Hydroponics is the technique of growing plants with their roots immersed in the nutrient solution without soil.
(a) It is useful in areas having infertile and dry soils.
(b) It is useful to cultivate plants in the areas deficient
in one or more nutrient.

• The metabolic pathway through which the electron passes from one carrier to another, is called the electron transport system (ETS).
• Electron transport system takes place in inner mitochondrial membrane.
• Electron transport chain comprises of the following:
• Complex I: NADH dehydrogenase
• Complex II: succinate dehydrogenase
• Complex III: cytochromes bc1
• Complex IV: cytochromes a-a₃
• Complex V: ATP synthase
• NADH₂ is oxidized by NADH dehydrogenase and electrons are then transferred to ubiquinone located in the inner mitochondrial membrane.
• FADH₂ is oxidized by succinate dehydrogenase and transferred electrons to ubiquinone.
• The reduced ubiquinone is then oxidized with transfer of electrons via cytochromes bc1 complex to cytochrome c.
• Cytochrome c is a small protein attached to the outer surface of the inner membrane and transfer electrons from complex III to complex IV.
• When electrons transferred from one carrier to another via complex I to complex IV, they are coupled to ATP synthesis of ATP from ADP and Pi.
• Oxygen plays a vital role in removing electrons and hydrogen ion and finally helps in the production of H₂

Glomerular Filtration Rate (GFR): The amount of the filtrate formed by the kidneys per minute is called glomerular filtration rate (GFR). GFR in a healthy individual is approximately 125 ml/minute, i.e., 180 litres per day. On an average, 1100-1200 ml of blood is filtered by the kidneys per minute which constitute roughly 1/5th of the blood pumped out by each ventricle of the heart in a minute.

Lacteals are the small lymphatic capillaries. Their function is to absorb fats and fat-soluble vitamins in the small intestine.

Apoplast is the space outside the plasma membrane consisting of intercellular spaces where the material diffuses freely. It does not involve protoplasm in the plant tissues but involves the non-living parts of the plant such as cell wall and intercellular spaces.

The pathways of ion and water created by symplast are known as the symplastic pathway. This pathway offers resistance to the flow of water since the selective plasma membrane of the root cells handles the intake of ion and water. Moreover, symplasty is affected by metabolic states of the root. The symplastic route occurs beyond the endodermis in plants with secondary growth.

Immobilization is the opposite of mineralization where the inorganic nutrients are taken up by soil microbes making them unavailable for plant uptake. Immobilization is the conversion of an element from an inorganic to organic form by microorganisms. ... Thus, under conditions of nutrient limitation, the microorganisms compete with plants for nutrient made available from mineralization, chemical weathering, and atmospheric deposition.

Total Lung Capacity: Total volume of air accommodated in the lungs at the end of a forced inspiration is called Total Lung Capacity. Total Lung Capacity = VC + RV = (ERV + TV + IRV) + RV.

There is an auto regulatory mechanism present in the kidney to regulate the glomerular filtration rate. This mechanism is carried out by juxta glomerular apparatus (JGA) which is a special sensitive region formed by cellular modification of the distal convoluted tubule and the different arteriole at the location of their contact. A fall in the GFR will activate the JG cells to release renin which converts the angiotensinogen in blood to angiotensin I and later into angiotensin II. The angiotensin II is a powerful vaso constrictor which increases the glomerular blood pressure and there by increase the GFR. The Angiotensin II also activates the adrenal cortex to release aldosteron which causes the reabsorption of Na+ and water from the distal parts of the tubule. This also results in the increase in blood pressure and GFR.

A nerve cell is like a receiver, transmitter and transmission line with the task of passing a signal along from its dendrites to the axon terminal bundle. ... This enhanced signal transmission is called saltatory conduction. Myelin insulates the axon to prevent leakage of the current as it travels down the axon. Nodes of Ranvier are gaps in the myelin along the axons; they contain sodium and potassium ion channels, allowing the action potential to travel quickly down the axon by jumping from one node to the next.

Digestion of fats:

Butter is a fat product and gets digested in the small intestine. The bile juice secreted by the liver contains bile salts that break down large fat globules into smaller globules, so as to increase their surface area for the action of lipase. This process is referred to as emulsification of fats.

After this, the pancreatic lipase present in the pancreatic juice and the intestinal lipase present in the intestinal juice hydrolyse the fat molecules into triglycerides, diglycerides, monoglycerides, and ultimately into glycerol and fatty acids.

FatsTriglycerides + Diglycerides

Diglycerides and monoglyceridesFatty acids + Glycerol

Absorption of fats:

Fat absorption is an active process. During fat digestion, fats are hydrolysed into fatty acids and glycerol. However, since these are water insoluble, they cannot be directly absorbed by the blood. Hence, they are first incorporated into small droplets called micelles and then transported into the villi of the intestinal mucosa.

They are then reformed into small microscopic particles called chylomicrons, which are small, protein-coated fat globules. These chylomicrons are transported to the lymph vessels in the villi. From the lymph vessels, the absorbed food is finally released into the blood stream and from the blood stream, to each and every cell of the body.

• Tissue has a free surface, which faces either a body fluid or the outside environment and thus provides a covering or a lining for some part of the body. The cells are compactly packed with little intercellular matrix.

• There are two types of epithelial tissues namely simple epithelium and compound epithelium, Simple epithelium is composed of a single layer of cells and functions as a lining for body cavities, ducts, and tubes. The compound epithelium consists of two or more cell layers and has protective function as it does in our skin.

• On the basis of structural modification of the cells, simple epithelium is further divided into three types. These are

(i) Squamous, (ii) Cuboidal, (iii) Columnar. 

• The squamous epithelium is made of a single thin layer of flattened cells with irregular boundaries. They are found in the walls of blood vessels and air sacs of lungs and are involved in a functions like forming a diffusion boundary.

• The cuboidal epithelium is composed of a single layer of cube-like cells. This is commonly found in ducts of glands and tubular parts of nephrons in kidneys and its main functions are secretion and absorption. The epithelium of proximal convoluted tubule (PCT) of nephron in the kidney has microvilli.

• The columnar epithelium is composed of a single layer of tall and slender cells. Their nuclei are located at the base. Free surface may have microvilli. They are found in the lining of stomach and intestine and help in secretion and absorption. If the columnar or cuboidal cells bear cilia on their free surface they are called ciliated epithelium. Their function is to move particles or mucus in a specific direction over the epithelium. They are mainly present in the inner surface of hollow organs like bronchioles and fallopian tubes.

• Some of the columnar or cuboidal cells get specialised for secretion and are called glandular' epithelium. They are mainly of two types: unicellular, consisting of isolated glandular cells (goblet cells of the alimentary canal), and multicellular, consisting of cluster of cells (salivary gland).

• Compound epithelium is made of more than one layer (multi-layered) of cells and thus has a limited role in secretion and absorption. Their main function is to provide protection against chemical and mechanical stresses. They cover the dry surface of the skin, the moist surface of buccal cavity, pharynx, inner lining of ducts of salivary glands and of pancreatic ducts.