Chap 3: Carbohydrates Flashcards
Carbohydrates are the body’s
main source of energy and provide the body’s need for dietary fiber
Carbohydrates (food sources)
Pasta, bread, cereal, grains, rice, fruits, milk, yogurt, and sweets
Carbohydrates (function) (6)
- Immediate respiratory substrate (glucose)
- Energy stores
(glycogen in mammals, starch in plants) - Structural components
(cellulose in plants cell walls, chitin in insect exoskeleton) - Metabolites
(intermediates in biochemical pathways - Cell to cell attachment molecules
(glycoproteins/lipids on the plasma membrane) - Transport
(sucrose in plant phloem tissue)
Two types of Carbs
- Simple Carbohydrates
- Starches or Complex Carbohydrates
Simple carbs have a bad rep. because
They are high in calories and low in nutritional value
Types of carbohydrates
Monosaccharides (1)
Disaccharides (2)
Oligosaccharides (3-10)
Polysaccharides (10+)
Monosaccharides - simple sugar ring molecule (Ex.)
- Glucose
- Galactose
- Fructose
Disaccharides (Ex.)
- Sucrose (Fructose + Glucose)
- Lactose (Galactose + Glucose)
- Maltose (Glucose + Glucose)
Oligosaccharides (Ex.)
Raffinose (Glucose + Glucose + Fructose)
Polysaccharides (Ex.)
- Starch
- Pectin
- Cellulose
Enzymes of digestion (4)
- Amylase
- Maltase
- Sucrase
- Lactase
Amylase (where & breakdown)
Saliva & duodenum
Starch –> Maltose + Glucose
Maltase (where & breakdown)
Intestine
Maltose –> Glucose + Glucose
Sucrase (where & breakdown)
Intestine
Sucrose –> Glucose + Fructose
Lactase (where & breakdown)
Stomach
Lactose –> Glucose +Galactose
Lactose Intolerance is an absence
of enzyme lactase (B-galactosidase)
Symptoms : diarrhea, gas, cramps
Glycemic effect
the ability of food to cause sharp increase in blood glucose levels
Easy digestibility & absorption -
Simple sugars -
- higher glycemic effect
- higher glycemic effect
Glycemic Index: Low, Medium, High
Low GI (<55)
Medium GI (56 - 69)
High GI (70>)
The amount of carbs in a food serving affects
blood glucose concentrations and insulin responeses
Glycemic Load =
(Carb (g) x Glycemic Index)/100
Glycemic Load : Low, moderate, high
Low GL (0-10)
Moderate GL (11-19)
High GL (20+)
Fiber
the plant material that does not break down when you digest food
Fiber (food sources)(5)
Oatmeal, fruits, vegetables, whole grains and legumes
Dietary Fiber:
Water Insoluble -
Water Soluble -
- Cellulose, Hemicellulose
- Pectin, Gums <– (thicken/binding agent)
Dietary Fiber Functions
- Prevents Constipation
Absorbs water
Increase stool bulk
Facilitates movement of food - Decrease transit time
- Reduces cholesterol
- Reduces incidence of chronic disease
*Cancer, Diabetes, Heart Disease
Starches or Complex Carbs (food sources)
Whole grain breads and cereals, pasta, vegetables, rice, tortilla, and legumes
Starches or Complex Carbs (function)
- Excellent source of fuel (energy) for body
- Rich in vitamins, minerals, & fiber
