1. Carbohydrates, Lipids, Proteins, and Nucleic Acids
The Molecules of Life
Carbohydrates, Lipids, Proteins, and Nucleic Acids

2. What is a molecule?
A collection of atoms bound together by covalent bonds.
Can be very small, 2 atoms, or very large, millions of atoms.
Exist in great diversity
Can be categorized by structure and function

3. Major Categories of bio-molecules
Carbohydrates – think sugars like glucose
Lipids – think fats and oils
Proteins – think muscle and amino acids
Nucleic Acids – think DNA and RNA

4. Other key terms…
Polymer – a long molecule consisting of many similar or identical building blocks (monomers) Condensation Reaction (dehydration synthesis)– the formation of a covalent bond between molecules, produces water as a byproduct Hydrolysis – the breaking up of a covalent bond, uses water molecules

5. Carbohydrates Include sugars and polymers of sugars
Commonly form ring structures
Function in energy storage and structural support
Monosaccharide – a single carbohydrate
Disaccharide – two covalently bound carbohydrates
Polysaccharide – a polymer of carbohydrates

6. Monomers and Polymers

7. Glucose: monosaccharide, energy storage

8. Ribose: monosaccharide, part of DNA and RNA
Ribose has 5 carbons, glucose has 6
Sugars differ in number of carbons, location of double bonds, and hydroxide groups.

9. More monosaccharides

10. Formation of a disaccharide

11. Breaking of a Disaccharide
What is this process called?
Why is water necessary for this reaction?
Is this reaction the same for other types of bio-molecules?

13. Starch and Cellulose
Starch is used as an energy storage molecule in plants
Cellulose is used for structural support creating the cell wall of plants
Both are polysaccharides

15. Look in the Book!
Find two polysaccharides used by animals and state their name and functions.

16. Lipids Includes triglycerides, steroids, phospholipids
Lipids are defined as non-polar molecules
They don’t dissolve in water
Tend to coalesce (stick together) when placed in an aqueous solution
Function as energy storage, membranes, and hormones

17. Some types of lipids

18. Triglycerides: also known as FAT
A molecule used to store energy
Energy is stored as potential energy within chemical bonds
Made up of two parts
glycerol molecule
three fatty acids

19. Glycerol
a 3-carbon molecule
Fatty acid chains attach here

20. Fatty Acid: long non-polar chains of carbon

21. Glycerol + Fatty acid = Triglyceride

22. Phospholipid Primary molecule used to create membranes
Typically found in bi-layers
Consists of a polar ‘head’ region, a glycerol neck, and a non-polar fatty acid ‘tail’
Head region is hydrophilic – likes water
Tail region is hydrophobic – fears water

23. Phospholipid structure

24. Phospholipid Bi-layer
Non-polar, hydrophobic tails turn inward
Polar, hydrophilic heads point outward
This creates a membrane that can separate two environments

25. Cell Membrane

26. Steroids Multiple ring shaped molecules
Function to increase or decrease fluidity of membranes, depending upon temperature.
Also used as hormones, chemical messengers sent through the blood stream

27. Common Steroids

28. Proteins Proteins are polymers of amino acids
They have more functions than all other bio-molecules combined
They can be used for catalyzing reactions, structural support, chemical messengers, and much more.
If you don’t understand proteins you don’t understand how life works.

29. Proteins cont’d
There are about 20 different types of amino acids used in most living organisms
But combining these monomers into long chains it is possible to create an immense variety of polypeptides (proteins)
The function of protein is determined by its shape, which is determined by its amino acid sequence, which is determined by a DNA sequence.

30. Amino Acids
Contains an amine group (NH2), a carboxyl group (COOH), and a side group (R)
The R-group is the variable part which distinguishes one amino acid from another

31. Peptide bonds are formed by condensation reactions

32. A di-peptide is a two amino acid molecule

33. Proteins have four levels of structure

34. Primary Structure
Primary structure is the actual amino acid sequence produced from the DNA code.
Peptide bonds are the only bonds involved in the primary structure of a proteins

35. Secondary Structure
Created by hydrogen bonding between the amino and carboxyl groups of the amino acid backbones
Results in two distinct structures
Alpha helix
Beta pleated sheet

36. Alpha Helix

37. Beta Pleated Sheet

38. Tertiary Structure
Bending and folding of protein chain based upon R-group interactions
Can be hydrogen bonds, ionic bonds, or covalent bonds

41. Quaternary Structure
The combination of 2 or more protein subunits to create a fully functional protein
A protein composed of two identical subunits is known as a dimer

42. The Effects of Temperature on proteins
High temperatures break hydrogen bonds
molecules have too much kinetic energy and do not remain still long enough to attract one another.
Protein subunits separate and unfold
Proteins lose their structure and thus cannot function
Known as denaturation

43. The Effects of pH on Proteins
Proteins function optimally at specific pH levels
Increasing or decreasing [H+] may alter protein function
Why do you think ion concentration effects protein function?

44. The effect of pH on the activity of enzymes