Materi Kuliah Kimia Organik Pertanian Fakultas Pertanian UGM

1. SISTEM PENILAIAN
Ujian Tengah Semester : 50%
Tugas Presentasi : 40% (Penguasaan
materi, keaktifan bertanya dan menjawab)
Kuis : 10%
Ketua Kelas : M. Rizky Ramadhan
Wakil : Nabilla Yumna
BIOKIMIA

2. TUGAS PRESENTASI
Tanggal Kel Topik
22 September I Struktur dan Fungsi Karbohidrat
II Reaksi Monosakarida
III Ikatan Glikosida
IV Fischer Projection dan Haworth Projection
29 September V Peptida
VI Struktur Protein
VII Fungsi Asam Amino dan Protein
VIII Biosintesis Protein
6 Oktober IX Definisi dan Fungsi lemak
X Asam lemak jenuh dan tidak jenuh
XI Reaksi asam lemak
XII Lipid dengan asam lemak
Lipid tanpa asam lemak

3. Concept of biochemistry

4. Carbohydrates
Tri Joko, Ph.D.
Dept. of Crop Protection UGM

5. Carbohydrates
 The most abundant biomolecules on Earth
 Each year, photosynthesis converts more than 100
billion metric tons of CO2 and H2O into cellulose
and other plant products
 Certain carbohydrates (sugar and starch) are a
dietary staple in most parts of the world
 Insoluble carbohydrate polymers serve as
structural and protective elements in the cell walls
of bacteria and plants and in the connective tissues
of animals

7. What is a Carbohydrate?
Aldehyde or ketone compounds with multiple
hydroxyl groups (OH)
Ketones – both groups attached to carbonyl
group are carbon
Aldehydes – one carbon and one hydrogen
attached to carbonyl group
Acetone: Acetaldehyde

8. Structures
• Carbohydrates exist as:
– Monosaccharides
• Single structure which can contain up to 8
carbon atoms
• Not degraded by hydrolysis
– Disaccharides
• Two monosaccharides bonded together
– Polysaccharides
• More than two monosaccharides bonded
together

10. What is a Carbohydrate?
Simplest carbohydrate molecule is
a monosaccharide : (C-H20)n :
carbon hydrate
Monosaccharides have 3 to 7
carbons
Either aldehyde or ketone group
and hydroxyl (OH) groups on
nearly every carbon
Polyhydroxyaldehydes or
Polyhydroxyketones

12. Polyhydroxyaldehydes
Ribose
GlucoseGalactose
R

13. Polyhydroxyketone
R R

14. Hexose: aldo & keto
R R
R

15. Monosaccarides

16. Monosaccharide Nomenclature
C Ketone Aldehyde Examples
4 Tetrose Tetrulose Erythrose,Threose
5 Pentose Pentulose Ribulose,Ribose
6 Hexose Hexulose Fructose,Glucose
7 Heptose Heptulose Sedoheptose, Sedoheptulose

17. Which classification fits this sugar?

18. Which classification fits this sugar?

22. Disaccharides
•Composed of two monosaccharide molecules
•Useful vocabulary:
Linked by glycoside (an ether), part of acetal functional group
Other anomeric carbon = hemiacetal functional group
glycoside linkage
C-O-C
OO
O
CH2OH
HO
HO
HO
HO
HO
CH2OH
OH
an acetal
C-O-C-O-C
OO
O
CH2OH
HO
HO
HO
HO
HO
CH2OH
OH
a hemiacetal
C-O-C-O-H
OO
O
CH2OH
HO
HO
HO
HO
HO
CH2OH
O H

23. Disaccharides
Carbohydrate Ring Numbering
•Anomeric carbon receives lowest number
•Carbon 1 in aldoses
•Carbon 2 (rarely 3) in ketoses
•All other carbons numbered in order
OO
CH2OH
HO
HO
1
2
3
4
5
6
O
Numbering for an aldohexose

24. Disaccharides
Maltose
1,4’-a-D-glucopyranosyl-D-glucopyranose
OO
O
CH2OH
HO
HO
HO
HO
HO
CH2OH
OH
a/b mixture
H3O+/H2O
hydrolysis
Starch
•Product of partial hydrolysis of starch
•Present in juice of cereal grains (from which beer is brewed)
•Compare with cellobiose (from partial hydrolysis of cellulose)
•An a-glycoside: easily digested by mammals
H3O+/H2O
hydrolysis
2
O
OH
CH2OH
HO
HO
HO
Glucopyranose

25. Disaccharide

29. Disaccharides
Lactose
1,4’-b-D-galactopyranosyl-D-glucopyranose
•Present in mammalian milk (up to 8 % by weight; varies with species)
•Readily digested by infant mammals; requires enzyme lactase
•Adults often less tolerant due to low levels of lactase
Lactose
O
O
O
CH2OH
HO
HO
OH
HO
CH2OH
OHHO
H3O+/H2O
hydrolysis
+
O
OH
CH2OH
HO
HO
HO
GlucopyranoseGalactopyranose
O
CH2OH
HO
HO
HO OH

34. Disaccharides
Sucrose
1,2’-b-D-fructofuranosyl-a-D-glucopyranose
•Unusual structure: 1,2’-a-glycoside
•Most common disaccharide in nature
•Produced only by plants such as sugar cane, sugar beats
•Annual commercial world production 9 x 109 kg yr-1 (~4 x 1013 sugar packets)
•An a-glycoside: readily digested by mammals
Sucrose
O
O O
CH2OH
HO
HO
HO
OH
OH
CH2OH
CH2OH
H3O+/H2O
hydrolysis
O
OH
CH2OH
HO
HO
HO
Glucopyranose Fructofuranose
+ O
OH
OH
CH2OHHO
CH2OH

40. Polysaccharides
•Polysaccharide: hydrolysis yields many monosaccharide molecules
•Most important are glucose polymers: cellulose, starch (high molecular weight)

46. Polysaccharides
OO
HO
CH2OH
HO
OO
HO
CH2OH
HO O
O
O
HO
CH2OH
HO
Amylose
Starch
•Two forms: amylose, amylopectin
Amylose
•Linear polymer of ~1K-6K glucopyranose
•20-25% of starch OO
HO
CH2OH
HO
OO
HO
HO O
O
O
HO
CH2OH
HO
O
O
O
HO
CH2OH
HO
Amylopectin
Amylopectin
•Branched polymer containing ~106 glucopyranose
•75-80% of starch
•1,4’-a-D-glucopyranose polymer
•Function: plant glucose/energy storage
•Hydrolysis  glucopyranose
•Easily digested by mammals

50. Polysaccharides
Cellulose
•Linear 1,4-b-D-glucopyranose polymer
•~5,000 - 10,000 glucopyranose molecules per cellulose molecule
repeating subunit:
glucopyranose
O
O
O
O
O
OO
HO
CH2OH
OH
HO
CH2OH
OH
CH2OH
HO
OH
•Most abundant organic substance in nature
•Function: support structure in plants
Wood is ~50% cellulose by weight
Strength due to intermolecular hydrogen bonding
H3O+/H2O
hydrolysis
O
OH
CH2OH
HO
HO
HO
Many glucopyranose
•Not easily digested by mammals