Download Nuclease Digestion

Unit 2: Informational
Macromolecules
Nucleic Acids, Amino acids and protein
structure
MACROMOLECULES
• organized molecules that form the
structure and carry out the activities of
cells
- Carbohydrates- Lipids
- Proteins
- Nucleic acids
CARBOHYDRATES
• Monosaccharides: simple sugars
= the building blocks
• Oligosaccharides: 2-10 sugar groups linked
–
These are often receptors for regulatory
molecules
•
•
Glycolipids (attached to lipids) and
Glycoproteins (attached to proteins)
• Polysaccharides: very long chains of sugars
•
i.e Glycogen
LIPIDS
• Fatty acids: building blocks
• Composed of a hydrophilic
“head” and hydrophobic
“tail”
• Function: energy storage
molecules in the form of
triacylglycerol
PROTEINS
• Amino acids = building blocks
• 4 classes:
– Basic
– Polar
- Acidic
- Non-polar
• Link together through peptide bonds
to form the primary structure of a
protein
• H-bonding and folding lead to
secondary and tertiary structure
Protein Structure
Tertiary structure:
• Side chain interaction determines
how the protein will fold within itself.
– i.e positively charged side chains might
bind negatively charged side chains.
• Changes to these amino acids can
results in changes to protein folding
and therefore affect function.
Quaternary structure: proteins
interacting with other proteins
Food for thought:
When a protein-containing solution
like milk is heated, a protein film
forms on the surface.
Why does it form?
NUCLEIC ACIDS
• Nucleotides: building blocks
• Can be deoxyribonucleic acid (DNA)
or ribonucleic acid (RNA)
• Are information molecules
• Made up of 3 major components:
– Nitrogen base, sugar, phosphate group
DNA
•
•
•
•
•
vs
Deoxyribonucleotides
Sugar = deoxyribose
Bases = A T C G
Double stranded
All DNA present in
every cell
RNA
•
•
•
•
•
Ribonucleotides
Sugar = ribose
Bases = A U C G
Single stranded
Only present in
cells that express
that gene
Nucleic acid Synthesis
• Synthesis occurs at
the 3’ end of DNA
• The 3’ OH group is
REQUIRED for
synthesis to occur
phosphodiester
bond
Hyrdogen bonding
• Hydrogen bonds are
between complimentary
pairs of purines and
pyrimidines
• Hold together the TWO
strands of DNA
• A-T = 2 hydrogen bonds
• G-C = 3 hydrogen bonds
WHY IS THIS IMPORTANT?
Practice Question
Which of the two double-stranded DNA molecules
shown below will be most resistant to the
effects of heating
A. 5’-AGCAGTTCATTATTCTCTCGTCGA -3’
3’-TCGTCAAGTAATAAGAGAGCAGCA-5’
or
B. 5’-TCCTCGAGCCTCCTGCGCCGCCGA -3’
3’-AGGAGCTCGGAGGACGCGGCGGCT-5’
Why?