quiz 5 chapter 19, 22, 23 Flashcards
components of viruses
contain either DNA or RNA and are enclosed in a capsid
why are they obligatory parasites
they can’t reproduce or carry out a metabolism and relay directing on the host and their membranes and viral organs.
host range and virus recognition of host cells
host range- the limited types of cell the virus can affect which is determined by the specific host cell proteins and receptors.
reproductive cycle
attachment, entry replication of viral genome, assembly of new virus, exit
lytic cycle
virus replicates rapidly breaking the host cell.
lysogenic cycle
viral DNA integrates into host genome and replicates with host and poetically enters the lytic cycle later
what is retrovirus
a virus that uses reverse transcriptase to convert RNA genome into DNA, which integrates the host genome.
role of vaccines and antiviral drugs
they stimulate the immune system to recognize fight and infections. antiviral drugs inhibit viral replication by targeting viral enzymes.
define evolution
change in genetic composition of a population over generations
adaptation
traits that enhance survival and reproduction in the given environment
natural selection
processes where individuals with favourable traits survive and reproduce more successfully.
what is lamarcks model
it proposed that inheritance of acquired characteristics meaning traits that were developed during an organisms life time could be passed on. this was rejected.
principle of common descent
all species share a common ancestor and have diverged over time through gradual changes.
key concepts of the evolutionary theory
individual fitness- ability to survive and reproduce.
variation- differences in traits among individuals.
heritability- traits must be passed on to offspring.
natural selection- some traits increase survival and reproduction.
no-goal oriented- evolution is not working towards a specific outcome.
evidence for evolution
biogeography- Species distribution shows common ancestry
fossil record- shows change over time
comparative anatomy- homologous structures indicate common ancestry.
comparative embryology- simaliar embryo development across species.
molecular biology- DNA/protein simarites across species.
smallest unit that can evolve
populations evolve because evolution involves changes in allele frequencies over generations.
source of genetic variation
mutations- random changes in DNA that creates new alleles.
sexual reproduction- shuffling of alleles in meiosis. independent assortment and crossing over.
reproductive rate- fast reproduction increases genetic variation.
define population, species, and gene pool
population- a group of interbreeding individuals in the same area
species- a group that can interbreed and produce fertile offspring.
gene pool- all alleles present in the population.
hardy-weinberg theorem
if the popluation isn’t evolving, allele frequencies remain constant from gen to gen provided not evolutionary forces act on it.
consequences and conditions of hardy theorem
if the population meets these expectations the population isn’t evolving. no mutations, random mating, no natural selection, no gene flow. if these conditions are violated then evolution happens.
