What Is A Viroid Disease?

What is a viroid give some examples?

Potato spindle tuber viroidAvsunviroidaeViroid/Representative species.

What is viroid in biology?

Viroids are single-stranded, circular, and noncoding RNAs that infect plants. They replicate in the nucleus or chloroplast and then traffic cell-to-cell through plasmodesmata and long distance through the phloem to establish systemic infection. They also cause diseases in certain hosts.

Do Viroids only infect plants?

Viroids, the smallest known pathogens, are naked, circular, single-stranded RNA molecules that do not encode protein yet replicate autonomously when introduced into host plants. … Viroids only infect plants; some cause economically important diseases of crop plants, while others appear to be benign.

What are bacteriophages 11?

A bacteriophage is a virus that infects a bacterial cell and reproduces inside it. They vary a lot in their shape and genetic material. A bacteriophage may contain DNA or RNA. The genes range from four to several thousand. Their capsid can be isohedral, filamentous, or head-tail in shape.

Which of the following is a human disease caused by prions?

In humans, prions are believed to be the cause of Creutzfeldt–Jakob disease (CJD), its variant (vCJD), Gerstmann–Sträussler–Scheinker syndrome (GSS), fatal familial insomnia (FFI) and kuru.

What disease causes Viroids?

The only human disease known to be caused by a viroid is hepatitis D. This disease was previously ascribed to a defective virus called the delta agent.

What do you mean by bacteriophages?

A bacteriophage is a type of virus that infects bacteria. In fact, the word “bacteriophage” literally means “bacteria eater,” because bacteriophages destroy their host cells. … Eventually, new bacteriophages assemble and burst out of the bacterium in a process called lysis.

Who discovered viroid?

Theodor 0. DienerThe pathogen is called a viroid by its discoverer, Dr. Theodor 0. Diener, to distinguish it from a virus.

What are prions made of?

This protein consists of about 250 amino acids. “Some researchers believe that the prions are formed when PrP associates with a foreign pathogenic nucleic acid. This is called the virino hypothesis. (Viruses consist of proteins and nucleic acids that are specified by the virus genome.

How do all Viruses differ from bacteria?

All viruses have is a protein coat and a core of genetic material, either RNA or DNA. Unlike bacteria, viruses can’t survive without a host. They can only reproduce by attaching themselves to cells. In most cases, they reprogram the cells to make new viruses until the cells burst and die.

Is a viroid a virus?

Viroids are plant pathogens: small, single-stranded, circular RNA particles that are much simpler than a virus. They do not have a capsid or outer envelope, but, as with viruses, can reproduce only within a host cell. Viroids do not, however, manufacture any proteins. They produce only a single, specific RNA molecule.

Do Viroids contain DNA?

Although viroids are composed of nucleic acid, they do not code for any protein. The viroid’s replication mechanism uses RNA polymerase II, a host cell enzyme normally associated with synthesis of messenger RNA from DNA, which instead catalyzes “rolling circle” synthesis of new RNA using the viroid’s RNA as a template.

What does prion mean?

A prion is a type of protein that can trigger normal proteins in the brain to fold abnormally. Prion diseases can affect both humans and animals and are sometimes spread to humans by infected meat products.

Are prions alive?

Prions, however, are not living organisms. Prions are infectious proteins. … Prions will then cause tissue damage and cell death to surrounding areas. Prion diseases are neurodegenerative, attacking the brain and are characterized by “holes” in the tissue.

What are the characteristics of Viroids?

Viroids consist of single-stranded, circular and low molecular weight RNA (246-496 nt), they do not possess a protein or membrane shell, however, and given their complex secondary structure they have unusual properties such as resistance to ribonuclease digestion and denaturation.

What is difference between virion and viroid?

A virion is the infectious particle that is designed for transmitting the nucleic acid genome among hosts or host cells. … Nucleic acid can be DNA or RNA. Viroid is formed only of RNA. A protein covering of coat is present.

Is a virus a prion?

Prions are virus-like organisms made up of a prion protein. These elongated fibrils (green) are believed to be aggregations of the protein that makes up the infectious prion. Prions attack nerve cells producing neurodegenerative brain disease.