life's internal secrets

life processes 
         Nutrition, respiration, excretion, transportation, reproduction, sensitivity and growth are some of the processes that help the living being to sustain. These processes that are common to all living beings are called as the life processes.
     
Energy for life processes

                 All living organisms require energy to perform various activities. This energy is derived from the food they eat. Thus food is a kind of fuel which provides energy to all the living organisms. Food contains several components called as nutrients. Based on their functions nutrients are divided into three types.

        (1) Energy giving nutrients  -  Carbohydrates, fats(2) Body building nutrients  -  Proteins(3) Protective and regulating nutrients  -  Vitamins and minerals

Heterotrophic nutrition

    Organisms that depend on other organisms for their food are heterotrophic organisms. All animals and fungi are heterotrophs. Different organisms use different strategis to obtain food depending upon their body design, organization, functioning and also availability of food material.

e. g.

1. Fungi like yeast, mushrooms and some carnivorous plants break down the food material into simple substances outside the body and then absorb it.
2. Some organisms take in whole food and then break it down to simple substances inside their bodies and then absorb it. E.g. human being, cat, cow, etc.
3. Some animals and plants derive nutrition from other plants or animals without killing them but during the process they harm the host plant or animal. E.g . cascuta,ticks, lice, leeches, tapeworms etc

  

  Nutrition in human beings

         All the processes involved in nutrition in human beings take place by association of digestive organs called digestive system. The digestive system includes alimentary canal and the digestive glands.

(1) Mouth:

        The alimentary canal beings with mouth. We eat a variety of food items which have to pass through the same digestive tract. Naturally the food has to be processed to generate particles with small size.

        Can you tell which organs of the body are involved in breaking the large food particles into smaller ones?

        Such crushed food is wetted with saliva secreted by the saliva glands so the food can smoothly pass through the soft lining of the alimentary canal. The food that we take is of complex nature. It is converted into simpler molecules with the help of biological catalysts called as enzymes. Enzyme salivary amylase breaks down starch into a simple sugar maltose. Thus digestion starts in the mouth itself.

(2) Stomach:

        The partly digestion food goes down through the oesophagus into a ‘J’ shaped stomach placed on the left side of the abdomen. The food is pushed forward in the canal due to rhythmic contraction and relaxation of the muscles of the canal called as peristaltic movement

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Digestive glands

liver

  

                                                                    villi

stomach

Excretion in human beings

     

           the excretory system in human beings includes a pair of kidney, a pair of ureters, urinary bladder and urethra. kidneys remove the waste products from the blood and urine.

                                                           

  

           Human Excretory System

school of elements

           you are know that matter can exist in the form of elements, compounds and mixtures. when element were discovered scientists adopted different ways to classify them. in earlier days very few elements were known. at that time they were classified as metals and non-metals on the basis of their properties. some elements showed properties of both metals and non-metals and they could not be placed in any of the two classes.to overcome these difficulties, scientists tried to find out some pattern or regularity in the properties of elements.

1.1-Newlands' octaves

       newlands' law states that  "when the elements are arranged in an increasing order of their atomic masses, the properties of the eights elements are similar to the first."

1.2-mendeleeves's periodic table

   the physical and chemical properties of elements are a periodic function of their atomic masses.

        the tabular arrangement of the elements based on the periodic law is called the mendeleev's periodic table.

1.3-modern periodic table

    

classification of elements