Nutrient Digestion 1 Flashcards
What are the principle dietary constituents?
Carbohydrates
Protein
Fat
Vitamins
Minerals
Water
What are different classes of carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
What are monosaccharides?
Hexose sugars (6C)
What are examples of monosaccharides?
Glucose
Galactose
Fructose
Where are monosaccharides absorbed?
Small intestine
What bond connects disaccharides?
Glycosidic bond
What and where are disaccharides broken down into monosaccharides?
By brush border enzymes in the small intestine
Why are all complex carbohydrates broken down into monosaccharides?
Only monosaccharides can be absorbed
What is lactose formed from?
Glucose and galactose
What enzyme breaks lactose down into glucose and galactose?
Lactase
What is sucrose formed from?
Glucose and fructose
What breaks sucrose down into glucose and fructose?
Sucrase
What is maltose formed from?
Glucose and glucose
What breaks maltose down into 2 glucose monomers?
Maltase
What are some examples of polysaccharides?
Starch
Cellulose
Glycogen
What is starch?
Plant storage form of glucose
What are some examples of starch?
a-amylose (glucose linked in straight chains)
Amylopectin (glucose chains highly branched)
What are glucose monomers linked by in starch?
a-1, 4 glycosidic bonds
What are a-1, 4 glycosidic bonds broken down by?
Amylases
What is cellulose?
Constituent of the plant cell wall
Unbranched linear chains of glucose monomers linked by B-1, 4 glycosidic bonds
What are B-1, 4 glycosidic bonds broken down by?
Cellulase
What is cellulose also known as?
Dietary fibre
Why is cellulose only broken down by bacteria and not enzyme?
Animals do not synthesis cellulase which is required to break down B-1, 4 glycosidic bonds
What is glycogen?
Animal storage form of glucose
How are glucose monomers linked in glycogen?
a-1, 4 glycosidic bonds