Carbohydrates, Lipids, Amino Acids: The images have big font size and reduced background color. Useful for classroom and printouts. The rest is standard stuff.

1. Molecular Biology 1-3
put together by: Linda Fahlberg-Stojanovska
Disclaimer: I put these together for my kid for his smartphone.
However, I found most images had very small type and increased the
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2. Contents
• Carbohydrates
• Lipids
• Amino Acids

3. Carbohydrates = Saccharides
• The term carbohydrate = saccharide in biochemistry.
• The carbohydrates (saccharides) are divided into four
chemical groupings:
– monosaccharides = simple sugar
– disaccharides (2 simple sugars)
– oligosaccharides (3-6 simple sugars) and
– polysaccharides (>6 simple sugars = macromolecule)
• monosaccharides and disaccharides = sugars

4. Carbohydrates = Saccharides
• A carbohydrate is an organic compound; it consists only of carbon,
hydrogen, and oxygen.
• General formula is: Cm(H2O)n with H:O atom ratio of 2:1 (like water).
• However, there are exceptions to this. One common example would
be deoxyribose, a component of DNA, which has the empirical
formula C5H10O4.
• Carbohydrates are not technically hydrates of carbon. Structurally it
is more accurate to view them as polyhydroxy aldehydes and
ketones.
• Monosaccharides and disaccharides are called sugars and are
“small molecules”; polysaccharides are large or “macromolecules”.

5. Chirality
• Chiral molecule is NOT superposable on its mirror
image.
– It lacks an internal plane of symmetry and thus is not
superposable on its mirror image.
– Chiral molecules usually have an asymmetric carbon atom.
An achiral (non-chiral,
symmetric) molecule and its
enantiomer (mirror image).
http://en.wikipedia.org/wiki/Chirality_%28chemistry%29

6. Monosaccharide = Simple Sugar
• Monosaccharides or simple sugars are the most basic
units of biologically important carbohydrates.
• Monosaccharides are monomers. They are used to build
disaccharides such as sucrose and polysaccharides (such as
cellulose and starch).
• Usually colorless, water-soluble, crystalline solids.
• Examples: glucose, fructose, galactose, xylose and ribose.
• Further, each carbon atom that supports a hydroxyl group
(except for the first and last) is chiral, giving rise to a number
of isomeric forms all with the same chemical formula.
• For instance, galactose and glucose are both aldohexoses,
but have different chemical and physical properties.

7. Monosaccharide = Simple Sugar
glucose fructose

8. Monosaccharides - Chirality
glucose galactose

9. Disaccharides
• A disaccharide is the carbohydrate formed when two
monosaccharides undergo a condensation reaction and
bind together in one molecule.
• As we shall see, a condensation reaction is a
synthesis or anabolic reaction that releases water.
• Common disaccharides are sucrose, lactose and
maltose.
• As we shall see, the bond formed between the 2 simple
sugars of a disaccharide is called a glycosidic bond.

10. Disaccharide – Maltose α(1-4)
glucose glucose
H2O
maltose
disaccharide glycosidic bond

11. Lipids
• Lipid is a group of naturally occurring molecules
– fats = triglycerides
– steroids
• steroid hormones
• subgroup sterols (example: chloresterol)
– phospholipids
– fat-soluble vitamins (such as vitamins A, D, E, and K),
– monoglycerides,
– diglycerides
– others.

12. Lipids
The main biological functions of lipids include
• energy storage
fat (adipose tissue)
• structural components of cell membranes
phospholipids, cholesterol, ...
• important signaling molecules
steroid hormones, prostaglandins

13. Lipids – Classification 1
http://www.fao.org/docrep/field/003/AB470E/AB470E03.htm

14. Fatty Acids
Fatty acid is
simplest lipid
http://www.biochem.arizona.edu/classes/bioc462/462a/NOTES/LIPIDS/Lipids.html

15. Fats = Triglycerides
• All fats are derivatives of fatty acids and glycerol.
• The molecules are called triglycerides, which are
esters of glycerol and 3 fatty acids.
• an ester is molecule formed from the reaction of the
– carboxylic acid and an
– organic alcohol
If “straightened”, the fatty acids would
each be a horizontal line; the glycerol
"backbone" would be the vertical line
that joins the 3 horizontal lines.
http://en.wikipedia.org/wiki/Fat

16. Esters Glycerol + Fatty Acids
The
hydrophobic
tail of a
phospholipid
•glycerol
•2 fatty acids
http://www.mhhe.com/biosci/pae/botany/uno/graphics/uno01pob/vrl/

17. Glycerol (3-C alcohol)
• Glycerol is an alcohol with multiple hydroxyl OH groups.
• The glycerol backbone is central to all glyceride lipids.
http://en.wikipedia.org/wiki/Glycerol

18. Keywords
• An alcohol is an organic compound in which the hydroxyl
functional group (-OH) is bound to a carbon atom and
this carbon center is saturated, having single bonds to three
other atoms.
• Alkanes (saturated hydrocarbons) compounds that have
only hydrogen and carbon atoms and have ONLY single
bonds (saturated compounds). The simplest alkane is
methane CH4.
• Cycloalkanes (naphthenes) are types of alkanes that
have one or more rings of carbon atoms (all with single
bonds). Steroids have four cycloalkane rings.

19. Steroids
• Steroid is an organic compound with a characteristic
arrangement of four cycloalkane rings
• The core of steroids is ≥17 carbon atoms bonded
together:
– 3 cyclohexane rings A, B, C and 1 cyclopentane ring D
– steroids vary by functional groups
attached to this four ring core and
by the oxidation state of the rings
• Examples:
– Hormones and sterols
http://en.wikipedia.org/wiki/Steroid

20. Steroids
http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookchem2.html

21. Steroids – Sterols - Cholesterol
• Sterols are special forms of steroids,
• with a hydroxyl group at position-3 and
• a skeleton derived from cholestane
• Examples: Vitamin D and Cholesterol
http://www.cytochemistry.net/cell-biology/membrane_intro.htm

22. Cholesterol
• Cholesterol = build and maintain membranes
– hydroxyl group on cholesterol interacts with the polar head
groups of the membrane phospholipids and sphingolipids,
– bulky steroid and the hydrocarbon chain are embedded in
the membrane, alongside the nonpolar fatty acid chain of
the other lipids.
• Cholesterol reduces the permeability of the plasma
(cell) membrane so only neutral solutes, protons H+ and
sodium ions can pass through.

23. Cholesterol
• Within cell membrane, cholesterol also functions
intracellular transport, cell signaling and nerve
conduction.
• Within cells, cholesterol is the precursor molecule.
• Cholesterol is an important precursor for the synthesis of
vitamin D and for the steroid hormones.
• In the liver, cholesterol is contained in bile.

24. Cholesterol - Steroid Hormones
• Steroid hormones are derived from cholesterol
• Sex hormones
– Progesterone
– Testosterone
– Estradiol
• Aldosterone
• Cortisol

25. Membrane Lipids
• Membrane lipids are lipids in the cell membrane.
Ex: phospholipids, glycolipids, and cholesterol
25
http://publications.nigms.nih.gov/insidethecell/chapter1.html

26. Phospholipid
26
http://en.wikipedia.org/wiki/Phospholipid

27. Bile – Digestion of Lipids
• Bile is mostly of water (85%) and bile salts (10%)
• Bile salts solubilize fats in the digestive tract and aid
in the intestinal absorption of fat molecules as well as
the fat-soluble vitamins, A, D, E, and K.
Bile salts
surround fat
(lipid) to
solubilize it.
http://en.wikipedia.org/wiki/Bile

28. Amino acids
Amino acids are molecules containing an amine group, a
carboxylic acid group, and a side-chain that is specific to
each amino acid.
The key elements of an amino acid are
carbon, hydrogen, oxygen, and nitrogen.
Structure of an
amino acid
28
http://www.hcc.mnscu.edu/chem/V.27/amino_acid_structure_2.jpg

29. Amino acids - Glysine
Side chain = H so it is smallest of the 20 amino acids
•Its codons are GGU, GGC, GGA, GGG
•M = 75 g/mol. Solubility=250 mg/ml
•Not essential. Can be manufactured artificially and in the body.
•Glycine is a colourless, sweet-tasting crystalline solid.
•It is achiral (not chiral); all other amino acids are chiral.
•It can fit into hydrophilic or hydrophobic environments, due to its
two hydrogen atom side chain.
29
http://www.daviddarling.info/encyclopedia/G/glycine.html

30. Amino acids - Lysine
• Lysine is an essential amino acid,
(human body cannot synthesize it).
• Lysine's codons are AAA and AAG.
• Lysine is a base
30

31. Amino acids - 1
31
http://www.geneinfinity.org/sp/sp_aaprops.html

32. Amino acids - 2
32
http://www.geneinfinity.org/sp/sp_aaprops.html