nutri exam 2 mod 3&4
How are fatty acids similar to one another?
-All fatty acids have a carboxyl group on one end (also called the acidic group), usually represented as: COOH. -All fatty acids have a methyl group on the opposite end, represented as CH3. The carbon in this group is referred to as the omega carbon.
When would the body store glucose as glycogen? Where is it stored? What is the name of this process? When would the body break down glycogen? What is the name of this process?
Glycogen-Found in the liver and muscles Liver glycogen is broken down to glucose to help maintain appropriate blood glucose levels.
Is there a problem with consuming a high amount of refined sugar? If so, what is the specific concern?
It is also okay to have a small amount of refined sugar if it is in moderation so that it doesn't promote cavities and it doesn't replace a significant quantity of more nutrient dense foods or lead to weight gain. This specific amount will be different for each person
What do we mean when we say that a fatty acid is saturated? monounsaturated? polyunsaturated?
One double bond between carbons= mono All single bonds between carbons=saturated two or more double bonds between carbons=poly
Where does the digestion of the disaccharides begin? What are the enzymes involved and where are they found?
The disaccharides are broken down by enzymes on the surface of the small intestinal tract cells that have names resembling the disaccharides themselves. Specifically, 1. maltose is broken down to two units of glucose by the enzyme maltase .2. Sucrose is broken down to fructose and glucose by the enzyme sucrase. 3. Lactose is broken down to glucose and galactose by the enzyme lactase.
What is meant by "trans" fatty acids? How do they differ from "cis" fatty acids in structure? Are these fatty acids saturated or unsaturated?
Trans: - More linear....(chair shape) - Hydrogens on opposing sides of double bond Cis: - Hydrogens on same side of double bond - bent back at the double bond (boomerang)
What is the definition of an oligosaccharide?
a carbohydrate whose molecules are composed of a relatively small number of monosaccharide units
What are the other dietary risk factors associated with cardiovascular disease?
age Gender (men and women past menopause) High Blood Cholesterol (high LDL, low HDL) Hypertension Diabetes Obesity (esp. excess abdominal fat) Physical Inactivity Smoking Homocysteine, cRP, etc...... Genetics
What is the definition of a polysaccharide?
are polymeric carbohydrate molecules composed of long chains of monosaccharide units bound together by glycosidic linkages and on hydrolysis give the constituent monosaccharides or oligosaccharides. They range in structure from linear to highly branched.
Why aren't ketones produced most of the time when fats (triglycerides) are burned for energy? When are ketones produced from fats? (think back to chapter 4)
because they cause health issues including loss of bone mineral, altered blood lipids, increased kidney stone risk, impaired mood, etc produced when body is deprived like in starvation or diabetes
What is glucose used for in the body (cell)? (name three ultimate fates)
broken down and used to create ATP (energy) in the mitochondria organelle of individual cells converted to glycogen in the liver and muscle cells converted to fat by the liver and then transported and stored in the adipose (fat) cells throughout the body
What are the three elements that make up the carbohydrate compounds?
carbon, hydrogen and oxygen. CHO
Which types of carbohydrate is not digested by human enzymes
cellulose
Give an example of a sterol. How does the structure of a sterol differ from other lipids (in general)?
cholesterol Sterols are lipids in that they do not mix with water but they have a very different structure from the triglycerides and phospholipids that we have been talking about. multi ring compound
What type of chemical reaction is needed to make a triglyceride from its component parts?
dehydration synthesis
The combining of two monosaccharides into a disaccharides involves what type of reaction. What molecule is formed as a byproduct of this reaction?
dehydration synthesis, H2O
What type of fatty acids are eicosanoids made from? How does the behavior of eicosanoids differ based on the type of fatty acid that they are made from? (Fig. 5.13)
fatty acids
Which type of carbohydrate forms the structural wall of a plant?
fiber
An article in the New York Times on January 26, 2001 made the following claim regarding how fiber lowers cancer risk. "Fiber may adhere to cancer causing particles in the bloodstream and help remove them from the body". What is wrong with this statement?
fiber isn't in the blood stream
What should you do if someone is going into insulin shock (i.e., a diabetic takes a shot of insulin but does not eat enough food to go with it)
give them some simple sugar in the form of a sugary beverage or "melt in your mouth" candy (be sure they are still able to swallow and won't choke)
Why can't fatty acids be converted to glucose? (pay attention to arrows in figure 5.14)
glycerol and odd chained fatty acids can undergo gluconeogenesis. Acetyl CoA cannot undergo gluconeogenesis because it can't be converted into Pyruvate.
What would you say if a person asked you whether there was any benefit to decreasing processed foods and increasing unprocessed foods in the diet?
id say do just so you know whats going into your food and its easier to keep track of but processed isn't the devil just look at the labels first and use good judgement
Why is a special compound needed to transport lipids in the blood?
if u didnt the lipid based substances would all group together and rise upward and you would literally have a "fat head". In order to prevent the fat from separating and joining with other lipid based compounds, we need to carry it around in an emulsifier
What are the long term ramifications of diabetes, particularly when blood sugar has not been well controlled?
impared circulation due to blood vessel damage leading too... blindness CVD gangrene needing amputation kidney disease neuropathy (tingly feeling/loss of feeling)
Which complex carbohydrate is the storage form of carbohydrate in a plant? animal?
in animals: Glycogen. in plants starch and fibers
Where does starch digestion begin?
in the mouth, the enzyme amylase is secreted in the saliva and breaks down some of the amylose and amylopectin (starch) into shorter polysaccharides
Where does the amylase come from that breaks down starch to maltose in the small intestine?
it is secreted from the pancreas
What are the major steps involved in breaking down fatty acids and glycerol for energy? In other words, how do triglycerides enter the cellular respiration process (figure 5.14).
it must be broken down in a process called beta-oxidation, which takes place in the matrix of the mitochondria. In beta-oxidation, the fatty acid tails are broken down into a series of two-carbon units that combine with coenzyme A, forming acetyl CoA. This acetyl CoA feeds smoothly into the citric acid cycle.
What foods contain cholesterol?
ones from animal/byproducts
What is the function of different carbohydrate types (i.e. fiber, starch, glycogen) in plants and in animals? Which are found exclusively in plants? animals?
only in plants Starch-Found in grains, vegetables, legumes Fiber-oats, legumes, fruits only in animals Glycogen-Found in the liver and muscles Liver glycogen is broken down to glucose to help maintain appropriate blood glucose levels.
What are the four major "ingredients" or subunits that make up this lipid transport vehicle?
phospholipid, protein, triglycerides and cholesterol
What are the four major "ingredients" or subunits that make up this lipid transport vehicle? Where in the compound is each ingredient located (i.e. what makes up the "shell"? What specifically is the role of the phospholipid subunit?
phospholipid, protein, triglycerides and cholesterol
Through what process are carbohydrates made in plants?
photosynthesis
Describe the digestion and absorption of triglycerides (fats) in as much detail as possible.
pic on pg 11 of mod 4 pdf
Are omega-3 fatty acids saturated or unsaturated? Where do we find them in foods? What is their influence on health?
polyUNSATURATED fat. found in fish flax seed walnuts lowers: blood clotting blood pressure risk of heart attack major depression and mental decline cancers inflammation of arthritis macular degradation irregular heartbeat helps w/immune function
Which complex carbohydrate is most branched in structure? Why does it need to be so branched?
polysaccharides like starch and glycogen Having a great deal of branching ensures that plants and animals can quickly add to their energy supply when energy is plentiful, or break it down the storage molecules when energy is in short supply.
Why is it better to consume whole grains and cereals rather than refined grains and cereals? What does "refined" mean?
refined means that they purified it but in doing so they took out a good chunk of nutri. Basically a refined grain wont have as much fiber, micronutrient and phytochemicals found in whole grain
What are some compounds made from cholesterol in the body?
sex hormones and bile acids
How do you know if a fatty acid is an "omega-3" or an "omega-6"?
simply find the omega carbon and count it as carbon number one
What does the hardness or softness of a dietary fat typically indicate?
smaller chains are more liquid, longer chains are more solid
What are the two types of fiber?
soluble and insoluble
What are the three components of a kernel of grain. Which component(s) has the majority of the starch? fiber? nutrients?
Endosperm, bran layers and the germ bran layers- good source of vitamins and fiber Germ- good source of vita E and vegi. oil endosperm- largely starch and some protein
What is the maximum amount of fat, saturated fat and cholesterol that a person should consume on average each day (from food)?
Fat - 20-35% of total kcals from fat (trigylcerides)* Saturated fatty acids - No more than 10% of total kcals for general population * - No more than 7% of total kcals if at risk for CVD Other fats - Avoid trans fats* - Emphasize omega-3 fatty acids
What are the subunits or compounds that link together to form the triglycerides?
1 glycerol + 3 fatty acid
How do fatty acids differ from one another?
1) chain length -4-24 carbons, smaller chains are more liquid longer chains are more solid 2) degree of saturation saturated, monounsaturated, polyunsaturated
What are the steps in plaque formation in an artery? What cells and compounds play a role in this process. What can precipitate a heart attack or stroke? (figure 5.16).
1)fatty streak formation 2)plaque accumulation 3)fibrous cap formation 4) fibrous cap rupture= clot and blockage of blood flow
Compared to a saturated fatty acid, for every double bond in an unsaturated fatty acid, _____ hydrogens are missing.
2
If we say that a fatty acid is a 22:6 fatty acid, what does this mean?
22 carbons, 6 double bonds
What are the basic recommendations for total carbohydrate intake and fiber intake? (minimum amount of carbohydrate? Acceptable Macronutrient Distribution Range (AMDR) for carbohydrate, approximate range for fiber intake?
25 grams fiber recommended 300 grams or 60% of kcals CHO AMDR-- •Minimum of 130 grams CHO
What is an acceptable blood cholesterol level? What is considered a borderline blood cholesterol level? What level of blood cholesterol is considered high?
Acceptable = less than 200 mg/dL - Borderline = 200 - 239 mg/dL (often stress diet and lifestyle to lower) - High = 240 mg/dL or greater (usually requires medication to lower)
Why do people suffer from frequent urination (polyuria) and thirst (polydipsia) as well as dehydration when their blood sugar is very high?
Because the body has too much glucose aka blood sugar is too high and since it cant get rid of it by using insulin the body dispels it thru the urine causing the person to pee more than norm. & causing them to become dehydrated and thirsty
What are the chemical elements (atoms) that make up triglycerides?
CHO
What are the names of the two hormones that are produced by the pancreas to regulate blood glucose and what specifically do they do to increase or decrease blood glucose as needed.
Insulin and glucagon Insulin is a vital hormone produced by cells in your pancreas. Insulin works to move glucose from the blood and into cells for energy or storage for later energy. Like insulin, glucagon is a protein hormone produced in the pancreas. It is a counterbalance to insulin. Approximately four to six hours after you eat, the glucose levels in your blood become reduced. This triggers the production of glucagon in the pancreas. When the pancreas secretes glucagon, it suppresses insulin. Glucagon signals the liver and muscles to break down glycogen into glucose and release glucose back into your bloodstream. This keeps your blood sugar levels from dipping too low.
Mr. X has coronary heart disease (cardiovascular disease affecting the heart vessels). What sort of lipid profile would you expect to see in his medical chart? For example, would his LDL be elevated or depressed? What about his HDL? Total Cholesterol? HDL to total cholesterol ratio?
LDL would be high and HDL would be low total cholesterol would be high
What influence do LDL and HDL have on the risk of cardiovascular disease? Why? What foods or lifestyle factors raise or lower the blood levels of these two lipoproteins?
LDLs (low density lipoprotein) can deposit cholesterol into the artery wall, causing a blockage to build up on the interior of the blood vessel. This is especially true for the smaller LDL compounds as they can more easily penetrate the artery wall HDL (high density lipoprotein)'s role is to bring cholesterol from the tissues back to the liver to be degraded or incorporated into other substances. This prevents the cholesterol from being laid down in the artery wall.
What are the three most common monosaccharides found in food?
Lactose, maltose, and sucrose.
What is the name of the particles that transport lipids in the blood?
Lipoprotein
Where do carbohydrates come from?
Most carbohydrates come from foods of plant origin. The major simple carbohydrates or sugars are glucose, maltose, fructose, and sucrose which come from plants. Lactose is found in milk.
Where do we find trans fatty acids in foods? How do you know if the food contains trans fatty acids? How can a food contain trans fatty acids even when the label indicates zero trans fat?
Most trans fats we consume come from oils that have been chemically altered, though small amounts of these fats are also found naturally in meats and full fat dairy products. if it says something like uses partial hydrogenation probs has trans or fried foods/pastries often have it because they allow the lables to mark it as 0 if it has less than .5g of it
identify any chemical substances secreted from any organs to facilitate triglyceride digestion.
Mouth- lingual lipase secreted Stomach- Triglyceride --------->Diglyceride + FA --Enzyme: gastric lipase and lingual lipase intestinal lumen- bile from liver emulsifies TG Forming lipid droplets called micelles lipase from pancreas breaks apart TG to fatty acids, glycerol and monoglycerides (MG)
Describe the structure of a phospholipid. How does it differ from a triglyceride? Identify the hydrophilic and hydrophobic portions of the phospholipid.
Phospholipids look like triglycerides with one exception. One of the fatty acids in the triglyceride is replaced by a phosphorus containing compound. So the compound is made up of a glycerol backbone, two fatty acids and a phosphorus containing compound (or phosphate group).
What are the non-dietary risk factors for heart disease?
Pressure or pain generally occurs in the center of the chest and can be continuous or can come and go over many minutes. It may resemble severe heart burn (acid stomach) but don't automatically attribute the pain to stomach distress..... get this checked out immediately pain can radiate down into one or both arms and can radiate into the back, neck, jaw and/or stomach shortness of breath that can occur prior to or during a heart attack sweating, nausea and/or dizziness
Why would the body break down glucose into pyruvate and then acetyl CoA. Where in the cell does glucose get broken down to pyruvate? acetyl CoA? What is the name of the process for breaking down glucose to pyruvate? What is the name of the process of converting Acetyl CoA to ATP (energy)?
So, how does CHO become Acetyl CoA? In short, through the series of reactions called glycolysis (Fig. 4.15). Literally, the six carbon sugar molecule is lysed into two molecules of pyruvate, or pyruvic acid. This happens in the cytosol of the cell, and can proceed without the need for oxygen (anaerobically). Pyruvate is then transferred to the mitochondria and converted into Acetyl CoA (Fig. 4.15). The subsequent steps that take Acetyl CoA forward through the remaining citric acid cycle and electron transport chain require oxygen glycolysis breaks down glucose into pyruvate the process of converting Acetyl CoA to ATP (energy)=citric acid cycle / electron transport system
What is an example of a soluble fiber? insoluble fiber?
Soluble--Examples: pectins, gums Food Sources: oats, legumes, fruits insoluble-- Example: cellulose Food sources: whole grains, vegetables, fruits
What are the complex carbohydrates discussed in the book and online lecture?
Starch Long chains of glucose units Amylose-straight chains Amylopectin-branched chains Found in grains, vegetables, legumes Glycogen Highly branched chains of glucose units storage form of carbohydrate in body Found in the liver and muscles Liver glycogen is broken down to glucose to help maintain appropriate blood glucose levels. Muscle glycogen is broken down when quick energy is needed. Fiber Definition: Indigestible chains of monosaccharides Classified as soluble or insoluble Soluble Examples: pectins, gums Food Sources: oats, legumes, fruits Insoluble Example: cellulose Food sources: whole grains, vegetables, fruits found in significant quantity in cell walls
What does the term "omega" refer to in a fatty acid?
The location of the first double bond determines whether a fatty acid is an omega
Why is the ratio of omega-6 to omega-3 fatty acids so much higher that it was 100 years ago?
The major reason for the imbalance in our omega-6 to omega-3 fatty acids is the invention and incorporation of omega-6 rich vegetable oils into our diet. This boosted our omega-6 fatty acids dramatically. Moving from grass fed animals to corn fed animals also lowered our omega-3 fatty acids.
What is meant by "essential" fatty acid? Name the two essential fatty acids. For each of the two fatty acids, indicate how many total carbons are in the chain, how many double bonds are present and whether they are omega-3 or omega-6 fatty acids.
The two essential fatty acids cannot be made by the body but are essential for health. linoleic acid and linolenic acid Both linoleic and linolenic acid have 18 carbons but they differ in the number of double bonds present and the location of the first double bond. Linoleic acid is an omega-6 fatty acid with 2 double bonds (18:2 omega-6) and Linolenic acid is an omega-3 fatty acid with three double bonds (18:3 omega-3).
How do trans fatty acids influence health?
These trans by-products of hydrogenation may contribute to the development of heart disease in a manner similar or worse than saturated fats.
How does the body regulate blood sugar (glucose)?
When blood sugar rises, cells in the pancreas release insulin, causing the body to absorb glucose from the blood and lowering the blood sugar level to normal. When blood sugar drops too low, the level of insulin declines and other cells in the pancreas release glucagon, which causes the liver to turn stored glycogen back into glucose and release it into the blood. This brings blood sugar levels back up to normal.
The breakdown of carbohydrates during digestion involves what type of reaction? What is water's role in this reaction?
When our body BREAKS DOWN complex carbohydrates to simple ones (e.g. glycogen to glucose), water must be used to help break bonds. This is called hydrolysis
What factors are required for the synthesis of glucose?
When our body MAKES complex CHO molecules from simple ones (e.g. glycogen from glucose), this is done through the process of dehydration. Water is created as a byproduct of this reaction. This reaction is also commonly called a "dehydration synthesis" reaction.
What is ketosis? What causes the formation of ketone bodies or ketosis? Is this dangerous? What are some of the health ramifications of chronic ketosis? Who might suffer from ketosis? How can you detect this condition?
ketosis is the buildup of compounds called ketone bodies because of the lack of glucose needed for efficient fat breakdown. If the glucose cannot get into the cell due to diabetes, it can't get into the mitochondria organelle where energy is produced from the macronutrients. Thus fat has to be broken down for energy in the absence of glucose and ketone bodies (small acidic compounds) are produced health issues including loss of bone mineral, altered blood lipids, increased kidney stone risk, impaired mood, etc Ketosis can be seen in uncontrolled type 1 diabetes, in starvation and in individuals on the first phase of diets such as Atkins. breath smells like nail polish remover
What is the difference between lipolysis and beta-oxidation?
lipolysis which refers to the breaking apart of a triglyceride into fatty acids and glycerol. beta-oxidation and begins when fatty acids are broken into 2-carbon units. A coenzyme A (CoA) unit is then added to each 2-carbon unit to make Acetyl CoA. Thus a 12 carbon fatty acid can make six acetyl CoA compounds and as well as high energy electrons. These acetyl CoA compounds then enter the citric acid cycle (also called TCA or Krebs cycle) where more high energy electrons are produced during their metabolism. These high energy electrons will travel to the electron transport system where they will be used to produce ATP
What are the end products of carbohydrate digestion? (in other words, what are the absorbable carbohydrates?)
maltose Sucrose Lactose
What is the effect of fiber consumption on health? Describe the mechanisms behind the benefits of each type of fiber. (ex. Why is insoluble fiber helpful in reducing the incidence of diverticulitis? Why is soluble fiber helpful in reducing blood cholesterol?)
may reduce risk of colon cancer (recent research has called this into question) helps prevent appendicitis helps prevent diverticulitis (inflamed pouches protruding from the large intestines. (see useful links for some real life pictures) Aids in cardiovascular health by reducing blood cholesterol levels (Soluble fiber binds with cholesterol in the GI tract.....both the cholesterol you eat and the cholesterol in bile. This cholesterol is then excreted in the feces rather than entering (or reentering) the blood. Aids in blood glucose regulation by improves the body's handling of glucose (the absorption of glucose is slowed)
How are carbohydrates classified?
monosaccharides, disaccharides and polysaccharides
Should a vegan be worried about developing a cholesterol deficiency? Why or why not?
no the body can make it
Does sugar cause hyperactivity? obesity? Please explain.
not hyperactivity but yes it can cause obesity when eaten in excessive amounts
What is the cause of lactose intolerance? What are the symptoms and what would you recommend to an individual who suffers from such a disorder?
occurs when individuals consume dairy products (high in lactose) but cannot produce enough of the enzyme lactase to digest the lactose. diarrhea and cramping take lactaid with milk products or dont consume dairy but get a calcium supplement
What monosachcarides make up each disaccharide?
sucrose- one molecule of glucose and one molecule of fructose lactose- one molecule of glucose and one molecule of galactose maltose-two glucose molecules
What does the term "saccharide" mean?
sugar
What happens to the end products of digestion of CHO when they reach the liver?
the liver converts fructose and galactose to glucose or fat after absorption.
What does it mean to "hydrogenate" a fat? Why does the food industry do this? What does hydrogenation do to oils?
this process literally adds hydrogen to fatty acids, replacing some of the double bonds and making it more saturated. solid fats are more desirable for frying (they have a longer shelf life) and baking (they result in more tender, flaky products). some of the hydrogens in the fatty acid's original double bonds simply change sides across the double bond [trans = across] and remain double bonds and it makes it solid
What is the fate of triglycerides in the cell (i.e. once the cell receives them, what can they be used for)?
to make atp
What are the 3 major categories of lipids found in foods?
triglycerides (fat) phospholipids sterols ( colesterol )
Compare and contrast type I and type II diabetes in terms of cause, presence or absence of insulin, symptoms when not in control, treatment, description of individual most likely affected.
type 1: cause lack of insulin production by pancreas absence of insulin likely to be younger treatment: inject insulin to regulate blood type 2: cause cells resistant to the insulin that is present strongly associated w/obesity typically older but young can get it have to take meds and maybe loose weight/change diet Symptoms: glucose in urine(glycosuria) increased urination (polyuria) dehydration increased thirst (polydispsia)
What is the major role of phospholipids? Give two examples of specific instances or substances where phospholipids serve this role. How is a phospholipid configured within the cell membrane?
used as part of the cell membrane and As coating of the lipoprotein (compound that transfers fat in the blood)
Does your body need cholesterol in order to thrive? If so, do you need to get it from food? If not, why not?
yes but the liver can make all the cholesterol we need
What are the recommendations for carbohydrate rich foods in the diet?
•Recommendations for Total CHO •DRI = 45 - 65% of kcalories •WHO: 50 - 70% of kcals •Daily Value: 300 grams or 60% of kcals •Minimum of 130 grams •note that www.choosemyplate.gov lists this as a recommended amount but it's a MINIMUM •No more than 10% kcals from added sugar
