2. AP Biology 2003-2004
Why study Carbon?
ī§ All living things are made of cells
ī§ Cells
īĩ ~72% H2O
īĩ ~3% salts (Na, Cl, KâĻ)
īĩ ~25% carbon compounds
īˇcarbohydrates
īˇlipids
īˇproteins
īˇnucleic acids
3. AP Biology 2003-2004
Chemistry of Life
ī§ Organic chemistry is the study of
carbon compounds
ī§ C atoms are versatile building blocks
īĩ bonding properties
īĩ 4 stable covalent bonds
5. AP Biology 2003-2004
Hydrocarbons
ī§ Simplest C molecules = hydrocarbons
īĩ combinations of C & H
ī§ Simplest HC molecule = methane
īĩ 1 carbon bound to 4 H atoms
īĩ non-polar
īĩ not soluble in H2O
īĩ hydrophobic
īĩ stable
īĩ very little attraction between molecules
īĩ a gas at room temperature
6. AP Biology 2003-2004
Hydrocarbons can grow
ī§ adding C-C bonds
īĩ straight line
ī§ ethane
ī§ hexane
īĩ branching
ī§ isohexane
īĩ ring
ī§ cyclohexane
ethane
hexane
cyclohexaneisohexane
methane
10. AP Biology 2003-2004
Geometric isomers
ī§ Molecules differ in arrangement around
C=C double bond
īĩ same covalent partnerships
11. AP Biology 2003-2004
Enantiomer (stereo) isomers
ī§ Molecules which are mirror images of
each other
īĩ C bonded to 4 different atoms or groups
ī§ assymetric
īĩ left-handed & right-handed versions
ī§ âLâ versions are biologically active
12. AP Biology 2003-2004
Form affects function
ī§ Structural differences create important
functional significance
īĩ amino acid alanine
ī§ L-alanine used in proteins
ī§ but not D-alanine
īĩ medicines
ī§ L-version active
ī§ but not D-version
īĩ sometimes with
tragic resultsâĻ
13. AP Biology 2003-2004
Form affects function
ī§ Thalidomide
īĩ prescribed to pregnant women in 50âs &
60âs
īĩ reduced morning sickness, butâĻ
īĩ stereoisomer caused severe birth defects
14. AP Biology 2003-2004
Diversity of molecules
ī§ Substitute other atoms or groups
around the C
īĩ ethane vs. ethanol
ī§ H replaced by an hydroxyl group (âOH)
ī§ nonpolar vs. polar
ī§ gas vs. liquid
ī§ biological effects!
ethanolethane
16. AP Biology 2003-2004
Functional groups
ī§ Components of organic molecules that
are involved in chemical reactions
īĩ give organic molecules distinctive
properties
īĩ ex: male & female hormonesâĻ
17. AP Biology 2003-2004
Viva la difference!
ī§ Basic structure of male & female
hormones is identical
īĩ identical C skeleton
īĩ attachment of different functional groups
īĩ interact with different targets in the body
18. AP Biology 2003-2004
Types of functional groups
ī§ 6 functional groups most important to
chemistry of life:
īĩ hydroxyl amino
īĩ carbonyl sulfhydryl
īĩ carboxyl phosphate
ī§ Affect reactivity
īĩ hydrophilic
īĩ increase solubility in water
20. AP Biology 2003-2004
Carbonyl
ī§ C=O
īĩ O double bonded to C
ī§ if C=O at end molecule = aldelhyde
ī§ if C=O in middle of molecule = ketone
21. AP Biology 2003-2004
Carboxyl
ī§ âCOOH
īĩ C double bonded to O & single bonded
to OH group
ī§ compounds with COOH = acids
īˇfatty acids
īˇamino acids
22. AP Biology 2003-2004
Amino
ī§ -NH2
īĩ N attached to 2 H
ī§ compounds with NH2 = amines
īˇamnio acids
ī§ NH2 acts as base
īˇammonia picks up H+
from solution
23. AP Biology 2003-2004
Sulfhydryl
ī§ âSH
īĩ S bonded to H
ī§ compounds with SH = thiols
ī§ SH groups stabilize the structure of proteins
24. AP Biology 2003-2004
Phosphate
ī§ âPO4
īĩ P bound to 4 O
ī§ connects to C through an O
ī§ PO4 are anions with 2 negative charges
ī§ function of PO4 is to transfer energy
between organic molecules (ATP)
25. AP Biology 2003-2004
Why study Functional Groups?
ī§ These are the building blocks for
biological molecules
âĻand that comes next!
Why do we study carbon -- is it the most abundant element in living organisms? H & O most abundant C is the next most abundant
Carbon chemistry = organic chemistry Why is it a foundational atom? What makes it so important? Canât be a good building block if you only form 1 or 2 bonds.
Like sugars: C 6 H 12 O 6 But can be arranged in different ways -glucose -galactose -dextrose
Same formula but different structurally & therefore different functionally. Molecular shape determines biological properties. Ex. Isomers may be ineffective as medicines
The properties of an organic molecule are not solely determined by the carbon skeleton but also by the arrangements of atoms attached to it. Certain groupings of atoms called functional groups are found to reoccur time and time again in many different molecules, often having important roles in the reactions the molecule can participate in.
For example the male and female hormones, testosterone and estradiol, differ from each other only by the attachment of different functional groups to an identical carbon skeleton.