Genetics #1 Flashcards
the structure of DNA made up of?
Repeating units of nucleotides (monomers)
What are the 3 components of a nucleotide?
Back:_ 1. Sugar group, 2. Phosphate group, 3. Nitrogenous base
What is the sugar group in DNA composed of?
Deoxyribose, a five-carbon sugar molecule
What is the phosphate group in DNA?
A phosphate molecule that forms a phosphodiester bond with the sugar molecule
What are the 4 nitrogenous bases in DNA?
. Adenine (A), 2. Guanine (G), 3. Cytosine (C), 4. Thymine (T)
What is the base pairing rule in DNA?
Adenine (A) pairs with Thymine (T), Guanine (G) pairs with Cytosine (C)
How does the deoxyribose sugar bind with phosphate?
At both its 3’ and 5’ (three prime and five prime) carbons
What is the significance of 3’ and 5’ carbons in DNA structure?
They are the binding sites for phosphate groups, forming phosphodiester bonds between nucleotides
What is the result of deoxyribose binding with phosphate at 3’ and 5’ carbons?
Back:_ Formation of a phosphodiester bond, linking nucleotides together in a polynucleotide chain (DNA)
What attaches to the deoxyribose sugar group?
A nitrogenous base
What are the two main forms of nitrogenous bases?
Pyrimidines and Purines
Which nitrogenous bases are pyrimidines?
Thymine (T) and Cytosine (C)
Which nitrogenous bases are purines?
Adenine (A) and Guanine (G)
What is the difference in chemical structure between Pyrimidines and Purines?
Pyrimidines have a single ring,
while Purines have a double ring
Which Pyrimidines have a single ring structure?
Thymine (T) and Cytosine (C)
What is the chemical structure of Purines?
Back: Two fused rings
Which Purines have a two-fused-ring structure?
Adenine (A) and Guanine (G)
What enzyme opens up the DNA at the replication fork?
Helicase
What proteins coat the DNA around the replication fork?
Single-strand binding proteins (SSBs)
What is the function of SSBs?
To prevent rewinding of the DNA
What enzyme works ahead of the replication fork?
Topoisomerase
What is the function of Topoisomerase?
To prevent supercoiling
What enzyme synthesizes RNA primers?
Primes
What is the function of RNA primers?
To provide a starting point for DNA synthesis
What enzyme extends the primers and makes the bulk of the new DNA?
DNA Polymerase III
What enzyme removes RNA primers and replaces them with DNA?
DNA Polymerase I
What enzyme seals the gaps between DNA fragments?
DNA Ligase
Can add DNA bases at 5’ end
Telomerase
Removes section of RNA primer and replaces with DNA nucleotide
DNA Polymerase I
