2. Plant Nutrition
What is Nutrients?
-refers to any substances required for growth and maintenance of an
organism.
Two types of organism that based on the mode of nutritions are
a. Autotrophs —organisms that obtain energy from sunlight and
chemicals to produce their food.
Examples: plants and chemosynthetic bacteria.
3. b. Heterotrophs —organism that cannot make their own food and
obtain their energy for other organisms.
Examples: animals and humans
THE NUTRIENTS REQUIREMENTS OF PLANTS:
• Water
• Carbon dioxide
a. Further , that water and carbon dioxide are the raw materials needed
for
b. photosynthesis, the process by which plants convert the energy from
sunlight into
• Chemical energy
4. 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
5. Animal Nutrients
A Calorie is a unit of energy that indicates of energy contained in the food. It
specially refers to the amount of heat energy required to raise the
temperature of 1kg (2.2 lb.) of water 1°C(1.8°F). The greater the number of
Calories in quantity of food , the greater energy it contains( Johnson and
Raven , 1996 ).
6. THE NUTRITIONAL REQUIREMENTS OF ANIMALS
• Carbohydrates —serve as a major energy source for the cells in the
body.
• Proteins –can also be used as an energy source but the body mainly
uses these as building materials for cell structures and as enzymes ,
hormones , parts of muscles , and bones.
• Fats –are used to builds cell membranes , steroids hormones , and
other cellular structures ; also used to insulate nervous tissue , and
also serve as an energy source.
7. • Essential Nutrients – includes substances that animals can only get from
the foods they eat because they could not be synthesized inside the body.
These include:
Essential amino acids –needed for synthesis of proteins and enzymes ;
among the 20 amino acid , eight could be synthesized by humans: lysine ,
tryptophan, threonine, methionine, phenylalanine, leucine, isoleucine and
valine.
Essential fatty acids –used for making special membrane lipids; an
example is linoleic acids in human.
Vitamins –examples include fat-soluble Vitamins A, D, E, K, and water-
soluble Vitamins B, B2, B3, B12, C.
8. THE MAIN STAGES FOOD
PROCESSING
1. Ingestion —the act for eating or feeding: this is coupled with the mechanical
breakdown of the food into smaller pieces allowing for a greater surface area for
chemical digestion.
2. Digestion —breakdown of the food into particles, then nutrients molecular small
enough to bs chemical digestion by enzymes involves breaking of chemical bonds
through addition of water.
3. Absorption —passage of digested nutrients and fluid across the tube wall and into the
body fluids; the cells take up( absorb ) small molecules such as amino acids and simpe
sugar
4. Elimination —expulsion of the undigested and unabsorb materials from the end of
the gut.
9. THE ORGANS INVOLVED IN FOOD
PROCESSING IN THE HUMAN DIGESTIVE
SYSTEM
A. The Oral cavity , pharynx , and esophagus
• Oral cavity —it is where food is initially chewed into shreds by the teeth, and mixed
with saliva.
• Pharynx —the region in the back of the tthroat that serves as the entrance of the
esophagus that connected to the stomach and tranchea that serves as a airway to the
lungs.
• Esophagus —its a muscular wall propel the food past a spincter , into the stomach.
10.
11. The gall bladder stores the bile that is produced by the liver
• Large intestine and Colon —it concentrates and stores undigested matter
by absorbing mineral ions and water.
• The Rectum and Anus
The rectum is a short extension of the large intestine and is the final
segment of digestive tract.