Week 1 - Solutions, Dimensional Analysis, and pH

Outline : 

Outline Biologically Important Atoms Representation of Molecules Amino Acids and Proteins Solutions and Dimensional Analysis pH – Acids, Bases and Buffers

Relative Sizes of Molecules : 

Relative Sizes of Molecules Height of a first grader - 10,000,000,000 Å Diameter of a eukaryotic cell - ~500,000 Å Diameter of a bacterium - ~50,000 Å Diameter of a virus - ~500 Å Diameter of a ribosome - ~200 Å Typical diameter of a protein - ~50 Å Thickness of a cell membrane - ~40 Å Carbon-carbon single bond length - 1.54 Å

Slide 3: 

The most important atoms in biological systems are: hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur

Slide 6: 

Basic Structure of An Amino Acid

Slide 8: 

Proteins Are Polymers of Amino Acids some proteins in your body have the same amino acid sequence as those found in the chimpanzee polypeptide chain

Solutions : 

Solutions What is a solution? Common solutions in lab Salt solutions Crystallization solutions Buffers (Discuss with pH) How to make solutions

Solution Composition : 

Solution Composition Different representations of concentration g/L (mg/mL) % composition (v/v or w/v) Molarity (moles/L) What is a mole? Hint: In chemistry a mole is not an animal!

Moles and Molarity : 

Moles and Molarity Mole definition a chemical mass unit, defined to be 6.022 x 1023 molecules, atoms, or some other unit. Avagadro’s number: 6.022 x 1023 Why do we measure in moles? Chemical equation? Does 1 mole of NaCl weigh the same as 1 mole of sucrose? Molarity = moles/L Represented by M

Dimensional Analysis : 

Dimensional Analysis What is dimensional analysis? Why is it used? Reminder, all undesired units must be crossed out!

Acids and Bases : 

Acids and Bases Definition of acid What acids do you know? Definition of base What bases do you know?

pH : 

pH What is pH? The measure of acidity/basicity of a solution “p” = –log10 , so pH = –log10([H+]) pH + pOH = 14 What happens to pOH if pH increases? Water H2O  H+ + OH- pH = 7 , pOH = 7 blood

pH < 7 : 

pH < 7 Acid example HCl HCl  H+ + Cl- Used to decrease the pH of a solution Common acids include: Acetic acid (vinegar), Sulfuric Acid, Hydrochloric acid (HCl)

pH > 7 : 

pH > 7 Base example NaOH NaOH  Na+ + OH- Used to increase the pH of a solution Common bases include: Sodium Hydroxide (NaOH), Potassium Hydroxide (KOH), Ammonium Hydroxide (NH4OH)

Buffers : 

Buffers What is a buffer? Definition: A solution which is resistant to changes in pH Why do we use buffers? To keep pH constant This keeps proteins and DNA happy and stable! This keeps reactions happy and active!

Buffers : 

Buffers How to make buffers. Mix solution then adjust pH with either acid or base Common Buffers Vary with pH range MES 5.5 - 6.5 MOPS 6.5 - 7.5 HEPES 7 – 8 Tris 7.5 - 8.5