What is recombinant DNA ?
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DNA structure
#1. DNA Structure (an overview)
• DNA has three main components
– 1. deoxyribose (a pentose sugar)
– 2. base (there are four different ones)
– 3. phosphate
#2. The Bases
They are divided into two groups
Pyrimidines and purines
Pyrimidines (made of one 6 member ring)
Thymine
Cytosine
Purines (made of a 6 member ring, fused to a 5 member ring)
Adenine
Guanine
The rings are not only made of carbon (specific formulas and structures are not required for IB)
#3. Nucleotide Structure
• Nucleotides are formed by the condensation of a pentose sugar, phosphate and one of the
4 bases
• The following illustration represents one nucleotide
• Nucleotides are linked together by covalent bonds called phosphodiester linkage
#3. Nucleotide Structure
#4. DNA Double Helix and Hydrogen Bonding
• Made of two strands of nucleotides that are joined together by hydrogen bonding
• Hydrogen bonding occurs as a result of complimentary base pairing
– Adenine and thymine pair up
– Cytosine and guanine pair up
– Each pair is connected through hydrogen bonding
– Hydrogen bonding always occurs between one pyrimidine and one purine
• Complimentary base pairing of pyrimidines and purines
#4. DNA Double Helix and Hydrogen Bonding
#4. DNA Double Helix and Hydrogen Bonding
#1. DNA Structure (an overview)
• DNA has three main components
– 1. deoxyribose (a pentose sugar)
– 2. base (there are four different ones)
– 3. phosphate
#2. The Bases
They are divided into two groups
Pyrimidines and purines
Pyrimidines (made of one 6 member ring)
Thymine
Cytosine
Purines (made of a 6 member ring, fused to a 5 member ring)
Adenine
Guanine
The rings are not only made of carbon (specific formulas and structures are not required for IB)
…