Lecture 23 Flashcards
What is glucose?
A hexose simple sugar monosaccharide
What is a hexose?
6 Carbon ring
What is the chemical structure of glucose?
C6H12O6
What is a carbohydrate?
A large macromolecule / polysaccharide
What are sources of glucose from carbohydrates?
Starch from plants and glycogen from meat
What is starch?
A polymer made up of up to 1 million glucose units joined by glycosidic bonds
What are the two forms of starch?
Amylose and amylopectin
What is the structure of amylose?
A liner polymer of glucose units
What is the structure of amylopectin?
A branched polymer of glucose units
What is glycogen?
A branched polymer of glucose units
What is a disaccharide?
two sugars joined by a glycosidic bond
What are the examples of disaccharides?
Sucrose, lactose and maltose
What is the structure of sucrose?
A glucose bound to a fructose by a glycosidic bond
Where are disaccharides found in the diet?
Fruit and raw sugar
What enzyme cleaves glycosidic bonds from polysaccharides to disaccharides?
Amylase hydrolase
What enzymes cleave the glycosidic bonds from disaccharides to monosaccharides?
Specific enzymes e.g. sucrase for sucrose
What is the end result of digestion of carbohydrates?
Glucose in the GI tract
Are sugars polar or non polar?
Highly polar
Are sugars water or lipid soluble?
Water soluble
How do glucose molecules cross the lipid membrane?
Through specific transporter proteins anchored in the membrane
What are the two types of transpot?
Active and facilitated transport
What is active transport?
The movement molecules against a concentration gradient, requiring energy input
What transporter protein transports glucose via active transport across the membrane in the GI tract?
The sodium-glucose linked transporter
What is facilitated transport?
The movement of molecules down a concentration gradient, not requiring energy input
