA or proteins in the early history of life.
The RNA World Hypothesis
300
The trapping of reflected heat by certain gases in Earth's atmosphere can raise the Earth's surface temperature over time. This phenomenon is known as the:
Greenhouse Effect
300
Based on our most recent evidence, where do we think life first began on Earth?
Near deep-ocean hydrothermal vents
300
Name the four types of nucleic acids which viruses may utilize to encode their genetic information.
dsDNA, ssDNA, dsRNA, ssRNA
300
Name the specific type of virus which Hershey and Chase used to prove that DNA -- and not protein -- is the genetic material.
Bacteriophage Lambda (aka Lambda Phage)
300
This is the one virus humans have eradicated, via vaccination.
Smallpox
350
The sun emits a huge quantity of ultraviolet radiation which was deadly to life on early Earth. Why are the sun's UV rays much less of a threat to life today?
Presence of ozone gas (O3) in the atmosphere (created by interactions between UV light and oxygen (O2))
350
What is one piece of evidence which strongly supports the existence of LUCA?
Main 3 pieces of evidence: Shared ribosomes, shared genetic code, some shared genes (ex. RNA polymerase)
Other answers accepted if biologically / rationally valid
350
Name the cell transport process which allows certain viruses to acquire an envelope when leaving a host cell.
Exocytosis
350
In our notes, we learned about a bacteriophage which uses a double-stranded DNA genome. It can reproduce through two different processes. Name both of these processes.
Lytic cycle and lysogenic cycle
350
This is the evolutionary concept which describes how and why species are constantly evolving in response to one another; in our unit, we saw how it applies to viruses and human immune systems, in that they are always adapting to one another, never stopping
The Red Queen Hypothesis
400
Early earth's atmosphere and today's atmosphere, due to their gaseous composition, were extremely different in that they facilitated two opposite kinds of chemical reactions. Name the type of chemical reactions associated with each of these time's in Earth's history, and identify which type of reaction corresponds to which time period.
Early Earth = Reducing atmosphere, Modern Earth = Oxidizing atmosphere
400
Radiometric dating is used to estimate the ages of samples we collect from rock layers of the Earth. Name one radioactive isotope used in this process, and provide its general half life, in approximate years.
Possible answers vary: Main two discussed in the notes are C14 for recent samples (~6,000 year half life), and U238 for very very old samples (~4.5 billion year half life)
400
A virus inserts its DNA into a host cell, and this DNA incorporates itself into the host cell's DNA. While the virus is no longer a visibly distinct particle/virion, the virus persists solely as a series of genes inside the host cell for multiple generations, sitting inactive until certain environmental cues initiate its genes' transcription. What process is this virus currently engaging in?
The lysogenic cycle
400
Why is HIV classified as a retrovirus?
It has reverse transcriptase, and uses this to reverse transcribe RNA into DNA
400
This is a gradual geologic process which causes parts of Earth's crust to sink below other parts; as each of these sections sinks into the mantle, any fossilized material here is destroyed, and this is why extremely old fossils (more than 500 million years old) are insanely rare.
Subduction
450
Name at least 3 gases which were found in high amounts in early Earth's atmosphere and oceans, and which are found in much lower amounts today.
Ammonia (NH3), Carbon Monoxide (CO), Hydrogen (H2), Methane (CH4)
Also accepted: Carbon Dioxide (CO2); still a fair amount today, but long ago there was MUCH more
450
Name all four features that are required for life to be able to arise from complex organic molecules.
Self-assembly, compartmentalization, self-replication, catalysis
450
Name the three viral origin hypotheses, and identify which corresponds to each figure shown here.
Top = Virus-First, Middle = Reduction, Bottom = Escape
450
Name the specific type of human cell which acts as a host cell for HIV.
Helper T Cells aka CD4 T Cells
(Would accept just T cells since we haven't covered immune system yet)
450
These are the chemicals used in refrigerants and spray cans which dealt serious damage to the ozone layer for years. Their use is now banned in all countries, and the ozone layer is now steadily recovering.
CFCs (Chlorofluorocarbons)