1.2 DNA Structure and Replication Flashcards
What is a nucleotide made of?
Phosphate, base and deoxyribose sugar
How many carbon atoms are in a deoxyribose sugar?
5 Carbons
What are the 4 bases called in DNA?
- Adenine
- Thymine
- Guanine
- Cytosine
What are the base pairings in DNA?
- Adenine and Thymine
- Cytosine and Guanine
What is the bond between a phosphate and deoxyribose sugar?
Strong chemical bond
What bond is between bases?
Weak hydrogen bonds
What end can nucleotides be added to?
3’ end
What direction to strands run in?
Anti-parallel
What are the 5 Steps in DNA Replication?
1- DNA molecule unwinds the double stranded helix and unzips the hydrogen bonds between complementary bases to separate strands
2- DNA primers join to the complementary sequences on the open DNA strand
3- DNA polymerase uses these primers as a starting point for adding new bases to the 3’ end and joining them with sugar phosphate bonds
4- DNA ligase joins all of the fragments together to make the new double strand
5- Finally both new double stranded DNA molecules twist back into the helix shape
What does DNA Polymerase control?
The sugar-phosphate bonding of the nucleotides into the DNA strand
What are the requirements for DNA Replication?
- DNA Template
- Primers
- Nucleotides
- Ligase
- DNA Polymerase
- ATP
What is PCR?
A technique that replicates short sections of DNA quickly outside the body
What is a primer?
A piece of single stranded DNA complementary to a specific sequence at the 3’ end of the strand to be replicated
What are the 4 PCR steps?
1- DNA is heated to between 92-98°C to separate the DNA strand by breaking the hydrogen bonds
2- DNA is cooled to between 50-65°C to allow primers to bind to target sequences
3- Heated again to between 70-80°C to allow heat tolerant DNA polymerase to replicate the DNA
4- Repeated cycles of heating and cooling amplify the target region of DNA
What can PCR be used for?
- Solve Crimes
- Settle Paternity Suits
- Diagnose Genetic Disorders
