Topic 5 - Dna Replication Flashcards
1
Q
Describe the structure of DNA
A
- DNA and RNA are both types of nucleic acids
- store of genetic information
-pentose sugar, nitrogenous bases (purines and
Pyrimidines) and a phosphate group. - double helix ( 2strands) held by hydrogen bases (antiparallel
- pairs adenine - thymine, cytosine-guanine
2
Q
Semi-conservative replication
A
- DNA untwists (enzyme DNA helicase breaks hydrogen bonds between bases)
- Original strand is a template. Free floating DNA nucleotides are attracted to complementary exposed base pairs
- Condensation reaction join the adjacent nucleotides ( catalysed by DNA polymerase). Hydrogen bonds form
- Two strands retwist
3
Q
Genetic mutations during DNA replication
A
- DNA replication is carefully controlled to preserve the genetic information
- however,changes in the genome occur sometimes known as mutations
4
Q
6 types of DNA mutations
A
- Substitution
- deletion
- addition
- duplication
- inversion
- translocation (sequence of bases is moved from one location in the genome to another.
