NEET Biology Solved Question Paper 2011

CAM plants are mostly succulent xerophytes. The stomata in these plants remain closed during the day. This helps to check the transpiration. In this way, water is conserved.

Hypertension is the term for blood pressure that is higher than normal (120/80). In this measurement, 120 mm Hg (millimeter of mercury pressure) is the systolic, or pumping, pressure and 80 mm Hg is the diastolic, or resting pressure. If repeated checks of blood pressure 190/100 mm Hg) of an individual is 140/90 (140 over 90) or higher, it shows hypertension. High blood pressure (190/100 mm Hg) leads to heart diseases and also affects vital organs like brain and kidney. 

The columnar epithelium is composed of a single layer of tall and slender cells. If the columnar cells bear cilia on their free surface they are called ciliated columnar epithelium. They are mainly present in the inner surface of hollow organs like bronchioles and fallopian tubes. Their function is to move particles or mucus in a specific direction over the epithelium.

The pituitary gland is located in a bony cavity called sella tursica and is attached to hypothalamus by a stalk. It is divided anatomically into an adenohypophysis and a neurohypophysis. The latter is also called pars nervosa or posterior pituitary. It stores and releases two hormone called oxytocin and vasopressin, which are actually synthesized by the hypothalamus and are transported axonally to neurohypophysis. Vasopressin acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules in the nephron and thereby reduces loss of water through urine (diuresis). Hence, it is also called as anti-diuretic hormone (ADH).

The bundle of his known as AV bundle (atrio ventricular bundle) is a collection of heart muscles cells specialised for electrical conduction. These specialised muscle fibres in cardiologist wilhelm His, Jr., Who discovered them in 1893.

Alveoli are the primary sites of exchange of gases. The exchange of gases (O2 and CO2) between the alveoli and the blood occurs by simple diffusion. 

Leghaemoglobin is an oxygen scavenger. It protects the nitrogen-fixing enzyme nitrogenase. 

The epiglottis is a flap that is made of elastic cartilage tissue covered with a mucous membrane, attached to the entrance of the larynx. It prevents the entry of food into the larynx, and directs it to the oesophagus. Due to improper movement of epiglottis, one may suddenly start coughing while swallowing some food.

Tuber is oval or spherical swollen underground modified stem lacking adventitious roots. It possesses a number of spirally arranged depressions called eyes. Each eye represents node and consists of 1-3 axillary buds in the axils of small scally leaves.

Arteries are blood vessels that carry blood away from the heart toward different organs. They generally contain oxygenated blood (except pulmonary artery which contains deoxygenated blood). The blood flows in an artery under alternate increased pressure and with jerks.