Photosynthesis
* The process that helps in carrying out metabolic functions of living organisms are called life processes.
* The process of obtaining energy from food is called nutrition.
* Preparation of organic compounds from inorganic substances is called autotrophic nutrition.
* Heterotrophs depend on autotrophs for nutrition.
* The process of fixation of atmospheric carbon dioxide into carbohydrate in the presence of water, sunlight and chlorophyll is known as photosynthesis.
* Photosynthesis involves a series of photochemical reactions that consists of two phases: Light and Dark reactions.
* Light reaction takes place in the thylakoids of the chloroplast of the leaves.
* Dark reaction takes place in the stroma of the chloroplast.
* Leaves have small pores called stomata for gaseous exchange.
Digestion
* Animals that depend on other organisms for their food are called heterotrophs. This type of nutrition is heterotrophic nutrition.
* Unicellular organisms absorb food through their body surface.
* An amoeba uses its pseudopodia to encircle the food and it eventually forms food vacuoles for digestion of food.
* A paramecium uses its cilia to push food into its food vacuole for digestion.
* Complex multicellular organisms have digestive systems for digestion.
* The alimentary canal comprises the mouth, oesophagus, stomach and intestines.
* Saliva contains amylase that breaks down carbohydrates into simpler form.
* Peristalsis induces the food to move from the throat to the stomach.
* In the stomach, food is broken down and converted to chyme.
* The small intestine after digestion absorbs the nutrients from chime.
* The small intestine consists of duodenum, jejunum and ileum.
* The large intestine absorbs water from undigested food and forms solid waste.
* The large intestine comprises cecum, appendix, colon and rectum.
* Liver produces bile, which helps to digest fats.
* Saliva repairs enamel and neutralises acids in the mouth. Thus, saliva prevents tooth decay.
Respiration
* Respiration is the process of oxidation of food and releasing energy.
* Breathing is the process of inhaling oxygen and exhaling carbon dioxide.
* Exhaled air contains more carbon dioxide than when compared to atmospheric air.
* Aerobic organisms break down their food into carbon dioxide and water while anaerobic organisms break down food into alcohol and carbon dioxide.
* Adenosine Triphosphate (ATP) is the molecular currency for transferring energy.
* Diffusion is the process by which a gas moves from an area of high concentration to an area of low concentration until a balance is reached.
* Plants release oxygen in the day time and give out carbon dioxide at night.
* The rate of breathing in aquatic organisms is much faster than in terrestrial organisms.
* Air enters a human body through the nostril. It moves through the throat and then the trachea. From the trachea, it enters the bronchi and then goes to the lungs.
* The bronchi form a network of tubes. Each bronchus has alveoli at the end.
* Haemoglobin absorbs oxygen from the lungs and carries it to tissues all over the body.
Transportation in Animals
* The circulatory system consists of the heart and blood vessels.
* Plasma contains suspended red blood cells, white blood cells and platelets.
* Red blood cells contain a pigment called haemoglobin.
* In newborn babies, 17 to 22 gm/dl of haemoglobin should be present in the blood.
* For children, the normal range is between 11 and 13 gm/dl and for adults is between 12 and 18 gm/dl.
* Arteries carry blood away from the heart.
* Arteries divide into smaller branches called capillaries.
* Veins carry blood to the heart.
* Lymph is a colourless fluid. It contains less protein than plasma.
* Fishes have two chambered hearts.
* Amphibians and reptiles have three chambered hearts.
* Birds and mammals have four chambered hearts.
* In birds and mammals, blood flows from the body to the heart, from the heart to the lungs and again back to the heart.
* In a fish, blood flows from the gills to the body to the heart.
* The force exerted by blood against the walls of blood vessels is blood pressure.
* Sphygmomanometer measures blood pressure.
Transportation in Plants
* The circulatory system consists of the heart and blood vessels.
* Plasma contains suspended red blood cells, white blood cells and platelets.
* Red blood cells contain a pigment called haemoglobin.
* In newborn babies, 17 to 22 gm/dl of haemoglobin should be present in the blood.
* For children, the normal range is between 11 and 13 gm/dl and for adults is between 12 and 18 gm/dl.
* Arteries carry blood away from the heart.
* Arteries divide into smaller branches called capillaries.
* Veins carry blood to the heart.
* Lymph is a colourless fluid. It contains less protein than plasma.
* Fishes have two chambered hearts.
* Amphibians and reptiles have three chambered hearts.
* Birds and mammals have four chambered hearts.
* In birds and mammals, blood flows from the body to the heart, from the heart to the lungs and again back to the heart.
* In a fish, blood flows from the gills to the body to the heart.
* The force exerted by blood against the walls of blood vessels is blood pressure.
* Sphygmomanometer measures blood pressure.
Excertion
* All living organisms that take in energy need to throw waste by-products out of their body.
* Unicellular and simple multicellular organisms have simple methods of ejecting the waste out of their body.
* Complex multicellular organisms have specialised organs for ejecting waste. This is called the excretory system.
* In humans, this system consists of a pair of kidneys, a pair of ureters, a urinary bladder and urethra.
* The kidneys are the main excretory organs of the body. They excrete water, salts and urea in the form of urine.
* They help maintain salt, water and body fluid balance, called homeostasis.
* If the kidney is not functioning properly, the blood is purified externally by a process called dialysis.
* The excretory system in plants greatly differs from that of animals. The technique used differs from plant to plant.
* Plants eject gaseous waste during respiration and photosynthesis. They eject water through transpiration and eject other wastes either through dead leaves or tissues such as cork, gum and resin.