Basic Nutrition Exam 2 Study Guide PDF

Exam 2 Review Questions: GI system & Carbohydrates Lecture 1: The GI System (Digestion, absorption and Transport) 1.​ What are 5 challenges posed to the human body when taking in food for digestion and nutrition? 1.​ Breathing vs eating (swallowing food and chewing)...

Exam 2 Review Questions: GI system & Carbohydrates Lecture 1: The GI System (Digestion, absorption and Transport) 1.​ What are 5 challenges posed to the human body when taking in food for digestion and nutrition? 1.​ Breathing vs eating (swallowing food and chewing) 2.​ Passageway for food to travel 3.​ Means for moving food from point A to point B 4.​ Means for breaking down food 5.​ Means for getting rid of what is not needed (waste) 2.​ Be able track the course of digestion (via anatomical structures) as food passes into our mouths and eventually exits our body. What are the key structures which influence safe and effective digestion? Mouth (Mechanical Chewing) (Saliva) Pharynx (Epiglottis- Prevents food getting into the lungs (Choking) Esophagus (Two sphincters) (Upper esophageal sphincter Opens during swallowing) (Lower esophageal sphincter Closes once bolus is in stomach to prevent stomach content from going backwards) Stomach (Gastric glands: Release acid (HCl) to kill bacteria and stop carbohydrate digestion. Pyloric sphincter: Controls the passage of food into the small intestine. Small Intestine (Duodenum → Jejunum →Ileum) 10 Feet (Major site of nutrient digestion and absorption) Large Intestine (Colon) (Cecum → Ascending → Transverse → Descending → Sigmoid). Removal of water. Undigested material, fiber and salts move into the large intestine. Most macronutrients are digested and absorbed by the time they reach the end of the small intestine. Rectum & Anus 3.​ What is chyme? Chyme is a semi-liquid mixture of partially digested food, stomach acid, and digestive enzymes. It is formed in the stomach and then slowly released into the small intestine for further digestion and nutrient absorption. 4.​ What two types of muscle contractions aid digestion and transport of food we eat?  Segmentation- Inner circular muscle contraction or “squeezing” to churns the chyme Peristalsis- Outer longitudinal muscles contract rhythmically to move chyme forward and some drugs, stress and illness can decrease GI motility 5.​ What is a key role of the pyloric sphincter? When acidic chyme is slowly released from the stomach, the pyloric sphincter senses acid chyme and immediately shuts. 6.​ What 5 structures/organs/glands release substances which aide in digestion? Salivary Glands – Release salivary amylase to begin carbohydrate digestion in the mouth. Stomach – Releases acid (HCl) and enzymes (pepsin) to break down proteins and kill bacteria. Pancreas – Releases pancreatic amylase, lipase, and proteases into the small intestine to digest carbs, fats, and proteins. Liver – Produces bile, which helps digest and absorb fats. Small Intestine (Brush Border Enzymes) – Releases maltase, sucrase, and lactase to break down sugars for absorption. 7.​ What is the definition of an enzyme? An enzyme is a protein that speeds up chemical reactions in the body, including the breakdown of food during digestion. 8.​ What is the pH of the stomach and how does the stomach tolerate such low acidity? Stomach needs to maintain a normal pH of 1.5 - 1.7. Stomach wall has a mucus coating that protects it and gastric enzymes these work well in an acidic environment, while salivary enzymes stop functioning in the stomach. 9.​ Why do we need a low pH (hydrochloric acid) in the stomach (two reasons) Breaks down protein – Hydrochloric acid (HCl) helps break down proteins so digestive enzymes can work. Kills harmful bacteria – The strong acidity destroys most bacteria, preventing infections. 10.​What is released from the pancreas that changes the pH of contents leaving the stomach? Why is this important? Pancreas releases bicarbonate to neutralize acid. It’s important because it neutralizes stomach acid to protect the small intestine. Helps digestive enzymes work properly in the small intestine. 11.​What is bile and what does it do? Bile is made by the liver, and stored in the gallbladder. Bile is not an enzyme, but an emulsifier. It breaks down (disperses) fat in water, allowing digestive enzymes to access and digest fats more easily. 12.​What part of the digestive system is responsible for most of the nutrient digestion and absorption? Small intestine 13.​Where is fiber digested and water resorbed? Fiber is digested in the large intestine, where gut bacteria ferment some fiber. Water is reabsorbed in the large intestine, helping form solid waste before elimination. 14.​What is unique about the lining of the small intestine? (describe the components and what they do) Looks smooth and slippery, but under a microscope. Wrinkled with hundreds of folds with thousands of finger like projections. Villi- Finger like projections that absorb nutrients into blood or lymph. Microvilli- Tiny hair like structures on villi, equipped with enzymes and protein pumps to help absorb specific nutrients. Crypts- Tubular glands that secrete intestinal juices. Goblet Cells- Secrete mucus (to protect and lubricate the intestine) 15.​Small water-soluble molecules are absorbed into the __bloodstream_____________ and transported to _liver_________.  16.​Larger fats, fat soluble vitamins are absorbed into the __lymphatic system_____________. 17.​What is the role of the liver? The liver produces bile which helps break down and digest fats. Also, it processes and distributes nutrients after absorption, nutrients from the bloodstream (hepatic portal vein) go to the liver, where they are processed, stored, or sent to the rest of the body. It also plays a role in detoxifying the blood. 18.​What is the difference between pre-biotics and pro-biotics? Why are these important to the body (refer to video in Brightspace for more info). Probiotic - Is bacteria in the foods we eat Prebiotic - Food for the bacteria in our gut microbiome. Plant based is best. Fiber is a considered a good prebiotic (Soluble fiber is best) 19.​What two systems help maintain homeostasis/feedback loops of the body? Endocrine System (Hormones) Neural System (Nerves) 20.​How do gastrin, stomach stretch receptors, pyloric sphincter, secretin and cholecystokinin control homeostasis of the GI system? Gastrin – Increases stomach acid for digestion, stops when pH is low enough. Stomach Stretch Receptors – Detect food, trigger digestive juices and muscle contractions. Pyloric Sphincter – Controls chyme release; stops too much acid from entering the small intestine. Secretin – Signals the pancreas to release bicarbonate to neutralize acid. Cholecystokinin (CCK) – Signals the gallbladder to release bile for fat digestion and slows stomach emptying. Lecture 2: Carbohydrates 21.​What are the sources of carbohydrates in our diet? Natural Sources Rich in Nutrients  Grains (Wheat, Rice, Oats, Corn) Vegetables (Potatoes, yams, Legumes) Fruits (Grapes, Apples, Oranges) Milk & Dairy ( Milk, Yogurt) Processed Foods High in Added Sugars and Low in Nutrients Soft drinks, Candy, Baked Goods Cereals with added sugars Processed Snacks NO ADDITIONAL Vitamins and Minerals 22.​How can carbohydrates be sub-divided (simple vs complex)? Simple Sugars - Monosaccharides (Single Sugar) Disaccharides (Pairs of monosaccharides) Complex Carbohydrates - Polysaccharides (Chains of monosaccharides) 23.​Which atoms are found in a carbohydrate? Carbon (C) , Hydrogen (H), Oxygen (O) 24.​What are the three monosaccharides, and which is the sweetest? Fructose, Glucose, and Galactose and Fructose is the sweetest 25.​Which monosaccharide is most used by our body and referred to as “blood sugar?” Glucose is commonly referred to as blood sugar. Glucose is the monosaccharide most used by our body. Essential energy source in the body and is essential for brain function. One of the sugars in all disaccharides. 26.​Which monosaccharide is present in all disaccharides? Glucose 27.​What are the three disaccharides and what monosaccharide makes up of each? Maltose = Glucose + Glucose (from starch breakdown)  Sucrose = Glucose + Fructose (table sugar, found in fruits & sugarcane) Lactose = Glucose + Galactose (milk sugar) 28.​What is a polysaccharide? A polysaccharide is a complex carbohydrate made up of many monosaccharides (glucose units) linked together. 29.​What polysaccharide is naturally found in humans? Glycogen 30.​What are the two polysaccharides found in plants? Starch – Stores energy (found in grains, potatoes, legumes). Fiber – Provides structure (found in plant stems, leaves, and skins). 31.​Can we break down ALL plant polysaccharides into glucose? If not, why can’t we and which one can’t we break down? No, we can’t break down all plant polysaccharides. Starch → Yes, we can digest it into glucose. Fiber → No, we can’t break it down because our enzymes can’t break its bonds. 32.​Which polysaccharide has a “soluble” and “insoluble” type? What are the differences? Differences Between Soluble & Insoluble Fiber: Type Function Benefits Soluble Forms a gel-like Helps with heart health, diabetes, Fiber substance in water weight loss, and acts as a prebiotic Insoluble Does not dissolve Supports GI health and digestion (adds Fiber in water bulk to stool) Prebiotic (Microbiota Health)  33.​Where does carbohydrate digestion begin, and which enzyme starts this process? Carbohydrate digestion begins in the mouth. The enzyme salivary amylase starts this process by breaking down starch into smaller polysaccharides and maltose. 34.​What is hydrolysis? Hydrolysis is a chemical reaction that breaks down molecules by adding water. It is used to split disaccharides into monosaccharides. Example: Sucrose → Glucose + Fructose (with water added). 35.​Does carbohydrate digestion continue in the stomach? No, carbohydrate digestion stops in the stomach because stomach acid inactivates salivary amylase. No other enzymes continue the process there. 36.​Where does carbohydrate digestion resume and what four enzymes are involved and where are they produced? Carbohydrate digestion resumes in the small intestine. Pancreatic Amylase (from the pancreas) breaks down starch into maltose and glucose chains. Maltase (from the small intestine) breaks maltose into glucose. Sucrase (from the small intestine) breaks sucrose into glucose and fructose. Lactase (from the small intestine) breaks lactose into glucose and galactose. 37.​What is NOT digested in the small intestine? Fiber 38.​About how long after a meal does a food bolus/chyme get to our large intestine? About 1 to 4 hours after a meal, the remaining undigested material (including fiber) reaches the large intestine.  39.​What digestive processes occur in the large intestine? Absorbs water to form solid waste. Bacteria ferment fiber for gut health. Forms and stores stool for elimination. 40.​Does fructose and galactose circulate around the body in the blood and get immediately used after absorption in the blood? If not, where does it go? No, fructose and galactose do not immediately circulate in the blood. They first go to the liver, where they are converted into glucose before being used by the body. 41.​What is lactose intolerance and which enzyme is the problem? Lactose intolerance happens when the body doesn’t have enough lactase (the enzyme that breaks down lactose in milk). Without lactase, lactose stays in the intestine, causing bloating, gas, and diarrhea. 42.​What percent of the population has adequate levels of lactose to break down lactose? Estimated that only 35% of the adult population have adequate levels of lactase. 43.​What are some side effects of lactose intolerance? Bloating, Gas, Abdominal Discomfort, Attracts water, and Diarrhea 44.​What is the primary purpose of glucose in the body? The primary purpose of glucose in the body is to provide energy for cells. It is the main fuel source for the brain, muscles, and red blood cells. Cells use glucose to create ATP, which powers body functions. 45.​Can we make glucose from protein? Yes, the body can make glucose from protein through gluconeogenesis when blood sugar is low. But this takes protein away from its main jobs, like building muscles and enzymes. 46.​What is the term for converting amino acids to carbohydrates and where does it take place? Gluconeogenesis  47.​About how many g/day of glucose is needed to prevent going into ketosis (ketone body formation from fat). 50-100g of carbohydrate in the diet per day (200-400kcal) will prevent the body from going into ketosis 48.​Can glucose make fat? Why/when would this happen and what is the process called? Yes, glucose can turn into fat if there is extra glucose after energy needs and glycogen stores are full. This process is called lipogenesis. 49.​What are the terms for high/low blood sugar? Hypoglycemia - Low Blood Sugar Hyperglycemia - High Blood Sugar 50.​What are the two of the main hormones which regular glucose homeostasis? Insulin and Glucagon 51.​What do these hormones do and where are they generated? Insulin (from the pancreas) – Lowers blood sugar by helping cells take in glucose after eating. Glucagon (from the pancreas) – Raises blood sugar by releasing stored glucose from the liver when needed. 52.​What is the glycemic response to food? What is a high response, what is a low response? How fast glucose is absorbed, how high blood sugar spikes, and how quickly it returns to normal. High Response: Fast absorption, big spike, then quick drop. Low Response (Ideal): Slow absorption, steady rise, smooth return to normal. 53.​Which is ideal, a high or low response? Ideal goal is Low Glycemic Response. Slow absorption of glucose. Moderate spike in blood sugar. Smooth return to normal. 54.​What are the criteria for low, medium, and high glycemic index foods?  Low GI: 55 or less Medium GI: Between 56 and 69 High GI: 70 or more 55.​What percentage of food intake in the United States comes from ultra-processed foods? More than 50% of food intake in the United States comes from ultra-processed foods. 56.​Which of the sugar types is most added to foods? High fructose corn syrup is the most commonly added sugar in foods. 57.​Why do manufactures like to use this sugar type? Cheaper than regular sugar Enhances flavor Improves texture and moisture Prevents crystallization Helps preserve color and freshness 58.​As added sugar content goes up in foods, what usually is happening to nutrient density? As added sugar increases, nutrient density decreases. Foods high in added sugar provide energy (calories) but lack important nutrients like protein, fiber, vitamins, and minerals. 59.​About how many tsp of sugar are in a can of soda? A can of soda contains about 10 teaspoons of sugar, which is 30-50 grams of sugar. 60.​What is the recommended max percent/kcal per day for added sugar in our diet? Dietary Guidelines for Americans limiting added sugar to 10% of total daily kcal. 5% has additional health benefits. 61.​About how many g/kg of carbohydrate is recommended daily for an individual? The recommended daily carbohydrate intake is 5 to 10 grams per kilogram (g/kg) of body weight, depending on activity level. 62.​About how much fiber g/serving is in grains, fruit, vegetables, and legumes? Grains: 1 to 5 grams per serving Fruits: 2 grams per serving Vegetables: 2 to 3 grams per serving Legumes: 5 to 8 grams per serving 63.​There are 5 health conditions which fiber has been linked to helping. Heart disease Diabetes Cancer Weight management Gut health (prebiotic benefits) 64.​How much fiber does the average American consume? Average American only consumes about 16g fiber daily, which is lower than the recommendation. 65.​How does that compare to the RDA daily value for a 2000 kcal diet? The Recommended Daily Value (RDA) for fiber on a 2000 kcal diet is 28 grams per day. 66.​Typically, about how many grams of CHO are in one serving of grain, fruit, and starchy and non-starchy vegetables? Grains: 15 grams per serving Fruits: 15 grams per serving Starchy Vegetables (corn, peas, potatoes): 15 grams per ½ cup Non-Starchy Vegetables (leafy greens, broccoli, green beans, tomatoes): 5 grams per ½ cup 67.​Are there carbohydrates in one serving of milk?  Yes, one cup of milk has 12 grams of carbohydrates. 68.​Are there carbohydrates in protein? Protein no carbohydrate content with two exceptions. Nuts – Contain a little starch and fiber along with fat. Legumes (beans, lentils, peas) – High in both starch and fiber (about 20g of carbohydrates per ½ cup, with 1/3 of that as fiber).