Thursday, April 24, 2014

The Plants Kingdom – Fungi

Fungi are considered to be the oldest plants. They do not contain chlorophyll. Like other thallophytes, they do not contain roots, stems, flowers and leaves. These plants cannot manufacture their own food and so for food, they depend on decaying organic matter, plants and animals. Fungi are, therefore, called parasitic or saprophytic. Most fungi reproduce asexually, but a few species have a sexually reproductive stage which alternates with an asexual stage. Their cell wall is made up of cellulose of chitin. They produce enzymes to digest food. Some familiar fungi are: yeast, molds, mushrooms, mildews, rusts and smelts. Fungi can grow in al kind of climates and environments. Some fungi are also found in air and water. Sir P. A. Nichelly is considered to be the father of fungi way back in 1729. He had discovered the fungi.

Fungi can be useful or harmful to human beings and other organisms.
Some fungi, such as Agaricus, morchella, etc. are consumed as food by man. Certain molds, such as camembert and Roquefort are added to cheese to provide a flavor and to help ripen the cheese. Yeast is used to manufacture bread and alcohol. It is a good source of protein and vitamin B. some molds are used to produce antibiotics. The famous antibiotic penicillin was obtained from a mold in 1929. Fungi are also helpful in maintaining soil fertility.

Rust, smut, mold, etc. cause many dreadful diseases in crops. They also cause diseases in man and domestic animals. They spoil our food. Some species of fungi are poisonous and if they are consumed by man, they may prove fatal. Among these, the highly poisonous fungus is toad stool. From ergot fungus, a hallucinating drug L.S.D. is prepared. Ringworm and athlete’s foot are diseases caused by fungus. Many varieties of mushrooms are poisonous and can cause sickness or even death if eaten. Reference: Children’s Science Library by A.H.Hashmi.
Different species of fungi

Wednesday, April 23, 2014

Environment - Noise Pollution

Today, noise pollution has become a serious health hazard in the big cities. Automobiles, trucks, motor, factory machines and even the means of entertainment like rock music, DJs, etc. produced loud, irritating sounds. Man feels disturbed by such sounds. The harmful effects of intense sounds are referred to as noise pollution.

  Noise is a hazard
The intensity of sound is measured in decibels. It is based on a logarithmic scale which means that ten decibels is ten times more powerful than one decibel and 20 decibels are 100 times more powerful, and so on. Man’s ears can tolerate the sound of up to 80 decibels. The sounds of higher intensity than this are harmful for ears. Normal human voice is of about 60 decibels. People living in noisy places become accustomed to high intensity sounds to send ears lose the sensitivity and capacity to send sound waves to the brain. This leads to deafness.
The clamor of motors, trucks and automobiles
          Studies reveal that in India ten percent people living in cities and seven percent in the villages are suffering from auditory defects. Abnormally high noise disturbs the sleep and increases heart beat. Noise pollution causes gastric problems, dilation of pupil of eyes, ulcers in stomach, weakening of teeth and defects in kidney. It is also harmful for the nerves of the womb and adversely affects the embryo of a pregnant woman. Noise pollution can only be checked by the people who are aware of its ill effects.
           The music systems producing very loud sounds can be banned to check noise pollution. Reference: Children’s Science Library by A.H.Hashmi.

Lithosphere or Crust

The uppermost layer of the earth is called litho-sphere or the crust. Its average thickness is 30 km to 40 km under the continents, 5 km to 10 km under the ocean the ocean floor and up to 60 km under the mountains. At certain places below the pacific floor, its thickness is very little. The earth’s crust consists of two layers- the upper layer and the lower layer. The upper layer is called SIAL (silicate + aluminum). It is made up of granite-like rocks which mainly consist of silica and alumina. Below the upper layer lies the lower layer called SIMA (silicate + magnesium) consisting of denser rocky material. Higher temperature prevails in this region. It is the same material of which the rocks on the surface of the earth are made.

There are three kinds of rock structure in the upper continents crust of the earth. Of them, the most abundant are the Pre-Cambrian crystalline shields. In the second place are the coastal areas formed of sedimentary rocks. The structure of the third part is folded mountains.

The crust of the earth is made up of a number of plates- large in size and of varied thickness, called the crustal plates. Some of them are in the form of ocean floor while others are in the form of continents. Earthquakes occur due to the upheavals of these plates. Reference: Children’s Science Library by A.H.Hashmi.

Geysers - Hot Springs

                                                          The Old Faithful Geyser
A geyser is jet of boiling water and steam issuing from the earth in a few volcanic regions. The jet of water may persist from a few moments to an hour or more. Beneath the geyser, there is some hot rock and a narrow fissure connects the rock to the mouth of the geyser. Water reaches the rock through this fissure where it is heated to about 100 degree Celsius. Now the steam pressure inside, forces the hot water to come out to the surface of the earth. The flow of hot water continues till such time as cold water does not return to the fissure. The cold water is again converted into steam and as the pressure rises, the hot water is thrown out.

The jet of hot water may rise in the air to a height of 100 meters or more. In some cases it rises to only 1 or 1.5 meters. Geysers are known to exist only in Iceland. New Zealand and Yellowstone national park in the USA. Of these three, Yellowstone has by far the most impressive display of geysers. These geysers are a delightful sight for the viewers and are popular tourist spots.

Hot Springs
 A Hot Spring in Iceland
  The temperature of water of a hot spring is higher than that of ordinary springs. According to scientific findings, ground water temperature rises with increasing depth. The rate of increase in generally about 1 degree centigrade for each 25 meter of increase in depth. When underground hot water flows out regularly through some crack or fissure, it is called a hot spring. In some volcanic regions, the steam formed by the heat of the molten rocks is forced out in the form of hot water.
Many minerals get dissolved in hot spring water. The hot spring water containing dissolved sulphur is good for skin diseases. The water of some springs is very hot.
The Maoris of New Zealand cook their food in the local hot spring water. In Haryana, a place called Sona has a hot spring which is quite famous and Manali also has a number of hot springs. Among the hot springs in Dehradun, the capital of the newly formed state of Uttaranchal, the Tapt Kund is a hot water sulphur spring which is quite famous throughout India. Reference: Children’s Science Library by A.H.Hashmi.

Saturday, April 19, 2014

How The Body Utilizes the Fat We Eat

With this brief background of fats, fatty acids and cholesterol, consideration may be given to what happens to the fats we eat in our ordinary diet. Fats are utilized by the body for quick energy; if excess fats are eaten, the liver stores them temporarily so that the fats may be gradually released over a period of time. The blood stream is the mechanism utilized by the body for distributing this energy throughout the system. Research chemists were puzzled about how the blood conveyed fat, since it was known that fat does not dissolve in watery substances such as blood. Research revealed the secret. The body creates what scientists call lipoproteins—that is, combinations of fats, protein and cholesterol—because lipoproteins can and do dissolve in the blood.

The body creates these lipoproteins—the combinations of fat, protein and cholesterol—primarily to transport the energy foods in solution in the blood stream. After the lipoproteins are formed, they flow out into the blood and are carried through the body. The fats, now in solution in the blood, burn readily and are soon disposed of. The proteins are soluble in the blood and are also easily used up. The remaining constituent of the lipoprotein is the cholesterol. Until very recently, it was assumed that the body could not use up cholesterol, for it was not a type of food, such as fat, protein or carbohydrate. But the last few years of study indicate that the consumption of cholesterol in foods does have an effect on the serum cholesterol level, tending to raise it in most persons. That is true in even comparatively modest amounts of dietary cholesterol; for example, three-quarters of a pound of steak with fatty marbling, containing 1 gram, eaten daily will increase the cholesterol level in the vast majority of individuals. Therefore, it suggested that the daily consumption of cholesterol should be lowered to not more than 300 milligrams per day. Later on, when the cholesterol level is reduced to 210 or less, it should be possible to relax the restriction, if the intake of polyunsaturated to saturates remains proportionately high. Obviously, this discussion is an oversimplification of the problem, with the more technical details being limited or omitted for the sake of clarity.

Other Factors      

Is diet the sole cause of coronary heart disease? It would appear that diet is vitally related to atherosclerosis, but many other factors remain to be resolved. Conclusions regarding certain unsolved factors may require many, many years. Some factors may be given increased importance as investigations and research continue, whereas others may eventually be eliminated from consideration. These factors include other diseases, the sex differential, overweight, heredity and family history, emotions and stress, age, occupation, exercise, salt in the diet, tobacco and alcohol, and starches.

Cellular Respiration

             Energy is not produced directly by the Oxidation of complex molecules. It is produced when glucose or fatty acids are oxidised in the cells in a process called Cellular Respiration. Energy is released in several stages. Mitochondria present inside the cells use the oxygen entering inside for respiration and energy production. First step of the reactions is glycolysis, which after series of reactions under goes Krebs Cycle and then Electron transport resulting in the production of energy. Let's see the process of Cellular Respiration.
The first step of respiration is the conversion of glucose to pyruvic acid (Glycolysis) which is common for all the three types of respiration i.e., Aerobic, Anaerobic respiration and fermentation.
Let's see the fate of pyruvic acid in aerobic respiration.
Food In Intestine (absorbed by) ----> Blood ---> Liver (through blood) -----> tissues ----> Oxidation of food takes place

Mitochondria are the sites of cellular respiration. Oxidation of food materials takes place in them. The energy released through oxidation is utilised by the mitochondria to synthesis ATP (Adenosine Tri Phosphate) which are energy rich compounds.
ATP provides energy required for various metabolic functions and reactions of the organism.

About Mitochondria
Meaning and Named by
Elementary/F1 Particles
Mito = thread Chondrion = granule
Uniformly distributed in cytoplasm
Two membranes outer and inner
These are on the crests
Biological oxidation of food materials like glucose and fatty acids.
granular cytoplasmic organelle named by --> Benda
No. of Mitochondria varies with the type of the cell and its functional state width varies from 0.5 - 2 μ length is variable upto 40 μ shape – mostly granular
outer one is smooth inner one projects into crests inner chamber is filled with matrix
They are round stalked bodies They are molecules of ATP as enzymes They are responsible for oxidative Phosphorylation
Mitochondriaon synthesizes stores and releases the high energy ATP, so referred as power house of the cell

Cellular Respiration
O2, ADP + Pi (inorganic phosphate), Carbohydrates, fats are required for the respiratory activity in mitochondria.
Glycolysis: Conversion of one molecule of glucose into two molecules of pyruvic
Glucose + Pi
glucose - 6 - Phosphate + Pi Fructose - 1, 6 di phosphate 2 CH3COCOOH (Pyruvic acid)

Result of Glycolysis: 4 ATP and 2 NADH are formed 2 ATP molecules are used in this process. So, net gain is 2 ATP molecules.
Kreb's Cycle: Takes place in mitochondrial matrix.

2CH3COCOOH (In presence of O2)---->2Carbon Compounds Acetyl CoA ( CO2 Removed) ----> 4 Carbon Compounds Oxaloacetic acid ---->6 Corbon atoms citric acid

H+ ions of Acetyl Co A are transferred to NAD+ and FAD+ (Forming) ---> NADH and
FADH2 (large amount of energy is released).

Electron Transport
NADH and FADH2 are oxidised in the elementary particles of mitochondria where 1 Proton & 2 electrons are formed from each molecule of NADH and are ejected into the inner membrane of mitochondria. These electrons are transferred from one acceptor to another which are arranged in a chain (The energy released is used for production of ATP). These electrons and protons are finally transferred to oxygen to form water.
Note: ADP + Phosphate ( in presence of O2 Forms ) ---> ATP (Oxidative Phosphorylation)
  • A net gain of 38 ATP molecules are formed from the total oxidation of one glucose molecule through Glycolysis, Krebs Cycle and Electron transport.
  • Each ATP molecule gives 7,600 calories of energy.
  • 40% of the total energy present in the glucose molecule is converted into ATP energy.