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Nutrition in Animals Learning Objectives for Nutrition in Animals Basic Biological Molecules Chemical Digestion The Human Alimentary Canal Absorption & Assimilation Lesson Objectives Different Biological Molecules Major Food Groups Food Tests Biological Molecules Food Groups Food Tests Biological Molecules Major Food Groups Carbohydrates Proteins Fats Food Test Demonstration Starch (Iodine Test) Reducing Sugar (Benedict’s Solution Test) Protein (Biuret Test) Fat (Ethanol Emulsion Test) Food Tests Starch (Iodine Test) Add Iodine to sample. Food Tests Reducing Sugar (Benedict’s Solution Test) Add Benedict’s Solution to sample. Boil mixture for no more than 2 minutes. Food Tests Protein (Biuret Test) Add Sodium Hydroxide (NaOH) to sample. Add Copper II Sulphate (CuSO4) drop by drop. Food Tests Fat (Ethanol Emulsion Test) Add Ethanol to sample and shake. Add Water to mixture and shake. Biological Molecules Water Carbohydrates Proteins Fats Water No one owes Singapore a living Discuss with your partner and write on: - the importance of water in our lives - methods to conserve water at home/school Learning Objectives for Nutrition in Animals Basic Biological Molecules Chemical Digestion The Human Alimentary Canal Absorption & Assimilation Lesson Objectives Chemical Digestion Structure and Functions of Biological Molecules Reflection time… DO NOT WASTE FOOD Food for thought. Carbohydrates Carbohydrases breaks down carbohydrates into simple sugars (monosaccharide) Polysaccharides=>Disaccharides =>Monosaccharides Chemical Digestion Carbohydrates Examples of monosaccharide - glucose, fructose, galactose Examples of disaccharide - maltose, sucrose, lactose Examples of polysaccharide - starch (amylose, amylopectin), glycogen Proteins Proteases breaks down proteins into amino acids Protein => Polypeptide => Amino acids Chemical Digestion Fats/Lipids Lipases breaks down fats into glycerol and fatty acids Lipid => Glycerol & Fatty Acids Chemical Digestion Revisiting the Carbohydrates Examples of monosaccharide - glucose, fructose, galactose Examples of disaccharide - maltose, sucrose, lactose Examples of polysaccharide - starch (amylose, amylopectin), glycogen Revisiting the Carbohydrates Hydrolysis Carbohydrases breaks downReaction carbohydrates into simple sugars (monosaccharide) Polysaccharides=>Disaccharides =>Monosaccharides Chemical Digestion Carbohydrates – Condensation Rxn Monosaccharides=>Disaccharides =>Polysaccharides Condensation Condensation Functions of Carbohydrates Glucose is required for cellular respiration to provide energy. Glycogen serves as an energy store. Revisiting the Proteins Hydrolysis Reaction Proteases breaks down proteins into amino acids Protein => Polypeptide => Amino acids Chemical Digestion Proteins – Condensation Rxn Proteases breaks down proteins into amino acids Amino Acid => Polypeptide => Protein Condensation Weak bonding Functions of Proteins Amino acids are converted into protein to make protoplasm. Enzymes are made of proteins. Antibodies are made of proteins. Excess amino acids are not stored and will be removed via deamination in the liver. Revisiting the Fats/Lipids Hydrolysis Reaction Lipases breaks down fats into glycerol and fatty acids Lipid => Glycerol & Fatty Acids Chemical Digestion Functions of Fats/Lipid Fat is required for the cell membrane. Adipose tissue helps to insulate the body and keep the body warm. Adipose tissue also helps protect the vital organs. Fats are energy store and can be utilised for respiration to provide energy. Summary for Nutrients Hydrolysis reactions Condensation reactions - A chemical reaction where a large and complex molecule into 2 smaller and simple molecules. A molecule of water is used up in the process. - A chemical reaction where 2 simple molecules are joined together to form a larger and more complex molecule. A molecule of water is produced in the process. - - Summary for Nutrients Carbohydrates Monosaccharide Disaccharide Polysaccharide (simple sugar) (double sugar) (complex sugar) e.g. glucose, galactose, fructose e.g. maltose, lactose, sucrose e.g. starch, glycogen, cellulose Summary for Nutrients Proteins Amino Acids Polypeptide Proteins Chains e.g. adenine, methionine e.g. enzymes, antibodies Summary for Nutrients Fats Fatty Acids Glycerol Fats/Lipids e.g. adipose tissues, phospholipids Learning Objectives for Nutrition in Animals Basic Biological Molecules Chemical Digestion The Human Alimentary Canal Absorption & Assimilation Lesson Objectives Parts of the Human Alimentary Canal Functions of the Human Alimentary Canal Peristalsis The Human Alimentary Canal Nutrition in Human Human Alimentary Canal Processes and Functions Ingestion – the process of taking in food into the alimentary canal through the mouth. Digestion - the process of the breaking down of large, complex and insoluble substances into small, simple and soluble molecules by the action of enzymes; so as to facilitate the absorption of nutrients into the body. Human Alimentary Canal Processes and Functions Absorption – the process where digested food substances are taken up by the body through the blood stream. Assimilation – the process where the nutrients absorbed are converted into new protoplasm and/or used to release energy for the body Human Alimentary Canal Processes and Functions Egestion – the process where indigestible and unabsorbed material are removed from the alimentary canal through the anus. Egestion = Excretion* *Excretion is the removal of metabolic waste products from the body through the excretory system (to be covered in later topics) Buccal Cavity - Salivary glands Salivary amylase Starch → Maltose Oesophagus Food is broken down into smaller bits by chewing (physical digestion). increases surface area of food substances. Salivary glands produce salivary amylase that breaks down starch into maltose. The bolus is swallowed and being pushed along the oesophagus by peristalsis. Peristalsis Peristalsis Longitudinal muscles Epidermal layer Lumen Circular muscles Antagonistic muscles Stomach Gastric juices is secreted into the stomach. Gastric juices contain hydrochloric acid, pepsin and rennin. hydrochloric acid kills bacteria. hydrochloric acid lowers the pH in the stomach (pH 2~3). pepsin breaks down protein to polypeptides. rennin curdles the milk. salivary amylase action stops due to the low pH. (non-optimal pH conditions) - - - Pepsin Protein → Poly-peptides Small intestine and peripheral organs Liver Gall bladder - Bile duct - Pancreas - Duodenum Lipase Fats → Fatty acid + Glycerol Liver makes bile Bile is stored in gall bladder and secreted into the duodenum via the bile duct. bile increases the pH (pH 9~10) bile emulsifies fat. emulsification of fat increases the surface area for fat digestion. lipases will break down the fats into fatty acid and glycerol. Small intestine and peripheral organs Liver Gall bladder Bile duct - Pancreas - Duodenum Trypsin Protein → Poly-peptides - - Pancreas produces pancreatic juices. Pancreatic juices are secreted into the duodenum via the pancreatic duct. pancreatic juices increases the pH (pH 9~10). pancreatic juices contains pancreatic amylase, pancreatic lipase, and trypsin. trypsin breaks down protein to polypeptides. gastric juices actions stop. Small intestine and peripheral organs Liver Gall bladder - Bile duct Pancreas - Duodenum Erepsin Poly-peptides → Amino acids Small intestine produces intestinal juices. Small intestine absorbs most of the nutrients at the end of ileum. intestinal juices contains erepsin, lipases and carbohydrases. erepsin breaks down polypeptides into amino acids. Large intestine, rectum and anus. colon appendix rectum anus Colon absorbs the remaining water content and mineral salts. Rectum serves as a temporary storage for indigestible material and unabsorbed material. The anus is the opening where faeces is egested out of the body. Digestion (pancreatic enzymes) Starch Protein Fat amylase trypsin lipase maltose polypeptides fatty acids and glycerol Digestion (intestinal enzymes) Maltose Polypeptides Fats maltase erepsin lipase glucose amino acids fatty acids and glycerol Learning Objectives for Nutrition in Animals Basic Biological Molecules Chemical Digestion The Human Alimentary Canal Absorption & Assimilation Lesson Objectives Absorption of nutrients Roles of the liver Absorption of nutrients Nutrients absorbed in the Digestive System would be carried to parts of the body via the Circulatory System (Blood). Adaptations in the Alimentary Canal The Human Alimentary Canal (from the mouth to the anus) is approximately 6.5 metres long. Why? -Food takes time to be digested. -The longer food stays in the body, more nutrients can be absorbed. Adaptations in the Alimentary Canal Increased surface area can help increase the rate of absorption of nutrients. The intestinal walls are lined with networks of blood capillaries. folds Adaptations in the Alimentary Canal Diagram of a villus showing the blood capillary network and the lacteal. microvilli folds Blood capillaries Lacteal The hepatic portal vein Nutrients absorbed from the small intestine is transported to the liver via the hepatic portal vein Nutrients absorbed from the large intestine is transported to the liver via the hepatic portal vein Roles of the Liver Metabolism of Glucose Metabolism of Amino Acid (Formation of Urea) Metabolism of Fats Breakdown of Red Blood Cells Breakdown of Alcohol Production of heat. Metabolism of Glucose - Insulin will promote the conversion of glucose into glycogen in the liver Glucagon will promote the conversion of glycogen into glucose in the liver - Insulin and Glucagon are secreted by the pancreas to regulate the blood glucose levels in the body. In a healthy individual, insulin is secreted when blood-glucose level is high. Insulin promotes the uptake of glucose into the liver and the conversion of glucose into glycogen. In a healthy individual, glucagon is secreted when blood-glucose level is low. Glucagon promotes the conversion of glycogen into glucose and the release of glucose into the bloodstream. Metabolism of Amino Acids The liver will deaminate excess amino acids to form urea. Excess amino acids will be found in the human body after the person has taken in large amount of protein. The excess amino acids will be deaminated to form urea. Urea is toxic and is removed from the body via the kidney. Urea is a metabolic waste product. Breakdown of Alcohol The liver will detoxify alcohol to form other harmless products. Alcohol is broken down in the liver into harmless substances through detoxification. When there is surplus of nutrients in the body, alcohol is converted into fats and stored in the body. When there is a shortage of nutrients in the body, alcohol is broken down by enzymes to release energy. Summary of Digestion Carbohydrates (polysaccharides) Proteins (polypeptides) Fats/Lipids (polymer) Glucose (monosaccharides) Amino Acids DIGESTION (monomers) Fatty Acids/Glycerol (monomers) e.g. Glycogen (polysaccharides) e.g. Enzymes ASSIMILATION (polypeptides) e.g. Adipose Tissue (polymers) File Case 00129042009 Annabel: found dead at home in her room by her mother at 3pm. Suspect 1: Joanne (Annabel’s mother) Recently divorced, Status complicated Has depression and suicidal tendency Suspect 2: Nicholas (Annabel’s brother) Studies at SARS University: Life-Sciences undergrad, specializing in toxins On bad terms with Annabel, Sibling rivalry. Suspect 3: Bruce (Joanne’s boyfriend) Bought all the food ate by Annabel before she died. Annabel finds him unworthy of her mother. Coroner’s Report Cause of death: Acute food poisoning due to presence of neurotoxin produced by mutant bacterial strain; Mutant bacterial strain is similar to Pseudoalteromonas tetraodonis, a well-known marine bacterium that produces a neurotoxin that is very potent, usually found in puffer fish and other venomous marine animals. Other evidences gathered Unpublished blog posting from Annabel. Recorded statements from suspects. Preliminary food test results. Food test results for the presence of mutant bacterial strains. (currently in progress) Directives: 1. Which are the food product/s that should be tested for the presence of the mutant bacterial strain? 2. Which are the food product/s likely to be utilized by the mutant bacterial strain for its metabolism? 3. Suggest a possible reason for the observation in the Iodine test performed on the food samples collected from the body of the deceased. 3. Suggest a possible reason for the observation in the Iodine test performed on the food samples collected from the body of the deceased. Directives: 4. Examine the results for the food test for presence of mutant bacterial strain so as to determine the cause of acute food poisoning. 5. Suggest who might be responsible for poisoning Annabel, indicating the contaminated food item, and support your deduction with logical reasoning.