Carbohydrates Flashcards
(26 cards)
What carbohydrates are described as simple and which are complex?
- Monosaccharides = Simple
- Poly/ogliossacharides = Complex
Describe the structure of a monosaccharide and name the three monosaccharides important in nutrition. Name the three disaccharides commonly found in foods and their component monosaccharides.
- Monosaccharides = Hexoses structure.
• Types: Glucose, Fructose, Galactose. - Disaccharides = Sucrose (Glucose + Fructose) , Lactose (Glucose + Galactose) , Maltose (Glucose + Glucose)
What happens in a condensation reaction?
- Joining of two molecules. 2 monosaccharides joining to make 1 disaccharide.
What happens in a hydrolysis reaction?
- Breaking of a molecule into two. IE. Digestion via enzymes.
Name some polysaccharides and important ones in nutrition.
Starches, dietary fibre, ogliosaccharides.
How are starch and glycogen similar, how do they differ?
- Starch is stored energy in plants.
* Glycogen is stored energy in animals
How does dietary fibre differ from these polysaccharides?
• Dietary fibre are un-digestible carbohydrates. Contains B-glycosidic bonds compared to A.
Describe carbohydrate digestion and absorption. What roles does dietary fibre play in the process?
• Digestion occurs in mouth, stomach and small intestine.
• Absorption occurs in mouth and small intestine.
o Certain sugars have different absorption ways:
Glucose & Galactose: Transverse the cells lining by active transport.
Fructose: is asorbed by facilitated diffusion (Slower) Creating smaller rise in B.G.L.
• Monosaccharides enter via capillaries of the intestinal wall.
• Monosaccharides travel to the liver via the portal vein
• In the liver, galactose and fructose are converted to glucose.
o Dietary fibre slows digestion and may impair nutrient absorption by binding to certain ions.
What are the fates of glucose?
o Stored as glycogen for storage.
o Stored as fat.
What effects does carbohydrates have on protein sparing?
o Prevents the breakdown of proteins to provide energy. Therefore, protein-sparing.
How does the body maintain its blood glucose concentration?
The liver releases insulin to bring down blood glucose levels or releasing glucagon to raise blood glucose levels.
What happens when the blood glucose concentration rises too high or falls too low?
The liver releases insulin to bring down blood glucose levels or releasing glucagon to raise blood glucose levels.
What are he health effects of starches and dietary fibre? What are the dietary recommendations regarding these complex carbohydrates?
o Reduced cholersterol (Binding) o Bowel frequency (Increased) o o Heart Health o Anti-cancer.
What foods provide starches and dietary fibre?
- Legumes, Beans, Lentils, Potato, fruits.
Carbohydrates are found in all foods except?
- Meat products
Disaccharides include?
- Surcrose, lactose and maltose.
The making of a disaccharide from two monosaccharides is an (reaction)?
- Condensation reaction.
The storage form of glucose in the body is?
- Glycogen
The significant difference between starch and cellulose is?
- Digestive enzymes can break the bonds in starch but not in cellulose.
o Starches contain a-glycosidic bonds.
o Celluloses/fibres contain b-glycosidic bonds.
The goal of carbohydrate digestion is to yield?
- Glucose.
The enzyme that breaks a disaccharide into glucose and galactose is?
- Lactase.
The enzyme that breaks a disaccharide into two glucose molecules is?
- Maltase
The enzyme that breaks a disaccharide into glucose and fructose is?
- Surcrase
With insufficient glucose in metabolism, fat fragments combine to create?
- Ketone bodies, that provide an alternative form of energy.
