What a cell needs to be a cell: water, macromolecules, ions and small molecules.
Chemical Properties making Bio-Molecules Water Soluble:
addition of functional groups
proteins, nucleic acids, carbs= soluble.
Lipids: usually are water soluble.
Properties of Carbon: non polar (doesn’t like mixing with water)
4 unpaired valence electrons so can form 4 separate covalent bonds.
Diagram: space-filling model shows true dimensions of molecular arrangement.
Covalent Bond Diagram:
1. hydrogen bonds
2. hydrophobic interactions: nonpolar (Ethane) hydrophobic because has electron
3. van der waals
4. Ionic bonds: molecules attracted need to be charged.
Diagram of Ionic Bonds:
Hydrophobic: nonpolar molecules are more attracted to one-another than to H20.
Chart of Covalent v. Noncovalent Bond Energy:
Important Characteristics of All Biomolecules:
-Solubility (in water) -Charge
-Size: know something is hydrophilic because H2 and O2 is on surface so soluble.
Amino Acids have multiple C,N,O (alanine and glucose is soluble).
-Shape: space-filling, stick model, and ribbon model molecule
-Environmental PH: Looking for: H ion concentration
Importance of Carbon in Biomolecules:
How Carbon-based molecules are made water soluble:
-Add polar groups- covalently linked to C-containing molecules (functional groups)
R-OH added to compound making alcohols. Polar. H bonds with H20 to help dissolve
molecules. Enables linkage to other molecules by dehydration.
C=O is very reactive. Impt in building molecules and E-releasing reactions
C=O groups important in Carbon and E rxns
4. Carboxylic: acidic, ionize so what they leave behind is negatively charged. Adds to
electronegativity impot in E-releasing.
5. Amino: Basic, accepts proton in living tissues for NH3. Enters into dehydration
synthesis by accepting H+.
6. Inorganic Phosphate: covalently linked to R. leaving other 2 O2 ionized. (-)charge.
Enters into Dehydration synthesis by giving up OH, releases lots of E when bonded
to another P.
7. Sulfhydrol Group: Found mainly in proteins. Plays roll in protein maintaing shape. By giving up H, 2-SH groups react to make a disulfide bridge. Stabilizing protein struction
through covalent bond.
-Organic Acids have a carboxyl group: weak acids are proton donors, not all acid
molecules dissacioate into ions.
--COOHCOO- + H+
-Amines: have amino group
---NH2+ H+NH3 + base=proton acceptor
Macromolecules: formed by joining monomers (polymerization)
-polymers formed by joining monomers in condensation(dehydration=removal of water
molecule) reactions. Produces water, universal.
-takes minimum of two moners to make molecule of water. Always 2:1 ratio. Needs
equivalent of a molecule of water.
-2 water molecules needed to hydrolyze a trimer into 3 individual monomers=2 because
water is added to the covalent bond.
-Hydrolysis: how polymers are broken down. Require water, cells add enzymes to break
down polymers by adding water back.
1. Monosaccharides=monomers. Glucose: C6H12O6. If aldehyde is off C1=aldo sugar.
-3 addition structural monomers of glucose:
mannose (diff at C2, C4) a-Galactose (diff at C2, C4) Fructose (diff at C1 and C2)
***a-d-glucose: monomer for starch and glycogen.
b-d-glucose: monomer for cellulose
both different from each other at C1 for isomers.
Isomers: same chem formula, atoms arranged diff
Structural (geometric)isomer: diff in how atoms joined together. Glucose ring closes at 1
and 5. Produces two isomers, two different ways in which you can close the ring. Alpha
and beta d glucose are examples.
“D” so shows that both are of same type in terms of stereo isomers and reflecting
polarized light. Optical is mirror images of each other.
At diagram: Carbon has covalently linked to four elements. Can arrange in one or two
different ways. Arrange so carbon itself is asymmetric. (chiral carbon)
Way to distinguish them: by forming an impression or mold that involved three of the
elements linked to Carbon.
Mirror images = D&L forms.
Stereo isomers can only be distinguished from one another optically: by illuminating
molecule with polarized light, one member of pair reflects light to one direction and vice
Result: two chemically different molecules although identical in atom type and make up. predominately D-Form: D&L, just has to do with reflecting light.
Carbs: DISACCHARIDES= two monosachh linked covalently by dehydration (dimer)
Dimer: two monomers linked covalently.
Alpha and beta linked through condensation reaction Covalent form connected by reaction=glycosidic linkage. Sugar covalent linkage.
Polarity of linkage: enzyme will look for alpha position hydroxyl group off of alpha-d and
will look for hydroxyl group off of carbon 4, and produce linkage that. Alpha 1-4
glycosidic linkage. Heterodimer because monosachh are different.