PHRM 825: Macronutrition Flashcards
Carbohydrates contain ___ kcal/g
4
Carbohydrates are used to generate what?
Metabolic intermediates
Excess carbohydrates are converted to what?
Glycogen and triacylglycerol
Glycogen is found in the ___ and is used for
liver and muscles; energy storage
Triacylglycerol is also know as ___ and is used for
Fat; energy storage
Simple carbohydrates include
- Sugars
- Fruits, vegetables, and milk
Examples of simple carbohydrates are
Monosaccharides and disaccharides
Monosaccharides are compose of ____ sugar molecules
single
Examples of monosaccharides include
Glucose, fructose, and galactose
Disaccharides are composed of ____ sugar molecules
two
Examples of disaccharides include
Sucrose, lactose, maltose
Complex carbohydrates include what 3 things?
polysaccharides, starch, glycogen
A polysaccharide is composed of what?
Many monosaccharides linked together in chains
Examples of polysaccharides
- Glycogen in animals
- Starch and fiber in plants
Glucose is also known as what?
Dextrose
What is the most important carbohydrate fuel for the body?
Glucose
Glucose is frequently referred to as what?
Blood sugar
This molecule rarely occurs as a monosaccharide in food - it occurs as part of a disaccharide or starch
Glucose
What molecule is found in fruits and vegetables and makes up more than half the sugar in honey?
Fructose
What sugar molecule does not cause a rise in blood glucose?
Fructose
Fructose causes a rise in what blood level?
Blood lipids
The increase in the use of high-fructose corn syrup is suggested to be related to what?
Increased incidence of diabetes and obesity
What disaccharide makes up common table sugar?
Sucrose
Where is sucrose found?
sugar cane, sugar bets, honey, and maple syrup
What 2 molecules make up sucrose?
Glucose + Fructose
What disaccharide is found in milk?
Lactose
What 2 molecules make up lactose?
Glucose + Galactose
What disaccharide is made when starch is broken down?
Maltose
What 2 molecules make up maltose?
Glucose + Glucose
What complex carbohydrate is a plant polysaccharide?
Starch
Amylose definition
Starch with linear chains of glucose molecules and alpha-1,4-glucosidic bonds
Amylopectin
Starch with branched chains of glucose molecules with very few alpha-1,6-glucosidic bonds in addition to alpha-1,4-glucosidic bonds
What process does alpha-amylase play a role in?
Digestion of carbohydrates
How does alpha-amylase help with digestion of carbohydrates?
Hydrolyzes starch and glycogen to maltose and maltotriose
Where is alpha-amylase found in the body?
Saliva and pancreatic juice
3 enzymes on the luminal surface of small intestine
Maltase, sucrase, lactase
What does maltase do?
Breaks maltose and maltotriose down to glucose
What does sucrase do?
Breaks sucrose down to glucose and fructose
What does lactase do?
Breaks down lactose to glucose and galactose
What causes lactose intolerance?
Lack of production of lactase
Only what can be absorbed in the body?
Monosaccharides
Indigestible carbohydrates are converted to monosaccharides by what?
Bacterial enzymes
Indigestible carbohydrates are metabolized ____ by bacteria
anaerobically
Anaerobic metabolism of indigestible carbohydrates result in what products?
Short chain fatty acids, lactate, H2, CH4, and CO2
When indigestible carbohydrates are metabolized by bacteria, it can cause a person to have ___ and ___
Flatulence and abdominal discomfort
What is raffinose?
An oligosaccharide in leguminous seeds (beans and peas) that cannot be hydrolyzed by human enzymes
What does the glycemic index measure?
How quickly individual foods will raise blood glucose level
How is glycemic index defined?
The ratio of the area of the blood glucose response curve to that of glucose
What is the preferred energy source for the brain?
Glucose
What is the glucose transporter in the brain and is it insulin dependent?
GLUT3; No
What is the glucose transporter in the muscle and adipose tissue and is it insulin dependent?
GLUT 4; Yes
What is the glucose transporter in the liver and is it insulin dependent?
GLUT 2; Yes
What is the end product of glucose metabolism in RBCs
Lactate
What organelle do red blood cells not have?
Mitochondria
What are examples of dietary fibers
Cellulose, hemicellulose, lignin, pectin
Where are cellulose and hemicellulose found?
Unrefined cereals, bran, whole wheat
Characteristics of cellulose and hemicellulose
- Insoluble
- Increase stool bulk and decrease intestinal transit time
Where is lignin found?
Woody parts of vegetables
Characteristics of lignin
- Insoluble
- Binds cholesterol and carcinogens
Where is pectin found?
Fruits
Characteristics of pectin
- Soluble
- Decreases rate of sugar uptake and decreases serum cholesterol
Lipids have ___ kcal/g
9
What macromolecule provides satiety and adds flavor and aroma to diet?
Lipids
Lipids act as a carrier for what kinds of vitamins?
Fat soluble vitamins (ADEK)
Triacylglycerol makes up ____ of the dietary fat
> 90%
What composes triacylglycerol?
Glycerol + 3 FA
Phospholipids, cholesterol, cholesterol esters, fatty acids are ____ of the dietary fat
<10%
2 types of fatty acids
Saturated and unsaturated
Saturated fatty acids have a ____ melting temperature than unsaturated fatty acids
Higher
Saturated fatty acids are ___ at room temperature
Solid
What are the 2 most common saturated fatty acids found in food
Palmitic acid (C16) and Stearic acid (C18)
Which type of fatty acid is associated with many health risks such as heart disease and stroke?
Saturated fatty acids
Unsaturated fatty acids have a ____ melting temperature than saturated fatty acids
Lower
What are the 2 most common unsaturated fatty acids found in food?
Oleic acid (18:1) and linoleic acid (18:2)
What are the 2 essential fatty acids?
Omega-3 and Omega-6
Omega 3 is found in what kinds of oils?
Vegetable and fish
Omega 6 is found in what oils?
Corn and meat and fish
Essential fatty acids are used to synthesize ___ in the body
Eicosanoids
Essential fatty acid deficiency is ___
Rare
Essential fatty acids may need to be added to what?
Artificial infant formula
The ratio of w-3 to w-6 in the diet is important in regulation of what processes?
Blood pressure, blood clotting, immune functions
We want to w-3 to w-6 ratio to be ____
High
Most unsaturated fatty acids found in nature have a ____ configuration
cis
What process is used to convert unsaturated fatty acids to saturated fatty acids while producing trans fatty acids as byproducts
hydrogenation
Hydrogenated or partially hydrogenated vegetable oils are a primary ingredient in what?
Margin and shortening
A trans fatty acid has a ____ melting point than the same fatty acid in the cis configuration
higher
Trans fats raise ____ levels and increase the risk of ____
Blood cholesterol; heart disease
Fat needs to be ___ in order to be digested
Solubilized
How is fat solubilized?
- Dispersion of lipid phase into small droplets
- Solubilization by bile acids
What enzymes hydrolyze triacylglycerol to fatty acids and monoacylglycerol?
Gastric and pancreatic lipases
Fatty acids produced via hydrolization of triacylglycerol via gastric and pancreatic lipases act as what?
Surfactants
What does esterase do in the digestion of lipids?
Hydrolyzes monoacylglycerol and cholesterol ester
What delivers lipids to peripheral tissues?
Chylomicrons
Muscle uses fat as what?
Energy source
Excess fat is stored where?
Adipose tissue
What can NOT sue fat as an energy source?
Brain
When the body is starved, the liver converts fatty acids to what?
Ketone bodies
Where are ketone bodies utilized as an energy source?
Brain and muscle
Role of dietary proteins
- Essential structural component
- Enzymes, hormones, plasma proteins, antibodies
Excess protein is a source of ___
energy
If the excess protein is a glucogenic amino acid, it is converted to ____ and then ____
Glucose; triacylglycerol
If the excess protein is a ketogenic amino acids, it is converted to _____ and then ____
Keto acids and fatty acids; triacylglycerol
Protein makes up what percentage of the human body weight?
~20%
Essential amino acids either _____ or ____
Cannot be synthesized by the body or cannot be synthesized in large enough amount
If we don’t consume enough essential amino acids in the diet, new proteins cannot be made without what?
Breaking down other body proteins
Some amino acids are conditionally essential. Give an example.
If phenylalanine is not enough, tyrosine cannot be made enough in the body
What is the pH of gastric juice?
<2
During gastric digestion of proteins, the low pH does what?
Denatures the proteins
Pepsins are involved in gastric digestion and are ___ and ___ at acidic pH
Stable and active
Example of pepsin
Aspartic protease
Intestinal digestion occurs with the help of ____ located at ____
peptidases; luminal surface
What is the brush border?
Luminal surface of epithelial cells in the intestines
Brush border is rich in what?
Peptidases
Intestinal digestion produces what?
Free amino acids and di- and tripeptides
Intestinal digestion can occur with the help of ______
intracellular peptidases
Intestinal digestion via intracellular peptidases results in ____ being released into the blood
Free amino acids
Absorbed amino acids are delivered to the liver via ___
The portal vein
Amino-acid metabolizing enzymes in the liver have high ____ values
Km
Most amino acids that go into the liver ___
end up passing through
tRNA-charging enzymes have low ___ values for amino acids
Km
Amino acids that escape the liver are used for ___ or ___
Protein synthesis or energy in other tissues
Celiac disease is caused by what?
Gluten intolerance resulting in inflammation and damage of the small intestine
Celiac disease is what kind of disorder?
Autoimmune
Gluten is a major ___ found in ____
Protein; wheat, rye, and barley
Protein has ___ kcal/g
4
Alcohol has ___ kcal/g
7
Excess energy in humans is stores as
fat in adipose tissue
Glycogen in the liver is used to
Maintain blood glucose levels
Glycogen in muscle is used for
exercise
___ is NOT a preferred energy reserve
Protein
Why is protein not a preferred energy reserve?
Not all proteins in our body can be used as energy
When does the well-fed state occur?
Right after a meal
What occurs during the well-fed state?
- Insulin release
- Glycolysis
- Glycogen synthesis
- Catabolism of amino acids
- Fatty acid synthesis
What does NOT happen during the well-fed state?
Gluconeogenesis
When does the early fasting state occur?
Early morning (a couple hours after meal)
What occurs during the early fasting state?
- Glucagon release
- Glycogen breakdown by liver
- Gluconeogenesis by liver (Cori cycle, alanine cycle)
What does NOT happen during the early fasting state?
Catabolism of amino acids (we want to reserve amino acids for protein synthesis)
During the cori cycle the liver converts ___ to ___
Lactate to glucose
Cori cycle is also known as the ___ cycle
Glucose-lactate
During the cori cycle, Glucose generated by gluconeogenesis in the liver is used for ___ in ____
Glycolysis; a peripheral tissue
During the cori cycle, NADH generated by glycolysis is used to ___
Reduce pyruvate to lactate
The cori cycle is important when ___ is not enough
Oxygen supply
What cells rely on the cori cycle and why?
Red blood cells because they do not have a mitochondria
The alanine cycle releases what?
Nitrogen
The alanine cycle is also known as what?
Glucose-alanine cycle
During the alanine cycle, glucose generated by gluconeogenesis in the liver is used for ___ in ____
glycolysis; a peripheral tissue
In the alanine cycle, NADH generated by glycolysis is used to produce ____
ATP
During the alanine cycle, amino nitrogen is transferred to the liver and disposed of as ___
urea
When does the fasting state occur?
When the body is very hungry and it is in energy save mode
What occurs during the fasting state?
- Glucagon release
- Gluconeogenesis
- Protein is used as a major carbon and nitrogen source
- Lipolysis in adipose tissue
- Fatty acid oxidation
- Ketogenesis
- Reduced thyroid hormones
During the fasting state, the basal energy requirement drops by ___%
25%
Blood levels of ___ is carefully regulated
glucose
If glucose is <1.5 mM, ___ will occur
Coma and death
Hyperglycemia can cause
Dehydration, hyperglycemic coma, complications of diabetes
High glucose levels are toxic
Brain uses more than ___% of the body’s glucose
20%
The brain uses ___ g of glucose per day
100-120
The brain uses ___% of the body’s total oxygen
15-20%
The brain uses the membrane potential created by ___
Na/K ATPase
How is energy stored in the brain?
The brain cannot store energy - it cannot use glycogen and it cannot store fat
What does the brain use for energy when the body is starving?
Ketone bodies made from acetyl-CoA in the liver
How is stored energy utilized during low level exertion?
- Fatty acid oxidation
- Aeorbic
How is stored energy utilized during moderate to high activity
- Glycogen to glycolysis (carbohydrate loading)
- Switch over to fatty acid oxidation
- Aerobic
How is stored energy utilized during maximum exertion
- Phosphocreatine and glycogen
- Anaerobic
- Lactic acid production
- Very little inter-organ cooperation
- <1 min
Protein-energy malnutrition is common is ___
Infants and young children in developing countries
Protein-energy malnutrition results in a reduced ability to ___
Fight off infection
Marasmus cause
Inadequate intake of both protein and energy
Marasmus presentation
- Thin, wasted appearance
- Small for his/her age
Kwashiorkor cause
Inadequate intake of protein with adequate energy intake
Kwashiorkor presentation
- Occurs in children 1-3 years of age
- Deceptive plump appearance due to edema
