Cover news reporter Zhang Zheng
Judging from the trend of college entrance examination propositions in recent years, the examination is not only an examination of the candidate's knowledge but also a test of ability. Social hotspots, discipline integration, problem-solving ability, etc. are all the focus of the propositioner's investigation. For this year's college entrance examinations, the new crown virus epidemic that the whole people are concerned about can be reviewed in combination with various disciplines. Combined with this hot spot, from the perspective of high school biology, what should students who are preparing for the college entrance examination know? The cover news reporter exclusively interviewed Wang Jianguo, head of the biology teaching and research team of the Chengdu Experimental Chinese School.
First, let's get to know the novel coronavirus. On January 12, 2020, it was named and abbreviated by the World Health Organization: 2019-nCoV, Chinese name: 2019 novel coronavirus, the pneumonia infected by the new coronavirus, tentatively named the new coronavirus pneumonia (COVID-19), referred to as new crown pneumonia, abbreviated as NCP.
Knowledge point 1: The structure of the new coronavirus
Novel coronavirus Wuhan strain 02
Structural pattern diagram
The new coronavirus is also a member of the biosphere, a non-cellular structure of the organism, there is no cell membrane, cytoplasm, nucleus and other structures (see the structure pattern diagram), its components are proteins and nucleic acids (only RNA, is genetic material), its nucleic acid is single-stranded + RNA, the structure is unstable, easy to produce genetic mutations, bringing difficulties to vaccine development.
Knock on the blackboard!!
Biological knowledge reserve of the new crown virus college entrance examination
1． What role does the virus play in the ecosystem? (Consumer)
2． Is it the structural hierarchy of living systems? (No, the most basic level is the cell)
3． Is it a prokaryote or a eukaryote? (Neither)
4． What are its constituent elements? （C、H、O、N、P）
5． Its composition is similar to the following complexes of structures or processes: (C, E, F)
A． Chromosome B. Centrosome C. Ribosome D. Transcription E. Reverse transcription F. Translation
6． What are the specific components of its genetic material compared to the genetic material of lung cells? (Ribose, uracil)
7． What are the types of complete hydrolysis products of their genetic material? (Phosphoric acid, ribose, 4 nitrogen-containing bases, 6 in total)
8． What are the heritable types of variation? (Genetic mutations, which are genetic recombination if recombinant RNA is formed)
Knowledge point 2: The reproduction of the new coronavirus
The life activity of the new coronavirus is inseparable from the cells, mainly parasitic in the lung cells (parasitic cells are called host cells), why is the virus more likely to infect the cells of the lungs? The reason is that the spike protein (S-protein, see figure above) in its constituent components infects human lung cells by binding to the ACE2 protein (angiotensin-converting enzyme 2) on the human cell membrane, and then using the raw materials in the host cell to multiply the progeny virus, the host cell lyses and dies to release the offspring virus, the infection attacks more normal cells, when the virus infects the lung cells, the body's immune system will also activate the defense function, resulting in an inflammatory response in the lung tissue.
The breeding process is:
College entrance examination knowledge reserve:
1． Does the example of the virus multiplying within host cells support the idea that life activity cannot be separated from the cell? (Support)
2． What is the function of the spike protein of the virus? (Specific Recognition)
3． The virus binds to ACE2 on the cell membrane to invade the cell, indicating what functions the cell membrane has? (Information exchange, control of the entry and exit of substances)
4． When the virus multiplies within host cells:
①． Please briefly describe the steps for the virus to multiply in the host cell and what conditions are required? （a． Synthetic RNA replication enzymes, Template: +RNA of viruses, raw materials: amino acids, energy (ATP), enzymes (components of ribosomes), site: ribosomes; Synthesis of +RNA of the progeny virus, Template: +RNA of the virus, Raw material: 4 ribonucleotides, energy (ATP), enzymes (RNA replication enzymes), obtained is -RNA, and then synthesized +RNA (genetic material of the offspring virus) in the -RNA template; Synthetic component proteins of progeny viruses;d. Assemble the offspring virus).
②． What structures are directly involved? (Ribosomes, endoplasmic reticulum, Golgi bodies, vesicles)
③． What are direct energy supply substances? (ATP), what are the places where the substance is synthesized? (cytoplasmic matrix, mitochondria)
④． What is the way in which the offspring virus excretes cells? (Cell spit), indicating what characteristics of biofilms have? (Certain liquidity)
⑤． Who provides the raw materials needed for the breeding process? (host cell)
⑥． What else is involved in the reproduction process? (rRNA and tRNA)
⑦． What are the ways in which bases complement each other in this process? （A-U、C-G）
⑨． How many free adenine ribonucleotides are needed for a +RNA containing m adenine and n uracils to obtain 100 strands of daughter strands + RNA? （100m+n）
5． How does the immune system of an infected person exert its defensive function? (The first and second lines of defense of the infected person are broken by the virus, and the third line of defense plays a role, that is, to activate specific immunity: humoral immunity and cellular immunity, produce effector cells, memory cells and antibodies, and fight together to destroy the virus.) ）
①． The virus mainly invades the human body through the respiratory tract, and the bactericidal substances in the respiratory mucus belong to the first line of defense? (First Line of Defense)
②． The virus invades lung cells, to completely eliminate it needs to go through cellular immunity and humoral immunity processes, and who are the immune cells involved in these two processes? (Phagocytes, T cells).
③． After the virus is infected, the immune system attacks the cells of the lungs and causes pneumonia, at this time, what can be used to treat the patient in moderation to avoid severe damage to the lungs? (Immunosuppressants)
④． Patients who have been cured are not easily infected by the virus again in the short term, please explain the reason (this is due to the production of antibodies and memory cells in their bodies, when exposed to the coronavirus antigen again, the existing antibodies can play a role, while memory cells rapidly proliferate and differentiate into plasma cells and effector T cells. ）
⑤． After the virus invades the human body, lymphocytes and phagocytes need to be destroyed, and what is the main internal environment in which lymphocytes and phagocytes live directly? (plasma and lymph).
⑥． What is the significance of the human body by promoting the apoptosis of infected cells to understand the virus? (Maintain the stability of the internal environment of the organism and resist the interference of various external factors)
⑦． Is cell lysis and death due to the proliferation of the virus apoptosis? (Does not belong, belongs to necrosis)
⑧． What is the principle of doctors advocating that people who have recovered from COVID-19 donate plasma to treat patients with critical covid-19? (Specific antibodies are contained in the plasma of people who have recovered from COVID-19)
6． Researchers are working hard to develop a vaccine to prevent COVID-19, from an immunological point of view, what is the vaccine equivalent to? (Antigen)
Knowledge point 3: The source of the new coronavirus
Through gene sequencing comparison, the gene sequence of the new coronavirus is very similar to SARS, MERS, etc., they belong to the same large family, SARS, MERS, etc. have been found in bats, so it is speculated that the original host of the new coronavirus may be bats. Bats are the natural host of a variety of zoonotic viruses, because it has a special immune system "ready to guard" and "properly regulated", which effectively curbs the virus flooding in the body, and successfully avoids harm in the process of fighting the virus. Over the course of their evolution, bats have become natural hosts for hundreds of viruses, how did these viruses infect humans? Are bats and pangolins the back of the pot? This is exactly what many workers are studying, and at the same time, China will more strictly implement the Wildlife Protection Law and prohibit the consumption of wild animals.
Since bats carry so many viruses, it is dangerous, should bats be exterminated in large quantities to ensure the safety of humans? The answer is: No!
First of all, it has its ecological value. In the primary forests of tropical and subtropical regions, bats (fruit bats) of the suborder Macroceller are propagators of pollen and seeds of specific plant groups; the vast majority of suborder bats are the most important controllers of large numbers of nocturnal insects (including mosquitoes, moths and many Coleoptera pests), without their help, the United States alone spends an additional $22 billion a year on insecticides; bats are predators of other predators, of which birds and snakes are the main predators.
Secondly, its scientific value, humans invented radar by imitating the echo positioning system of bats, and stealth aircraft developed by some countries are also copies of bats to some extent.
There is also economic value, in medicine, anticoagulant proteins extracted from the saliva of vampire bats dissolve blood clots faster than some clinically used drugs. The feces of insectivorous bats are called "luminous sand" in traditional Chinese medicine, which has the function of clearing heat and bright purpose. The excreta accumulated in bat colonies is an economical, high-quality agricultural fertilizer.
1． What are the results of the special immune system function of bats? (Genetic variation)
2． Bats are "inviolable" and can coexist with many viruses, what is the result of this? (Natural Selection)
3． What methods are used to investigate the population density of bats in a certain place? (Mark Recapture Act)
4． If the novel coronavirus has an intermediate host, what is the lowest nutritional level in the food chain? (Third Nutrition Level)
5． What is the significance of bats playing the role of consumers in ecosystems? (Promote material circulation in ecosystems and help plants pollinate and spread seeds)
6． What is the source and destination of energy in bat feces? (is the amount of assimilation of the previous nutrient level, flowing to the decomposer)
7． Specific plant groups require bats to spread pollen and seeds, invent radar by mimicking bats' echo positioning systems, and what value of biodiversity is reflected? (Indirect value, direct value)
8． What information do bats use to prey on insects, and what is the significance? (Physical information, which is conducive to the progress of normal life activities, regulates the interspecific system, and maintains the stability of the ecosystem)
9． If bats go extinct, what impact will it have on ecosystem stability? (Species richness decreases, food chains and food webs are destroyed, ecosystem self-regulation ability is weakened, and resistance stability is reduced))
10． Pangolins are national second-level protected wild animals in China, and what is the main reason for the sharp decline in their numbers? (Heavy Capture)
Knowledge point 4: Novel coronavirus detection
How to quickly and accurately detect and isolate carriers of the new coronavirus from close contacts and suspected patients is extremely important for controlling the spread of new crown pneumonia, so scientific researchers have been working hard, and at present, 4 products such as the new coronavirus 2019-nCoV nucleic acid detection kit (fluorescent PCR method) and the 2019 new coronavirus nucleic acid sequencing system have been urgently approved.
1． If part of the base sequence of the novel coronavirus gene is: ┄CGGAUACGU┄, please say the detection principle and write out the base sequence of the nucleic acid detection kit. (Principle: HYBRIDIZATION OF DNA MOLECULES, ┄GCCTATGCA┄OR ┄GCCUAUGCA┄)
2． If the antibody is detected with an antigen-antibody hybridization experiment, please state the principle. (The organism produces a specific immune response to the antigen of the new coronavirus, producing a specific antibody that can specifically bind to the antigen of the new coronavirus)
3． How do I get a large number of nucleic acid detection kits quickly? (Amplification using PCR technology)
Knowledge point five: how to prevent
The CDC recommends strengthening personal protection, avoiding contact with wild livestock, and eliminating work and gatherings with illness. After returning from a trip to Wuhan and other places, if there is a symptom of respiratory infection such as fever and cough, you should choose the nearest hospital fever clinic for medical treatment according to the condition, and wear a mask for treatment, and inform the doctor of similar patients or animal contact history, travel history, etc.
1． Is COVID-19 a genetic disease? (No, it's an infectious disease)
2． Name measures to prevent infectious diseases (control of the source of infection, cutting off transmission routes, protection of susceptible populations)
3． Name the specific effects of the following measures:
①． Lockdown of Wuhan, traffic suspension (control of the source of infection) (2). Staying at home and enclosing communities (protecting susceptible people) (3). Wear a mask and wash your hands frequently (cut off the route of transmission)
bibliography:
1． "Novel Coronavirus Infection Protection", Edited by He Jianfeng and Song Tie, Guangdong Science and Technology Press, 2020.1
2． In Wuhan, 27 cases of viral pneumonia were found in December, most of which were operating households in Seafood City. CCTV . [2020-1-16]
3． WHO has named the Wuhan novel coronavirus virus with a doorway . NetEase . [2020-1-16]
4． Wuhan Municipal Health Commission: 27 cases of pneumonia have been found and preliminarily analyzed as viral pneumonia. CCTV . [2020-1-16]
5． Xi Jinping made important instructions on the pneumonia epidemic of the new coronavirus infection. China News Network . [2020-1-20]
6． Umar Abuliz, Anivar Tomir, Mahmuti Khalik. The role of bats in maintaining ecosystems[J]. Biol Chin 05: 16-18
7． The State Food and Drug Administration continues to do a good job in the emergency approval of nucleic acid detection reagents for the new coronavirus. State Food and Drug Administration[Cited 2020-01-29]
8． Standard experimental textbook for general high school curriculum, compulsory one, two, three, elective one. People's Education Press.
<b>[If you have a news thread, please report to us, once adopted, there is a fee reward.] WeChat attention: ihxdsb, QQ: 3386405712].</b>