Cycle 1 Flashcards
Why are viruses not considered to be “dead” or “alive”
Viruses are not made out of cells, they can’t control their internal state, they don’t grow, and they can’t make their own energy, however, they replicate and adapt to their environment.
Which of the following is the hardest to design and has more side effects? (antivirals/antibiotics/antifungals)
Antivirals because to kill the virus the host cell dies
What happens when a virion fuses with its host
Viral reverse transcriptase reverse transcribes viral RNA to DNA, with a high mutation rate
What enzyme splices viral DNA into the host
integrase
What happens after viral DNA is spliced into the host?
Viral DNA gets transcribed, translated and forms new virions
Why did AZT become ineffective after months in HIV trials
HIV’s genetic variation and high mutation rate develops a mutation that is AZT resistant, which then gets passed from parent to offspring
Is there proof that non-living things can evolve
Yes, AZT-resistance within HIV virions is proof
examples of “scala natura” thinking, and why this type of classification is not compatible with modern evolutionary theory
one example is angels being better then humans, humans being better then monkeys. not compatible because we all evolve from the same common ancestor, thus we have all been evolving for the same amount of time, there is no hierarchy
evidence from geology and the fossil record and comparative morphology, that supports the idea of evolution from darwin
Fossil findings convinced Darwin that the geology of the Earth changes over time.
scientists had uncovered fossil animals and plants that were unlike the living species of the time.
the earths surface was constantly changing by natural events such as earthquakes, volcanoes over a long period of time.
Ex: Fossils indicated that some species had become extinct
What is and provide an example of comparative morphology
Comparative morphology: Animals have homologous traits characteristics that are similar bc they are inherited from an ancestor. Example pigs, dolphins, and bats who have similar leg/fin/wing bone structure
The geographic distribution of species that supports the idea of evolution
species that were on oceanic islands were most similar to species inhabiting the nearest continent; animals and plants on different islands varied slightly (believed they were related but had changed over time);
homologous traits
Similar in structure, but does not have same function; they are inherited from a common ancestor; eg. arm of a human, wing of a bat/bird, flipper of a dolphin are homologous structures;
Importance of mutation in evolution
Mutation creates a new DNA sequence for a particular gene, creating a new allele. Recombination also can create a a new allele for a specific gene. Mutation acting as an evolutionary force by itself has the potential to cause significant changes in allele frequencies over gradual periods of time.
Misconception: Evolutionary theory implies that life evolved (and continues to evolve) randomly, or by chance.
important mechanisms of evolution are non-random and these make the overall process non-random. Consider the process of natural selection
Misconception: Evolution results in progress; organisms are always getting better through evolution.
Natural selection does not produce organisms perfectly suited to their environments. It allows the survival of individuals with a range of traits — individuals that are “good enough” to survive. Hence, evolutionary change is not always necessary for species to persist.
Where did HIV originate?
Africa
Heritable variation
genetic differences between organisms that allow for genetic variation (different allele frequencies)
Non-random reproduction/survival
A population of organisms undergoes random mutation and NON-random selection. The result is non-random evolutionary change.
Change of genotype in population
evolution is a change in the gene pool in a population of organisms. This occurs when the frequencies of genotypes change. factors: natural selection, mutation, random genetic drift, and migration into or out of the population.
basic features of animal viruses
-tiny packages of protein and nucleic acid
-protein shell, or capsid, and genetic material made of DNA or RNA that’s tucked inside the caspid
-They may also feature an envelope, a sphere of membrane made of lipid.
What structure or process found in cells is NOT also a characteristic of viruses?
lipid surrounding cytoplasm
Similarities between cell life and viruses
Both have nucleic acid genomes, genes that encode proteins and can reproduce
Differences between cell life and viruses
Only cells have lipid membranes that surround cytoplasm, while virus lipids surround protein shells, not cytoplasm
Why is HIV hard to eradicate
high RT rate allows for genetic variation against vaccinations, viruses in general are hard to eradicate because they cannot be taken away from the host cell
