Nutrition PDF

NUTRITION  PLANT NUTRITION Nutrition is the process of providing or obtaining food necessary for health, survival, and growth of an organism. In this process, an organism takes in, digests, and uses the different substances obtained from various food sources. These substances, ca...

NUTRITION  PLANT NUTRITION Nutrition is the process of providing or obtaining food necessary for health, survival, and growth of an organism. In this process, an organism takes in, digests, and uses the different substances obtained from various food sources. These substances, called nutrients. Nutrient - refers to any substance required for the growth and maintenance of an organism. The two types of organisms based on the mode of nutrition are:  AUTOTROPHIC Autotrophs – organisms that obtain energy from sunlight and chemicals to produce their own food. Examples: plants; chemosynthetic bacteria.  AUTOTROPHIC (2 types) a. Photoautotrophic organisms directly use the energy from the sun and other inorganic substances such as carbon dioxide and water to form organic food. Organisms that have this type of nutrition are called photoautotrophs. Examples of photoautotrophs are plants and some forms of bacteria and protists.  AUTOTROPHIC (2 types) b. Chemoautotrophic organisms use chemicals to create simpler organic substances important for their survival. Such organisms are called chemoautotrophs. Most bacteria and members of the group Archaea that live in extreme environments such as volcanoes and deep-sea vents are classified in this group. Common inorganic substances synthesized by the chemoautotrophs include hydrogen sulfide, sulfur, and ammonia.  HETEROTROPHIC Heterotrophs – organisms that cannot make their own food and obtain their energy from other organisms. Examples: animals, fungi.  HETEROTROPHIC Saprophytic/saprotrophic Parasitic Holozoic  Saprophytic/saprotrophic In this type of nutrition, organisms obtain their nutrients from dead organic matter. These organisms secrete digestive juices to the surroundings, which will be later absorbed through their body surface. Such organisms are called saprophytes, and they include fungi and bacteria.  Parasitic In this type of nutrition, an organism takes food from another organism. Parasitic nutrition is exhibited by some plants and animals. The organism that takes food is called a parasite, and the organism from where the food is taken is called the host. The parasite can be either outside or inside the host.  Parasitic Ectoparasitism - This type of parasitism happens when the parasite is outside the body of the host. Some examples are fleas in dogs and head lice in humans. Endoparasitism - this type of parasitism involves parasites that live inside the body of the host. Some endoparasites include roundworms and hookworms. Both worms negatively affect the health of humans.  Holozoic In this mode of nutrition, organisms ingest solid or liquid food. The food is then digested and absorbed by the body. This type of nutrition is subdivided based on the type of organic matter ingested.  Holozoic Herbivorous Carnivorous Omnivorous  Herbivorous Herbivorous - Organisms that take in only plants as source of their energy are classified as herbivores. Sheep, rabbits, and cows are examples of herbivorous animals.  Carnivorous Carnivorous - Organisms that eat other animals are called carnivores. LIons, tigers, and sharks are examples of carnivorous animals.  Omnivorous Omnivorous - Organisms that take in both plants and animals are called omnivores. Pigs, hens, and bears are examples of omnivorous animals. The nutritional requirements of plants: water carbon dioxide A. Further, note B. photosynthesis, that water and the process by carbon dioxide which plants convert the energy are the raw from sunlight into materials chemical needed for. energy. C. essential nutrients or elements – which include macronutrients which are normally required in amounts above 0.5% of the plant’s dry weight; and micronutrients which are required in minute or trace amounts; examples of macronutrients: C, H, O, N, K, Ca, Mg, P, S examples of micronutrients: Cl, Fe, B, Mn, Zn, Co, Mo  ANIMAL NUTRITION A Calorie is a unit of energy that indicates the amount of energy contained in food. It specifically refers to the amount of heat energy required to raise the temperature of 1 kg (2.2lb.) of water by 1oC (1.8oF). The greater the number of Calories in a quantity of food, the greater energy it contains (Johnson and Raven, 1996).  Carbohydrate Serve as a s major energy source for the cells in the body. These are usually obtained from grains, cereals, breads, fruits, and vegetables. On average, carbohydrates contain 4 Calories per gram.  Fats Are used to build cell membranes, steroid hormones, and other cellular structures; also used to insulate nervous tissue, and also serve as an energy source. Fats also contain certain fat- soluble vitamins that are important for good health. Fats are obtained from oils, margarine, butter, fried foods, meat, and processed snack foods. They contain a higher amount of energy per gram than carbohydrates or proteins,  Carbohydrate Serve as a s major energy source for the cells in the body. These are usually obtained from grains, cereals, breads, fruits, and vegetables. On average, carbohydrates contain 4 Calories per gram.  Essential Nutrients Include substances that animals can only get from the foods they eat because they could not be synthesized inside the body. These include:  Essential Nutrients Essential amino acids Needed for synthesis of proteins and enzymes; among the 20 amino acids, eight could not be synthesized by humans: lysine, tryptophan, threonine, methionine, phenylalanine, leucine, isoleucine and valine.  Essential Nutrients Essential fatty acids Used for making special membrane lipids; an example is linoleic acid in humans.  Essential Nutrients Vitamins Organic molecules required in small amounts for normal metabolism; examples include fat-soluble Vitamins A, D, E, K, and water-soluble Vitamins B, B2, B3, B12, C.  THE MAIN STAGES OF FOOD PROCESSING: 1. Ingestion 2. Digestion Digestion is the process of The act of eating or mechanically and feeding; this is coupled enzymatically breaking with the mechanical down food into substances breakdown of food into for absorption into the smaller pieces allowing bloodstream. The food for a greater surface contains three macronutrients that area for chemical require digestion before digestion. they can be absorbed: fats, carbohydrates, and proteins.  THE MAIN STAGES OF FOOD PROCESSING: 3. Absorption 4. Passage of digested Elimination Expulsion of the nutrients and fluid undigested and across the tube wall unabsorbed and into the materials from the body fluids; the cells take up (absorb) small end of molecules such as the gut. amino acids and simple sugars. THE ORGANS INVOLVED IN FOOD PROCESSING IN THE HUMAN DIGESTIVE SYSTEM: A. The Oral Cavity, Pharynx, and Esophagus  Oral Cavity It is where food Saliva is secreted is initially into the mouth by three pairs of chewed into salivary glands shreds by the located above the teeth, and mixed upper jaw and with saliva by the below the lower tongue. jaw.  Pharynx The region in the back To block breathing of the throat that as food leaves the serves as the entrance pharynx, a flap- to the esophagus that like valve (the connects to the stomach and trachea epiglottis) and the (windpipe) that serves vocal cords close as airway off the trachea. to the lungs.  Esophagus Connects the pharynx The rhythmic waves with the stomach. No of contraction of the digestion takes place smooth muscle wall within the esophagus of the esophagus are but the contractions called peristaltic within its muscular contractions or wall propel the food peristalsis. The past a sphincter, into esophagus is about the stomach. 25 cm (10 in.) long.  B. The Stomach The stomach is a muscular, stretchable sac located just below the diaphragm. It has three important functions. First, it mixes and stores ingested food. Second, it secretes gastric juice that helps dissolve and degrade the food, particularly proteins. Third, it regulates the passage of food into the small intestine. The gastric juice is a combination of HCl and acid-stable proteases. The churning action of the stomach together with the potent acidity of the gastric juice convert food into a thick, liquid mixture called chyme. B. The Stomach  C. Small Intestine The small intestine is approximately 6 meters long and is composed of three regions: the duodenum, jejunum, and ileum. It is where most enzymatic hydrolysis of the macromolecules from food occurs. The complete digestion of carbohydrates, fats, and proteins occurs in the duodenum, about the first 25 cm. of the small intestine. The rest of the small intestine is devoted to absorbing water and the products of digestion into the bloodstream. Absorption of the end products of digestion takes place in the ileum, the surface area of which is increased by villi and microvilli. C. Small Intestine  D. The Accessory Digestive Organs Pancreas, Liver, and Gallbladder  D. The Accessory Digestive Organs The Large Intestine or Colon  The large intestine is much shorter than the small intestine, about 1 meter.  It concentrates and stores undigested matter by absorbing mineral ions and water. A small amount of fluid, sodium, and vitamin K are absorbed through its walls.  Unlike the small intestine, it does not coil up and does not have villi and has only one thirtieth of the absorptive surface area of the small intestine.  Many bacteria live and thrive within the large intestine where they help process undigested material into the final excretory product, feces. D. The Accessory Digestive Organs The Large Intestine or Colon  D. The Accessory Digestive Organs The Large Intestine or Colon  The large intestine is much shorter than the small intestine, about 1 meter.  It concentrates and stores undigested matter by absorbing mineral ions and water. A small amount of fluid, sodium, and vitamin K are absorbed through its walls.  Unlike the small intestine, it does not coil up and does not have villi and has only one thirtieth of the absorptive surface area of the small intestine.  Many bacteria live and thrive within the large intestine where they help process undigested material into the final excretory product, feces.  D. The Accessory Digestive OrgansThe Rectum and Anus  The rectum is a short extension of the large intestine and is the final segment of the digestive tract. It is where the compacted undigested food from the colon are pushed via peristaltic contractions.  The distention of the rectum triggers expulsion of feces.  The anus is the terminal opening of the digestive system through which feces are expelled. D. The Accessory Digestive OrgansThe Rectum and Anus