Viruses
Chapter 15
Q.1. Rhabdo means rod-shaped
Q.2. Rhabdoviridae are bacilliform particle shaped or bullet-shaped with a length of 100-430 nm and diameter 45-100 nm. It has helical nucleocapsid and with a matrix layer surrounding it and envelope of lipid. Although some of the rhabdoviruses do not have to envelop filament virions.
Q.3. VSV is a widely studied prototype of negative-strand RNA viruses, which is nonsegmented. The replication habit in a wide range and combined relative safety of VSV have favoured its use in laboratory research.
Q.4. It is transmitted through direct contacts such as mucous membrane: mouth, nose, eyes, or broken skin. Most people get it through rabid animal bites. Rabies causes about 59,000 deaths annually. Rabies immune globulin is the treatment used to cure disease in humans. Raccoons are the main rabies reservoir species in Florida
Q.5. (i) Nucleoproteins contain deoxyribonucleoproteins, which involve in homologous recombination. The process helps repair DNA
(ii) Phosphoprotein; they record ongoing signal pathway events that their functional relevance is very high to the aim of therapeutic selection and toxicity prediction.
(iii) Matrix protein they are huge molecules that are tightly bonded into an extensive network of insoluble fibres. The fibres may eventually develop and exceed the size of the cells themselves. These types of proteins exist in two types that are structural and adhesive.
(iv) Glycoproteins are proteins that are attached to the sugar. They help in digestion, immune system, and reproductive system.
(v) Large protein L is L-P polymerase complex, and responsible are enzymatic components that add neosynthesized RNA chains and cap-structure synthesis of Viral mRNAs.
Q.6. The first step is the entry of the infectious virus life circle. The attachment of the cell surface is facilitated by phosphatidylserine lipids interaction.
Q.7.
Q.8.Transcription takes place in the genes. An enzyme that synthesizes long chains of polymers or nucleic acid is called polymerase. The five caps are formed through a 5-5 linkage between two substrates. The tails are acquired when transcription of genes terminate.
Q.9.
Q.11. They form part of the internal structural framework of a cell nucleus. The nonchromatin structure is responsible for keeping the shape of nuclear, Plans DNA activities, and plays an essential role in DNA replication.
Q.12. Capsid assembly, release and maturation
Q.13.
Q.14. The situation where both genome and its complement contains coding information.
Chapter 16.
Q.1. They are single-stranded, enclosed in helical nucleocapsid. They are enveloped on the outer part.
Q.2. It spread primarily through the transmission of the respiratory droplet.
Q.4. HA1 – It attaches to sialic acid that contains receptors on the surface of the cell.
HA2 – contains a fusion peptide, a receptor-binding site, and structural motif of metastable.
NA- reduces hemagglutination titer and the activity of human influenza.
M1- its function is to form a coat in the viral infection.
M2- it creates an ion channel that needed for the efficient release of the viral genome during the entry of the virus.
NS1- is a protein that multifunction to protect host cell pre mRNA in the processing and prevent host cells’ antiviral responses.
NEP- it contains a highly conserved NES motif in its amino-terminal region that is required for nuclear export.
Q.4. The virus enters the cells by letting its hemagglutinin attach to sialic acid that is found glycoproteins or glycolipids receptors of the host.
Q.5. in a cell nucleus. The polymerase is an enzyme that synthesizes long chains of nucleic acid or polymers.
Q.6. +RNA directly causes infection; however, it can be less infectious than the whole virus. -RNA by itself is not contagious; it should be transcript into positive-sense RNA.
Q.7. Host Plasma Membrane. M2 is essential because of its ability to highly selective, pH-regulated, proton-conducting channels.
Q.8. HA protein is a three identical protein combination that is confined together to make an elongated cylindrical shape. They are clearage by the cellular enzyme.
Q.9. RNP is ribonucleoprotein. RNP contains snRNA and various proteins. It exits the nuclear through the NPCs and dissociates by hydrolysis of the Ran-GTP.
Q.10. After being released, it enters the nucleus and vRNP appears to be exported out of the nucleus via CRM1 dependent through nuclear pores. They bud from the apical plasma membrane of the infected epithelial cells.
Q.11. The viruses are helped by enzymes to be released after budding from a host cell plasma membrane. Matrix protein is one potential target; the budding process is driven by critical viral protein by viral-host mediating interaction to the facilitated efficient release of virions from the infected cell.
Q.12. Antigenic drift is minor antigenic change, while the Antigenic shift is significant antigenic change.
Q.13. Hemagglutinin is 18, and neuraminidase is 11. And hemagglutinin affect humans
Q.14.they have not acquired the ability to sustain transmission among humans.
Chapter 17
Q.1. It is a type of virus that uses RNA as its genetic material.
Q.2. consist of a dimer of linear, positive sense. ssRNA
Q.3. NC are small essential proteins generated by cleavage of the structure polyprotein.
CA-they is a protein that is involved in the calcium cell signalling pathway.
MA- are fatty-acylated, allowing them to interact tightly with cellular membranes to form budding sites.
TM- is an integral membrane protein type that spans the entirety of the cell membrane.
SU- it initiates direct binding of virions to a cell surface receptors.
RT and IN play a central a role of replicating and integrating of retroviral and retrotransposon in the chromosomes host cells.
Q.4. Retroviral genomes consist of four genes, env, pro, pol, and gag. Gag encodes polyprotein structure. Env takes care of viral surface glycoprotein, and pol produces integrase, reverse transcriptase, and RNase H.
Q.5. Targeted cells are specifically binded by retroviral particles in a plasma membrane; they reverse-transcribe their RNA genome as they uncoat the core and get into the nuclear membrane. Most retroviruses use pH-independent.
Q.6. It is a transitory structure where reverse transcription takes place.
Q.7. Primer for (+)DNA is cellular tRNA, and for (-)DNA is Lysyl tRNA. The role of PBS it replicates by serving as a binding site for the human TrnaLysRNA.
Q.8. It reverses transcription; it acts like endonuclease that hydrolyzes the RNA strand in an RNA/DNA hybrid.
Q.9. are DNA identical sequences that repeat hundreds or even thousands of times. They are formed by reverse transcription of retroviral RNA.
Q.10. dsDNA is longer.
Q.11. PIC contains integrase, cDNA, viral protein, matrix antigen, and reverse transcription. PIC migrates to a nuclear where provirus integrase enzyme
Q.12. Integrase.
Q.13. Cytoplasm. The polymerase is an enzyme that is used to long synthesis chains of polymers or nucleic acids.
Q.14. (+)RNA is added to the first nucleotide in transcription. It protects the transcript from synthesis. Also, it helps the ribosome attach to the mRNA.
Q.15. in Viral protein U. Posttranslational modification.
Q.16. They work together in virion assembly involving binding the plasma membrane.
Q.17. They are used for packing. Lipids anchor them.
Q.18. Viral polyprotein processing of essential for retrovirus infectivity.
Q.19. Simple retroviruses do not encode the additional proteins that specifically and directly affect viral RNA processing or synthesis. Whereas, complex retrovirus have multiple splice donors in the genome that produces a complex pattern of mRNA. Rous sarcoma virus is a simple virus, and HIV is involved.
Q.20. PROS: the DNA integration into a new cell genome that replicates stably with genomic DNA and low immunogenicity. CONS: lower titers and replication efficiency in self-inactivity.
- ERVs are an endogenous viral element in the genome that closely resembles and can be derived from retroviruses.
Chapter 18.
Q.1 Human immunodeficiency Virus type 1 (HIV-1)
Q.4. there are also nef, vif, vpr, and vpu
- 5. White blood cells, specifically CD4 cells. CD4 is the primary receptor while co-receptor is CCR5 or CXCR4
Q.6. CCR5 and CXCR4 are protein on the surface of the immune system cells. R5 strains are frequently transmitted.
Q.7. Deletion causes an alteration in T-cell response to inflammation.
Q.8. HIV enters cells by fusing the viral membrane with the cellular plasma membrane. Gp41 attaches to the host cell. Fusion proteins are ALK, ROS1 gene, NTRK fusion protein, and gastric adenocarcinoma.
Q.9. VPR is a multifunctional accessory protein that is critical for efficient viral infection of target CD4+ T cells and macrophages.
Q.11. When the DNA is inside the cell’s nucleus, it instructs the cell to create new HIV. Enzymes will be produced to create new genetic materials known as mRNA.
Q13. Nef-localizes basically on the cytoplasm and partially on the plasma membrane.
Tat- is a protein that regulates drastically to enhance the efficiency of viral transcription.
Rev- is a protein that is essential to the regulation of HIV-1 protein expression.
Q.14. TAR is a DNA binding protein. It resides in the nucleus and binds the splicing of DNA and RNA.
Q.15. RRE is a highly structured protein that helps in viral replication. It is located in the ENV coding region of the viral genome.
Q.16. Frameshifting mechanism