Bio 1010: DNA, Chromosomes and Genes - Oh My!
I. What is the Structure of DNA
• DNA is a Polymer
◦ Chains of nucleotides (monomers)
▪ Nucleotides have 3 Parts:
▪ 1. Phosphate group
▪ 2. Sugar
▪ 3. Base
▪ 4 types of bases:
▪ 1. Adenine (A)
▪ 2. Guanine (G)
▪ 3. Thymine (T)
▪ 4. Cytosine (c)
◦ Nucleotides link by sugar and phosphates (the sugar molecule connects to
the phosphate of the other) to form a single strand
A ◦ complementary strand forms on the other side.
▪ Complementary means A always binds to T and G to C
◦ Sugar and Phosphates make the "Backbone"
◦ Paired bases make up the "rungs"
◦ Average of 139 million rungs on a human DNA molecule
• DNA makes up Chromosomes▯
II. What is a Chromosome?
• 1 Long molecule of DNA
• DNA twisted around proteins called histones • We have 46 Chromosomes
◦ 23 different types
◦ Two of each type
◦ How do we get two of each type? One from each parent!!
◦ All 46 found in Every single cell in your body
◦ Are chromosomes really X-shaped?
▪ Chromosomes mostly in unraveled form
▪ Only X-Shaped when replicated in cell division
▪ When X-shaped, they actually have TWO DNA molecules per
III. Does a skin cell have the DNA sequence for eye color?
• YES! Within a person, the DNA sequence is the same in every cell.
• However, DNA sequences between people are different.
IV. DNA Fingerprinting
◦ Isolate DNA from individuals
◦ Cut DNA with Restriction Enzymes
▪ Restriction Enzymes:
▪ Made By Bacteria
▪ Bind to SPECIFIC DNA sequences Example: Mbo1 "looks for"
▪ Cuts that DNA sequence
◦ Visualize DNA pieces on gel
▪ Gell is a Jello-like matrix with wells molded into one end
▪ Cut DNA is loaded into wells
▪ An electrical current is applied
▪ DNA is negatively charged
▪ DNA moves towards positive end
▪ Shorter DNA fragments move faster
▪ Vizualize the DNA fragment
◦ Forensics - Compare DNA from crime scenes to suspect's DNA
◦ Paternity testing - Analyzes DNA fingerprint to identify the parents
◦ Historical Analysis - Finds likely identity/relationships of historical figures
◦ Diagnose inherited diseases - Mutations (that cause genetic diseases)
change the restriction enzyme cutting sites.
◦ Pre-implantaton Genetic Diagnosis
▪ Relatively new biotechnology
▪ Tests the genetics of an embryo before it is implanted in the mother.
▪ Screen for genetic diseases
▪ Select gender
▪ Select characteristics of babies