Republic of the Philippines Department of Education REGION I SCHOOLS DIVISION OF CANDON CITY Candon City, Ilocos Sur GENERAL BIOLOGY 2 Quarter 4 – Week 2 - Module 2: Prepared by: Elsa B. Biswelan Lesson 1 I. Plants and Animals: Nutrition OBJECTIVES: 1. Identify the nutritional requirements of plants and animals. 2. Describe the mode of nutrition of plants and the feeding mechanism of animals. 3. Compare and contrast the following processes in plants and animals: Nutrition (STEM_BIO11/12IVa-h-1) II. GUIDE QUESTIONS: 1. How do we identify the nutritional requirements of plants and animals? 2. How do we describe the mode of nutrition of plants and the feeding mechanism of animals? 3. How do we compare the following processes in plants and animals: Nutrition? III. DISCUSSION As you know that all living organisms require food to survive, grow and reproduce so every organism takes in food and utilizes the food constituents for its requirements of growth. A series of processes are involved in the synthesis of food by breaking down the food into simpler substances and utilization of these simpler substances for life processes. Nutrition in plants may thus be defined as a process of synthesis of food, its breakdown, and utilization for various functions in the body. Essential elements may be required in small amounts or large amounts. Accordingly, they have been grouped into two categories. Microelements/Micronutrients Macroelements/Macronutrients Required in minute quantities like 0.1 mg per gram of dry matter or less than that. Also called trace elements. Required in relatively large quantities like one to 10 milligram per gram of dry matter. General Biology 2 - Page 1 of 8 Examples: Manganese, Boron, Cobalt, Copper, Molybdenum, Iron, Zinc, and Chlorine are required in very small quantities Examples: Carbon, Hydrogen, Oxygen Phosphorous, Potassium, Calcium and magnesium, Nitrogen, Sulphur Essential elements perform various functions. They carry out several metabolic processes in the plant cells like the maintenance of turgidity of the cell, transportation of electrons, membrane permeability, and enzyme activity. Essential elements also act as important constituents of the biomolecules and co-enzymes. Most of the essential elements are taken from the soil and some from the atmosphere. The table given below focuses on the sources of different essential elements for plants. Elements Sources of the elements Carbon Taken as CO2 from the atmosphere (air) Oxygen Absorbed in the molecular form from the air or water. It is also generated within a green plant during photosynthesis. Hydrogen Released from water during photosynthesis in the green plant Nitrogen Absorbed by the plants as nitrate ion – + (NO3 ) or as ammonium ion (NH4 ) from the soil. Potassium, calcium iron, phosphorus Sulfur magnesium Some organisms like bacteria and cyanobacteria can fix nitrogen from the air directly. Absorbed from the soil (are derived from the weathering of rocks. They are called mineral elements). Nutrition in plants is classified into two main categories: autotrophic and heterotrophic. Heterotrophic plants are further classified into saprophytes, parasites, and insectivores. Autotrophic Nutrition is a type of nutrition in which living organisms manufacture their organic food from simple inorganic raw materials. The green plants exhibit an autotrophic mode of nutrition and are hence called autotrophs. Autotrophs require an external energy source for the manufacture of organic substances. Green plants obtain energy from sunlight and therefore are called photoautotrophs. The process of synthesizing food in plants in the presence of sunlight is called photosynthesis. The insectivores are autotrophic but they develop specific structures to trap insects to overcome N2 deficiency because they grow in soils having acute N2-deficiency. General Biology 2 - Page 2 of 8 Heterotrophic nutrition is certain non-green organisms like fungi and many bacteria fail to synthesize their organic nutrients from inorganic substances. These organisms are thus dependent on some other external sources for their organic nutrition. Such plants are called heterotrophic plants and the mode of nutrition is called heterotrophic nutrition. The heterotrophic plants are broadly categorized into two main groups depending upon the source from which they get their nourishment. Saprophytes, and parasites. (a) (b) (c) Saprophytes: are those plants that grow and live on dead organic matter including animal and plant remains. Most of these plants secrete some extracellular enzymes (enzymes secreted and poured out on food) which break down the complex organic compounds into simple forms. The simple form is then absorbed by the plants. Saprophytes include mainly fungi and bacteria. Parasitic Plants: Dodder (Cuscuta) known locally as Amarbel/Akashbel is a parasitic plant that lacks both chlorophyll and leaves. It is a yellow color climber that attaches itself to the host. It gives out haustoria or the suckers that get attached to the phloem of the host and derive nutrition. Cuscuta does not have roots in the mature condition. It produces bunches of whitish or yellowish bell-shaped flowers. Insectivorous Plants: These are plants that are autotrophic but develop adaptations to trap insects to supplement the deficiency of Nitrogen in the soil. They feed on insects. They are generally found in nitrogen-deficient habitats and hence to compensate for the loss, they use insects as a source of nitrogen. Some examples are Pitcher plant: Nepenthes, Sundew: Drosera, Venus flytrap: Dionaea, and Bladderwort: Utricularia. The pitcher has nectar-producing glands below its rim. The shiny surface of the pitcher and nectar secreted by nectar glands attract the insects. Insects once trapped cannot escape due to the presence of numerous downward-pointing hairs in the pitcher. The digestive glands present at the base of the pitcher secrete enzymes. The insects are digested by the enzymes and the products which are mainly amino acids are absorbed by the inner surface of leaves (a pitcher). Animal Nutrition A calorie is a unit of energy that indicates how much energy is found in each amount of food. It refers to the amount of heat energy needed to increase the temperature of one kilogram (2.2 pounds(lbs.)) of water by one degree Celsius (1.8oF). The more calories in each amount of food, the more amazing energy it contains. Nutritional requirements of animals: (a) (b) Carbohydrates – serve as a significant energy source for the cells in the body. These are usually obtained from grains, cereals, bread, vegetables, and fruits. Carbohydrates contain, on average, four calories per gram. Proteins- can also be used as a source of energy, but the body primarily uses them as building materials for cell structures, hormones, enzymes, bones, and muscle parts. General Biology 2 - Page 3 of 8 (c) Proteins are extracted from meat, poultry, fish, milk, and grain products. Like carbohydrates, protein also contains four calories per gram. Fats are used to produce steroid hormones, cell membranes, and other cell structures; they are also used to insulate nervous tissue and act as a source of energy. Fats often contain unique fat-soluble vitamins that are important for good health. Fats are derived from oils, margarine, butter, fried foods, beef, and snack foods that are refined. They produce higher energy per gram, about nine calories per gram. Essential nutrients are compounds that can only be derived from animals because they cannot be synthesized within the body but only from the foods they consume. These include: (a) (b) (c) (d) Essential amino acids – The amino acids lysine, tryptophan, threonine, methionine, phenylalanine, leucine, isoleucine, and valine are eight twenty amino acids that humans cannot synthesize. Essential fatty acids are used to make unusual membrane lipids; an example is a linoleic acid in humans. Vitamins – Vitamins A, D, E, and K, as well as water-soluble Vitamins B, B2, B3, B12, and C, are organic molecules that are needed in small amounts for normal metabolism. Trace Elements or Minerals –Iodine, cobalt, copper, molybdenum, manganese, and selenium are examples of inorganic nutrients that the body requires in minute quantities found in hormones, and body tissues, and body fluids. The mechanisms of digestion and absorption: (a) (b) (c) (d) Carbohydrate digestion begins in the mouth but could not continue in the stomach due to the acidic pH that destroys the amylase. It resumes in the small intestine where the resulting monosaccharides are absorbed. Proteins are digested in the stomach and small intestine. The resulting amino acids are absorbed in the small intestine where they leave the intestinal cell and enter the blood through a facilitated diffusion carrier in the plasma membranes on the opposite side. Fat digestion occurs entirely in the small intestine. Although fatty acids and monoglycerides enter epithelial cells from the intestinal lumen, it is triglycerides that are released on the other side of the cell and carried by blood capillaries to be transported throughout the body. Most water-soluble vitamins are absorbed by diffusion or active transport. Fat-soluble vitamins follow the pathway for fat absorption. The different types of animals based on feeding mechanisms: General Biology 2 - Page 4 of 8 (a) (b) (c) (d) Substrate-feeders – animals that live in or on their food source. Examples: earthworms that feed through the soil where they live; caterpillars that eat through the leaves where they live on. Filter-feeders – include many aquatic animals which draw in water and strain small organisms and food particles present in the medium. Examples: whales and coelenterates Fluid-feeders – suck fluids containing nutrients from a living host. Examples: mosquitoes, leeches, head lice, aphids Bulk-feeders – eat relatively large chunks of food and have adaptations like jaws, teeth, tentacles, claws, pincers, etc. that help in securing the food and tearing it to pieces. Examples: snakes, cats, man The different kinds of digestive compartments in animals: (a) (b) (c) Food vacuoles in unicellular organisms – these fuse with lysosomes that contain hydrolytic enzymes. Example: food vacuole in protozoa like Paramecium The gastrovascular cavity or incomplete digestive system – is composed of a single opening through which food is taken in and where wastes are disposed of; it is a saclike body cavity. Examples: in the cnidarian Hydra and flatworm Planaria Complete digestive system – essentially like a tube with an opening at one end for taking in food (mouth) and an opening at the other end where unabsorbed waste materials are eliminated (anus). In between the mouth and anus, are specialized organs that carry out transport, processing, and absorption of digested nutrients. General Biology 2 - Page 5 of 8 IV. EXAMPLES: Plant and Animals Nutrition-The comparison https://www.google.com/search?q=Diagram+on++the+nutrition+of+plants/animals https://www.google.com/search?q=Diagram+on++the+nutrition+of+plants General Biology 2 - Page 6 of 8 https://www.google.com/search?q=Diagram+on++the+nutrition+of+animals V. GENERALIZATION Plant nutrition can be differentiated from animal nutrition based on distinctive traits that plants are autotrophic while animals are heterotrophic. Plants by themselves obtain their supply of energy from the sun and absorb nutrients from the air and soil. In contrast, animals are heterotrophic, that is, they are not capable of directly utilizing the radiant energy from the sun. They must obtain their supply from plants in the form of chemical energy either directly or indirectly. In both organisms, it is this food that serves as a source of energy (chemical energy) that is required in life processes. VI. EXERCISES: Activity 1 DIRECTIONS: Fill out the table by classifying each word from the box if it relates to plants or animals. Write on a separate sheet of paper. Holozoic Saprophytes PLANTS Autotrophic Chlorophyll Bulk feeder Fluid feeder ANIMALS General Biology 2 - Page 7 of 8 Activity 2 DIRECTIONS: Fill in the table to see the similarities and differences between the organs/structures used to obtain nutrients with their corresponding function. Write your answer in a separate sheet of paper. Organs/ Structures used for Nutrition PLANTS Animals Functions 1. 2. 3. 1. 2. 3, 4. 5. 6. 7. VII. REFERENCES: Tiamson, M.E. (2016). General Biology (Philippine Edition). Vibal Group Reece JB, Urry LA, Cain ML, Wasseman SA, Minorsky PV, and RB Jackson. Campbell Biology. Tenth Edition. Boston, USA: Pearson Education, Inc. 1279p. Starr C and R Taggart. 2004. BIOLOGY: The Unity and Diversity of Life. Tenth Edition. Australia: Thomson – Brooks/Cole. 933p. Barrion AA, Tudor MFVA, Colle MCD, Reamillo MCS, and MAP Robles. 2000. BIOLOGY II Laboratory Manual: An Investigative Approach. VIII. ANSWER KEY: Activity 2 Answers May Vary holozoic chlorophyl fluid feeder Autotrophic bulk feeder Saprophytes PLANTS Activity 1 ADDITIONAL ACTIVITY General Biology 2 - Page 8 of 8 ANIMALS