1. Water, pH, and Biological Molecules
9/22/2018
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 H20 POLAR UNEVEN ELECTRICAL CHARGE- COMPOUND===
Area by oxygen slight neg. charge
Area by hydrogen slight pos. charge

3. Water, pH, and Biological Molecules
9/22/2018
For Polar Molecules, Water Is a Wonderful Solvent
Dissolving table salt (sodium chloride)
Ionic compounds dissociate or break apart into ions.
In biological processes Na ions are necessary for reactions to occur
G. Podgorski, Biol. 1010

4. Water, pH, and Biological Molecules
9/22/2018
Water Holds Immense Amounts of Heat
High thermal capacity
COHESION-when one molecule of water is
attracted to another water molecule by hydrogen bonds
** due to hydrogen atoms positive charge attracting to
Negitively charged oxygen on another water
G. Podgorski, Biol. 1010

5. Water, pH, and Biological Molecules
9/22/2018
Water Has High Surface Tension
Cohesion allows water to be pulled up
To leaves ( Capillary action)
High surface tension allows long water columns to be drawn from roots to leaves – even in a redwood.
G. Podgorski, Biol. 1010

6. Water, pH, and Biological Molecules
9/22/2018
Water Is Lighter as Solid than as a Liquid
This means that ice forms an insulating blanket over water.
G. Podgorski, Biol. 1010

7. DISSOCIATION OF WATER
In pure water no. of hydronium ions
To hydroxide ions are equal (neutral)

8. Acid/ base/neutral
Acidic solution- when a substance dissolves in water forms hydronium ions and results in more hydronium than hydroxide ions
Basic- more hydroxide
Neutral – equal

9. Water, pH, and Biological Molecules
9/22/2018
pH Matters
pH scale
1 to 14
G. Podgorski, Biol. 1010

10. Water, pH, and Biological Molecules
9/22/2018
Acids and Bases
An acid produces H+
A base absorbs H+
G. Podgorski, Biol. 1010

11. Water, pH, and Biological Molecules
9/22/2018
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.
G. Podgorski, Biol. 1010

12. Water, pH, and Biological Molecules
9/22/2018
Carbon is the Central Atom of Life.
glucose
amino acids
fat
G. Podgorski, Biol. 1010

13. Water, pH, and Biological Molecules
9/22/2018
Some Useful Nomenclature
Learn to recognize these chemical groups.
G. Podgorski, Biol. 1010

14. Water, pH, and Biological Molecules
9/22/2018
In Biology, Molecular 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 major types of biological molecules.
G. Podgorski, Biol. 1010

15. Water, pH, and Biological Molecules
9/22/2018
Molecules of Life
How do you build a cell?
Start with water, add lots of small carbon-containing molecules and …….
use these four major classes of biological molecules.
G. Podgorski, Biol. 1010

16. Water, pH, and Biological Molecules
9/22/2018
Monomers, Polymers and Macromolecules
Many biological molecules are macromolecules – huge assemblies of atoms.
Biological macromolecules are formed by linking together a set of building blocks (monomers) into long chains (a polymer).
G. Podgorski, Biol. 1010

17. Water, pH, and Biological Molecules
Carbohydrates
9/22/2018
Carbohydrates are used for energy and to create structures.
The building blocks for carbohydrates are simple sugars.
Three views of glucose, a common simple sugar.
G. Podgorski, Biol. 1010

18. Water, pH, and Biological Molecules
9/22/2018
Linking Simple Sugars – the First Step to a Polymer
monosaccharides
a disaccharide
A complex carbohydrate is a long-chain polymer made of simple sugars.
G. Podgorski, Biol. 1010

19. Water, pH, and Biological Molecules
9/22/2018
Some Familiar and Important Complex Carbohydrates
Note the way complex macromolecule are built by linking simple repeating units.
G. Podgorski, Biol. 1010

20. Water, pH, and Biological Molecules
9/22/2018
Carbohydrates are Central Players in Energy Production and Storage
G. Podgorski, Biol. 1010

21. Water, pH, and Biological Molecules
9/22/2018
Complex Carbohydrates Are Often Used to Create Structures
Cellulose is the most abundant macromolecule on earth – and you’re probably wearing it now.
G. Podgorski, Biol. 1010

22. Water, pH, and Biological Molecules
9/22/2018
Lipids are Hydrophobic Molecules That Exist In Three Primary Forms
Fat
Sterol
Phospholipid
G. Podgorski, Biol. 1010

23. Water, pH, and Biological Molecules
9/22/2018
Space-filling model of a fat
Fats Are Made By Linking Fatty Acid Chains to Glycerol, a Three Carbon Molecule
A fatty acid
G. Podgorski, Biol. 1010

24. Water, pH, and Biological Molecules
9/22/2018
Molecular Structure of a Fat
Figure: 03-15
Title:
The Triglyceride Tristearin
Caption:
This lipid molecule is composed of three stearic fatty acids, stemming rightward from the glycerol OH “heads.” Tristearin is found both in beef fat and in the cocoa butter that helps make up chocolate.
G. Podgorski, Biol. 1010

25. Water, pH, and Biological Molecules
9/22/2018
Fats are Used in Energy Storage and Production
G. Podgorski, Biol. 1010

26. Water, pH, and Biological Molecules
9/22/2018
The Degree Of Saturation In A Fat Affects Its Physical And Health Properties
Where are the double bonds?
G. Podgorski, Biol. 1010

27. Water, pH, and Biological Molecules
9/22/2018
all cis polyunsaturated
Cis and Trans Unsaturated Fats
“Good”
Omega-3-fatty acids
mono-
and poly-unsaturated
saturated
trans
“Bad”
G. Podgorski, Biol. 1010

28. Water, pH, and Biological Molecules
9/22/2018
At a Store Near You
The new line showing levels of trans fat
Beginning January 1, 2006, the FDA required that the amount of trans fat be listed on all food labels.
G. Podgorski, Biol. 1010

29. Water, pH, and Biological Molecules
9/22/2018
Sterols
Note the four ring structure common to all sterols.
Sterols are: 1) essential membrane components and 2) form many hormones.
G. Podgorski, Biol. 1010

30. Water, pH, and Biological Molecules
9/22/2018
Sterols As Hormones
Estrogen, testosterone, progesterone, and corticosteriods (cortisol) are all steroid hormones.
G. Podgorski, Biol. 1010

31. Water, pH, and Biological Molecules
9/22/2018
Sterols As Hormones
A heavily muscled Linford Christie who was disqualified from international competition after testing positive for a banned steroid.
“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

32. Water, pH, and Biological Molecules
9/22/2018
Phospholipids are Building Blocks of Cellular Membranes
The hydrophilic head group and hydrophobic tails are the keys to phospholipid function.
Phospholipids have a molecular Jekyll and Hyde split personality.
G. Podgorski, Biol. 1010

33. Water, pH, and Biological Molecules
9/22/2018
Hydrophilic Head Group And Hydrophobic Tails Are The Keys To Phospholipid Function
G. Podgorski, Biol. 1010

34. Water, pH, and Biological Molecules
9/22/2018
Phospholipids Form Double-Layered Biological Membranes
G. Podgorski, Biol. 1010

35. Water, pH, and Biological Molecules
9/22/2018
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.
G. Podgorski, Biol. 1010

36. Water, pH, and Biological Molecules
9/22/2018
Some of the Diverse Functions of Proteins
G. Podgorski, Biol. 1010

37. Water, pH, and Biological Molecules
9/22/2018
Strands of the Protein Keratin Create Hair
G. Podgorski, Biol. 1010

38. Water, pH, and Biological Molecules
9/22/2018
Proteins are Linear Chains of Linked Amino Acids
G. Podgorski, Biol. 1010

39. Water, pH, and Biological Molecules
9/22/2018
A Common Thread and a Unique Identity
G. Podgorski, Biol. 1010

40. Water, pH, and Biological Molecules
9/22/2018
Amino Acids, Peptide Bonds, Polypeptides, Protein
Peptide bonds
Proteins are linear chains of 20 different building blocks called amino acids.
Amino acids are linked by peptide bonds – a form of covalent bond.
G. Podgorski, Biol. 1010

41. Water, pH, and Biological Molecules
9/22/2018
Proteins are Folded Structures Whose Shape (and therefore function) Depends on Amino Acid Sequence
G. Podgorski, Biol. 1010

42. Water, pH, and Biological Molecules
9/22/2018
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.
Recently, we’ve learned that RNA also plays important regulatory roles.
DNA
G. Podgorski, Biol. 1010

43. Water, pH, and Biological Molecules
9/22/2018
Nucleotides Are the Monomers That Create Polymers of DNA and RNA
G. Podgorski, Biol. 1010

44. Water, pH, and Biological Molecules
9/22/2018
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