1. Anderson Spring 2017 College of the Redwoods
Biomolecules
Anderson
Spring 2017
College of the Redwoods

2. Let’s Review
Atoms – made up of protons, neutrons, and electrons that have the properties of a chemical element
Molecules – result of chemical bonding between electrons of atoms
Macromolecules – large molecules built from smaller molecules
Octet Rule – elements can and want to hold 8 electrons in their outermost shells (except the 1st ring holds just 2)
Elements are abbreviated by capital letters: C, O, H (sometimes 1 capital and 1 lower case, like Cl)

3. Biological Macromolecules
Large molecules necessary for life
Built from smaller organic molecules (organic = contains carbon)
4 major classes of biological macromolecules
Carbohydrates (sugars)
Lipids (fats/cholesterol)
Proteins
Nucleic acids (DNA)
Mostly carbon-based, but also include hydrogen, oxygen, nitrogen, phosphorus, sulfur, and a few others

4. Carbon Bonding
Remember: Carbon has 6 protons, 6 neutrons, and 6 electrons
That means, according to the Octet Rule, that there are 4 electrons in the outermost ring
These are called valence electrons
Therefore, carbon can form 4 covalent bonds with other atoms/molecules

5. Simple Carbon Molecules
Remember:
1 dash between molecules = 2 electron being shared
2 dashes = 4 electrons are being shared
3 dashes = 6 electrons are being shared

6. Scientists like shorthand
Every corner and end of line = Carbon
Carbon can form up to 4 bonds – carbons not bound to other elements are bonded with hydrogen

7. 1. Carbohydrates
Provide energy to the body in the form of starch and sugars
Represented by the formula (CH2O)n
n = number of carbon atoms, n also multiplies H and O
The ratio of C:H:O is always 1:2:1
3 subtypes: monosaccharide (1 sugar ring), disaccharide (2 sugar rings) and polysaccharide (multiple sugar rings)

8. Monosaccharides (monomers of carbohydrates)
# carbons range 3 to 6 (trioses, pentoses, and hexoses)
Glucose is most common
C6H12O6
Notice they all have 6 carbons yet they’re different
These are called isomers (same chemical formula, different structurally and chemically)

9. Why is glucose so important?
Photosynthesis
6CO2
6H2O
C6H12O6
6O2
light +
carbon dioxide
water
sugar
oxygen
Cellular Respiration
6CO2
6H2O
C6H12O6
6O2 +
carbon dioxide
water
sugar
oxygen
ATP
energy

10. Disaccharides
Dehydration (removal of water) of 2 monosaccharides to covalently bond them together

11. Common Disaccharides Sucrose – table sugar Lactose – milk sugar
Maltose – malt sugar

12. Polysaccharides Long chain of monosaccharides covalently linked
May be branched or unbranched
May contain different types of monosaccharides
They can be very large molecules

13. Starch
Stored form of sugars in plants – plants make glucose, then store extra as starch, especially roots and seeds
Made up of amylose (unbranched) or amylopectin (branched), which are glucose polymers
Broken down by enzyme called “amylase” into maltose (glucose disaccharide)

14. Glycogen, Cellulose and Chitin
Glycogen – storage form of glucose in humans and vertebrates
Animal equivalent to starch (made of monomers of glucose)
Glycogen is broken down into glucose when glucose levels decrease
Insulin stimulates the production of glycogen (without insulin, your blood sugar would increase)
Cellulose – makes cell walls in plant cells (providing structural support), also made of glucose monomers
Cellulose in our digestive system is called dietary fiber, but we can’t actually digest it.
Chitin – exoskeleton of arthropods (insects, spiders, crabs)

15. 2. Lipids Hydrophobic (water fearing) non-polar molecules
Mostly carbon-carbon and carbon-hydrogen bonds
We call these hydrocarbons
Functions
Long-term energy storage for cells (fats)
Insulation from environment (keep animals dry)
Building blocks of many hormones
Important constituent of plasma membrane of cells
Made of fatty acids and glycerol (monomers)

16. Fats Glycerol Fatty acid tails Fatty acids = monomers
Saturated with hydrogen (no double bonds)
Each carbon does not have 2 hydrogens, has double bonds
Fatty acids = monomers

17. Phospholipids
Major constituent of plasma membranes (phospholipid bilayer)
Has both hydrophobic and hydrophilic regions

18. Steroids 4 linked carbon rings
Cholesterol – steroid mainly synthesized in liver and precursor to many hormones
Helps to maintain cell membrane structure

19. 3. Proteins
One of the most abundant organic molecules in living things
Functions of proteins vary from:
catalyzing reactions (enzymes)
molecule transportation
DNA replication
hormone signaling
and many more
What makes the functions and structure of proteins so diverse are the sequence of the 20 chemically different amino acids

20. Monomers that make up proteins
Amino Acids
Monomers that make up proteins
Each has same fundamental structure:
Central Carbon
Amino group (NH2)
Carboxyl group (COOH)
R group - variable
To form proteins, amino acids attach to each other by peptide bonds
The result of peptide bonds is polypeptide
back
bone
Amino group
Carboxyl group

21. 20 Amino Acids

22. 20 Amino Acids Amino Acid 3 Letters 1 Letter Alanine Ala A Arginine
Asparagine
Asn N
Aspartic acid
Asp D
Cysteine
Cys C
Glutamic acid
Gln Q
Glutamine
Glu E
Glycine
Gly G
Histidine
His H
Isoleucine
Ile I
Amino Acid
3 Letters
1 Letter
Leucine
Leu L
Lysine
Lys K
Methionine
Met M
Phenylalanine
Phe F
Proline
Pro P
Serine
Ser S
Thrionine
Thr T
Tryptophan
Trp W
Tyrosine
Tyr Y
Valine
Val V

23. Protein Structure Proteins have different shapes and molecular weights
Some are globular, some are fibrous in shape
Sequence of amino acids determines the structure, the structure determines the function
There’s an estimated 2 million different types of proteins in the human body, all made from just 20 amino acids!

24. How does a protein get it’s shape?
4 Levels of Protein Structure
Primary
Secondary
Tertiary
Quaternary
Sequence and number of amino acids

25. What determines the AA sequence?
Genes (DNA) encode for proteins!
Any change in gene sequence can alter amino acid sequences
Sickle cell anemia
Hemoglobin β – protein that binds oxygen in red blood cells
Has 600 amino acids in protein sequence
ONE amino acid substitution causes red blood cell to form crescent shape

26. How does a protein get it’s shape?
4 Levels of Protein Structure
Primary
Secondary
Tertiary
Quaternary
Hydrogen bonding of peptide backbone

27. How does a protein get it’s shape?
4 Levels of Protein Structure
Primary
Secondary
Tertiary
Quaternary
3-D folding due to side chain (R group) interactions

28. How does a protein get it’s shape?
4 Levels of Protein Structure
Primary
Secondary
Tertiary
Quaternary
2+ amino acid chains (called subunits)

30. Denaturation of Proteins
Structure determines function!
Changes in temperature, pH, or chemical exposure can change protein shape
Denaturation = proteins losing their shape
Can be reversible because amino acid sequence hasn’t changed
Can be irreversible (can’t refold) which leads to loss of function

31. 4. Nucleic Acids
Carry out genetic blueprint of a cell and carry instructions for the function of a cell
Two main types:
Deoxyribonucleic acid (DNA)
Genetic material found in all living organisms
Ribonucleic acid (RNA)
Involved in protein synthesis
Communicator between nucleus of cell and rest of cell
DNA and RNA are made up of monomers called nucleotides

32. Nucleotides 3 Components of Nucleotides Phosphate group
Pentose (5-carbon) sugar
Nitrogenous base
Adenine
Thymine
Cytosine
Guanine
Uracil
Difference between DNA and RNA is the pentose sugar (and a nitrogenous base)

33. DNA Backbone

34. Double Helix Structure of DNA

35. Have you been paying attention?!
Socrative Time
Have you been paying attention?!