mRNA processing in eukaryotes

Messenger RNA Processing:-

A newly synthesized eukaryotic mRNA undergoes several modifications before it leaves the

nucleus(Fig.). The first is known as capping. Very early in transcription the 5' -terminal

triphosphate group is modified by the addition of a guanosine via a 5' -5'-phosphodiester

link. The guanosine is subsequently methylated to form the 7-methyl guanosine cap. The

3' ends of nearly all eukaryotic mRNAs are modified by the addition of a long stretch of

adenosine residues, the poly-A tail (Fig.). A sequence AAUAAA is found in most

eukaryotic mRNAs about 20 bases from where the poly-A tail is added and is probably a

signal for the enzyme poly-A polymerase to bind and to begin the polyadenylation process.

The length of the poly-A tail varies, it can be as long as 250 nucleotides. Unlike DNA,

RNA is an unstable molecule, and the capping of eukaryotic mRNAs at their 5' ends and

the addition of a poly-A tail to their 3' end increases the lifetime of mRNA 

molecules  by protecting them from digestion by nucleases.

Many eukaryotic protein-coding genes are split into exon and intron sequences. Both

the exons and introns are transcribed into mRNA. The introns have to be removed and the

exons joined together by a process known as RNA splicing before the mRNA can be used

to make protein. Removal of introns takes place within the nucleus. Splicing is complex

and not yet fully understood. It has, however, certain rules. Within an mRNA the first

two bases following an exon are always GU and the last two bases of the intron are AG.

.Several small nuclear RNAs (snRNAs) are involved in splicing. These are complexes with

a number of proteins to form a structure known as the spliceosome. One of the snRNAs is

complementary in sequence to either end of the intron sequence. It is thought that binding

of this snRNA to the intron, by complementary base pairing, brings the two exon sequences

together, which causes the intron to loop out (Fig.). The proteins in the spliceosome

remove the intron and join the exons together. Splicing is the final modification made to

the mRNA in the nucleus. The mRNA is now transported to the cytoplasm for protein

synthesis.

As well as removing introns, splicing can sometimes remove exons in a process called

alternative splicing. This allows the same gene to give rise to different proteins at different

times or in different cells. For example, alternative splicing of the gene for the molecular

motor dynein produces motors that transport different types of cargo.

Fig. mRNA processing in eukaryotes.

WHAT ARE ENZYMES

 WHAT ARE ENZYMES?

Enzymes are biological catalysts. They increase the rate of chemical reactions taking

place within living cells without themselves suffering any overall change. The

reactants of enzyme-catalysed reactions are termed substrates. Each enzyme is

quite specific in character, acting on a particular substrate or substrates to produce a

particular product or products.

All enzymes are proteins. However, without the presence of a non-protein

component called a cofactor, many enzyme proteins lack catalytic activity. When

this is the case, the inactive protein component of an enzyme is termed the

apoenzyme, and the active enzyme, including cofactor, the holoenzyme. The

cofactor may be an organic molecule, when it is known as a coenzyme, or it may be

a metal ion. Some enzymes bind cofactors more tightly than others. When a cofactor

is bound so tightly that it is difficult to remove without damaging the enzyme, it is

sometimes called a prosthetic group.

To summarize diagrammatically:

CO-ENZYME < INACTIVE-PROTEIN+ACTIVE PROTEIN+COFACTOR < METAL ION+COENZYME 

As we shall see later, both the protein and cofactor components may be directly

involved in the catalytic processes taking place.

Elephantiasis/Filariasis

Elephantiasis/Filariasis 

Synopsis:-

• Introduction
• Types of Diseases
• Elephantiasis
• History
• Pathogen
• Symptoms
• Prevention And Treatment
• Conclusion
• Reference

                         

                                                   Introduction

Illness or disease is that condition. In which the organism becomes Structurally and Functionally deformed or irregular. When an organism has a disease. Then some symptoms appear in his body due to his structural or functional irregularity. These symptoms are called symptoms of that disease. When some organisms found in nature enter our body cause many disease.

Types of Disease:-

Diseases are divided into two categories on the basis of their nature and causes.

       A. Congenital Disease

       B. Acquired Disease

A. Congenital Disease:-

They are disease who lives in the organism from birth These disease dries due to developmental or metabolic disorders. Examples- hemophilia, diabetes,

B. Acquired Disease:-

They are disease which dries in living beings after birth due to various factors. It is of two types

              1. Communicable or infectious disease

              2. Non-communicable or Non infectious

        

Communicable or infectious disease:-

Those are disease which are caused by living factors such as Bacteria, Viruses, Protozoa, Fungi and Warms and spreads person to person.

These are of the following Types:-

Ø 1. Protozoan Diseases

Ø 2. Helminth Disease

Ø 3. Bacterial Disease

Ø 4. Viral Disease

Ø 5. Fungal Diseases

1. Protozoan Disease:-

These parasites spread due to infection of Protozoa Example- Malaria, dysentery,

2. Helminth Disease:-

These disease are caused by different types of warms, Examples- Filariasis, Ascariasis,

3. Bacterial Disease:-

These are caused by the infection of parasitic bacteria Example- Typhoid, Pneumonia,

4. Viral Disease:-

These are caused by due to infection of Viruses, Example- Dengue, Rabies,

5. Fungal Disease:-

These are caused by different types of fungi Example- Ringworm

2. Non-communicable or Non infectious    Diseases:-

They are disease which does not spread from person to person. The causative dgents of these disease are not organism rather, They happen for redsons other than organisms.

Example- Rickets, Cancer,

Elephantiasis:-

Elephantiasis is also known as lymphatic Filariasis. It’s caused by parasitic worms and can spread from person to person through mosquitoes. Elephantiasis causes swelling of the legs or breasts (chest).

Elephantiasis is considered a neglected tropical disease (NTD). It’s mare common in tropical and subtropical area of the world, including Africa and Southeast Area.

Which is commonly found in such areas in India. Where there is mare outbreak of mosquitoes and people use dirty water mare.  

History:-

• In 1876 Joseph Bancaroft discovered the adult form of the worm.
• Wuchereria bancrofti named in honor of the astralian physician Joseph Bancroft.
• 
  
  
  

Pathogen:-

Elephantiasis is caused by parasitic worms

The worms affect the lymphatic system in the body. There are three types of worms involved,

                  1. Wuchereria bancrofti

                  2. Brugia Malayi

                  3. Brugia timori

Ø That are spread by mosquitoes.

Ø Lymphatic Filariasis is mosquitoes for example by the culex mosquito widespread across urban and semi-urban areas.

Ø Anopheles mainly found in rural areas.

Aedes mainly in endemic island in the pacific.

Symptoms:-

Mild fever and body aches.

Hardening and thickening of the skin

Swelling of the legs, arms, (chest) breast and genitals.

Prevention:-

The best way to prevent elephantiasis is to avoid mosquito bites.

Sleep in an air conditioned room or under a mosquito net at night.

Dirty water should not be used.

Treatment:-

Gently washing the swollen and damaged skin every day with soap and water.

Moisturizing the skin.

Exercising regularly to support the lymphatic system. AS directed by a doctor.

Check for wounds and use medicated cream on any sore spots.

Conclusion:-

Elephantiasis is a highly uncommon phenomenon in western countries.

Wuchereria Bancrofti can cause elephantiasis and it left untreated. It can cause death.

Reference:-

Center for Disease control and prevention “Lymphatic Filariasis”

U.S centers for Disease control lymphatic Filariasis Treatment.

Sources of dietary fiber

Sources of dietary fiber

Fruits, leafy vegetables, vegetables, whole wheat legumes, rice bran etc. are rich

sources of fiber. The ideal way to increase fiber intake is to reduce intake ofrefined carbohydrates, besides eating vegetables, fresh fruits and whole grains.

In general, vegetarians consume more fiber than non-vegetarians. An average

daily intake of about 30g fiber is recommended.

Applications of DNA fingerprinting

Applications of DNA fingerprinting

The amount of DNA required for DNA fingerprint is remarkably small. The

minute quantities of DNA from blood strains, body fluids, hair fiber or skin

fragments are enough. Polymerase chain reaction is used to amplify this DNA

for use in fingerprinting. DNA profiling has wide range of applications—most of

them related to medical forensics. Some important ones are listed below.

• Identification of criminals, rapists, thieves etc.

• Settlement of paternity disputes.

• Use in immigration test cases and disputes.

In general, the fingerprinting technique is carried out by collecting the DNA

from a suspect (or a person in a paternity or immigration dispute) and matching

it with that of a reference sample (from the victim of a crime, or a close relative

in a civil case).

Uttaranchal College of Science and Technology is best for BSC biotechnology

 Uttaranchal College of Science and Technology is best for BSC biotechnology

Here you can know about best college in Uttaranchal

Click on this link:- Best college in Uttaranchal