BIOL 112 Lecture Notes - Lecture 6: Carbonyl Group, Stereoisomerism, Ketose
15 Jun 2018
School
Department
Course
Professor
6
SUGARS & LIPIDS:
Plant Cells: sugar has a storage function to be used as food, green is the cell wall, purple is
starch
Three Major Categories of Carbohydrates:
- Monosaccharides
- Disaccharides → which consist of 2 monosaccharides
- Polysaccharides → composed of thousands of monosaccharides
2 groups of sugars: Carbonyl group (C=O) / Hydroxyl group (OH)
Aldose (when the carbonyl is at the end)
Ketose (carbonyl group is in the middle)
- Sugars have the same amount of C as they do O
Isomers: fundamentally different (a group is attached to different carbon atoms)
Optical Isomers – Stereoisomers:
- a group is attached in different ways to the same carbon atom (mirror images) occurs
whenever a carbon has 4 atoms/groups attached that are NOT the same
o Asymmetric Carbon Atoms: different chemicals entirely
Glucose: 2 different stereoisomers at C2, C3, C4, C5
Galactose: OH group points backward on C4, chemically different from Glucose
- Combinations: 24= 16 different stereoisomers in Glucose
Sugar in Water → Glucose forms a ring, O from the 5 carbon bonds to the 1-carbon → this
creates two stereoisomers − −
Glycosidic Linkage: always happens between carbon atom 1 and any hydroxyl group, 2 glucose
molecules can form 11 different disaccharides (only 2 are important → − 1,4 − 1,4
Alpha 1-4:
Maltose: specific enzyme forms an alpha linkage → free OH- allows conversion to aldehyde →
squiggle bond denotes unknown or unspecified orientation
Starch (amylose in plants, unbranched): repeating alpha 1-4 links create a non-reducing end and
reducing end at the squiggle end
Starch: moderately branched, amylopectin in plants → highly branched, glycogen in animals
Beta 1-4:
find more resources at oneclass.com
find more resources at oneclass.com
27
BIOL 112 Full Course Notes
Verified Note
27 documents
