Molecular Biology Flashcards
Hydrogen bonds between bases
2 bonds between A &T
3 bonds between G& C
Eukaryotic vs Prokaryotic chromosomes
Pro-Circular
Eu- Linear
Organization of DNA
Sugar, Nucleoside, Nucleotide, Helix, Nucleosomes, Chromatin, Chromosomes
Central Dogma
DNA, RNA, protein
Doesn’t account for retroviruses
Stop Codons
UAG, UAA, UGA
Types of Genetic Mutation
Point
Insertion
Deletion
Types of Point Mutation
Transition - pyrimidine for pyrimidine
Transversion- purine to pyrimidine
Missense- One amino acid is replaced with another acid
Nonsense-amino acid replaced with stop codon
Silent- change in codon buy same AA produced
Consequences of deletions and insertions
Cause change in reading frame (Frameshift)
6 Facts of DNA Replication
DNA Replication is semi-conservative
Polymerization occurs 5 to 3 direction
DNA polymerase requires a template
DNA polymerase requires a primer
Replication forks grow away from the origin in both directions
All RNA primers are replaced by DNA. All frgaments are joined by ligase
Enzymes of replication
Helicase-unwinds and separates strands
Topoisomerase- relieves tension (Gyrase)
Single stranded binding proteins- Keeps strands separated
Origin of Replication (Pro vs. Eu)
Pro- 1 origin (theta)
Eu- Multiple origins (bubbles)
Prokaryotes DNA polymerase
DNA Pol III- basic polymerase. 3’ to 5’ exonuclease activity
‘DNA pol II- unknown
DNA pol I- remove primer and replace with DNA. 5’ to 3’ exonuclease activity
3 Differences in RNA from DNA
RNA is single-stranded
Uses Uracil instead of thymine
Ribose instead of deoxyribose
Eukaryotic mRNA vs. Prokaryotic mRNA
Eu- monocistronic (One gene, one proteins)
Pro- polycistronic (One gene, many proteins)
DNA gyrase specificity
Only found in prokaryotes. Eukaryotes use other topoisomerases
