Nutrition Exam 2

Know that alcohol contains 7 kcal/g, so a standard drink contains about 100 kcal from alcohol (plus additional calories from other ingredients)

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Know that most alcohol absorption takes place in the small intestine. A full stomach causes slower gastric emptying, which will decrease the rate of alcohol absorption

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Know that we need to consume protein to replenish the amino acids that are lost in dead cells (e.g. shedskin cells) and to replace the amino acids that were converted into energy. Most individuals with atypical American diet meet and exceed their body's need for protein

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Understand that alcohol requires no digestion: the ethanol molecule can directly enter metabolic pathways

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Understand that moderate alcohol consumption is defined as one drink per day for women and two perday for men. The risk of disease due to this level of consumption is likely very small but not zero

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A standard drink contains _____ grams of alcohol.

- 14

Which of the following individuals would show signs of alcohol intoxication the fastest?

- 25-year-old male with a normal BMI who has not eaten today

Of the total day's energy intake, most dietary guidelines recommend that carbohydrates provide _____________ of energy.

- 45-65%

The ADH pathway of alcohol metabolism converts ethanol into ________.

- Acetyl-CoA

Which of the following statements about the metabolizing of alcohol is TRUE?

- Alcohol that is not immediately metabolized circulates throughout the body.

Amylose and amylopectin contain ___________ bonds, which are responsible for the digestibility of these starches.

- Alpha

Define complete (high quality) and incomplete (low quality) protein

- Animal proteins (except gelatin) contain all essential amino acids and are called complete proteins - Plant proteins (except quinoa and soy) do not contain all 9 essential amino acids or are low in at least one: incomplete, or low quality, proteins - Can get complete protein from plants by making complementary combinations

Which apolipoprotein is responsible for activating lipoprotein lipase?

- Apo C-II

When plant proteins are compared to animal proteins, they ________.

- Are usually deficient in one or more essential amino acids

Edema in the lower extremities may appear when there is a severe lack of dietary protein because ________.

- Blood protein levels drop and fluid shifts into interstitial spaces

Lipoprotein lipase functions to ________.

- Break down triglycerides from lipoproteins for transfer into cells

Match the term with its description.

- Cholesterol: Sterol manufactured in the body - Phospholipid: Major lipid class that contains phosphorus, fatty acids, and glycerol - Fat: Lipid that is solid at room temperature - Oil: Lipid that is liquid at room temperature - Triglyceride: Comprised of glycerol and fatty acids only

When 2 or more plant proteins are combined to compensate for deficiencies in essential amino acid content in each protein, the proteins are called ________.

- Complementary proteins

Describe the process of protein digestion. Explain how cooking aids digestion. Explain the function of pepsin, HCl, and pancreatic proteases

- Cooking denatures proteins and softens the connective tissue in meat: makes proteins easier to chew, digest, and be absorbed - In the body, digestion starts in the stomach: • Hydrochloric acid denatures protein • Pepsin breaks down long polypeptide chains • Can only break certain peptide bonds - Chyme entering the small intestine triggers the release of secretin and cholecystokinin (CCK) • These hormones stimulate the pancreas to release proteases: • Trypsin • Chymotrypsin • Carboxypeptidase - Amino acids/small peptides are absorbed by active transport and enter the portal circulation

Regina's pregnant sister is interested in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two fatty acids that can be made from alpha-linolenic (omega-3) acid. She has heard that EPA and DHA are important for cancer prevention, brain health, cardiovascular disease prevention, and immune function. Which food is the best source of EPA + DHA?

- Fatty Fish

Drag the monosaccharide that needs to be added to the glucose molecule to create its resulting disaccharide.

- Glucose + Fructose = Sucrose - Glucose + Galactose = Lactose - Glucose + Glucose = Maltose

Fats that are liquid at room temperature can be made more solid by the process of ________.

- Hydrogenation

The liver is important in carbohydrate digestion as it processes the monosaccharides galactose and fructose into glucose. What happens to this glucose once it is done being processed in the liver? Check all that apply.

- If glucose is present in excess, some can be turned into fat. - If glucose is present in excess, some can be stored as glycogen. - The liver can release the glucose directly into the bloodstream for transport to organs.

When the MEOS pathway is induced, alcohol tolerance _______ because the rate of alcohol metabolism __________.

- Increases, decreases

Describe the concepts of glycemic index and glycemic load

- Indicates how blood glucose responds to various foods Glycemic index: Ratio of blood glucose response of a food compared with a standard (usually pure glucose) Influenced by food's: - Starch structure - Fiber content - Food processing - Physical structure - Temperature - Amount of protein and fat in a meal Glycemic Load - Takes into account the glycemic index and also the amount of carbs perserving - Better reflects a food's effect on blood glucose. - To calculate (Grams of carbohydrate in serving x glycemic index) / 100 Foods with a high glycemic load elicit - Increased insulin response - Sharper rise and drop in blood glucose Chronically high insulin output can lead to: - Increased fat synthesis in liver - More rapid return of hunger after meal - Limitation of GI/GL: mixed meals

A vegan diet may be low in ________.

- Iron - Calcium - Vitamin B-12

A high-protein diet is discouraged for patients with ________.

- Kidney disease

Match the lipoprotein with its description

- LDL: Lipoprotein with the greatest cholesterol content - Chylomicron: Lipoprotein made in the GI tract from digested fat - VLDL: Lipoprotein that transports fat made in the liver - HDL: Lipoprotein that delivers cholesterol back to the liver and to other lipoproteins

Primary lactose maldigestion results from ________.

- Lactase insufficiency

Explain how an individual can develop lactose intolerance

- Lactase production begins to decrease after early childhood - Primary lactose intolerance: insufficiency of lactase production: • Symptoms include abdominal pain, bloating, gas, diarrhea • Amount of lactose tolerance varies by individuals; some foods such as hard cheese and yogurt may be tolerated - Secondary lactose intolerance: • Conditions of the small intestine damage the lactase producing cells • Symptoms can cease if intestine recovers

Describe the progression from fatty liver to cirrhosis. Understand that almost all people who exceed 2-3 drinks per day will develop some degree of fatty liver, but this is reversible. A subset will go on to develop cirrhosis, which is irreversible.

- Loss of functioning hepatocytes - Decreased synthesis of plasma proteins, often leading to ascites - Not reversible and liver failure develops • 50% chance of death in 4 years - Susceptibility varies, but generally associated with drinking >3 drinks per day for 10+ years - Cirrhosis may be due to: • Increased concentration of acetaldehyde • Accumulation of fat in liver resulting in inflammation and cell damage • Production of free radicals from alcohol metabolism - While a nutritious diet may delay or lessen some complications of cirrhosis, it will not prevent

Describe the molecular and physiological effects of alcohol

- Molecular • Potentiates effects of GABA • Blocks effects of glutamate • Endogenous opioid release • Activates reward pathway - Physiologic • Decreased inhibition • Decreased motor control • Disrupted sleep and memory consolidation • At high doses, central nervous system and respiratory depression, can lead to death

Drag the digestion description to the place in the body where it occurs.

- Mouth: Where salivary amylase is produced - Pancreas: Site of amylase and dextrinase secretion - Liver: The site to which monosachharides are transported - Large Intestine: Where bacteria ferment soluble fiber - Stomach: Has acidic environment where salivary amylase is inactivated - Small Intestine: Has alkaline environment and is where the majority of carbohydrate digestion and absorption occurs

The presence of ___________ chemically distinguishes protein from carbohydrate and fat.

- Nitrogen

Define essential and nonessential amino acids (I will not ask you to know which ones are essential)

- Nonessential amino acids can be made by the body, while essential amino acids cannot be made by the body so you must get them from your diet. 11 Nonessential amino acids: body can make them in great enough quantities -9 Essential amino acids: • Cannot be synthesized in the body because cells cannot do at least one of these: • Make the carbon skeleton • Attach an amino group to the carbon skeleton • Make a sufficient quantity

Define what it means for an amino acid to be conditionally essential

- Nonessential amino acids may be classified as "conditionally essential": • Infancy • Disease • Trauma Example: • Person with phenylketonuria (PKU) has limited ability to metabolize phenylalanine and convert it to tyrosine • Tyrosine is conditionally essential in people with PKU

Understand that a sufficient glucose levels in the body will spare protein (i.e. the body does not need to break down protein for energy)

- Normal fasting blood glucose levels: 70-100mg/dl - Above 126mg/dl is classified as diabetes: • Hunger • Thirst • Frequent urination • Weight loss - Below 50mg/dl is classified as hypoglycemia: • Hunger • Shakiness • Irritability • Weakness • Headache - Most important organs for blood glucose regulation: liver and pancreas - Liver determines how much glucose enters the blood after a meal, and how much is stored as glycogen - Pancreas secretes insulin and glucagon

Define positive and negative nitrogen balance

- Positive nitrogen balance: childhood growth, pregnancy, intense athletic training - Negative balance: serious illness, bed rest, dietary deficiency

Describe the alcohol dehydrogenase and MEOS pathways for alcohol metabolism

- Primary pathway: alcohol dehydrogenase (ADH) • Active at low to moderate intakes • Acetaldehyde is a toxic intermediate • Acetyl-CoA can be used for energy or fatty acid synthesis - During moderate to excessive alcohol intake, ADH pathway cannot keep up: • Liver activates microsomal ethanol oxidizing system (MEOS, CYP2E1) • Produces same intermediates, but uses energy • Induction of MEOS is one factor in tolerance development

Describe the levels of organization for protein structure

- Primary structure: • Sequential order of amino acids • Determines the protein's shape - Secondary structure: • Spiral-like or pleated sheet shape • Formed by weak chemical bonds between amino acids - Tertiary structure: • 3-dimensional folding • Determines overall shape and function of protein - Quaternary structure: two or more separate polypeptides interacting

A diet that is deficient in carbohydrate will ultimately force the liver and, to a lesser extent, the kidneys to ________.

- Produce glucose from amino acids

Describe benefits of fiber in the diet

- Promotes bowel health - Prevents: constipation, hemorrhoids, diverticulosis - Reduces the risk of colon cancer -Reduces obesity risk by promoting fullness - Enhances blood glucose control - Reduces cholesterol absorption

What would happen to dietary protein if HCl were not being produced in sufficient quantities?

- Protein digestion could not fully occur because proteins could not be denatured and pepsinogen could not be converted to pepsin.

Know the standard definition for one drink in terms of grams ethanol and amount of commonly consumed alcoholic beverages

- Provides approximately 14 g ethanol • 98 calories from ethanol alone • Additional calories primarily from sugars • Beer: 12 ounces • Wine: 5 ounces • Hard liquor:1.5 ounces

What is the difference between simple carbohydrates, complex carbohydrates, and dietary fiber?

- Simple carbs break down easier and contain sugars. - Complex carbs contain starch and fiber. - Dietary Fiber: A family of carbohydrates that are linked by beta bonds • Cannot be broken by human enzymes • Bacteria convert some components of fiber into fatty acids which can be used by cells of the large intestine

Identify the following factors that cause women, in general, to have a higher BAC when consuming the same amount of alcohol as men.

- Smaller body size - More body fat

Know the common carbohydrates that are found in our diet. Know the composition of common disaccharides and polysaccharides.

- Sugars, fibers, startches - Plants are the main source - Disaccharides: Two monosaccharides linked by covalent bonds - Ex: Maltose: - Glucose-glucose • Found in seeds and alcoholic beverages - Sucrose: • Glucose-fructose • Table sugar • Sugarcane, sugar beets, maple tree sap - Lactose: • Glucose-galactose • Milk and milk products - Polysaccharides: many glucose molecules linked together. Contain more than 10 sugar units - Starch: • Amylose • Amylopectin • Glycogen - Fiber: Indigestible polysaccharide

Understand the difference between alpha and beta glycosidic bonds and how they are related to our ability to digest carbohydrates

- The alpha bonds of carbohydrates are broken down during digestion by specific enzymes. Lactose contains a beta bond, which is digestible by lactase. Most carbohydrates that contain beta-glycosidic bonds are not digestible because humans lack the enzyme needed to break down the bond.

Which is correct regarding trans fatty acids?

- They raise blood cholesterol and lower HDL cholesterol.

What would happen to the liver of an individual who was diagnosed with steatosis if he or she abstained from alcohol?

- They would reverse his or her condition.

Moderate drinking is most accurately defined as ________.

- Up to 1 drink per day for women and 2 drinks per day for men

Understand how insulin regulates the glucose level in blood

- When blood glucose levels rise, beta cells of the pancreas release insulin into the blood. This causes the body cells to take up more glucose from the blood stream and the liver cells to store glucose as glycogen. As a result, blood glucose levels decline.

Tomas has taken up bodybuilding and is starting to become more interested in a diet to improve athletic performance. He read an article in a bodybuilding magazine that said he should dramatically increase his dietary protein intake. What happens to excessive dietary protein intake?

- With excessive protein intake, amino acids may be used to meet energy needs or converted to and stored as fat.

List the types of lipids found in our diet

- fats and oils (triglycerides or triacyglycerols), fatty acids, phospholipids, and cholesterol - These do no dissolve in water and triglycerides are the most common type of lipid in food

Arachidonic acid is associated with ________

- omega-6 fatty acid metabolism

Dietary sugars and starches are called "protein sparing," which means ________.

-Dietary protein can be used for protein synthesis and other vital processes, rather than being used as a source of energy

Put the components of fat digestion and absorption in their appropriate order from first (1) to last occurring event (8).

1) Lipase breaks triglycerides down into monoglycerides and fatty acids in the small intestine 2) Monoglycerides and fatty acids absorbed by the small intestine cells are repackaged into trigylcerides 3) Small Intestine cells package triglycerides into chylomicrons 4) Chylomicrons enter the lymphatic system and the bloodstream 5) Triglycerides in the chylomicron are broken down into fatty acids and glycerol by lipoprotein lipase 7) Muscle cells use absorbed fatty acids immediately for fuel and adipose cells re-form fatty acids into triglycerides for storage 8) Chylomicron remnant is removed from circulation by the liver and its components are recycled to make other lipoproteins and bile acids

Put the protein digestion steps in order of their occurrence during the digestive process.

1) Stomach acid denatures protein 2) Pepsin unravels polypeptide chains 3) Partially digested protein moves from stomach into the small intestine with nutrients and chyme 4) CCK is released from walls of the small intestine 5) CCK travels in the bloodstream to pancreas 6) Trypsin is released from the pancreas 7) Mixture of CCK and trypsin breaks partially digested proteins down into amino acids

The energy value of dietary carbohydrates is _____ kcal per gram.

4

Place the hormone into each sentence to make it correct.

After a late night, you overslept this morning and woke up late for class. In a rush to leave the house, you failed to eat breakfast. A few hours later, with an empty stomach, your blood glucose drops. This prompts your pancreas to release (glucagon)to stimulate breakdown of glycogen in the liver into glucose After morning class, with your stomach growling, you stagger to the cafeteria and devour a large pasta entree for lunch. Following this meal, your blood sugar rises and the pancreas releases (insulin) in an attempt to shuttle blood sugar into your cells. You go to your next class, but because you're so full from lunch, you doze off. You awake to your classmate poking you in the arm as you realize the teacher is calling your name to answer a question. With your heart racing, your body now releases (epinephrine) that increases glycogen breakdown in the liver and raises your blood sugar.

Explain the potential fates for an amino acid in your body, including conversion of the amino group into urea

Amino acids can lead to: - synthesis of proteins for cell structure, function, etc. - synthesis of non-protein nitrogen-containing compounds - energy production from amino acid skeletons - ketone production from carbon skeletons of some amino acids - glucose production from carbon skeleton of some amino acids by gluconeogenesis **ammonia can be produces from the amino acids and transports to the liver where it is synthesized into urea and then excreted by the kidneys

Explain how plasma proteins help to regulate capillary filtration and maintain blood pressure

Blood proteins maintain oncotic pressure Extreme low protein in the diet can cause low blood protein levels and subsequent edema (flow of fluid out of capillaries into the tissue)

Know the nutrients that may be deficient in a vegetarian diet

Decreased intakes of: • Saturated fats • Cholesterol Nutrients of greatest concern: • Vitamin B-12: found only in animal sources • Calcium: found in green leafy vegetables, but in a form that is not well absorbed • Iron: found in whole grains and other plant sources, not absorbed as well as animal sources • Vitamin D: get from sun

Describe the process of protein denaturation

Denaturation: • Alteration of protein's 3-dimensional structure • Destroys protein's function - Caused by: • Exposure to acid or alkaline solutions • Enzymes • Heat • Agitation

Understand that fiber is actually a variety of different indigestible carbohydrates

Dietary fiber consists of a group of complex carbohydrates found mostly in vegetables, fruits and legumes. Their fibrous structure makes them indigestible by humans, so they contribute no calories or energy to your diet. Most dietary fiber passes through your intestinal tract completely undigested.

Determine whether each statement about alcohol is true or false.

False: - Alcohol digestion is a complex process - The majority of alcohol detoxification occurs in the stomach - Drinking caffeinated beverages often leads to drinking less alcohol as the caffeine enhances the ability to feel intoxication True: - Drinking alcohol on an empty stomach speeds up the rate at which alcohol enters the bloodstream when compared to drinking after eating - Generally speaking, a woman who is of comparable size to a man will get drunk more quickly when she consumes the same amount of alcohol - Binge drinking is classified as a five or more drinks per occasion for males and four or more drinks per occasion for females

Determine whether each statement about alcohol and alcohol consumption is true or false.

False: - Excess alcohol can be stored in the body - Moderate True: - Alcohol requires no digestion - The liver is the primary site of alcohol metabolism - Given the same amount of alcohol, a woman is likely to reach a higher blood alcohol concentration than a man of similar size due to differences in body fat and body water

Describe the process of carbohydrate digestion and absorption

Food preparation starts digestion of carbohydrates: - Cooking softens tough, fibrous tissues - Starch granules swell as they soak up water, making them easier to digest -In the mouth, salivary amylase begins breaking down starch - Pancreatic amylase continues the process in the small intestine - Disaccharides are digested by brush border enzymes in the absorptive cells of the small intestine - Indigestible carbohydrates cannot be broken down: - Pass into the large intestine - Fermented by bacteria into acids and gases or excreted Absorption - Glucose and galactose: -Absorbed by active absorption -Pumped into absorptive cells with sodium• Fructose: - Absorbed by facilitated diffusion - Slower absorption than glucose or galactose - Some fructose is converted to glucose in absorptive cells; remainder converted in the liver - Galactose is converted to glucose in the liver. - Glucose is than sent to cells for use; liver stores extra as glycogen - If glycogen storage capacity is exceeded, glucose is converted to fat

Compare and contrast high fructose corn syrup and sucrose

High-fructose corn syrup: • Treatment of cornstarch with acids and enzymes break starch down into glucose • Enzymes convert glucose to fructose so that final product is about 55% fructose • Similar in sweetness to sucrose • Health effects probably not much different than sucrose HFCS: -45% glucose -55% fructose Sucrose: -50% glucose -50% fructose

Define kwashiorkor and marasmus

In developing countries people may suffer from malnutrition and disease due to protein and/or total energy deficits - Kwashiorkor: protein deficiency with moderate energy deficit - Marasmus: overall energy deficit

Explain the difference between nutritive and non-nutritive sweeteners

Nutritive: metabolized to yield energy- contribute calories to diet Non-Nutritive: not metabolized to yield energy Synthetic vs Natural

An example of an oligosaccharide is ________.

Raffinose

Describe the difference between soluble and insoluble fiber and the effects of each type on the body

Soluble fibers: • Dissolve in water • Found inside and around plant cells • Pectins, gums, mucilages, and some hemicelluloses • Oat bran, fruits, legumes, and psyllium • Insoluble fibers: • Do not dissolve in water • Form structural part of the plant cell • Cellulose, hemicellulose, lignins • Seeds, whole grains

Know the vitamins and minerals most likely to be deficient in people with who consume large amounts of alcohol and why these nutrients are specifically affected.

Thiamin: Wernicke-Korsakoff syndrome • Severe effects on brain and nervous system • Confusion, ataxia, memory impairment - Vitamin A: normally stored by liver - Vitamin D: liver involved in synthesis of active form - If vitamin D levels are low, what mineral would you expect to be low? • Iron: bleeding (increased loss) and poor absorption

Understand that trans fats are a type of unsaturated fat, but unlike other unsaturated fats they are linked to elevated cholesterol and inflammation

Trans fats are unsaturated fatty acids found in polyunsaturated oils modified by food manufacturers using a process called hydrogenation.

Understand the role of LDL in atherosclerosis

a. Atherosclerosis: chronic inflammatory response to endothelial injury - Injury can occur due to oxidized LDL, smoking, hypertension, some infections - Asymptomatic for many years unless there is a rupture

Explain why cholesterol is important in our diets and some potential sources (including synthesis by our bodies)

a. Cholesterol is important for the diet as it makes: sex hormones, active form of vitamin D, adrenal hormones, bile, cell membranes, shell-covering chylomicrons b. Sources of sterol include: meat, fish, poultry, eggs, dairy products - Plants make other types of sterol (ergosterol) - Body synthesize about 3x dietary intake

Describe how triglycerides are important for energy, insulation/protection, and vitamin absorption/transport

a. Essential for health - Concentrated source of energy 1. Provide 9 kcal/g 2. Main fuel source for all cells except nervous system and red blood cells 3. When at rest or during light activity 30-70% of energy is supplied by triglycerides - Insulate and cushion organs 1. Subcutaneous fat is found below the skin: helps it stay at constant temperature 2. Visceral fat is found around the organs - Cushion, protects organs from injury iii. Helps transport nurtients Dietary fats - Carry fat-soluble proteins to the small intestine - Aid in the absorption of these vitamins - Fat double vitamins are transported in the blood stream with dietary fats

Know that the essential fatty acids in our diet are alpha-linolenic acid (omega-3) and linoleic acid(omega-6)

a. Humans can synthesize a wide variety of fatty acids but not 2 PUFAs (polyunsaturated fatty acids): omega-3 and omega-6 - Both are these are essential fatty acids, we need to get them from food because our body is unable to synthesize these fatty acids - Moral of the story: we cannot make these in our body

Describe the function of LDL, HDL, VLDL and chylomicron particles in the transport of fat and cholesterol

a. LDL (cholesterol): Carries cholesterol made by the live and from other sources to cell b. HDL (protein): Helps remove cholesterol from cells and, in turn, excrete cholesterol from the body c. VLDL (triglyceride): Carries lipids both take up and made by liver to cells d. Chylomicron (triglyceride): Carries dietary fat from the small intestine to cells

Compare omega-3 and omega-6 fatty acids and their functions in our bodies

a. Omega-3: reduces inflammation responses, blood clotting, and plasma triglycerides b. Omega-6: regulates blood pressure and increases blood clotting

Describe the structure of a phospholipid and the process of emulsification

a. Similar structure of a phospholipid except one fatty acid is replaced with phosphate compound - Phosphate head is hydrophilic b. Phospholipid functions - Cell membrane component - Emulsifier: 1. Forms a shell around fat droplets and suspends them into watery solution 2. Essential for fat digestion and transportation 3. Bile and lecithin 4. Used in foods such as mayo c. Phospholipid is synthesized by the body - High does can cause gas, diarrhea, and weight gain - Found in egg yolks, wheat germ, and peanuts

Explain the process of fat digestion and absorption

a. Small amount of digestion in mouth and stomach - Lingual lipase: active during infancy, minor role in adults - Stomach: fat not yet emulsified Most digestion in the small intestine: - Fat in small intestine triggers releases of cholecystokinin - Bile, lipase and collapse released from pancreas Bile emulsifies fat - Breaks down fat into micelles - Increase the surface area for lipase to work - Fatty acids and monoglycerides are absorbed by brush border cells - Chain length of fatty acid determines were they go

Describe how apolipoproteins help to direct lipoproteins to target cells

a. The protein portion of the shell contains apolipoproteins - These help enzymes functions and act as a lipid-transfer protein, or assist in the binding of a lipoprotein to a cell-surface receptor b. LPL is activated by apo C-11

Describe the structure of a triglyceride and the major classes of fatty acids: saturated, monounsaturated, polyunsaturated, trans, omega-3, omega-6

a. Triglycerides are built from glycerol backbone and 3 fatty acids b. Fatty acids have long chains of carbon atoms - One individual molecule is a free fatty acid c. Saturated fatty acid structure do not have a double bond d. Monounsaturated has one double bond in the middle e. Polyunsaturated has two double bonds f. Monounsaturated trans has a trans isomer in the middle g. Omega-3 has the first double bond after the third carbon h. Omega-6 has the first double bond after the sixth carbon