VÍRUS - LIVE +30MIN DE BIO - QUESTÕES ENEM

Live broadcast held on April 24, 2023. ENEM QUESTIONS SOLVED IN THE LIVE STREAM: 1. (Enem 2022) Among the various techniques for diagnosing COVID-19, genetic testing stands out. Considering the different variants and viral loads, one example is PCR, a reaction performed by a polymerase-type enzyme. This technique allows for the reliable identification of the genetic material of SARS-CoV-2, an RNA virus. To confirm infection by this coronavirus, samples of secretions from the individual are collected. A step preceding the PCR reaction needs to be performed to allow the amplification of the virus's genetic material. This step should be performed to: a) concentrate the viral RNA to optimize the technique. b) identify anti-SARS-CoV-2 antibodies in the samples. c) proliferate the virus in cultures, increasing the viral load. d) purify viral nucleic acids, facilitating the action of the enzyme. e) Obtain viral cDNA molecules through reverse transcription. 2. (Enem 2021) Between 2014 and 2016, the central and western regions of Africa suffered a severe epidemic of hemorrhagic fever caused by the Ebola virus, which manifests itself up to 21 days after infection and whose case fatality rate (patients who die) can reach 90%. In tropical and subtropical climate regions, another virus can also cause hemorrhagic fever: the dengue virus, which, although it has a shorter incubation period (up to 10 days), has a case fatality rate below 1%. According to the information in the text and applying principles of biological evolution to pathogen-host relationships, which of the two viruses has been infecting humans for longer? a) Ebola, because the longer incubation period reflects a longer duration of the pathogen-host coevolution process. b) Dengue, because the shorter incubation period reflects a longer duration of the pathogen-host coevolution process. c) Ebola, whose high lethality indicates greater efficiency of the virus in parasitizing its hosts, established throughout its evolution. d) Ebola, whose epidemic outbreaks are concentrated on the African continent, recognized as the cradle of the evolutionary origin of human beings. e) Dengue, whose low lethality indicates greater efficiency of the virus in parasitizing its hosts, established throughout the pathogen-host coevolution. 3. (Enem PPL 2019) Female dengue mosquitoes, Aedes aegypti, have an extremely refined sense of smell. In addition to identifying water bodies for oviposition, they are able to accurately and effectively detect human presence by interpreting odor molecules released during sweating. After spotting the individual, they fly quickly towards the food source, beginning the blood meal during which they can transmit the dengue virus. Therefore, the sense of smell plays an important role in the survival of this species. Measures that interfere with the vector's location of the host through this sensory modality include: a) placing screens on windows. b) eliminating oviposition sites. c) installing water sprayers in open areas. d) raising awareness of the need for daily baths. e) using creams or ointments with active ingredients. 4. (Enem 2011) During the rainy seasons, dengue prevention campaigns increase in Brazil, aiming to reduce the proliferation of the Aedes aegypti mosquito, which transmits the dengue virus. What preventive measure could be implemented to reduce the reproduction of this mosquito? a) Placing screens on doors and windows, as the mosquito needs covered and closed environments for its reproduction. b) Replacing mud houses with brick houses, since mosquitoes reproduce in the walls of mud houses. c) Removing containers that can accumulate water, because mosquito larvae develop in this medium. d) Proper food hygiene, since mosquito larvae develop in this type of substrate. e) Installing water filters in houses, since mosquito reproduction occurs in contaminated water. 5. (Enem PPL 2009) Instead of worrying about whether viruses are living beings or not, molecular biologists are interested in observing how they distort, for their own benefit, the functioning of a cell, triggering diseases. When infecting a cell, the virus loses its envelope and leads the cell's genetic material duplication system to reproduce its own nucleic acid and produce viral proteins. Considering the physiological characteristics of the virus, it can be inferred that: a) the organism infected by it is an animal. b) the genetic material of the virus is DNA. c) the host will die soon after infection. d) the virus can also exist in a free-living form. e) its genetic material alters the metabolism of the host cell.