Chromosomes and Cell Cycles Flashcards
What do nucleic acid rules apply to?
DNA replication in a cell
RNA synthesis in a cell
DNA replication in a test tube
Nucleic Acid Rules
- Made using triphosphate nucleotides
- Made 5’ to 3’
- Made using an ssDNA template
- Pair antiparallel
- Pair with complementary base pairing
Where does replication of circular pieces of DNA occur?
- Prokaryotic chromosomes and plasmids
2. Eukaryotic organelle chromosomes
What is the mechanism of the replication of circular pieces of DNA?
One origin of replication but two replication forks
Where does the replication of linear pieces of DNA occur?
Eukaryotic nuclear chromosomes
What is the length problem in human DNA?
Human mtDNA = 16 kb
Human chromosome 1 = 285 Mb
The solution to the length problem
We have thousands of origins on each chromosome
What is the replication problem?
Regular DNA polymerase cannot go to the ends
The solution to the replication problem
Don’t have important genes on the end of the chromosome - have telomeres instead
Telomeres are made with telomerase
What is telomerase made of?
RNA and protein
Telomerase is an exception to which rule?
Telomerase is not made with an ssDNA template
They use RNA as a template and are RNA dependent
Nucleosomes
The combination of DNA and histones.
Histones wrap around the DNA to protect it but allows polymerase to access the DNA for replication, repair, and RNA synthesis
Condensins
DNA must be compact and mobile during mitosis and meiosis
Condensins condense the DNA
What do metaphase chromosomes contain?
DNA
Histone proteins
Cohesion proteins
Condensin proteins
