UNIT 5 Flashcards
Carbohydrates
compounds composed of single or multiple sugars. the name means carbon and water, and a chemical shorthand for carbs is CHO
Complex carbs
long chains of sugar units arranged to form starch or fibre. (polysacchrides)
Simple carbs
sugars, including both sugar units and linked pairs of sugar units. the basic sugar molecule contains 6 carbon atom, with 1 oxygen and hydrogen.
Used interchangeably with simple sugars
“added sugars”
The sugars added to food and drinks by manufacturers or consumers. Includes single sugar units, such as glucose, and pairs of sugar units, such as sucrose(table sugar), as well as concentrated sugars, such as syrups, honey, and fruit juice concentrates.
“free sugars”
all those sugars added to food by manufacturers and consumers, plus those that occur naturally in fruit juices.
photosynethsis
The process by which green plants makes carbohydrates from CO2 and water using chlorophyll to capture the suns energy,
Glucose
a single sugar used in both plant and animal tissues for energy
it is the most important monosaccharide in the body. Most other monosaccharide and disaccharides breakdown and become glucose in the body
monosaccharides
single sugar units
disaccharides
pairs of single sugars linked together
fructose
a monosaccharide, sometimes known as a fruit sugar
galactose
a monosaccharide, part of the disaccharide lactose
lactose
a disaccharide composed of glucose and galactose (milk sugar)
maltose
a disaccharide composed of two glucose units (malt sugar)
sucrose
a disaccharide composed of glucose and fructose, sometimes know as table sugar.
glycogen
a highly branched polysaccharide composed of glucose that is made and stored by liver and muscle tissues of human beings and animals as a storage form of glucose.
fibres
the indigestible parts of plant foods, largely nonstarch polysaccharides that are not digested by human digestive enzymes, although some are digest by bacteria in the colon.
soluble fibres
food components that readily dissolve in water and often impart gummy or gel-like characteristics to food.
viscous
having a sticky, gummy, or gel-like consistency that flows relatively smoothly.
insoluble fibres
the tough, fibrous structurs of fruits, vegetables, and grains; indigestible food components that do not dissolve in water.
can human digestive enzymes break bonds in fibre?
No, most of it passes through the digestive tract unchanged,. Some fiber is susceptible to fermentation by bacteria in the colon.
What is the chemical formula for glucose
C6H12O6
How many atoms can a carbon, nitrogen hydrogen, and oxygen atom bond with respectively?
carbon: 4
Nitrogen: 3
Oxygen: 2
Hydrogen: 1
Blood Sugar
Refers to glucose in the blood
refined Sugars
Pure, simple carbohydrates that are nutritionally empty (Ex: table sugar)
Refined cereals
grains that have been milled to remove the bran and germ, leaving only the endosperm. (White Flour, white rice, cornstarch)
Refined carbohydrates
includes refined sugars and refined cereals
Resistant starch
The fraction of starch in a food that is digested slowly, or not at all, by human enzymes
How is starch digested and absorbed in the body
- starch is initially broken down in the mouth during chewing by saliva ( salivary amylase) and begins to split into maltose (a sugar)
- When the maltose reaches the stomach, the saliva is deactivated by the stomach acid and starch digestion stops
- starch digestion begins again in the small intestine after a different starch splitting enzyme is released by the pancreas. This enzyme breaks down into disaccharides and small polysaccharides.
How are sugars absorbed into the body
Sucrose and lactose from food, along with maltose and small polysaccharides freed from starch, undergo one more split to yield free monosaccharides before they are absorbed.
The enzyme responsible for the split is attached to the cells of the lining of the small intestine.
lactose intolerance
impaired ability to digest lactose due to reduced amounts of the enzyme lactase.
Fiber Absorption Process?
Largely digested (fermented) by the bacterial inhabitants of the human digestive tract. The bacteria will metabolize some of the fibers that pass through the large intestine, resulting in several odorous gases.
Lactase
The intestinal enzyme that splits the disaccharide lactose to monosaccharides during digestion
What is the general remedy to Lactose intolerance?
The method to alleviate the symptoms of lactose intolerance is to find ways of generating sufficient levels of lactase in the digestive system.
This allows lactose to be split into glucose and galactose. the split then allows the body to absorb it, rather than leaving the lactose undigested to feed the bacteria of the colon.
What is the difference between viscous and non-viscous fibre
Vicous fiber refers to soluble dietary fibers that form a gel-like substance when mixed with water, slowing digestion and promoting a feeling of fullness.
Non-viscous fiber adds bulk to stool, aiding digestion without forming a gel
Constipation
Difficult, incomplete, or infrequent bowl movements, associated with discomfort in passing dry, hardened feces from the body
hemorrhoids
Swollen, hardened veins in the rectum, usually caused by the pressure resulting from constipation
Appendicitis
Inflammation and/or infection of the appendix, a sac protruding from the intestine
Diverticula
sacs or pouches that balloon out of the intestinal wall, caused by weakening of the muscle layers that encase the intestine. Painful inflammation or one or more of these diverticula is known as diverticulitis
butyrate
a small fat fragment produced by the fermenting action of bacteria on viscous, soluble fibres; a major source of energy for the colon cells.
What are the four parts the wheat kernal
germ
Endosperm
Bran
Husk
chelating agents
Molecules that attract or bind with other molecules and are therefore useful in either preventing or promoting movement of substances from place to place.
Glycolysis
an important metabolic pathway in the cytoplasm of our cells that releases a small amount of energy by splitting glucose in half
Krebs Cycle
an important metabolic pathway in the mitochondria of our cells from which we derive most of the energy from molecules like glucose and fatty acids
protein-sparing action
the action of carbohydrate and fat in providing energy that allows protein to be used for purposes it alone can serve.
Ketone bodies
acidic, fat-related compounds that can arise from the incomplete breakdown of fat when carbohydrate is not available.
ketosis
an undesirable high concentration of ketone bodies, such as acetone, in the blood or urine
Insulin
A hormone released by the pancreas in response to a high blood glucose concentration.
It assists cells in drawing glucose from the blood.
Glucagon
A hormone secreted by the pancreas that stimulates the liver to release glucose into the blood when blood glucose concentration dips.
What does glucagon trigger when released?
Glucagon is released when blood glucose falls too low. It triggers to breakdown of glycogen in the liver to free the reserve of glucose
What is the glycemic index
A ranking of foods according to their potential for raising blood glucose relative to a standard such as glucose or white bread
What is the glycemic load
a mathematical expression of both the glycemic index and the carbohydrate content of a food, meal, or diet.
hypoglycemia
A blood glucose concentration below normal, a symptom that may indicate any of several diseases, including impending diabetes
postprandial hypoglycemia
an unusual drop in blood glucose that follows a meal and is accompanied by symptoms such as anxiety, rapid heartbeat, and sweating; also called “reactive hypoglycemia.
fasting hypoglecemia
hypoglycemia that occurs after 8-14 hours of fasting.
When is is insulin released, what is it released by, and what does it do
Insulin is released after a meal due to blood sugar rising. It is secreted by the pancreas.
Insulin is designed to reduce blood sugar by: increasing the permeability of cell membranes to allow glucose into those cells.
It also facilitates the conversion of glucose to glycogen in the muscle and liver cells.
What is glucagon?
Where is it secreted from?
What does it do?
Glucagon serves as a means to increase blood sugar and is secreted by the pancreas.
It facilitates the conversion of glycogen stored in the liver to glucose, which enters the bloodstream and circulates to the brain and other parts of the body.
It also stimulates gluconeogenesis which is the conversion of protein to glucose.
What is epinephrine
What does it do
What is it secreted by
Epinephrine is secreted by the adrenal glands and ensures that the body has sufficient energy available should an emergency situation arise by stimulating the conversion of glycogen in the liver and muscles into glucose and energy.
It works in a manner similar to glucagon.
How do foods that are rich in viscous fiber lower blood cholesterol?
Viscous fiber has been proven to lower blood cholesterol by binding with cholesterol-containing bile in the intestine and carrying it out with the feces.
As well, small fatty acids that are released during bacterial fermentation of fiber are absorbed and travels to the liver where is it thought to reduce cholesterol synthesis.
Transit TIme
The time it takes for fecal matter to move through the entire GI tract.
Transit time INCREASES with LESS fecal bulk and DECREASES with MORE fecal bulk
Naturally Occurring Sugars
Sugars that are not added to a food by are present as its original constituents, such as the sugars of fruit or milk
Which of these substances is NOT a disaccharide?
Maltose
galactose
sucrose
lactose
Galactose
When glycogen is digested, it yields?
glucose only.
What three elements are carbohydrates composed of.
Hydrogen, oxygen, carbon
What is the storage form of glucose in plants
starch
What should the average carbohydrate intake be in regards to TOTAL energy intake?
50%-55%
What is the average daily intake of dietary fiber in Canada?
17 grams
Name Three sources of dietary fiber?
Fruits, Vegetables, Legumes, grains
Describe the chemical digestion process for the carbohydrate in bread made from enriched flour, including digestion sites, enzyme names, and digestion products.
the major carb in bread made from enriched flour is starch.
In the mouth, amalyse digests a little starch into maltose. the remaining starch will pass into the small where it is further digested.
Amylase breaks down starch into maltose, and maltase.
