English 2

1/Nastic Movement: "Nastic movements are non-directional responses to stimuli (e.g. temperature, humidity, light irradiance). The movement can be due to changes in turgor or changes in growth. Nastic movements differ from tropic movements in that the direction of tropic responses depends on the direction of the stimulus, whereas the direction of nastic movements is independent of the stimulus. The rate or frequency of these responses increases as intensity of the stimulus increases. An example of such a response is the opening and closing of flowers (photonastic response). Nastic responses are usually associated with plants. (iii) Thermonasty - It is induced by temperature. For example, the opening and closing of the flowers of tulip
(iv) Photonasty - It is induced by light. Leaves of Oxalis take up horizontal position in sunlight and droop down during the night. Many flowers open during the day and close during night or under cloudy sky.
(v) Thigmonasty - In the leaves of certain insectivorous plants, e.g. Drosera, Dionaea the tentacles show variation in movements on coming in contact with an insect. The touch stimulus due to the insect is transmitted to the entire leaf and all the tentacles bend over the insect.
2/DIGESTION AND ABSORPTION=The small intestine is where the majority of food digestion occurs. At this point carbohydrates and proteins are already partially digested, while lipids have not yet begun. Chyme leaves the stomach and enters the duodenum (the 1st portion of the small intestine) via the pyloric sphincter. Here, maltase breaks down maltose into glucose monomers and peptidases break down peptides into amino acids. Bile is then released from the gall bladder and enters the small intestine via the bile duct to aid in the digestion of fats into glycerol and fatty acids. The chyme then enters the jejunum (the 2nd portion of the small intestine) where digestion continues and absorption begins(the jejunum is composed of many fold that increase its