5th Class Part 3 Nutrition and Digestion PDF

Chapter One: Nutrition and Digestion Introduction Explain/ All organisms, primarily humans need energy? A/ To survive. Q/ Mention the main source of energy on earth? A/ The Sun Q/What does the life on earth depend on? A/ Sun light energy Q/ Mention the types of nutrition among living organis...

Chapter One: Nutrition and Digestion Introduction Explain/ All organisms, primarily humans need energy? A/ To survive. Q/ Mention the main source of energy on earth? A/ The Sun Q/What does the life on earth depend on? A/ Sun light energy Q/ Mention the types of nutrition among living organisms? A/ there are two types of nutrition among living organisms, 1/ Autotrophic nutrition: mainly in plants. In this type, organisms prepare their own food 2/Heterotrophic nutrition: mainly animals. In this type, organisms depend on the autotrophs or other organisms for food. Q/How do plants produce their own food? A/ Plants get water, carbon dioxide and necessary minerals from their environment. Plants absorb sun light energy by chlorophyll in their chloroplast and convert sun light energy into chemical energy. As a result plants produce their own food. Define autotrophs? Autotrophs: are organism that can produce their own food using light, water, carbon dioxide,and necessary minerals from their environment, or they use other chemicals. Most autotrophs are photosynthetic organisms and contain chlorophyll. Plants are a main type of autotroph, but there are other different kinds of autotrophic organisms like bacteria. Q/ How can some bacteria be used to synthesize organic materials? Some kinds of bacteria don't use sun light energy but they use chemical bond energy to synthesize the organic materials. Q/What makes an animal a heterotroph? A/ because they cannot produce their own food, they get their food or energy from outside sources. Q/ What is the importance of food for animals? Animals get energy for continuity of their generation and survival 1  Chapter One: Nutrition and Digestion Q/ What is the source of food to gain energy for living organisms?? Most of animals get energy from plants. Some animals get it from other animals. And these ingested food digestion to be used as source of energy. Nutrition in Unicellular Organisms Q/ Mention the types of nutrition among living organisms? A/ Unicellular Organisms can be autotroph or heterotroph. Q/ Give an example for an autotrophic unicellular organism but has heterotrophic types also? Explain A/ Euglena is an autotrophic organism but it has heterotrophic types also. Euglena diverse in nutrition because autotrophic types get food from environment in absence of light and if live in dark continuously it loses it’s chloroplast and live as heterotrophic organism for rest of life. Q/ Mention the origin of food vacuole? cell membrane of the organism (cell) surrounds the food. Q/ What is the fait for the digested food inside the food vacuole? A/ the digested food pass to the cytoplasm Q/ Name the type of enzymes found inside the lysosome? A/ digestive enzymes Transport of materials across cell membrane What is the process for transfer of material across the cell membrane? 1/Diffusion: It is the movement of materials from high concentrated medium to low concentrated medium without using energy 2/Osmosis: is movement of water through a semi-permeable membrane. Water exchange takes place between cytoplasm and external medium. 3/Active transport: is taking of necessary materials from low concentrated medium to high concentrated medium by using energy (ATP). 4/Phagocytosis: it is a process of cell swallowing, by taking large particles which cannot pass through pores in plasma membrane into the cytoplasm. for example (White blood cells devour the bacteria and viruses which infect the body). 5/Pinocytosis: Cell drinking 6/Exocytosis: it is a process of waste removing after completing the digestion inside the food vacuole by lysosome enzymes. 2  Chapter One: Nutrition and Digestion Q/ Describe the steps in the process of phagocytosis? 1. the cell membrane forms pseudopodia and surrounds the food 2. These pseudopods unite surround the food and a food vacuole is formed in cytoplasm 3. This vacuole fuses with lysosome which contain digestive enzymes to complete digestion 4. The digested food pass to the cytoplasm. Q/ What type of nutrition is saprophytic? What organism is saprotrophic nutrition? A/ In saprophytic type of nutrition digestive enzyme secreted out of cell. Materials formed as result of extracellular digestion are transported to the cell cytoplasm. Digested food materials may pass by diffusion which is movement of materials from high concentrated medium to low concentrated medium without using energy. Q/What organism is saprotrophic nutrition? Why? Fungi are saprophytic organisms. They get energy by converting organic materials of dead organisms into inorganic materials. As a result they have role in recycling of materials in nature by this way. Nutrition in Plants Define Photosynthesis: is an anabolic reaction by autotrophs in which water, carbon dioxide and radiant energy used, while glucose and oxygen are produced. The photosynthesis is usually carried out by chloroplast in eukaryotic cells such as plants. 3  Chapter One: Nutrition and Digestion Structure of Chloroplast The chloroplast is the organelle where photosynthesis occurs in photosynthetic eukaryotes. The organelle is surrounded by a double membrane. Inside the inner membrane is a complex mix of enzymes and water. This is called stroma and is important as the site of the dark reactions, Embedded in the stroma is a complex network of stacked sacs. Each stack is called a granum and each of the flattened sacs which make up the granum is called a thylakoid. Each thylakoid has a series of photosystems contain chlorophyll. Thylakoid membranes are the site for the light reactions in which light energy is converted to chemical energy needed for the Calvin cycle in the dark reaction. Q/ What does a chloroplast consist of? 1. Thylakoid membranes: are the site for the light reactions 2. stroma as the site of the dark reactions Q/ What does a Thylakoid membranes contain? A/ Chlorophyll pigments and other pigments Q/ What does a stroma contain? A/ Enzymes and water Define Thylakoids? A/ a flattened sacs which make up a stack called the granum, a complex network of stacked sacs embedded in the stroma. Each thylakoid has a series of photosystems contain chlorophyll. Thylakoid membranes are the site for the light reactions in which light energy is converted to chemical energy needed for the Calvin cycle in the dark reaction. 4  Chapter One: Nutrition and Digestion Q/What two types of reactions occur in photosynthesis? A/ Light and dark reactions Light Reactions Dark Reactions Requires Sun light Does not require Sun light Takes place in the thylakoid sacs of the Takes place in the stroma in the chloroplast chloroplast Water is split into oxygen and hydrogen. CO2 is converted into glucose through a series of chemical reactions called Calvin cycle using ATP and NADPH Light energy is converted into chemical energy ATP and NADPH from light reactions are used stored as ATP and NADPH to reduce CO2 Q/Who discovered that photosynthesis occurs in two different reactions? A/The scientist Blackman. Q/Who discovered the dark reactions? A/ The scientist Calvin, and the cycle was known as Calvin’s cycle. Define NADPH: Nicotinamide adenine dinucleotide phosphate or (NADPH) is a reduced coenzyme that plays a key role in the synthesis of carbohydrates in photosynthetic organisms. It is the reduced form of NADP+ and as such is a high energy molecule that helps drive the Calvin cycle. 5  Chapter One: Nutrition and Digestion Q/Where do plants use the chemical energy A/ It is necessary for cell activities. for growth and life activities and remain energy stored in form organic materials as carbohydrates. Q/ Explain Light Reactions? 1. There are chlorophyll pigments in thylakoid membrane of chloroplast and they absorb sun light. 2. One electron separates from the chlorophyll pigment when it is activated by light 3. This electron transport along the electron transport system (ETS). During this transportation electron lose energy. 4. This lost energy is used in production of adenosine tri phosphate (ATP) molecule. As a result light energy transformed into chemical bond energy. 5. Water is split into hydrogen (H) and oxygen (O₂) as a result of light reaction. 6. Hydrogen reduce the NADP (Nicotinamide Adenine Dinucleotide Phosphate) and forms the NADPH. Note: ATP and NADPH are two important compounds of light reactions Q/ Explain Dark Reactions (Calvin’s cycle)? 1. Dark reactions take place in stroma of chloroplast. Light is not used directly in these reactions but the products of light reactions (ATP and NADPH) are used 2. CO2 is reduced by ATP and NADPH. 3. At the end of dark reactions carbohydrates or different organic materials are formed. Note: Stored energy in body of organisms can be used for many years. Coal and petroleum contain energy which stored by photosynthesis before thousands of years. Q/What are the three stages of the Calvin cycle? 1. Fixation of CO2 2. Reduction of 3-phosphoglycerate to G3P (Glyceraldehyde 3-phosphate) 3. Regeneration of RuBP (Ribulose bisphosphate) from G3P 6  Chapter One: Nutrition and Digestion Figure 1.3: Photosynthesis consist of light and dark reactions (Calvin’s cycle) Photosynthetic pigments Define Photosynthetic pigments: they are molecules found in thylakoid membrane in chloroplasts which can absorb light with distinct wave length and other light reflect or pass through it. Such as Chlorophyll (A and B), Carotenoids , and Xanthophyll’s that have role in photosynthesis. *Note: Organisms vary according to type of chlorophyll they have. Chlorophyll A and B have active role in photosynthesis. Q/What is the function of pigments in a chloroplast? 1. absorb light with distinct wave length 2. reflect light 3. pass through it. (transport light ‫)الصحيح هو‬ Q/ What types of organisms contain chlorophyll? A/ Plants, Blue green algae and bacteria. Q/What pigments absorb light in chloroplast? A/ chlorophyll A and B, xanthophyll and carotenoids. Q/ List the photosynthetic pigments and their absorbance? 1. Chlorophyll (A and B) can absorb most of purple, blue and red wave length. Chlorophyll reflect most of green wave length so it is in green colour. 2. Carotenoids 3. Xanthophyll’s are yellow colored and insoluble lipids pigments and appear in autumn season. )‫(الصحيح انها ال تذوب في الماء لكنها تذوب في الدهن‬ 7  Chapter One: Nutrition and Digestion Q/ why does a plant appear green? A/ Because Chlorophyll reflect most of green wave length so it appears green in colour. Q/How much percent of sun light energy reach to Earth? A/ 42% Q/ What is the fate of most solar energy when it enters the Earth? 1. Only 42 % of sun light energy reach the earth. 2. Only 1-2 % of this energy is used in photosynthesis. 3. Remain energy absorbed by atmosphere or transform into heat. Q/ List the similarities between Mitochondria and chloroplast? A/ Mitochondria and chloroplast are similar in 1. structure of membranes. 2. They both have their own genetic material Materials used in photosynthesis Photosynthesis is a series of reactions in which simple monomers are used and complex polymers are formed. Q/What raw materials are used in the photosynthesis process? 1. Water 2. CO2 a. Water (H2O) Water is an essential reactant of photosynthesis. Ways of water entering the photosynthetic organisms 1. In aquatic plants: Water is absorbed directly through cell wall and transported to the chloroplast. Plants take large amount of water from environment, but only 1% of this water used in photosynthesis and remain water lost through stoma by transpiration. 2. Terrestrial plants: absorb water from soil by roots and transport it to the mesophyll layer of leaves where contain large amount of chlorophyll by xylem vessels. *While Some photosynthetic bacteria: don't use water as source of hydrogen (H) but they use alcohol, organic acids or hydrogen Sulphur(H₂S). For example reaction in green Sulphur bacteria as follows: 2H2S+CO2+ Light/Chlorophyll→ 2S+(CH₂O)+ H₂O b. Carbon dioxide (CO2) Q/ How does carbon dioxide reach the chloroplast? A/Plants absorb carbon dioxide from atmosphere by stoma which found in leaves and use it in photosynthesis. When carbon dioxide concentration decrease in leaves the absorbed carbon dioxide diffuse in spaces of mesophyll layer. Carbon dioxide dissolve in water and pass easily through the cell wall and reach the chloroplast in cytoplasm to be used in photosynthesis. 8  Chapter One: Nutrition and Digestion Factors affecting the photosynthesis:  Water  Carbon dioxide  Light  Temperature  Minerals  Soil Ventilation  Plant Diseases  Atmospheric Pollutant  Genetic Factors 1. Water Water is used in light reactions of photosynthesis and NADPH formed as a result. NADPH is used by dark reactions of photosynthesis for organic material synthesis. How does less water affect the rate of photosynthesis in plants? 1. Hydrogen molecules used in dark reactions decrease as a result of decreasing in water level. 2. Decreasing in water level causes the decreasing of osmotic pressure in guard cell of stoma then stoma closes and gas exchange decrease therefore transmission of carbon dioxide to the cells decrease and at last photosynthesis level decreases too. 3. Also photosynthesis level decreases when water level decrease in leaves they crisped because it affects the structure of chloroplast. 2. Carbondioxide (CO2) Q/What are the three sources of CO2? 1. Atmosphere is main source of carbon dioxide. 2. Respiration of organisms 3. Burning fossil products release carbon dioxide to the atmosphere. Q/ What is the concentration of CO2 in atmosphere? A/ Concentration of carbon dioxide in atmosphere is 0.03%. Q/ Does the concentration of CO2 affect the photosynthesis rate? A/ Increasing in carbon dioxide concentration causes increasing in photosynthesis level. 3. Light Light is source of energy for photosynthesis. What are the two responses plants according to light? There are two kinds of plants according to their response to light. They are 1. shadow plants 2. sun plants Each kind of plants can grow at a different level of light. Q/ Does light affect the photosynthesis rate? A/ Less or more light affects photosynthesis level adversely. Light wavelength affects the photosynthesis level. Photosynthesis level is high in red and blue wavelength because chlorophyll absorb most of light in these wavelength. 9  Chapter One: Nutrition and Digestion Q/ Explain Photosynthesis level is high in red and blue wavelength? A/ because chlorophyll absorb most of light in these wavelength. 4. Temperature  Temperature affect the dark phase of photosynthesis most since its reactions are catalyzed by enzymes.  Any increase in temperature up to approximately 40°C accelerates the rate of photosynthesis.  Above this temperature, reactions slow as proteinaceous enzymes denature and it causes decreasing in photosynthesis level Q/ How does temperature affect the dark reaction? A/ Temperature affect the dark phase of photosynthesis most since its reactions are catalyzed by enzymes. (Effect of Temperature on Photosynthetic enzymes) 5. Minerals Q/How do mineral elements affect photosynthesis?  Iron (Fe) and magnesium (Mg) are minerals that dissolve in soil. Insufficiency of these minerals chlorophyll and photosynthesis rates decreases.  Phosphate found in structure of Ribulose diphosphate and Adenosine tri phosphate (ATP), which are important molecules in photosynthesis.  Manganese and magnesium are important elements and they are important for activation of enzymes used in light and dark reactions. 6. Soil ventilation Q/How does Soil ventilation affect photosynthesis?  Soil ventilation helps root cells to absorb more oxygen. Insufficiency of oxygen in soil cause root cells to lose their vitality.  Roots cannot absorb enough water and minerals and it affects the photosynthesis adversely. 10  Chapter One: Nutrition and Digestion 7. Plant diseases Q/What plant affect photosynthesis? and how? 1. Viruses 2. Bacteria 3. Fungi infect the leaves of plants and decrease in rate of photosynthesis. 8. Atmospheric pollutant Q/What atmospheric pollutants affect photosynthesis? and how?  Dust  Pesticides  smoke of factories effect photosynthesis directly or indirectly. These pollutants can close the stoma on leaves of plants. Then enough carbon dioxide cannot be absorbed and rate of photosynthesis decrease. 9. Genetical factors Q/What genetic factors affect photosynthesis?  Thickness of cuticle layer on surface of leaves  number of stoma  structure of cells in mesophyll layer  number of chloroplasts and amount of chlorophyll they contain  enzymes which used in photosynthesis and production of chlorophyll synthesis Leaves and photosynthesis: Water and carbon dioxide are used in photosynthesis.  Water absorbed by roots and transported by xylem vessels in plants.  Carbon dioxide is absorbed by stoma and diffuse to the chloroplasts. Remember chloroplast consist of two main parts; grana and stroma.  There are chlorophyll A and B inside the thylakoid membrane. These pigments absorb sun light. Reaction in which carbon dioxide used take place in stroma and organic materials are used at the end of these reactions. Chemosynthesis: Some kinds of bacteria produce their own food by chemosynthesis. Inorganic materials are converted into the organic materials without sun light. These bacteria get necessary energy for production of organic substances by oxidizing some inorganic materials. There are some kinds of this bacteria:  Nitrosomonas These bacteria found in soil and convert ammonia (NH3) into nitrite (NO₂) as follows: Nitrite bacteria 11  Chapter One: Nutrition and Digestion  Nitrobacter These bacteria found in soil and can convert nitrite (NO2) into nitrate (NO3) as follows; Nitrate bacteria  Sulphur bacteria These bacteria found in sulphuric water sources. These bacteria oxidize hydrogen sulfide into water and Sulphur. Energy produced at the end of reaction and used in reduction of CO2. Q/ What is the source of energy for chemosynthetic bacteria (chemoautotrophics)? A/ These bacteria get necessary energy for production of organic substances by oxidizing some inorganic materials Nutrition in animals: Animals are heterotrophic organisms because they get organic food materials from plants or other animals But these food particles are not so small to pass through plasma membrane so they need digestion. Q/Why are animals considered heterotrophic organisms? A/ because they get organic food materials from plants or other animals. Q/Divide Animals into groups according to source of food? 1. Herbivores 2. carnivores 3. omnivores. Groups Food Type Carnivores Animals Frugivorous Fruits Herbivorous Plants Insectivorous Insects Omnivorous Plants and animals Detritivores Dead organic materials 12  Chapter One: Nutrition and Digestion Q/Compare between Green Sulphur Bacteria and Sulphur Bacteria? Green Sulphur Bacteria Sulphur Bacteria 1 autotrophic bacteria autotrophic bacteria found in sulphuric water sources 2 photosynthetic bacteria chemosynthetic bacteria 3 Has Chlorophyll pigments Doesn’t Have Chlorophyll pigments 4 get necessary energy for production of get necessary energy for production of organic substances from sunlight organic substances by oxidizing some inorganic materials (hydrogen sulfide into water and Sulphur) 5 Light/Chlorophyll 2H2S + O₂ Sulphur bacteria 2S+2H₂O + Chemical energy 2H2S+CO2 2S+(CH₂O) + H₂O 2H₂S + CO₂ Chemical energy (CH₂O)+H₂O + 2S Define/ catabolism: breaking down the ingested large food particles into their monomers like glucose by cellular respiration in cells, then energy and heat release at the end of reactions. Note: Ingested large food particles are broken down into their monomers and transported to the body cells by help of circulatory system. Feeding mechanisms All organisms need to get food to survive and they have different adaptations to do it. There are different methods of getting food among animals, some of them are; 1- Direct method 2- Feeding on planktons 3- Feeding on solid particles 4- Feeding on liquids 1-Direct method  Only little amount of animals take the food directly from environment.  They are parasitic organisms get the ingested food in form of monomers from the host.  Examples:  Some kinds of worms like tapeworm  Some aquatic invertebrate animals get some food directly from water. 2-Feeding on planktons  Planktons are tiny plant like (phytoplankton) or animal like (zooplanktons) tiny organisms which live in sea and oceans.  They hunted by invertebrate and vertebrate animals by  filter feeding method. Examples are: 1. Worms 2. bivalves 3. cephalochordates They take the planktons with water in their body and capture them By:  mucous in their mouth and send them to their digestive tract. 13  Chapter One: Nutrition and Digestion  Some animals have cilia around their mouths to capture the planktons  deposit feeding :as some animals feed on accumulated organic materials in the deep of water. Example is : 1. Some kinds of hemichordate 2. Some insects 3-Feeding on solid particles Animals have different body structures according to type of nutrition. 1. There are cutting regions in mouth of invertebrates to increase surface area of food to accelerate the digestion. Examples are: A. Insects have:  chitinous teeth  tongue  absorption tubes. They involved in:  detection  grinding  absorption of food particles. B. Nereis from invertebrates has muscular pharynx supported by chitinous teeth. Pharynx extend out of body capture the food and take into the body quickly. C. Some vertebrates catch their prey strongly by their front extremities and paralysis them by poison secretion. D. Complete chewing is performed only by mammals which have four different kin- ds of teeth. Each kind has a different function as follows; A. Incisors: They used in biting and cutting. B. Canines: They used in partition, especially meat fibers. C. Premolar: They used in chewing and grinding. D. Molars: They used in chewing and grinding. *Example for mammals with complete chewing is Human also have these kinds of teeth. Q/ Explain why are teeth different in animals? A/ according to type of nutrition. For example:  Herbivores have no canine teeth but have more developed molar teeth.  Incisors in rodents grow continuously during their life span. But they corrode gradually to limit their size. Q/ What purpose do canine teeth serve in elephants A/ Elephants use their canine teeth for defense and attack. Q/ What purpose do rodent mouth parts (Chewing mouth parts ‫ (الصحيح هو‬serve in Grasshopper? Some invertebrates have rodent mouth parts as in Grasshopper which has jaws Involved in cutting and grinding. 14  Chapter One: Nutrition and Digestion Bone A Q/ What purpose do bended molar teeth serve in Herbivore mammals like horse and cow? A/ to break the cellulosic wall of plant cell. This process facilitate the digestion of cellulose by microorganisms that live in their digestive system. 4-Feeding on liquids  It is kind nutrition in: 2. Parasites 3. some non-parasitic organisms feed by this method.  Examples: 15  Chapter One: Nutrition and Digestion  Some internal parasites absorb:  digested food of host organisms  some of them absorb blood through damaged wall of intestine.  some External parasites absorb:  blood by using their driller and absorber mouth parts, as in Some insects and leech. Digestion Digestion: is breaking down of big molecules into their monomers. Carbohydrates, proteins and lipids are main nutrients that need digestion to be used by organisms in production of energy and building new organic molecules. Q/ Mention the types of Digestion? A/ Digestion takes place in cell are:  ( Intracellular Digestion)  (Extracellular Digestion)= out of cell 1. Intracellular digestion: is the breakdown of substances within the cytoplasm of a cell, and forming Food vacuole which formed at the end of phagocytosis, it unites with lysosome. Digested food particles which can be used directly, like (glucose and amino acids) diffuse into cytoplasm. Wastes are removed from the cytoplasm by exocytosis. (figure 1.9) Q/ Who is responsible for breakdown of substances inside the Food vacuole? A/ lysosome Figure 1.9 Exocytosis in cell 16  Chapter One: Nutrition and Digestion 2. Extracellular digestion Extracellular digestion: is a process by secreting enzymes through the cell membrane into the food. The enzymes catalyze the digestion of the food into molecules small enough to be taken up by diffusion phagocytosis. Since digestion occurs outside the cell, it is said to be extracellular. It takes place either in the lumen of the digestive system, in a gastric cavity or other digestive organ, or completely outside the body. Extracellular digestion is a form of digestion found in annelids, crustaceans, arthropods, lichens and chordates, including vertebrates. Q/ Where does Extracellular digestion takes place? A/ It takes place either: 2. in the lumen of the digestive system 3. in a gastric cavity 4. in other digestive organ 5. completely outside the body Q/ In which type of organisms Extracellular digestion occurs? A/ Extracellular digestion is a form of digestion found in: 1. annelids 2. crustaceans 3. arthropods 4. lichens 5. chordates, including vertebrates. 17