SBI4U Intro to Carbohydrates
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Transcript of SBI4U Intro to Carbohydrates
CARBOHYDRATES
3 different categories 1. monosaccharides: simple sugars
a) trioses ex. G3P (glyceraldehyde 3 phosphate)
CARBOHYDRATES ¢ all contain (C H O) ¢ high energy compounds due to high
potential energy in C-H
empirical formula
2- 8 C atoms
(3C) C3H6O3 1
2
3
2 n
b) pentoses
ex i. ribose (in RNA) ii. deoxyribose (in DNA)
CARBOHYDRATES (5C)
C5H10O5
C5H10O4
c) hexoses
ex. glucose • exists in chain (linear) or ring structures
CARBOHYDRATES
(6C)
(crystallized)
C6H12O6
(dissolved)
1
2
3
4 5
6
• internal rearrangement in solution as C1 joins with C5
1
2 3
4 5
6 + H2O
- H2O
• forms a(n) ________ linkage ether D glucose
isomers: • same molecular formula, but different structure ex. fructose & galactose are isomers of glucose
• all have same formula
CARBOHYDRATES
C6H12O6
α - glucose β - galactose fructose
stereoisomers
+
2. disaccharides • synthesized by condensation rxn’s
CARBOHYDRATES
β
glucose
glucose + glucose maltose
+ α - H2O
1 2 3
4 5
6
1 2 3
4 5
6
ether linkage
+
α (1-4)
ether linkage β (1-4)
1
2 3
4 5
6
α
H2O
CARBOHYDRATES
sucrose + glucose fructose + H2O
lactose + glucose galactose + H2O
main transport sugar in plants
disaccharride found in milk
3. polysaccharides • polymers of 1000’s of monosaccharides ex. a) starch
• short term energy storage in plants • long chains of glucose [α (1-4) ether linkages] • short branches
2. disaccharides (continued)
twisted into a helix
CARBOHYDRATES 3. polysaccharides(continued) ex. b) glycogen
• short term energy storage in animals
• like starch [α (1-4) ether linkages] but highly branched
• side chains [α (1-6) ether linkages]
c) cellulose • makes up cell walls in plants • no side branches • forms long rigid molecules,
linked by β (1-4) ether linkages • indigestible to humans (fibre)
CARBOHYDRATES 3. polysaccharides (continued) ex. d) chitin
• modified cellulose with amide groups • very tough resistant molecule • forms cell wall of fungi & exoskeleton on insects
starch
glycogen
cellulose
HOMEWORK Enzyme & Energy Quiz on Monday