Question

My Questions

1 :- What are

(i) Prions
(ii) Viroids


2:- What is the relationship between Surface-area to Volume ratio and Cell Size (a little explained please)

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Answer 1

$\huge\green{ASSALAMUALAIKUM!}$

(i) Prions:- Prions are misfolded proteins which characterize several fatal neurodegenerativediseases in animals and humans.The word prion derives from "proteinaceous infectious particle"Prions composed of the prion protein (PrP) are hypothesized as the cause of transmissible spongiform encephalopathies (TSEs),including scrapiein sheep, chronic wasting disease (CWD) in deer, bovine spongiform encephalopathy(BSE) in cattle, commonly known as “mad cow disease”, and Creutzfeldt-Jakob disease(CJD) in humans.

(ii) Viroids:-Viroids are the smallest infectious pathogens known. They are composed solely of a short strand of circular, single-stranded RNA that has no protein coating. All known viroids are inhabitants of higher plants, in which most cause diseases, some of which are of slight to catastrophic economic importance.The first recognized viroid, the pathogenic agent of the potato spindle tuber disease, was discovered, initially molecularly characterized, and named by Theodor Otto Diener, plant pathologist at the U.S Department of Agriculture's Research Center in Beltsville, Maryland, in 1971. This viroid is now called Potato spindle tuber viroid, abbreviated PSTVd.

(iii) The relationship between Surface-area to Volume ratio and Cell Size:-

The reason cells can grow only to a certain size has to do with their surface area to volume ratio. Here, surface area is the area of the outside of the cell, called the plasma membrane. The volume is how much space is inside the cell. The ratio is the surface area divided by the volume. This indicates how much surface area is available compared to how big the cell is. If the surface area to volume ratio is small, the cell is very big. If the ratio is big, the surface area is greater than the volume and the cell is small. For example, picture a balloon. The air inside is the volume, and the latex outside is the surface area. As a balloon gets bigger, the volume expands, but there is a limit to how big the surface area can get.

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Answer 2

(i) Prions:- Prions are misfolded proteins which characterize several fatal neurodegenerativediseases in animals and humans.The word prion derives from "proteinaceous infectious particle"Prions composed of the prion protein (PrP) are hypothesized as the cause of transmissible spongiform encephalopathies (TSEs),including scrapiein sheep, chronic wasting disease (CWD) in deer, bovine spongiform encephalopathy(BSE) in cattle, commonly known as “mad cow disease”, and Creutzfeldt-Jakob disease(CJD) in humans.

(ii) Viroids:-Viroids are the smallest infectious pathogens known. They are composed solely of a short strand of circular, single-stranded RNA that has no protein coating. All known viroids are inhabitants of higher plants, in which most cause diseases, some of which are of slight to catastrophic economic importance.The first recognized viroid, the pathogenic agent of the potato spindle tuber disease, was discovered, initially molecularly characterized, and named by Theodor Otto Diener, plant pathologist at the U.S Department of Agriculture's Research Center in Beltsville, Maryland, in 1971. This viroid is now called Potato spindle tuber viroid, abbreviated PSTVd.

(iii) The relationship between Surface-area to Volume ratio and Cell Size:-

The reason cells can grow only to a certain size has to do with their surface area to volume ratio. Here, surface area is the area of the outside of the cell, called the plasma membrane. The volume is how much space is inside the cell. The ratio is the surface area divided by the volume. This indicates how much surface area is available compared to how big the cell is. If the surface area to volume ratio is small, the cell is very big. If the ratio is big, the surface area is greater than the volume and the cell is small. For example, picture a balloon. The air inside is the volume, and the latex outside is the surface area. As a balloon gets bigger, the volume expands, but there is a limit to how big the surface area can get.