Viriods and prions, Biology

Assignment Help:

Viriods and Prions

Viroids 

      In 1971, T.O.Diener reported that the  spinde tuber disease of potato causing gnarling and cracking of the tuber, is caused by multiplication of a pathogen much smaller than viruses and present in tuber cells themselves, This pathogen found to be a free short and circular RNA strand of about 300nucleotides. Diener  named it viroid. It was found that viroids are infectious because, after multiplying  in a plant cell, these disperse in the tissue and invade new cells. About a dozen plant diseases have since been shown to be caused by viroids.it is also possible that the causative agents of some more plant and animals diseases turn out to be viroides.

Prions

While searching for the cause of a mental disease kuru widespread in a tribe of New Guinea, D,C Gajdusek(1968) discovered that the disease is caused  by a slow virus infection. He shared the 1976 Nobel Prize this work. Later he suspected that other neurological disorders. Like mad cow disease in cows and human dementia and Parkinson disease might also be of this  category, Prisoner (1985) speculated that Creulzfeldt Jacob disease extremely   minute (4-6 nm in diameter ) protein particles which are coded by the genome of certain brain cells, and act as infectious pathogens, These particles have been named prions.


Related Discussions:- Viriods and prions

Simple proteins, SIMPL E PROTEINS The proteins are made of amino acids...

SIMPL E PROTEINS The proteins are made of amino acids only. Additional chemicals are absent. These are of two types -    (i) Fibrous        (ii) Globular ( i )

Precautions for determination of iodine number of lipids, Precautions for d...

Precautions for determination of iodine number of lipids? 1. If using the pipette for transferring the oil, allow the pipette to drain slowly and completely, as oil takes time

State the series of stimuli, State the series of stimuli ERPs a series ...

State the series of stimuli ERPs a series of stimuli such as tones or light flashes are presented to the participant, and the raw EEG for a precise one or two second period fol

Active transport, Active transport is the transport of the molecules again...

Active transport is the transport of the molecules against the concentration gradient (from area of low concentration to area of high concentration) with the help of proteins in t

Define the process of digestion of proteins, Define the Process of Digestio...

Define the Process of Digestion of Proteins? The daily protein intake (of about 50-100 g) and the protein of enzymes, sloughed (bled or drop off) epithelial cells and mucins, w

What is human glucose transporters (glut), What is Human Glucose Transporte...

What is Human Glucose Transporters (GLUT)? All GLUTS are the integral proteins, which penetrate and span the lipid bilayer of plasma membrane. Six isomers of GLUT have been des

What are all possibilities of genotypes and phenotypes, What are all possib...

What are all possibilities of genotypes and phenotypes formed in the combination of alleles responsible for the production of factor VIII? Considering the alleles X and Xh, whe

Which are the living beings that carry out photosynthesis, Which are the li...

Which are the living beings that carry out photosynthesis? Which is the cell organelle responsible for the absorption of light for the photosynthesis process in plants and algae?

What are the most important worm infections, Q. What are the most important...

Q. What are the most important worm infections? The most significant human worm infections are taeniasis, schistosomiasis, cysticercosis, ascariasis and ancylostomiasis (hookwo

Pineal gland, PINEAL GLAND (EPIPHYSIS CEREBRI) - It develops from th...

PINEAL GLAND (EPIPHYSIS CEREBRI) - It develops from the ectoderm of the embryo. The pineal gland is located between the cerebral hemispheres, where it protrudes from the

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd