Pancreas is known as a mixed gland because it performs functions of both exocrine and endocrine glands.

It has both exocrine and endocrine cells. Exocrine cells secrete Pancreatic juice and endocrine cells secrete insulin and glucagon.

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Anura is the scientific name of frog and the most common species of Indian frog is Rana tigrina.

(i) It will be found in the meristems (meristems are the regions in plants, where cell divisions occur for plant growth).
(ii) The element is calcium.
(iii) It is also present in the middle lamellae of cells.

• Sliding filament theory explains the mechanism of muscle contraction, which states that contraction of a muscle fibre takes place by the sliding of the thin filaments over the thick filaments.
• The junction between a motor neuron and the sarcolemma of the muscle fibre is called the neuromuscular junction or motor-end plate.
• A neural signal, released by central nervous system, when reaches the junction releases a neurotransmitter (Acetyl choline) which generates an action potential in the sarcolemma, which spreads through the muscle fibre and causes the release of calcium ions into the sarcoplasm.

• Water potential is the difference between free energy of water molecules in a pure solvent and free energy of water molecules in a solution.
• Solute potential (Ψs) and pressure potential (Ψp) are the two main components that determine water potential.
• The greater the concentration of water in a system, the greater is its kinetic energy or ‘water potential’.
• Water potential is denoted by the Greek symbol Psi or Ψ and is expressed in pressure units such as pascals (Pa).
• The water potential of pure water at standard temperatures is taken to be zero.
• All solutions have a lower water potential than pure water; the magnitude of this lowering due to dissolution of a solute is called solute potential.
• For a solution at atmospheric pressure (water potential) Ψw = (solute potential) Ψs.
• The pressure exerted by the protoplasts due to entry of water against the rigid walls is called pressure potential (Ψp).
• When water enters a plant cell due to diffusion causing a pressure built up against the cell wall, it makes the cell turgid, which increases the pressure potential.
• Water potential of a cell is affected by both solute and pressure potential: Ψw = Ψs + Ψp

Matrix is the tissue in animal or plant cells in which specialized structures are fixed to a surrounding mass. For example, there are matrix such as mitochondrial matrix and Golgi apparatus matrix.

The gastric glands are located in different regions of the stomach. These are the fundic glands, the cardiac glands, and the pyloric glands. The glands and gastric pits are located in the stomach lining. The adrenal glands are small glands located on top of each kidney. They produce hormones that you can't live without, including *** hormones and cortisol. Cortisol helps you respond to stress and has many other important functions. With adrenal gland disorders, your glands make too much or not enough hormones.

Bundle of HIS is a collection of heart muscle cells specialized for electrical conduction. As part of the electrical conduction system of the heart, it transmits the electrical impulses from the AV node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the bundle branches. 

DISCOVERY OF ELECTRON:

The Electron was discovered by J.J Thomson by conducting a Cathode ray tube experiment.

For the experiment he used Crooke’s tube, which was 60cm long glass tube and had a small tube attached. To this small tube vacuum pump was attached, it also had two metal plates which were connected to battery by wires.

The tube contained gas at atmospheric pressure. when current at high voltage (10,000volts) was passed following observations were made:

1. When current was passed through a gas at 1 atmospheric pressure and at a very high voltage, nothing happened. That is no visible effect was seen inside the tube.
2. Then further the pressure of gas was reduced by pumping the air out, with the help of vacuum pump. The pressure was reduced to 10^-2atm, then on passing current it was seen that whole tube started glowing green.
3. Then further the pressure was reduced to 10^-4It was seen the whole glow vanished, but it was seen that at the end of the tube (anode side) there was a faint green glow observed.

To confirm the faint glow anode was made perforated, and a zinc sulphide screen (fluorescent material) was placed behind it.

When current was passed under same conditions it also started   glowing green. This confirmed that under those conditions some rays were emitted through cathode, and were travelling towards anode. Those rays were called as cathode rays and found to consist of negatively charged particles called electron.

The Process of Breathing :
Breathing involves the ribs, the intercoastal muscles, lungs and the diaphragm. Breathing process is carried out in two phases :
• Inhalation or Inspiration
• Exhalation or Expiration.
Inhalation : To make inhalation possible the intercoastal muscles contract and lift the ribs upward and outward. The diaphragm muscle also contracts and flattens. These movements increase the size of chest cavity; as a result the pressure inside the lungs decreases. As the pressure outside the lungs is greater and the air moves into the lungs.
Exhalation: When breathing out, the muscles relax, the ribs go back to their normal unexpanded position, and the diaphragm springs back into place. With the chest activity back to its normal size, the pressure inside the lungs increases and is greater than the atmospheric pressure. As a result the air moves out of the lungs through nose or mouth.

When the rate of evaporation is low, at night or in the early morning, excess water gets collected in the form of droplets at the special openings of veins of leaves of many herbaceous plants. Such water loss in its liquid phase is called guttation.

The proenzyme pepsinogen; in stomach; gets converted into the active enzyme pepsin; on exposure to hydrochloric acid. Pepsin converts proteins into proteoses and peptones (peptides).

Pepsinogen + HCl → Pepsin + Protein → Proteose + Peptone

Proteins, proteoses and peptones are acted upon by the proteolytic enzymes of pancreatic juices (in small intestine); as given below:

Proteins/Peptonse/Proteoses + Trypsin/Chymotrypsin/Carboxypeptidases → Dipeptides

The enzymes in the intestinal juice act on dipeptides to make amino acids.

Dipeptides + Dipeptidases → Amino acids

The proenzyme pepsinogen; in stomach; gets converted into the active enzyme pepsin; on exposure to hydrochloric acid. Pepsin converts proteins into proteoses and peptones (peptides).

Pepsinogen + HCl → Pepsin + Protein → Proteose + Peptone

Proteins, proteoses and peptones are acted upon by the proteolytic enzymes of pancreatic juices (in small intestine); as given below:

Proteins/Peptonse/Proteoses + Trypsin/Chymotrypsin/Carboxypeptidases → Dipeptides

The enzymes in the intestinal juice act on dipeptides to make amino acids.

Dipeptides + Dipeptidases → Amino acids

Brain is the highest coordinating centre in the body. It is protected by a bony box called cranium, within which are present three layers of fluid-filled membranes called meninges for absorbing shock.

 The brain is divided into three regions (i) Forebrain (ii) Midbrain and (iii) Hindbrain.

The forebrain is the largest part of the brain. It is the main thinking region. It is made up of cerebrum, hypothalamus and thalamus. The midbrain does not have any further divisions. The hindbrain consists of cerebellum, pons and medulla.

The symbiotic nitrogen-fixing bacteria invade the root hairs of host plants, where they multiply and stimulate formation of root nodules, enlargements of plant cells and bacteria in intimate association. Within the nodules the bacteria convert free nitrogen to ammonia, which the host plant utilizes for its development. Rhizobium is a bacteria found in soil that helps in fixing nitrogen in leguminous plants. It attaches to the roots of the leguminous plant and produces nodules. These nodules fix atmospheric nitrogen and convert it into ammonia that can be used by the plant for its growth and development.

Chlorophyll, any member of the most important class of pigments involved in photosynthesis, the process by which light energy is converted to chemical energy through the synthesis of organic compounds. Chlorophyll is found in virtually all photosynthetic organisms, including green plants, cyanobacteria, and algae. Chlorophyll is the molecule that absorbs sunlight and uses its energy to synthesise carbohydrates from CO2 and water. This process is known as photosynthesis and is the basis for sustaining the life processes of all plants. In addition to giving plants their green color, chlorophyll is vital for photosynthesis as it helps to channel the energy of sunlight into chemical energy. With photosynthesis, chlorophyll absorbs energy and then transforms water and carbon dioxide into oxygen and carbohydrates.

  Lichens grow on the surface of rock and extract minerals from them. This creates small crevices at places where a thin layer of soil builds up.