Exam 2 Flashcards
What are the base (smallest) units of carbohydrates? How are these units combined to form larger carbohydrate molecules?
Monosaccharide- carb consisting of a single sugar
Disaccharide- two sugar molecules
Together they are simple carbohydrates or simple sugars
How do we categorize carbohydrates? What are the primary monosaccharides, disaccharides, oligosaccharides and polysaccharides?
Simple Carbohydrates- Monosaccharites (Glucose, Furcturose, Galactose)
Disaccharides (Lactose, Sucrose, Maltose)
Complex Carnohydrates- Oligosaccharides {3-10 sugar units} (Raffinose, Stachyose)
- Polysaccharides {>10 sugar units} (Glycogen, Starch, Dietary Fiber
What is the significance of glucose to the body?
Glucose is the most abundant monosaccharide in the body, provides cells with a source of energy (ATP). Glucose is the preperfed energy source for the nerbous syatem and the sole source of energy for red blood cells.
What are example food sources for each of the mono and disaccharides?
Mono: Fructose: fruits and veggies Galactose: milk products Glucose: not found in many food sources Disaccharides: Lactose: milk Maltose: not found in many foods (brewing process) Sucrose: plants, sugar cane, beats,
What is starch? What is the difference between amylose and amylopectin?
Starch is converted glucose. Two types of starch amylose and amylopectin.
Amylose – consisteing of linear (unbranched) chain of glucose molecules
What is the difference between glycogen and starch?
Glycogen is a highly branched arrandement of glucose molecules. When the body is low on glucose the body turns to glycogen for energy.
Why is fiber important in our diets?
Nourishing cells to colon, promotes the selective growth of intestinal bacteria, protects against cardiovascular disease, obesity, and type 2 diabetes.
What are good food sources of fiber?
Whole grains, legumes, veggies, fruits, oats, barley, rice, bran, seeds, soy,
Functional Fiber
– fiber that is added to food to provide beneficial physiological effects
Dietary Fiber
Fiber that naturally occurs in plants
Total Fiber
combination of dietary and functional fiber
Discuss the digestive process for carbohydrates. Begin with significant events in the mouth and trace digestive activity all the way through fiber in the colon.
Chemical digestion of starch begins in the mouth. Enzymes amylase and almylopection released resulting in shortes polysaccharide chains called dextrins. Dextrins pass uncharnged from the stomch to the small intestine. Digestion of disaccharides takes place entirely in the small intestine.
What are the special enzymes located in the small intestine?
enterocytes
What is the collective term for these enzymes?
Disaccharides
What does our body do with galactose and fructose?
Breaks them into tow glucose molecules
What happens after carbohydrates are absorbed into circulation? Where do they go?
Glucose and Galactose are absorbed into the enterocytes by carrier dependent. Energy requiring and active transport. Fructose is absorbed be facilitated diffuisoin. Once absorbed, monosaccharides are circulated to the liver via hepatic portal system.
Explain how blood glucose is regulated after a meal is consumed.
a. What hormones are involved?
Insulin and Glucagon
b. What effects do these hormones exert?
Assist in blood glucose regulation and energy storage
c. What event triggers their release?
When meals provide more glucose than we require. Pancreas is a glucose stabilizer
e. What happens if blood glucose goes too low (hypoglycemic)?
Can make people feel nauseated, dizzy, anxious, lethargic, and irritable
what are dipeptides, tripeptides, oligopeptides and polypeptides?
Polypeptides- a stirng of more than 12 amino acids held together via peptide bond.
What are the four basic components of an amino acid?
- A central carbon atom bonded to a hydrogen atom
- A nitrogen- containing amino group (NH2)
- A carboxylic acid group (-COOH)
- R-Group: The portion of an amino acids structure that distinguished it from other amino acids
How are amino acids combined to form proteins?
Joined together by peptide bonds. Condensation reactine in which a hydroxyl group form one amino acid is joined with a hydrogen atom from another amino acid
What differentiates protein from other macronutrients chemically?
Proteins contain appreciable amounts of nitrogen which makes them chemically distinct
What does “conditionally essential” mean?
When nonessential amino acids become essential because they must be obtained fro the diet
What is transamination?
The process by which an amino group is formed via the transfer of an amino group from one amino acid to another organic compound
Describe complete vs. incomplete. Provide examples of each.
Complete: a food that contains all the essential amino acids in relative amounts needed by the body. Ex) meat, poultry, eggs, dairy
Incomplete: a food that lacks or contains very low amounts of one or more essential amino acids. Ex) plant products
Describe the concept of protein complementation. Provide an example.
Combining incomplete protein sources to provides all of the essential amino acids in relatively adequate amounts
Describe the four layers of protein structure.
Primary structure- primary sequence and is determined by the DNA code, determines the most basic chemical and physical characterisitcs
Secondary structure- folding of a protein becaue of weak bonds that form between elements of the amino acid backbone
Tertiary structure- folding of a plupeptide chain becaue of interactions amoung the R groups of the amino acid
Quaternary structure- the combinging of peptide chains with other peptide chains of a protien
What component or interaction plays the biggest role each layer of structure?
Primary
What is the term fro disruption of the 3-D structure of a protein?
denaturation
d. What are some agents that can cause disruption of this structure?
Ex) when an egg is heated the proteins unfold and the egg white changes from a think clear liquid to an opaque solid.
- Trace the process of digestion and absorption of a protein molecule starting in the mouth
- Gastric cells release the hormone gastrin which enters the blood, causeing release of gastic juices
- Hydrochloric acid in gastric juice denatures protiens and converts pepsinogen to pepsin which begins to digest protiens by hydrolyzing peptide bonds
- Partially digested protiens enter the small intestine and cause release of the hormones secretion and CCK
- Secretin stimulates the pancrease to release bicarbonate neturalizes chyme. CCK stimulates the pancrease to release proenzymes into the small intestine
- Pancreatic proenzymes are converted to active enzymes in the small intestine. These enxymes digest polypeptides into tripeptides, dipeptides, and free amino acids
- Intesetinal enzymes in the lumen of the small intestine and within mucosal cells complete protein digeston
What is/are the major organ(s) involved in protein digestion?
small intestine
What role does hydrochloric acid play in protein digestion?
denatures protein
Do protein digesting enzymes require activation?
Yes, CCK stimulates the pancreas to release proenzymes
Where are the amino acids absorbed?
Small intestine
What system transports amino acids away from the site of absorption
passive and active transport
What do enzymes do?
Function as biological catalysts driving the myriad chemical reations that occur in the body
What step/process must occur before amino acids can be used for energy?
Muscle tissue is broken down, the liver takes up the amino acids,
Nitrogen balance-
the condition in which protein (nitrogen) intake equals protein loss by the body
What are some reasons athletes may need more protein than the typical person? How much more is needed?
Increaded hemoglobin to carry oxygen, increased ise of protein for energy, increased use of protein for glucose production, increased tissue damage
Strength training: up to 2x RDA
Endurance training: up to 1.75x RDA
Vegetarian
- someone who does not consume any or selected foods and beverages made from animal product
Lacto-ovo-vegetarian-
- consumes dairy products and eggs but has an otherwise plant based diet
Vegan
consumes no animal products
Protein Energy Malnutrition
Protien defiecieny accompanied by inadequate intake of protein and often of other essetnail nutriets as well
Marasmus
a form of PEM characterized by extreme wasteing of muscle and adipose tissue
Kwashiorkor
- a form of PEM often characterized by edema in the extremities (hands feet)
Ascites
Abnormal accumulation of fluid in the abdominal cavity
Are there concerns with excess protein consumption?
no
What does AMDR stand for?
Acceptable macronutrient distribution range
What is the AMDR for protein?
10-35%
What is the AMDR for fats?
20-35%
lipids
organic molecule that is relatively insoluble in water and soluble in organic solvents
Fatty acid-
one end of its carbon chair in the alpha end contains a carboxylic acid group, and the other end called the omega end containing a methyl group
What is the difference between an oil and a fat
Oils: liquid at room temp
Fats: solid at room temp
Saturated fat
a fatty acid that contains only carbon-carbon single bonds in its backbone
unsaturated fat
contains at least one carbon-carbon double bond
Using a diagram or flow chart of the digestive system, trace the path of digestion for dietary fats.
Mouth- minimal digestion of triglycerides, lipase in mouth
Stomach- Some digestion(~30%)
Small Intestine: Release of acidic chyme from stomach into duodenum causes CCK and secretion release, lipids emulsified by bile, digested by pancreatic lipase, Micelles are taken up by enterocytes
What is the role of bile? Where does it come from? How is its release stimulated? What dietary implications would removal of the gall bladder have?
Lipids emulsified by bile, bile salts surround digestion products and form micelles, lipids into small intestine stimulates the release of the CCK which in turn signals the gallbladder to contract and release bile.
In the small intestine, what system are lipids absorbed into?
Absorbed into the enterocytes and circulated away from the small intestine
Are there differences between various types of lipids?
Depending on how water soluble a lipid is and how long the chain is
What are micelles
a water soluble spherical structure formed in the small intestine via emulsification
what are chylomicrons
A lipoprotein made in the enterocyte that transports large lipids away from the small intestine into the lymph
How are lipids circulated in the body?
Albumin- short and medium chain fatty acis
Chylomicrons- released into lymph, carries dietary fat from small intestine out to cells of body
Which organ regulates lipoprotein synthesis and circulation?
liver
Very low density lipoproteins
carries TGs and cholesterol from liver out to the cells
intermediate density lipoproteins
VLDL become IDL when some fatty acids are gone and only cholesterol remains
High Density Lipoproteins
reverse cholesterol transport (bringing cholesterol back to liver)
What is the AMDR for fats?
20-35%
What dietary lipids should we give special attention to limiting
Minimal trans fat and less than 10% saturated fat
What is the recommendation for seafood consumption?
Twice a week because it has omega 3 fatty acids
What are some health concerns for over consumption of dietary fat?
obesity, cardiovascular disease, cancer
