1. Water, pH, and Biological Molecules
2/23/2019
Water, pH and Biological Molecules
What’s so special about water?
It’s a great solvent.
It hold’s tons of heat.
It has high surface tension.
Its less dense as a solid than a liquid.
G. Podgorski, Biol. 1010

2. Water as a Solvent
Dissolving table salt (sodium chloride)

3. Water Is Lighter as Solid than as a Liquid
This means that ice forms an insulating blanket over water.

4. Water Has High Surface Tension
The attraction of one water molecule for another also accounts for ability to hold huge amounts of heat.

5. pH is a Big Deal
pH is a measure of proton (hydrogen ion or H+) concentration .
Low pH = lots of H+s, high pH = few H+s.
In biology, keeping H+ levels within a narrow range is critically important.

6. Acids and Bases
An acid produces H+
A base absorbs H+

7. Carbon’s Cool Carbon is the central atom of life.
Because carbon contains 4 electrons in its outer shell, it can pair in many ways with many different atoms in an “attempt” to fill its outer shell.

8. Carbon is the Central Atom of Life.
glucose
amino acids
fat

9. Some Useful Nomenclature

10. In Biology, Shape Matters
Its not just chemical formula, it’s the shape of the molecule that lets it do its “job”.
Never forget the axiom – structure dictates function.
Some biological molecules.

11. Ah, That Smell!
Once again, shape matters. It’s the good fit between odorant and receptor molecule that lets us detect aromas.

12. Molecules of Life Four Major Classes of Biological Molecules
How do you build a cell?
Start with water, add lots of small carbon-containing molecules and …….
Four Major Classes of Biological Molecules

13. Rules of the Game
Macromolecules are built by linking a set of building blocks (monomers) together into long chains (a polymer).
Each hexagon is this figure is a monomeric building block linked together to form a polymer.

14. Macromolecules Are Built By Linking a Set Of Building Blocks (Monomers) Together Into Long Chains (A Polymer).

15. Glucose: A Simple Carbohydrate Used For Energy Production and as a Building Block For Complex Carbohydrates

16. Linking Simple Sugars – the First Step to a Polymer and the Last Step to Some Familiar Compounds

17. Some Familiar and Important Complex Carbohydrates
Note the way complex macromolecule are built by linking simple repeating units.

18. Carbohydrates are Central Players in Energy Production and Storage

19. Lipids are Hydrophobic Molecules That Exist In Three Primary Forms
Fat
Sterol
Phospholipid

20. Space-filling model of a fat
Fats Are Made By Linking Fatty Acid Chains to Glycerol, a Three Carbon Molecule
A fatty acid

21. Fats are Used in Energy Storage and Production

22. The Degree Of Saturation In A Fat Affects Its Physical And Nutritional Properties
Where are the double bonds?

23. saturated
monounsaturated
polyunsaturated
The Degree Of Saturation In A Fat Affects Its Physical And Nutritional Properties
Where are the double bonds?

24. Water, pH, and Biological Molecules
2/23/2019
Sterols Are Part of Cellular Membranes and Act as Hormones
Note the four ring structure common to all sterols.
G. Podgorski, Biol. 1010

25. Water, pH, and Biological Molecules
2/23/2019
Sterols As Hormones
Estrogen, testosterone, progesterone, and corticosteriods (cortisol) are all steroid hormones.
G. Podgorski, Biol. 1010

26. Water, pH, and Biological Molecules
2/23/2019
A heavily muscled Linford Christie who was disqualified from international competition after testing positive for a banned steroid.
Sterols As Hormones
“Designer steroids” are major sporting news where they have been used illegally in track and field, baseball, football and countless other sports.
G. Podgorski, Biol. 1010

27. Phospholipids are Building Blocks of Cellular Membranes
The hydrophilic head group and hydrophobic tails are the keys to phospholipid function.

28. Hydrophilic Head Group And Hydrophobic Tails Are The Keys To Phospholipid Function
Phospholipids have a Jekyll and Hyde personality.

29. Phospholipids Form Biological Membranes

30. Protein
Proteins are THE key elements of life. Forget DNA, proteins rule.
Remember the principle - structure determines function.
Since proteins are the key players of the cell, it follows that protein structure determines cell function.

31. Some of the Diverse Functions of Proteins

32. Strands of the Protein Keratin Create Hair

33. Proteins are Linear Chains of Linked Amino Acids

34. A Common Thread and a Unique Identity

35. Amino Acids, Peptide Bonds, Polypeptides, Protein
Proteins are linear chains of 20 different building blocks called amino acids.
Amino acids are linked by peptide bonds – a form of covalent bond.

36. Proteins are Folded Structures Whose Shape (and therefore function) Depends on Amino Acid Sequence

37. Nucleic Acids
There are two kinds of nucleic acids, DNA and RNA. Both are involved in the storage and flow of information from gene to gene product.
DNA

38. Nucleotides are DNA and RNA Building Blocks

39. Water, pH, and Biological Molecules
2/23/2019
Nucleotides are Important in Their Own Right
ATP, the cell’s primary energy currency.
Nucleotides fuel the cell and coordinate its metabolism.
G. Podgorski, Biol. 1010