Lecture 1: Knowledge Checks

Polar

Are molecules that have a charge on one side of the molecule that is not canceled out. Hydrophilic

Glycosidic bonds

Carbohydrates are made up of monosaccharides linked together into polysaccharide chains by a type of covalent bond known as a glycosidic bond.

Non Polar

Charge distribution is spherically symmetric when averaged over time. Hydrophobic

Phosphodiester bonds

a covalent bond in RNA or DNA that holds a polynucleotide chain together by joining a phosphate group at position 5 in the pentose sugar of one nucleotide to the hydroxyl group at position 3 in the pentose sugar of the next nucleotide. Facilitated by the enzyme DNA or RNA polymerase.

2) Know the properties of the four types of covalent bonds. How are they formed? What is condensation reaction?

Covalent bonds are bonds in which the electrons are shared by the participating atoms. IRREVERSIBLE

Peptide bonds

are covalent bonds between amino acids facilitated by the enzyme Pepidyltransferase

Van der Waals interactions

The attraction between two molecules based on transient electron asymmetry around an atom that induces a complementary asymmetry in a nearby molecule. Very Weak(Example: Enzyme/Substrate or Antibody/Antigen

Understand how buffer works.

-Buffers are aqueous solutions that resit changes in pH as acid or base are added -mixture of a weal acid (proton donor) and its conjugate base (proton acceptor) or a weak base and its conjugate acid -buffer capacity is generally best within ~ +/- pH unit of pKa -Buffering maintains cellular pH & pH of body fluids -buffers work best when Ph =pKa. which happens when [HA]=[A-]

3) Why water is dipolar and cohesive? Know the properties of hydrogen Bond.

-Water is dipole because it has an uneven distribution of electrons between the hydrogen and the oxygen.(oxygen is more electronegative) -Hydrogen bonds cause water to be exceptionally attracted to each other. Therefore, water is very cohesive.

6) What is pH? Learn how to solve problems involving pH.

check lecture 1 (slide 35)

Know to use Henderson-Hasselbalch equation to calculate how to make or change the pH of a buffer

look at slide or notes in lecture 1

1) Know the four types of biological molecules & their general roles in Cells. 1/4

1. Proteins are linear polymers of L-Amino Acids that are joined by peptide bonds(formed by condensation reactions).

1) Know the four types of biological molecules & their general roles in Cells. 2/4

2. Nucleic Acids is a polymer of joined monomers which are a 3 part molecule(Phosphate group + sugar + base) called a nucleotide. The monomers are joined by phosphodiester bonds in condensation reactions. Nucleic acids are the information molecules of the cell.

1) Know the four types of biological molecules & their general roles in Cells. 3/4

3. Carbohydrates are linear or branched polymers of monosaccharides( aka sugars). Monosaccharides are joined to form disaccharides, oligosaccharides, and polysaccharides via glycosidic bonds. 0 Carbs have many functions as a fuel source(glucose), structural molecules(cellulose, chitin), signaling molecules(cell-cell recognition), and lubricants.

1) Know the four types of biological molecules & their general roles in Cells. 4/4

4. Lipids are water-insoluble molecules that are highly soluble in organic solvents. a. Major component of membrane(phospholipid bilayer) b. Long term energy storage(fat) c. Protection against heat loss d. Protection against physical shock and water loss e. Chemical messengers(Hormones)

Ionic Bonds/Electrostatic Interactions

A weak interaction between ions having opposite charges. Na+/Cl-

Amphipathic

Have polar and nonpolar regions.

Hydrogen Bonds

Hydrogen bond is an attractive force between a partially positive charged hydrogen and a partially negative charged atom (oxygen and nitrogen). Hydrogen bonds are usually shown as dotted lines between two atoms.

Hydrophobic Effect

Non-Polar molecules are driven together in aqueous solutions because of the resulting increase in entropy of water molecules.(Example: Membrane formation and protein folding)

Ester Bonds

Triglycerides are lipids consisting of one glycerol molecule bonded with three fatty acid molecules. The bonds between the molecules are covalent and are called Ester bonds.

Condensation Reaction

Two molecules combine to form one molecule, usually with the loss of water.