What is Global Warming?

Definition of Global Warming

Global warming is the observed and projected increases in the average temperature of Earth's atmosphere and oceans. The Earth's average temperature rose about 0.6° Celsius (1.1° Fahrenheit) in the 20th century.

Reasons/Causes of Global Warming

Some of the major contributors of global warming are:

* Carbon Dioxide
* Methane
* Water Vapors
* Nitrous Oxide
* Deforestation

1- Carbon Dioxide Emission

Carbon Dioxide Emission from Burning of Fossil Fuels

In 2002 about 40% of U.S. carbon dioxide emissions stem from the burning of fossil fuels for the purpose of electricity generation. Coal accounts for 93 percent of the emissions from the electric utility industry.

Coal emits around 1.7 times as much carbon per unit of energy when burned as does natural gas and 1.25 times as much as oil. Natural gas gives off 50% of the carbon dioxide, the principal greenhouse gas, released by coal and 25% less carbon dioxide than oil, for the same amount of energy produced. Coal contains about 80 percent more carbon per unit of energy than gas does, and oil contains about 40 percent more. For the typical U.S. household, a metric ton of carbon equals about 10,000 miles of driving at 25 miles per gallon of gasoline or about one year of home heating using a natural gas-fired furnace or about four months of electricity from coal-fired generation.

Carbon Dioxide Emission from Vehicles

About 33% of U.S carbon dioxide emissions come from the burning of gasoline in internal-combustion engines different types of vehicles. Vehicles with poor gas mileage contribute the most to global warming. For example, according to the E.P.A's 2000 Fuel Economy Guide, a new Dodge Durango sports utility vehicle (with a 5.9 liter engine) that gets 12 miles per gallon in the city will emit an estimated 800 pounds of carbon dioxide over a distance of 500 city miles. In other words for each gallon of gas a vehicle consumes, 19.6 pounds of carbon dioxide are emitted into the air. Sports utility vehicles were built for rough terrain, off road driving in mountains and deserts. When they are used for city driving, they are so much overkill to the environment. If one has to have a large vehicle for their family, station wagons are an intelligent choice for city driving, especially since their price is about half that of a sports utility.

Carbon Dioxide Emission from Aviation Services

According to UN's Intergovernmental Panel on Climate Change aviation causes 3.5 percent of global warming that could rise up to 15 percent by 2050.

2- Methane

While carbon dioxide is the principal greenhouse gas, methane is second most important. According to the IPCC, Methane is more than 20 times aseffective as CO2 at trapping heat in the atmosphere. US Emission Inventory 2004 Levels of atmospheric methane have risen 145% in the last 100 years. Methane is derived from sources such as rice paddies, bovine flatulence, bacteria in bogs and fossil fuel production. Most of the world’s rice, and all of the rice in the United States, is grown on flooded fields. When fields are flooded, anaerobic conditions develop and the organic matter in the soil decomposes, releasing CH4 to the atmosphere, primarily through the rice plants.

3- Water Vapor in the Atmosphere Increasing Global Warming

Water vapor is the most prevalent and most powerful greenhouse gas on the planet, but its increasing presence is the result of warming caused by carbon dioxide, methane and other greenhouse gases. Water vapor holds onto two-thirds of the heat trapped by all the greenhouse gases. As the Earth heats up relative humidity is able to increase, allowing the planet's atmosphere to hold more water vapor, causing even more warming, thus a positive feedback scenario.

According to NCDC,” Because the air is warmer, the relative humidity can be higher, leading to more water vapor in the atmosphere”.

4- Nitrous oxide

Nitrous oxide (N2O) a colorless and non-flammable greenhouse gas with a sweetish odor, commonly known as "laughing gas". It is naturally produced by oceans and rainforests. Man-made sources of nitrous oxide include nylon and nitric acid production, the use of fertilizers in agriculture, cars with catalytic converters and the burning of organic matter. All chemical reactions involving sunlight causes break down of Nitrous oxide present in atmosphere.

5- Deforestation

Deforestation comes next after the human activities causing carbon dioxide emissions. Deforestation is being considered responsible up to 25% of all carbon emission entering the atmosphere, by the burning and cutting of about 34 million acres of trees every year, losing millions of acres of rainforests. The destroying of tropical forests alone is throwing hundreds of millions of tons of carbon dioxide into the atmosphere each year. The number of temperate forests is being reduced which account for an absorption rate of 2 billion tons of carbon annually.

Permafrost

Permafrost is a solid structure of frozen soil, extending to depths of 2.200 feet in some areas of the arctic and sub-arctic regions, containing grasses, roots, sticks, much of it dating back to 30,000 years. Permafrost is under 85% of Alaska land surface and much of Canada, Scandinavia and Siberia and holds about 14% of world’s carbon. The hard permafrost on which is built homes and other buildings, can, with rising temperatures, turn into a soft material causing subsidence and damage to buildings, electric generating stations, pipelines and other structures. Ground instability would cause erosion, affect terrain, slopes, roads, foundations and more.

"Permafrost has acted as a carbon sink, locking away carbon and other greenhouse gases like methane, for thousands of year. But there is now evidence that this is no longer the case, and the permafrost in some areas is starting to give back its carbon. This could accelerate the greenhouse effect."

Svein Tveitdal, Managing Director of the Global Resource Information Database (GRID) in Arendal, Norway, a UNEP environmental information center monitoring the thawing of permafrost, told a meeting at the 21st session of the United Nation's Governing Council in Nairobi, Kenya on February 7, 2001.

Tundra

Tundra means ‘treeless plain’ is a name used for environs of the arctic and sub-arctic. The tundra is a biome home to about 1700 kinds of plants, including shrubs, mosses, grasses, lichens and 400 kinds of flowers.

About 50 billion tons of carbon is estimated to be held in a frozen state in the tundra, and now the tundra is beginning to become a source of carbon dioxide. In the 1970's University of California biologist Walter Oechel studied carbon dioxide emissions in the tundra, which until this time had been thought of as a carbon sink. Doing further tests in the 1980's, Oechel discovered that this was no longer the case, that warming temperatures had changed the tundra to a net emitter of carbon dioxide.

“We found to our great surprise that the tundra was already losing carbon dioxide to the atmosphere. So that by the start of these experiments, which was in 1982, the tundra had already warmed and dried enough, that its historic role as a carbon sink had reversed and changed. It was now losing carbon dioxide to the atmosphere. That was totally unexpected." Oechel said.

Total Amount of Carbon Present Everywhere

In Atmosphere: 750 billion tons of Carbon
In Forests: 610 billion tons of Carbon
In Soils: 1580 billion tons of Carbon
In Deep Ocean: 38100 billion tons of Carbon
In Surface Layer of Oceans: 1020 billion tons of Carbon

What is an Ecosystem?

Definition of Ecosystem

An ecosystem is a biological community of interacting living things and their environment. In an ecosystem plants, animals and human beings exist together and depend upon each other for their survival.

OR

An ecosystem is generally an area within the natural environment in which physical (abiotic) factors of the environment, such as rocks and soil, function together along with interdependent (biotic) organisms, such as plants and animals, within the same habitat.

Explanation of Ecosystem

Ecosystems can be permanent or temporary. Ecosystems usually form a number of food webs. Living plants provide food, oxygen and shelter, while dead plants are used as a great source of fossil fuels. Animal provide carbon dioxide used by plants during photosynthesis and excretory waste used as manure for plants. Dead animals decompose to provide basic soil continents. Vital balance is required for survival of all components, malfunctioning can disturb the balance of ecosystem.

Examples of Ecosystem

* Agroecosystem
* Aquatic Ecosystem
* Chaparrel
* Coral Reef
* Desert
* Forests
* Human Ecosystem
* Marine Ecosystem
* Littoral Zone
* Prairie
* Pond Ecosystem
* Rainforest
* Savanna
* TundraUrban Ecosytem

Biomes

Biomes are similar to ecosystems, climatically and geographically defined area of ecologically similar climatic conditions such as communities of plants, animals and soil organisms, often referred to as ecosystems. Biomes are defined based on factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest, woodland, savanna), and climate. Unlike ecozones, biomes are not defined by genetic, taxonomic, or historical similarities. Biomes are often identified with particular patterns of ecological succession and climax vegetation.

Biodiversity

Biodiversity is the variation of life forms within a given ecosystem, biome, or for the entire earth. Biodiversity is often used as a measure of the health of biological systems. The biodiversity found on Earth today consists of millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution. 2010 is the International Year of Biodiversity.

Functions of Ecosystem

From an anthropological point of view, some people perceive ecosystems as production units that produce goods and services, such as wood by forest ecosystems and grass for cattle by natural grasslands. Meat from wild animals, often referred to as bush meat in Africa, has proven to be extremely successful under well-controlled management schemes in South Africa and Kenya. Much less successful has been the discovery and commercialization of substances of wild organism for pharmaceutical purposes. Services derived from ecosystems are referred to as ecosystem services. They may include:

* Facilitating the enjoyment of nature, which may generate many forms of income and employment in the tourism sector, often referred to as eco-tourisms.
* Water retention, thus facilitating a more evenly distributed release of water.
* Soil protection, open-air laboratory for scientific research, etc.

Hovering Satellites

Hovering Satellites

Satellites are man-made objects revolve around the earth for certain scientific purposes. The satellites apparently static in relation to earth are put into such orbits that their orbital velocity cancels the spinning velocity of earth and both becomes synchronized, such satellites are called ‘Hovering Satellites’.

Geostationary Orbits

The orbits in which such hovering satellites appear stationary from the earth are called geostationary orbits.

Explanation of Hovering Satellites

* Hovering satellites are usually situated at the height of about 35600km above the earth. A number of hovering satellites are situated at various parts around the earth for instant communication facilities round the globe.

* Communication satellites provide reliable and continuous telephone and TV transmission throughout the globe and change their position with respect to ground stations.

* Surveillance satellites placed either in geostationary orbit or in lower orbits, gather info about enemy troops and military installations through visual and infrared imaging.

* Weather satellites provide daily info about changing weather conditions expected to prevail in the region.

* Research satellites provide info about earth’s magnetic field and cosmic rays e.g. MRI Skylab.

* Moving satellites do not serve for establishing communication links between different continents as communication through space require these satellites to have specific position relative to earth for efficient transmission of signals between ground station and a satellite.

A - C

ACTH

Adreno Cortico Tropic Hormone

ADH

Antidiuretic Hormone$Alcohol Dehydrogenase

ADP

Adenosine Di Phosphate

AFM

Atomic Force Microscope

AHF

Anti-Haemophilic Factor

AIDS

Acquired Immune Deficiency Syndrome

ALGOL

Algorithmic Language

AMF

Action Message Format

AMU

Atomic Mass Unit

APS

Advanced Photo System

APS-C

Advanced Photo System type-C

AR

Aqua Regia/

Androgen Receptor

ARDS

Adult Respiratory Distress Syndrome

ATM

Automated Teller Machine/

Asynchronous Transfer Mode

ATP

Adenosine Tri Phosphate

ATS

Anti Tetanus Serum

AV

Atrio Ventricular

BASIC

Beginners All-Purpose Symbolic Instruction Code

BBS

Bulletin Board System

BCG

Bacillus Calmette Guerin/

Ballisto Cardio Graphy

BeV

Billion Electron Volt

BIT

Binary Digit

BJT

Bipolar Junction Transistor

BMR

Basal Metabolic Rate

BSD

Berkeley Software Distribution

BTU

British Thermal Unit

BWR

Boiling Water Reactor

CAD

Computer Aided Design

CAG

Cytosine Adenine Guanine

CAL

Common Application Language

CAT

ScanComputed Axial Tomography Scan

CDMA

Code Division Multiple Access

CFC

Chloro Fluoro Carbon

CGI

Common Gateway Interface/

Computer Generated Imagery

CMOS

Complementary Metal Oxide Semiconductor

CNG

Compressed Natural Gas

COBOL

Common Business Oriented Language

CPR

Cardio Pulmonary Resuscitation

CPU

Central Processing Unit

CRO

Cathode Ray Oscilloscope

CRT

Cathode Ray Tube

CSS

Cascade Style Sheet

CT Scan

Computed Tomography Scan

CU

Control Unit

CW

Continuous Wave

D - L

DBMS

Database Management System

DBS

Digital Broadcast Satellite/

Deep Brain Stimulation

DDT

Dichloro Diphenyl Trichloro Ethane

DNA

Deoxy Ribonucleic acid

ECG

Electro Cardio Graphy

EEG

Elctro Encephalo Graphy

EM

Electron Microscope

EMF

Electro Magnetic Field/

Electro Motive Force

ENIAC

Electronic Numerical Integrated And Computer

EROM

Erasable Read Only Memory

ERP

Enterprise Resource Planning

EST

Expressed Sequence Tag

ETT

Endo Tracheal Tube

FAD

Flavin Adenine Dinucleotide

FMN

Flavin Mono Nucleotide

FORTRAN

FORmula TRANslation language

FSH

Follicle Stimulating Hormone

GAC

Guanine Adenine Cytosine

GeV

Giga Electron Volt

GIGO

Garbage In Garbage Out

GMT

Greenwich Mean Time

GPS

Global Positioning System

GSM

Global System for Mobile communication

HDL

High Density Lipoprotein

HDLM

Handheld Device Markup Language

HDPE

High Density Polyethylene

Hi-Fi

High Fidelity

HIV

Human Immunodeficiency Virus

HSD

High Speed Data

HST

Hubble Space Telescope

HTML

Hyper Text Markup Language

HWT

Heavy Water Reactor

IPC

Inter Process Communication

IRDS

Infant Respiratory Distress Syndrome

IT

Information Technology

JSP

Java Server Pages

KWH

Kilo Watt Hour

LAN

Local Area Network

LASER

Laser Amplification by Stimulated Emission of Radiation

LCD

Liquid Crystal Display

LDI

Light Dependent Inductor

LDL

Low Density Lipoprotein

LDPE

Low Density Polyethylene

LED

Light Emitting Diode

LPG

Liquified Petroleum Gas

LWR

Light Water Reactor

M - R

MAF

Million Acre Feet

MASER

Microwave Amplification by Stimulated Emission of Radiation

MBTU

Million British Thermal Unit

MeV

Million Electron Volt

MHD

Magneto Hydro Dynamics

MIDI

Musical Instrument Digital Interface

MIMD

Multiple Instruction Multiple Data/

Multiple Data Stream

MMS

Multimedia Messaging Service

MRI

Magnetic Resonance Imaging

NMR

Nuclear Magnetic Resonance

NPN

Negative Positive Negative(Diode)

NTP

Normal Temperature & Pressure/

Nitrogen Triphosphate

OPV

Oral Polio Vaccine

ORS

Oral Rehydration Salts

OS

Operating System

OSI

Open Systems Interconnection

PABA

Para Amino Benzoic Acid

PCM

Pulse-Code Modulation/

Protein Calorie Malnutrition

PCR

Polymerase Chain Reaction

PDA

Personal Digital Assistant

PERL

Practical Extraction & Reporting Language

PET

Positron Emission Tomography

PHP

Hypertext Preprocessor

PNP

Positive Negative Positive (Diode)

PROM

Programmable Read Only Memory

PTCA

Percutaneous Transluminal Coronary Angioplasty

PTFE

Poly Tetra Flouro Ethylene

PTH

Para Throid Hormone

PTC

Poly Vincyl Chloride

PWR

Pressurized Water Reactor

RADAR

Radio Angle Direction And Range

RAM

Random Access Memory

RBC

Red Blood Cell

RDS

Respiratory Distress Syndrome/

Radio Data System

RNA

Ribo Nucleic Acid

ROM

Read Only Memory

RQ

Respiratory Quotient

RSS

Really Simple Syndication

S -X

SA

Sino Atrial

SARS

Severe Acute Respiratory Syndrome

SEM

Scanning Electron Microscope

SEO

Search Engine Optimization

SGML

Standard Generalized Markup Language

SIMD

Single Instruction Multiple Data

SLBM

Submarine Launched Ballistic Missile

SLR

Single-Lens Reflex

SMS

Short Messaging Service

SOAP

Simple Object Access Protocol

SONAR

Sound Navigation And Ranging

STD

Sexually Transmitted Disease/

Subscriber Trunk Dialing

STEM

Scanning & Transmission Electron Microscope

STM

Scanning Tunneling Microscope/

Software Transactional Memory

STP

Standard Temperature & Pressure

TCP/IP

Transmission Control Protocol/

Internet Protocol

TEM

Transmission Electron Microscope

TNT

Tri Nitro Toluene

TPN

Triphospho Pyridine Nucleotide/

Total Parenteral Nutrition

UHF

Ultra High Frequency/

Ultra High Fidelity

UPS

Uninterruptible Power Supply

VCR

Video Cassette Recorder

WAN

Wide Area Network

WAP

Wireless Application Protocol

WBC

White Blood Cell

WLL

Wireless Local Loop

WR

Water Reactor

WSDL

Web Services Description Language

WWW

World Wide Web

W3C

World Wide Web Consortium

XHTML

Extensible Hypertext Markup Language

XML

Extensible Markup Language

XSL

Extensible Stylesheet Language

XSLT

Extensible Stylesheet Language Transformation

Polycystic Kidney Disease

"PKD" stands for polycystic kidney disease characterized by the formation of multiple cysts on kidney surface causes increase in its size and weight. The weight of cyst filled kidney can reach 20-30 pounds. It is the most common heredity kidney disorder passes down through families. If both parents are carrier of this disease there is 50% chance for child to develop this disease but if one of the parents carries it the chance of its occurrence in child remains 25%. In this case child does not develop it but simply passes it to the next generation. It occurs in two forms; Autosomal dominant PKD and Autosomal recessive PKD. Autosomal dominant PKD shows symptoms in adulthood while Autosomal recessive PKD shows symptoms in infancy and early childhood.

In Autosomal dominant PKD there is chance for a person to live for several years so it is also called "adult polycystic kidney disease". Symptoms of Autosomal dominant PKD are abdominal pain or pain in back and lower portion,excessive urination at night,headache, high blood pressure,abnormal heart valves,kidney stones, nail abnormalities,drowsiness and painful menstruation etc. Some other severe conditions include hematuria,aneurysms (bulges in walls of blood vessels) and direvticulosis (small pouches bulge outward through the colon). Hematuria (blood in urine) can be classified into microscopic and gross hematuria. In microscopic hematuria blood spots are so small that they can only be seen through a microscope. While in gross hematuria large spots of blood can be seen through naked eye.

Autosomal recessive PKD is rare form caused by mutation in Autosomal recessive PKD gene (PKHD1). Signs of this form of PKD appear before birth so it is also called "infantile PKD". In many cases child with Autosomal recessive PKD develops kidney failure before reaching adulthood. Severity of this condition varies from case to case as in some cases baby die after some hours or days due to respiratory difficulties or total respiratory failure. Its symptoms are high blood pressure,urinary tract infection, frequent urination, effects on liver and spleen, low blood cells count, varicose veins and hemorrhoids (formation of masses or clamps of tissues within anal canal) etc. Growth factor is considered a primary feature of Autosomal recessive PKD as child shows less growth activity (smaller in size) than average growth rate.

It is important to remember that there is no specific cure for PKD. But antibiotics can be used for pain reduction,high blood pressure and for urine related problems. Dialysis and kidney transplantation are also used as alternative methods of cure to avoid its severity.

What is Cell Nucleus?

Cell nucleus is spherical or semi spherical body present usually in the center of eukaryotic cells. In prokaryotic cell, nuclear material is dispersed throughout the cytoplasm without a definite membrane. Nucleus is often called 'Brain Of The Cell' as it contains cell's hereditary material DNA and coordinates its all metabolic activities including growth, metabolism, protein synthesis and reproduction (cell division) etc. As far as its size is concerned it occupies about 10 percent of total eukaryotic cell's volume.

Nuclear membrane is nuclear envelope that separates the nuclear material from the cellular cytoplasm. It is double layered membrane that encloses the nuclear material during most of the cell's life cycle. These two unit membranes run parallel to each other with a space between them called perinuclear space which is an electron transport area. At some places outer membrane gives out tubular structures called endoplasmic reticulum. Annuli are openings in nuclear envelope through which nucleoplasm communicates with the cytoplasm. These nuclear pores regulate the passage of molecules between the nucleus and cytoplasm allowing them to pass through the nuclear membrane. It is believed that these pores can open and close but its definite mechanism is not clear. During cell division (mitosis), the nuclear membrane disintegrates into vesicles which disappear in the cytoplasm. But soon at the reformation stage when two cells complete their formation and the chromatin begins to appear these vesicles again combine to reform nuclear membrane.

The semi-fluid matrix bounded by nuclear membrane is called nucleoplasm. Within nucleoplasm, a mass of thin fibrils called chromatin is present. This chromatin network is the actual site of genetic activities as it contains DNA and become highly coiled at the time of cell division to form chromosomes. Chromatin is so organized that it gives reticulate appearance. About 6 feet of DNA is present in every human cell, divided into 46 individual molecules (chromosomes). Chromosomes are chemically composed of DNA, RNA, Histone (basic proteins) and Hertones (non histone proteins). Calcium is also present in it. Genes, the fundamental units of heredity, are present on chromosomes on specific position called locus.

The nucleus also contains one or more dark, spherical, colloidal bodies called nucleoli (singular; nucleolus). Nucleolus is associated with a special region called 'Nucleolar Organizing Region' present in the chromosome. It is rich in RNA which passes to cytoplasm to take part in protein synthesis. Nucleoli are involved in manufacturing ribosomes. A nucleolus consists of RNA, acidic and basic dyes, phospholipids and alkaline phosphates. Under microscope nucleolus looks like a large dark spot within the nucleus. A nucleus may contain several nucleoli which sometimes merge to form a single and large nucleolus.

Reiki - A technique for Stress Reduction and Healing

Reiki,a Japanese technique for stress reduction and for healing purposes introduced in Canada and US in 1970s by Mrs.Hawayo Takata. Reiki is made up of two Japanese words,"Rei" means God's wisdom "ki" means "life force energy. So Reiki means "Spiritually guided life force energy" a technique based upon the idea of unseen life force energy flows through us.Reiki was founded by Dr Mikao Unsi,a Japanese Buddhist in 1870s. He experienced a profound spiritual enlightenment after a 21 days period of fasting and meditation. He began to deliver this technique to other people as well and opened his teaching clinic in Japan.

Reiki treats the whole person with his physical and spiritual problems. It is a lying on hands healing technique to balance subtle energies within the body. During the treatment patient is laid down on massage table dressed in loose garments. Atmosphere during session is kept relaxing using dimmed lights with complete silence or with light music. Reiki master places his hands on different parts of body for 2-5 minutes. Energy flows through the palms of his hands to the recipient's body. During session It is not necessary to touch the patient body. Some reiki masters hover their palms few inches above the body. Energy flow to the effected part is automatic regardless of hands position and sequence of hands placements.

Unlike other techniques it is not learned but is transferred from reiki master to his students during class. It is taught in three levels,level 1 & 2 in one day class. Level 3,more intensive,longer involves a ritual(Attunement) and learning of placing hands for treatment. Attunement is the initiation to open up crown,heart and palm chakras to allow "Rei" energies to flow through. The time period for its training can be varied. This technique is not difficult to learn as it does not depend upon intellectual capacity of a person. No specific belief or intellectual capacity is required to learn it. An important reason for its unique way of learning is to avoid its misuse by people for illicit purposes so it is transferred to student not learned through written material to keep its spiritual nature sacred.

There are also some myths and misconceptions about this technique. First one is that it is a related to religion or any dogma or belief. No it is not true,as it is purely spiritual in nature and promotes spiritual growth of person. Second misconception is that after treating a patient the energy level of reiki master get lowered. It is again wrong as "rei" energies are infinite and can not run out. If somebody feels tired after treating a patient it is because of his or her own internal weakness not because of reiki treatment. Thirdly it is considered a massage therapy as it is also used in massage therapies but it is not true as well. As discussed earlier it is energy based technique not involving bones and tissues. Another misunderstanding is about the process of attunement that it will open the doors of spiritual world and a person will be able to find solution about all spiritual problems. It is not so as well though reiki promotes spiritual growth but assuming it the way to spiritual world would be an exaggeration.

What is Mitochondria?

A Brief Look at Mitochondria

Mitochondria are sausage-shaped, double membraned cytoplasmic bodies usually called "Power House Of Cell". These are responsible for ATP synthesis through cellular respiration. Mitochondria are present in almost all eukaryotic cell with the exception of protist Chaos (Pelomyxa) carolinensis.They show constant motion within the cell and tend to aggregate at places where energy requiring process is going on or at the parts of cell associated with active processes e.g in flagellated protozoas mitochondria are present around the base of flagella and in cardiac muscle, they surround the contractile elements. One of the richest sources of mitochondria is Hummingbird flight muscle.

Mitochondria with 0.5 to 1.0 micrometer diamete are bounded by outer and inner membrane, composed of phospholipid bilayers and proteins. Both membranes differ in their structure and function. Outer membrane is smooth and elastic helps in its extension & contraction. Porins (integral protein) present in outer membrane form channels through which small ions, nutrient molecules, ATP etc can pass easily. Any disruption in outer membrane allows proteins in the intermembrane space to leak into the cytosol (cytoplasmic matrix) which can lead to cell death.

Explaining the Structure of Mitochondria

Let’s have a look at the structure of mitochondria.

Inner membrane shows folded structure, forms invaginations into the mitochondrial cavity to increase the surface area for cellular respiration. These invaginations are called cristae which can be branched or unbranched. Cristae are the sites for ATP synthesis. Inner membrane is permeable only to oxygen, carbon dioxide, and water etc. About 1/5 of the total protein in a mitochondrion is present here.

Inter Cellular Space is the space between outer and inner membrane play important role in oxidative phosphorylation. Due to the permeablility of outer membrane it is rich in protein especially cytochrome C and other small molecules.

Matrix is the fluid or substance fill the mitochondrial cavity inside the inner membrane. It is rich in ribosomes, DNA, proteins and manganese. Ribosomes (of 70S type) present here are different from cytoplasmic ribosomes. Its DNA is of circular shape called mitochondrial DNA. About 2/3 of the total protein of mitochondrion is present in matrix. The matrix contains highly-concentrated mixture of enzymes. Enzymes for Kreb s cycle are also present here. The matrix play important role in ATP synthesis with the help of the ATP synthase present in inner membrane.

Oxysomes are knobs like structures present on the outer surface of outer membrane and on the inner surface on inner membrane. Oxysomes present on outer side are stalkless while those attached to inner surface have small stalk for attachment, this stalk is called F0 particles and rounded part is called F1 particle. Both have enzyme ATP-ase and are related to ATP synthesis. These are proteinaceous in nature. Oxysomes act as electron carrier and oxygen released results in the formation of water and ATP molecule.

How do a mitochondria works?

Functions of Mitochondria

1- Main function of mitochondria is energy production through ATP synthesis. It makes impossible for multicellular organisms to exist without mitochondria. They provide energy through the break down of respiratory substances for ATP synthesis used in cell metabolism.

2- Through oxidative phosphoryation mitochondria make efficient use of nutrient molecules.

3- Mitochondria are also involved in cell signalling (communication system to control basic cellular activities), cellular differentiation, apoptosis (PCD-programmed cell death), cell cycle and cell growth as well. Certain amount of protein synthesis also takes place here.

4- Mitochondrial perform specific function in specific types of cells e.g mitochondria present in liver cells contain enzymes that allow them to detoxify ammonia (waste product of protein metabolism).

5- Additionally mitochondria also regulates membrane potential, cellular proliferation and certain heme and steroid synthesis reactions. Mitochondria can also store calcium. There is a significant interplay between the mitochondrion and ER (significant storage site of calcium) regarding calcium storage.

Diseases/Disorders Related to Mitochondria

Aftermaths of Mutations or Damage to Mitochondria

Any damage to mitochondria can cause a wide range of disorders which mostly present as neurological disorders. Its improper functioning lead to energy break down which causes poor coordinations, sensory poblems and reduced mental activity etc. Errors in cellular information processing are responsible for diseases such as cancer, autoimmunity and diabetes.

Diseases caused by mutation in the mtDNA include Kearns-Sayre syndrome and MELAS syndrome. Mostly these diseases are transmitted by mother as the zygote derives its mitochondria and its mtDNA from the ovum. Large-scale mtDNA mutations can cause Kearns-Sayre syndrome, Pearson's syndrome and progressive external ophthalmoplegia while MELAS syndrome, Leber's hereditary optic neuropathy, myoclonic epilepsy with ragged red fibers are the outcome of small-scale or point mutations in mtDNA.

Environmental factors may also influence mitochondrial disease. Influence of pesticide exposure on Parkinson's disease is an example of environmental influences.

Aging process also lead to a number of changes in mitochondria. Tissues of elderly patients show a decreased enzymatic activity. Even large deletions in the mitochondrial genome can lead to high levels of oxidative stress and neuronal death in Parkinson's disease. Hypothesized links between aging and oxidative stress show their symptoms after the age of 50 years.

What is Protein Synthesis?

Definition of Protein Synthesis

Protein synthesis, a way of gene expression in which gene produces a product, usually a protein.

Stages of Protein Synthesis

It involves two stages:

1- Transcription
2- Translation.

1- Transcription

Transcription is a process of RNA synthesis in which RNA molecules are synthesized on DNA template. As in eukaryotes DNA is restricted to nucleus does not participate in protein synthesis directly. An intermediate RNA molecule is involved in it which is synthesized in nucleus where genetic information stored in DNA is transferred to this RNA molecule. This RNA is called mRNA (messanger RNA) or transcript as it contains a message to direct the ribosomes to assemble amino acids for given kind of protein. During this process only one of the DNA strand is transcripted which is called sense strand and other strand is called antisense strand.

Transcription comprises three stages; Template binding and initiation, Elongation and Termination. Template binding involves a DNA molecule and RNA polymerase. RNA polymerase is a holoenzyme composed of a core enzyme and a sigma factor. Sigma factor recognises promoters along the sense strand. Promoters (initiation sites) are attachment points where initial binding of RNA polymerase and a DNA molecule occurs. In the absense of sigma factor, core enzyme is responsible for this binding but not specifically to the promoters. During elongation RNA polymerase passes along DNA molecule to unwind the double helix and a structure called open promoter complex is formed at the point of breakage. The synthesized portion of RNA molecule gradually dissociates from the strand allowing it to return to its original helical structure. Finally termination occurs at suitable positions after the ends of genes.

2- Translation

Translation, the final stage of gene expression in which RNA molecule is translated into polypeptides. This complex process involves ribosomes and three types of RNA molecule (mRNA,rRNA,tRNA produced during transcription). The main thing during translation process is that genetic code determines the sequence of nucleotides in mRNA molecule to specify the sequence of amino acids in a polypeptide. There must be a code for each of 20 amino acids found in polypeptide. Translation comprises four stages; tRNA charging (aminoacylation), Initiation, Elongation and finally Termination of polypeptide chain. tRNA charging involves linkage of tRNA molecules to its respective amino acids. This charging is controlled by a group of enzymes called aminoacyl synthetases. Each aminoacyl synthetases is specific for each amino acid. First amino acid become activated by reacting with ATP and then linked with itsrespective enzyme to form a complex. This reacted complex get linked with specific tRNA molecule through a covalent linkage.This process is called amino acid activation.

After this charging stage,initiation, elongation and termination of polypeptide chain is carried out respectively. During initiation process small ribosomal sub-unit binds to a mRNA molecule and then a charged tRNA (charged by Methionine, an amino acid coded by AUG) pairs with this small sub-unit to form a resultant structure called Initiation complex. After the formation of initiation complex elongation process starts. When large sub-unit of ribosome binds with this complex. The large sub-unit have two binding sites for charged tRNA molecule; P-site (peptdyl) and A-site (aminoacyl site). The tRNA binds to P-site and specific charged tRNA become attached to A-site.The attachment of tRNA to A-site is dictated by sequence of second triplet (anticodon) in mRNA. An enzyme peptidyl transferase, present in large ribosomal sub-unit, catalyses the formation of peptide bond to link two amino acids together. At the same time the covalent bond between amino acid and tRNA (on P-site) molecule is broken and a dipeptide is formed. This increase in the length of polypeptide chain by one amino acid is actually called elongation. Before elongation repeats itself another process called translocation occurs. During translocation tRNA (now uncharged) attached to P-site is released from the large sub-unit and A-site becomes vacant again for coming charged tRNA to repeat the process. The final stage termination is signalled when a termination codon UAG,UAA or UGA enters the A-site. Release factors enter the A-site and cleaves the polypeptide chain from tRNA. Ribosomes releases the polypeptide and mRNA and dissociates into its sub-units. Released polypeptide chain folds up into tertiary structure to begin its functional life.

How to treat Hashimoto's Disease?

To treat a disease it is important to treat its cause. The basic cause behind Hashimoto's disease is faulty immune system which attacks the thyroid gland and causes its inflammation and under activity which is called hypothyroidism. Up until now there is no treatment discovered to treat faulty immune system. The only thing which can be done in this case is try to keep the hormone level normal which can be adversely disturbed due to hypothyroidism.

Treatment for Hashimoto's disease starts with careful observation to determine the possibility of hypothyroidism. If no symptoms found then doctor apply wait and see approach rather than suggesting some medication. But in case of disturbed level of thyroxine, hormone replacement therapy is started to prevent long term effects of disease. To treat thyroid hormone deficiency doctor prescribes daily use of synthetic thyroid hormone pills called levothyroxine. It is identical to thyroxine and taken orally to restore the adequate level of thyroid hormone in blood and to reverse the symptoms of hypothyroidism.

A physician has to consider several factors while recommending the dosage of levothyroxine. These factors include severity of disease, patient's age and weight, presence of another disease or use of other medication etc. Because for most people taking pills daily and having blood test regularly causes no problem, but some people complain that they feel fatigued after taking medicine. The reason behind such feeling is lowering of blood cholesterol level. Levothyroxine lowers the level of blood cholesterol elevated by disease and reverses the weight gain. Therefore, having regular blood tests is suggested to keep track of medicine and to check the level of other hormones which are related to thyroid functioning.

Persons with heart related problems are initially treated with a smaller amount of medication and doctor gradually increases this amount to allow their heart to adjust with increasing metabolism. After a few weeks of medication doctor checks the level of thyroxine and TSH (thyroid stimulating hormone) hormones to prevent their excessive amount in blood. Because over-treatment can lead to over activity of thyroid gland which is called hyperthyroidism. It can further cause several problems including allergic reactions, stomach upsets, osteoporosis and serious heart rhythmic problems etc.

The period how long a person needs to take the medicine also depends upon the results of blood test. Some patients require monitoring and treatment for a long time than others. If a person is feeling better after few weeks of treatment and wants to change the course of medication, he should get professional advice from his doctor instead of skipping doses. Because in such a condition there is a chance of reversing the symptoms of Hashimoto's disease with more severity, always consult the doctor in case of any change in medication to prevent further problems.

As far as the side effects of levothyroxine are concerned, levothyroxine has no side effect if taken properly. But remember that certain foods and supplements like iron supplements, aluminum hydro-oxide and calcium supplements etc can affect its absorption in blood. If a patient is already taking such supplements he must tell the doctor about it to avoid any complication during treatment.

What are Enzymes?

Enzymes are the catalysts or chemical substances synthesized in living cell and responsible for metabolic activities within the organism. Subatances which react with the help of enzymes are called "Substrates" and materials produced as the result of a chemical reaction are called "Products". Active sites are present on the surface of enzyme to combine with a substrate through hydrogen bonds or ionic forces. Substrates and enzyme combine to form enzyme-substrate complex. It involves a "lock and key" machanism in which some part of substrate establishes a close fit into some part of enzymes.

Enzymes are essentially proteins. But some of them consists of protein part called "apoenzyme" ans a non-protein part called "prosthetic group". Prosthetic group is divided into two catagories i-e activators and coenzymes/cofactors. Acticator is the inorganic metal portion attached to apoenzyme to help in binding a substrate to the enzyme. Loss of activator causes the inactivity of an enzyme. Some known acticators are copper, calcium, cobalt, iron etc. Coenzyme is the organic prosthetic group of enzyme. Coenzymes have loose association with enzyme acts as donors or acceptors of atoms in forming enzyme-substrate complex. Some coenzymes are NAD (nicotinamide adenine dinucleotide), NADP (nicotinamide adenine dinucleotide phosphate), FAD (flavin adenine dinucleotide) and COA(coenzyme A). Certain vitamins also act as coenzymes.

Some specific features of enzymes differentiate them from inorganic catalysts as enzymes are specific in their action associated with particular chemical reaction, these are not as passive during reaction as catalysts as sometimes molecules of enzymes get destroyed during reaction and velocity of a reaction is not always proportional to the concentration of the enzyme. But usually enzymes retain themselves during the reaction and can be reused for some other reaction. The chemical reactions involving enzymes are reversible if product get accumulated for a long time.

Enzymes catalyses a reaction by reducing the its energy of activation to make molecules more reactive. It brings the substrates closer either binding them in closer association or putting them under stress or strain. Activation energy is the energy required to start a chemical reaction. Enzymes can bring about those reactions at low temperature which only occur at high temperature. So it also act in the place of "thermal agitation".

Factors Affecting the Activity of Enzymes

Certain factors affect the activity of enzymes including temperature, pH and poisons. Rise in temperature causes rise in enzyme activaty. But at very high temperature denaturation of apoprotein results in the inactivation of enzyme due to the breaking of its hydrogen bonds present in enzyme. Change in pH causes changes in ionic state of a substrate results in the formation of charged particles which may not correspond with the ionic groups present in the active sites of enzymes. As a result no enzyme-substrate complex formed. Certain poison or inhibitors mask the active sites of enzymes forming the enzyme-inhibitor complex. In this situation substrate have to compete for its active site so it is called "competitive inhibition".It can be removed by increasing the concentration of substrate. The conformational change in the enzyme due to the formation of enzyme-inhibitor complex is called "allosteric effect".

Enzyme nomenclature follows some rules. Some enzymes are named after the name of their substrate by adding a suffix 'ase'. For example lipase reacts with lipids (fats), Carbohydrase reacts with carbohydrates and proteinase reacts with proteins. Sometime the name of enzyme refers to the reaction rather than the substrate e.g decarboxylase, dehydrogenase, mutase and oxidase etc. In this case the name of substrate is added to the name of enzyme such as pyruvic acid decarboxylase, succinic acid dehydrogenase, glucomutase and cytochrome oxidase. Old names of enzymes formulated before the nomenclature have been retained.