Biological Classification Test 5

Viroids are considered as the smallest infectious disease causing pathogens. The body of the viroid is composed of circular and single-stranded RNA which is the genetic material. The body is without any protein coat. The viroids are agents which cause infections commonly in the plants. 

Thus, the correct answer is option c

Scrapie disease caused by prion that affects the central nervous system of sheep and goat.

Stages of Virus Replicaton

A virus will replicate many times when it invades a host cell. There are 4 stages involved in this process:

1. Attachment: The virus attaches to a host cell. In the case of the bacteriophage it will attach to a bacterium.
2. Entry: The virus forms a hole in the membrane or cell wall of the host. The nucleic acid of the virus enters the host cell.
3. Synthesis: The virus’ nucleic acid is used to make new viral nucleic acid and proteins for the new viruses being produced. (The host cells’ DNA becomes deactivated.
4. Assembly: New viruses are made inside the host cell.
5. Release: The host cell bursts to release the new viruses. The bursting is called lysis.

Prions are the infectious proteinaceous particles. Prion proteins are designated as PrP. Prions are very stable to thermal degradations and thus, they don't get denatured easily.

At 100°C, both bacteria and Mycoplasma can't survive. Mycoplasma lacks cell wall so it can't resist such a high temperature. A normal bacteria also can't resist such high temperature unless and until it is a thermophilic bacteria that can thrive in extremely hot conditions. At high temperature, enzymes get denatured which results in the death of the organism.

But prions are extremely resistant to the high temperature so even after boiling at 100°C they can be found as such.

So the correct answer is A.

The citrus tristeza virus (Citrus Tristeza virus -CTV-) is a species of the genus Closterovirus (family Closteroviridae), causing an economically important disease that affects such trees (citrus) worldwide virus where there are citrus crops. The name of the virus was given in several countries in South America for the demonstrations presented by the affected tree.

Satellite tobacco necrosis virus (STNV), the first plant satellite virus, was discovered as a virus-like particle abundantly present in cultured medium of tobacco necrosis virus (TNV), a host virus. Its identity as a satellite virus was revealed by its dependence on TNV for propagation.

Virus is protein synthesis, in order of translation take place, it is a transcript to get information from the chromosome, then it will create more virus.

In 1935 Wendell Stanley crystallized tobacco mosaic virus (TMV); an accomplishment for which he was awarded a share of the 1946 Nobel Prize in Chemistry. As a matter of history, Stanley’s Nobel award was the first ever bestowed on a virologist.

Cryptogram of virus is the descriptive code summarising the main properties of a virus. The viruses have been named by a system of nomenclature as designated by International Committee of Virus Nomenclature. It consists of two parts. The first part is the common name of the virus and the second part consists of a coded information of it. 
Cryptogram of TMV : R/1 : 2/5 : E/E : S/X. Thus, option B is correct.

Phase particles in copper-based alloys could potentially initiate stress corrosion cracking when the particles undergo selective dissolution or induce galvanic corrosion. 
Phase particles in radiation detector employ a variety of physical effects to convert radiation into a readable output Scavenging of particles or gases may take place in clouds by cloud droplets or below clouds by precipitation. In genetic research, genotype-phenotype relations are usually inferred from a deterministic point of view.

Tobacco mosaic virus is a positive-sense single stranded RNA virus in genus Tobamovirus that infects a wide range of plants, especially tobacco and other members of the family Solanaceae. The infection causes characteristic patterns, such as "mosaic"-like mottling and discoloration on the leaves.

Virus has only one type of nucleic acid either DNA or RNA with protein coat . these are smaller than bacteria.viruses are connecting link between living and non-living.virus can replicate inside bacteria (Bacteriophage virus), plant, animal.

Red Rot of Sugarcane:
The first external evidences of disease are the drooping, withering, and finally yellowing of the upper leaves. This is followed by a similar wilting of the entire crown, and finally the entire plant shows indications of disease and dies. When not severe, the eyes frequently die and blacken and the dead areas extend out from the nodes.

Citrus canker it is a disease affecting Citrus species caused by the bacterium Xanthomonas axonopodis. Infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit.

Common animal viral diseases include African horse sickness, Foot and mouth disease of cattle, Virus pneumonia of pigs, Rabies etc. Common human viral diseases include Influenza, Measles, Herpes, Dengue, Smallpox, Mumps, Common cold, Hepatitis, AIDS. The recent viral pandemics / epidemics include Ebola Virus Disease, Rift Valley fever, Bolivian hemorrhagic fever, Crimean Congo Hemorrhagic Fever, SARS, and MERS etc.

Chickenpox is an infection caused by the varicella-zoster virus. It causes an itchy rash with small, fluid-filled blisters. Chickenpox is highly contagious to people who haven't had the disease or been vaccinated against it. Today, a vaccine is available that protects children against chickenpox. Routine vaccination is recommended by the Centers for Disease Control and Prevention (CDC).

Virus particles contain the viral genome packaged in a protein coat called the capsid. For some viruses, the capsid is surrounded by lipid bilayer that contains viral proteins, usually including the proteins that enable the virus to bind to the host cells.

Ganga water is known to possess antibacterial properties. This is due to the presence of bacteriophages in it. These phages help bacteria in genetic recombination via transduction. Bacteriophages(viruses attacking bacteria) capture the machinery of the cell and use it for their multiplication and ultimately kill host cell.

Like all viruses, phages are simple organisms that consist of a core of genetic material (nucleic acid) surrounded by a protein capsid. The nucleic acid may be either DNA or RNA and may be double-stranded or single-stranded.
Fungi are eukaryotes and have a complex cellular organization. As eukaryotes, fungal cells contain a membrane-bound nucleus where the DNA is wrapped around histone proteins. A few types of fungi have structures comparable to bacterial plasmids (loops of DNA).
The genetic material of bacteria is DNA. Bacterial viruses (bacteriophages or phages) have DNA or RNA as genetic material. The two essential functions of genetic material are replication and expression.

HIV is a spherical, enveloped, single-stranded RNA virus containing two copies of its genome. The genome is encased in a core capsid protein.

Capsid is sythesized in ribosome of the host.

In general, the virus relies on the enzymes already present in the host cell or makes enzymes that it needs using its own genome inside the host cell.

HIV is virus in viruses genetic material is mostly ssRNA is found.

Transduction, a process of genetic recombination inbacteria in which genes from a host cell (abacterium) are incorporated into the genome of abacterial virus (bacteriophage) and then carried to another host cell when the bacteriophage initiates another cycle of infection.

Interferons inhibit protein synthesis and cell growth, only attach to cells infected by viruses, prevent modification of viruses inside cell. So, we can say that interferons active against viruses.

 Cells infected by virus produce interferons which is antiviral. It spreads to neighbouring cells and makes them resistant to virus infections by inhibiting viral growth.

Caulimovirus (Cauliflower mosaic virus) contains double stranded (ds) DNA. Influenza virus contains single stranded RNA (ss RNA). Parvovirus contains single stranded DNA (ss DNA).

Transduction involves the picking up of DNA by bacteriophage from one bacterial cell and carrying it to another where the DNA fragment may get incorporated into the bacterial host's genome.

TMV is Elongated rod-like, 3000 (300 nm) long and 180 (18 nm) in diameter.

Retroviruses are so named because they contain enzyme reverse transcriptase or UNA dependent DNA polymerase. The genetic material of these viruses is RNA. e.g., Rous Sarcoma virus.