By: Nicole Raine S. Cabasa

1. BIOCHEMISTRY -
CARBOHYDRATES
Nicole Raine S. Cabasa

2. BIOCHEMISTRY
• “CHEMISTRY OF THE LIVING CELL”
• The study of life at the molecular level
• Lead us to fundamental understanding of life

4. BIOMACROMOLECULES
• Biomacromolecules are large biological polymers, such as nucleic
acids, proteins and carbohydrates, that are made up of monomers
linked together.
• Self-assemble into cellular structures and complexes
• Recognize and interact with one another in specific ways to perform
essential cellular functions
• Interactions are weal and reversible

5. 4 MAJOR CLASSES OF
BIOMOLECULES
• CARBOHYDRATES
- mainly used as sources of cellular energy
• LIPIDS
- also known as fats; components of cell membranes
• AMINO ACIDS
- used as building blocks for proteins
• NUCLEOTIDES
- used as building blocks for DNA and RNA precursors

6. CARBOHYDRATES

7. CARBOHYDRATES
GENERAL FORMULA: Cn(H2O)n
• FUNCTIONS OF CARBOHYDRATES:
- Energy source
- Energy storage
- Carbon source
- Structure/Protection
- Recognition/Signaling
- Can be attached to other macromolecules

8. CARBOHYDRATES
• CLASSES OF CARBOHYDRATES:
- Monosaccharides
- Disaccharides
- Trisaccharide
- Polysaccharides (oligosaccharides)

9. MONOSACCHARIDES
• Common monosaccharides contain 3 to 6 carbon atoms
• Monosaccharides are either aldehydes or ketones
• For Aldoses and Ketoses – the name is based on the location of the
carbonyl (C = O)
• Combining these terms describes the essential structure of sugars
- glyceraldehyde is an aldotriose
- glucose is an aldohexose
- fructose is a ketohexose

10. MONOSACCHARIDES
Simplest KETOSE is
DIHYDROXYACETONE
• Contains a KETONE
• Only monosaccharide that does
not have a chiral center
Simplest ALDOSE is
GLYCERALDEHYDE
• Contains an aldehyde
• Contains a chiral center
Isomers – same
chemical formula,
different structure
Epimers – isomers that
differ at only 1 Carbon
Enantiomers – isomers
that are mirror images
(D and L)
Anomers – isomers
that differ only at

11. FISCHER PROJECTIONS
RULES:
• Carbons are numbered from the top
• Most oxidized C (one with the most number
of bonds to O) goes at top
• Last carbon will always be part of a CH2OH
group (Not chiral)
• If –OH is to the RIGHT -> D-isomer
• If –OH is to the LEFT -> L-isomer

12. CYCLIZATION OF
MONOSACCHARIDES
• TWO CASES OF CYCLIZATION:
- HEMIACETALS: Carbonyl
reacting with hydroxyl group ->
addition product called
hemiacetal. Carbon center
bonded to one R-group, a H
atom, an –OH and an –OR.
- HEMIKETALS: Hemiketal
functional group includes a
carbon center with 2 R-groups,
an –OH and an –OR group.
Formed when C5 hydroxyl
interacts with C2 carbonyl of a
ketose.

13. DISACCHARIDES
• Formed between monosaccharides via a glycosidic bond
• Involves OH of anomeric carbon and any other OH

14. DISACCHARIDES

15. POLYSACCHARIDES
• Two main functions:
- Energy storage
- Structure
• STORAGE POLYSACCHARIDES:
• - STARCH – found in
chloroplasts of plant cells
- Mixture of 2 types of GLUCOSE
POLYMERS: Amylose and
Amylopectin.

16. POLYSACCHARIDES
• STORAGE POLYSACCHARIDES:
- GLYCOGEN – animal
carbohydrate storage
Functions:
- Used to generate ATP
during anerobic muscle contraction
- The source of glucose for
maintaining blood glucose
- Stored in liver and muscle
as granules or particles
- Branched glucose
polysaccharide

17. POLYSACCHARIDES
GLYCOPROTEINS – oligosaccharides can also be attached to proteins

18. POLYSACCHARIDES
FUNCTIONS OF OLIGOSACCHARIDES ON
PROTEINS:
• Influence structure, folding and stability
of protein
• May determine the lifetime of a protein
• Serve as markers to identify a cell type

19. LIPIDS
• Very important biomolecules
• Insoluble in water
• Soluble in organic solvents and other lipids
• FUNCTIONS OF LIPIDS:
- Storage molecules for energy
- Structural components of cellular membranes
- Protective molecules
- Hormones and vitamins
- Intracellular messengers
- Pigments
- Insulation

20. LIPIDS
• FOUR MAIN CLASSES OF LIPIDS:
1. Triacylgylcerols (TAGs) – also
known as triglycerides; storage lipids
(non-polar)
2. Phosphoacylglycerols –
membrane structural lipids (polar)
3. Sphingolipids – membrane
structural lipids (polar)
4. Non-saponifiable Lipids –
steroids, hormones, cholesterol

21. LIPIDS
FATTY ACIDS
• Long chain carboxylic acids
• TWO TYPES:
- Saturated: - hydrocarbon has no
double bonds
- pack close together
- less fluid
- higher melting
temperature because it takes more
energy to break interactions
- likely to be solids at
room temperature
- Unsaturated: - Hydrocarbon chain
has one or more double bonds
 Do not pack as closely
 More fluid than saturated
 Lower melting temperature than saturated
 Likely to be liquid at room temperature

22. LIPIDS
TRIACYLGLYCEROLS
• Are made up from 3 fatty acids ester linked to glycerol
• Each –OH on glycerol can react with a fatty acid
• Start with C1 -> C2 -> C3
• Release H2O upon formation of ester linkage

23. LIPIDS
FAT SUBSTITUTES
• Olestra – chemically synthesized fat (TAG) substitute
• Mixture of sugars and fatty acids
•Nor absorbed and metabolized
•Depletes the body of fat soluble vitamins and may lead o
gastrointestinal distress

24. LIPIDS
1. TRIACYLGLYCEROLS
- hydrolyzed into 3 fatty acids and 1 glycerolSAPONIFICATION:

25. LIPIDS
2. PHOSPHOACYLGLYCEROLS
- very similar in structure to triacylglycerols except one of the
alcohols of glycerol is esterified by phosphoric acid instead of fatty
acid = phosphatidic acid
- the phosphoric acid group is then esterified by a second
alcohol to form the phosphoacylglycerol

26. LIPIDS
3. SPHINGOLIPIDS
- membrane lipids based on the core structure of SPHINGOSINE,
a long chain amino alcohol
- Glycerol is replaced by sphingosine

27. LIPIDS
4. NON-SAPONIFIABLE LIPIDS/STEROIDS
- based on a fused ring system – RIGID structure
- No ester linkages
- Includes hormones

28. LIPIDS
BIOLOGICAL MEMBRANES
• Membranes surround all cells and organelles
• Membranes are based on LIPID BILAYERS (phospholipids,
glycosphingolipids, sphingolipids and cholesterol)
• Non-polar components minimize exposure to water by forming a
bilayer
• Polar head groups face outward and H-bond with water
• Lipid fatty acid chains face inward and interact via hydrophobic
interactions

29. LIPIDS
EFFECT OF CHOLESTEROL ON MEMBRANES
• Bulky rigid molecule
• Moderates fluidity of membranes
- Cholesterol in membranes decreases fluidity because it is
rigid
- Prevents crystallization (making solid) of fatty acyl side chains
by fitting between them. Disrupts close packing of fatty acyl chains.
Thus, increased fluidity.

30. LIPIDS
INTEGRAL MEMBRANE PROTEINS
• Located within the lipid bilayer
• Hydrophobic amino acids interact with fatty acid chains in the hydrophobic
core of the membrane
•Usually span the bilayer one or more times – called transmembrane proteins
• FUNCTIONS: Transporters & Receptors
• Beta-Barrel Integral Membrane Proteins – barrel shaped protein that is made
up of antiparallel beta strands with hydrophilic head and hydrophobic tails
• Alpha-Helical Membrane Proteins – can cross the membrane once or many
times and have multiple transmembrane segments. Major category of
transmembrane proteins.

31. LIPIDS
PERPHERAL MEMBRANE PROTEINS
• Interact weakly with the membrane with lipid head groups or integral
membrane proteins
• Interactions are mainly hydrogen bonds or electrostatic interactions
• Functions: enzymes, signal transduction proteins, cytoskeletal
proteins
• Lipid anchors protein in the membrane: Farnesyl, Myristoyl, Palmitoyl

32. LIPIDS
FLUID MOSAIC MODEL OF MEMBRANE STRUCTURE

33. LIPIDS
MEMBRANE FUNCTION
- Separate cytoplasm from environment
- Provide system for uptake and export of compounds
- Mediate interactions with environment
- Provide environment for catalysis

34. MEMBRANE TRANSPORT
CLASSES OF ACTIVE AND PASSIVE TRANSPORTERS
• Symporters – moves a small molecule inside a cell during transport
of target molecule inside a cell
• Antiporters – moves a small molecule outside the cell during
transport of a target molecule inside a cell
• Uniporters – binds and transports target molecule only

35. MEMBRANE TRANSPORT
PASSIVE TRANSPORT
- move from HIGHER concentration to LOWER concentration
region
- no need for energy input for this transport
- Two types:
Simple Diffusion – molecule passes through membrane
pore opening without interacting with other molecules
Facilitated Diffusion – transport assisted by specific
membrane protein

36. MEMBRANE TRANSPORT
ACTIVE TRANSPORT
- move from LOW concentration
area to HIGH concentration area
- cells must use energy to
transport. ATP is used.
- Examples: Glucose Transport into
Intestinal Cells
Na+-K+ Ion Pump

37. THANK YOU!