DNA Flashcards
What do 5’ to 3’ Antiparallel Strands mean in terms of structure?
The two strands have opposite orientations.
Antiparallel strands’ benefits?
- Stability of the molecule
- Replication wouldn’t occur otherwise
Nucleotide Structures?
Which nucleotides go into which category?
Purine→Double carbon ring Adenine guanine
Pyrimidine→Single carbon ring cytosine thymine
Function of DNA
1)Replication 4)Cellular Metabolism
2)Mutations 5)DNA Fingerprinting
3)Transcription 6)Gene Therapy
Major and Minor Groove
DNA isn’t entirely symmetrical
Different transcription factors bind and cause grooves to be major/minor
Changes the rate of transcription, expression
Relationship between proteins and chromosomes?
Chromatin is wrapped around histone proteins
50% composed of proteins
Telomere
Protects the ends of chromosomes
Repetitive sequences
Centromere
Connects sister chromatids
Contains histones
Kinetochores
Coordinates the movement of chromosomes and spindle fibers
Heterochromatin
Tightly packed region
Less expressed
Sometimes regulated in accordance with life stages
Euchromatin
Active, coding region
Loosely packed
Position Effect
The effect of how packed the region is.
If (often due to translocation) in heterochromatin region, repressed.
Polytene Chromosomes
Paired homologs
Eukaryotes
Unusually long chromosomes
Puffs
Regions that open up for transcription/genetic processes
They are active sites/havehigh gene activity
Prokaryotic chromosome structure and cause of variety
Circular
Single
In cytosol
No telomeres
No histones because already small no need to compress
Variety is achieved by horizontal gene transfer
