Practice Questions Nutrition in Humans PDF

What is Nutrition? ◦Nutrition is the process by which an organism obtain food and energy for growth, repair and maintenance of the body What does nutrition consist of and brie y describe them? (Hint: 5) ◦Ingestion - food is taken into the body ◦Digestion - large food molecules are br...

What is Nutrition? ◦Nutrition is the process by which an organism obtain food and energy for growth, repair and maintenance of the body What does nutrition consist of and brie y describe them? (Hint: 5) ◦Ingestion - food is taken into the body ◦Digestion - large food molecules are broken down into smaller, soluble molecules that can be absorbed ◦Absorption - nutrient move from the small intestine into the bloodstream ◦Assimilation - nutritients are used by cells to provide energy or to make new cytoplasm for growth ◦Egestion - undigested matter is removed from the body Name the organs in alimentary canal? ◦Mouth ◦Oesophagus ◦Stomach ◦Small intestine ◦Large intestine ◦Anus Name the other essential organs. ◦Liver ◦Gall bladder ◦Pancreas WHAT IS DIGESTION?  ◦Digestion is the process whereby large food molecules are broken down into small, soluble molecules that can be absorbed into body cells What are the 2 types of digestion? ◦Physical digestion - the mechanical break-up of food into small particles ◦Chemical digestion (with the help of enzymes) - the breaking down of the large molecules in (such as proteins, starch and fats) into small soluble molecules that can be absorbed What is peristalsis? (Talk about the muscles) ◦Peristalsis is the rhythmic, wave-like contractions in the wall of the alimentary canal ◦When the circular muscles (the inner muscles) contracts, the longitudinal muscles (outer muscles) relaxes, causing the wall of the gut to constrict, pushing the food forwards ◦When the longitudinal muscles constrict, the circular muscles relaxes, the gut dilates and widen the lumen for food to enter Describe the physical and chemical process taking place in the mouth. ◦[c]The salivary glands in the mouth secrete salivary amylase, which digests starch to maltose ◦[p] Cheweing in the mouth breaks up food into smaller pieces, increasing the surface area to volume ratio for the salivary amylase to work on ◦[p] peristalsis in the walls of the oesophagus Describe the physical and chemical processes taking place in the stomach. ◦[p] peristalsis in the stomach walls churns and breaks up the food and mixes food well with gastric juice ◦[c] gastric glands in the stomach secretes gastric juices. Gastric juices contains: ‣ Hydrochloric acid that stops the action of salivary amylase by denaturing it, provide a low pH environment within the stomach (abt pH2) which is the optimum pH for protease to digest proteins and kills potentially harmful microorganisms in food ‣ Protease that digest proteins into polypeptides ‣ Mucus that protects the stomach wall against being digested by the enzymes it produces and moistens food to allow easy movement within the stomach (optional) what is chyme? ◦Chyme is partially digested food that becomes liqui ed that is passed into the duodenum in small s amounts Describe the physically and chemical processes taking place in the small intestine. ◦[p] Peristalsis moves chyme though the small intestine ◦[c] pancreas is stimulated and secretes pancreatic juice, which contains the enzymes pancreatic amylase, pancreatic protease and pancreatic lipase, that enters in the duodenum ◦[p] gall bladder is stimulated to release bile which passes through the bile duct into the duodenum. Bile does not contain any digestive enzymes but bile salts help speed up the digestion fo fats ◦[c] The epithelial cells in the small intestine are stimulated to secrete maltose, protease and lipase  Why are all 3 uids (pancreatic juice, intestinal enzymes, bile) all alkaline? ◦This helps neutralise the acidic chyme and provide a suitable alkaline medium for the action of pancreatic and intestinal enzymes Name the digestive enzyme(s) of carbohydrates. ◦Carbohydrases such as amylase and maltase Describe the digestion of carbohydrates through the alimentary canal. ◦Starch is rst broken down in the mouth into maltose by salivary amylase. Maltose is then fully digested into glucose by maltase. Any remaining starch is digested by pancreatic amylase into maltose and then into glucose by maltase. ◦Summary: starch —> maltose —> simple sugars/glucose Name the digestive enzyme(s) of proteins. ◦Proteases Describe the digestion of proteins through the alimentary canal. ◦Proteins are rst digested into polypeptides by the stomach protease and then into amino acids by intestinal proteases in the small intestine. ◦Summary: Proteins —> polypeptides —> amino acids Name the digestive enzyme(s) of fats. ◦Fatty acids & glycerol Descirbe the digestion of fats. (Talks about bile) ◦Bile is released in the duodenum and bile salts emulsify fats by lowering the surface tension of the fats. This causes teh fats to break into tiny fat droplets, increasing the surface area to volum ratio of the fats, speeding up their digestion by lipase. Emulsi ed fats are digestion by pancreatic and intestinal lipase into fatty acids and glycerol ◦Summary: fats —> fatty acids & glycerol Represent the digestion of carbohydrates, proteins and fats with their visual representations. MA Car carbohydrates simplesugars A O N I O AT x̅ Proteins aminoacids is is Fats fattyacids glycerol What is absorption? ◦Absorption is the process by whereby digested food substances are absorbed into body cells What is absorbed in the small intestine? ◦Simple sugars, amino acids, fatty acids and glycerol, water and mineral salts What are the adaptations of the small intestine for absorption? ◦Inner surface of the ileum has numerous nger-like projections called villi that increase surface area for absorption ◦The epithelium/wall of the villi is 1 cell thick, this provides a shorter diffusion distance for nutrient to pass through ◦Each villi has many blood capillairies which allow the blood to transport the absorbed glucose and amino acids in order to maintain a diffusion gradient ◦Each villi contain a lacteal to transport the absorbed fats away and maintain a steep diffusion gradient ◦The epithelial cells contain many mitochondria to provide energy for active transport of nutrient to villi Describe the absorption of glucose, amino acids and fatty acids and glycerol in the small intestine. ◦Glucose and amino acids are absorbed by diffusion into the blood capillaries of hte villi and by active transport which occurs when there is a lower concentration of the digested food substance in the lumen of the small intestine than in blood capillaries ◦Fatty acids and glyceroldiffuse into the epithelium and combine to form minute fat globules that enter the lacteals What is assimilation? ◦Assimilation is the process whereby some of the absorbed nutrients are converted into new cytoplasm or used to provide energy. What is the hepatic portal vein? (Note: hepatic vein and artery is different) ◦The hepatic portal vein is formed from blood capillaries. It transports nutrients from the small intestine to the liver Explain the assimilation of glucose. ◦Glucose is assimilated and then broken down during tissue respiration to release energy. Excess glucose is turned to the liver and stored as glycogen. When the body needs energy, the liver concerts the stored glycogen back to glucose and is transported by the blood to the cells. Explain the assimilation of amino acids. ◦Amino acids that enter the cells are coonverted into new cytoplasm that is used for growth and repair of worn-out parts of the body. Excess amino acids are deaminated in the liver. What happens to fats in the liver? ◦When there is suf cient supply glucose, fats are not broken down or stored but used to build protoplasm ◦When glucose is in short supply, fats are broken down to provide energy needed for the vital activities of the body ◦Excess fats are stored in special tissues called adipose tissues, which can be found new Earth the skin a nd around the heart and kidneys. WHAT ARE THE 5 MAIN FUNCTIONS OF THE LIVER? ◦Production of bile, deamination of amino acids, regulation of blood glucose concentration, breakdown of hormones, detoxi cation ◦PDRBD De ne Deamination. ◦Deamination is the process by which amino groups are removed from amino acids and converted into urea. (optional) what happens to the remains of any deaminated amino acids? ◦Converted into glucose in the liver How does the liver regulate the blood glucose concentration? ◦The pancreas contains a group of cells known as the islets of Langerhans which secret the hormones insulin, which allow the liver to convert excess glucose into glycogen) and glucagon, which allows the liver to convert glycogen into glucose into the bloodstream. State the harmful effects of alcohol consumption on the digestion and nervous system? Digestive ◦Alcohol stimulates acid secretion in the stomach. Excess stomach acid increases the risk of gastric ulcers. Too much alcohol may also lead to cirrhosis in the liver, a disease that destroys liver cells and replace it with brous tissue, making the liver less able to function Nervous ◦Alcohol is a depressant. Alcohol may affect one’s self-control. Alcohol could slow down one’s reaction time and hence affect their judgement. Alcohol could cause dementia and brain shrinkage. (Optional) What are the social implication of alcohol addiction? ◦Neglecting of their work and families, violent behaviour and commit crimes