Chromosome Structure Flashcards
Types of Chromatin?
Heterochromatin (condensed)
Euchromatin (open)
Arms of a chromosome?
q is long
p is short
Wheres heterochromatin found in a chromosome?
Around centromere & telomeres
Why package DNA?
- Condenses it
- neutralises -ve DNA with +ve histones
Kinetochore?
Part of centromere that binds to spindle fibre microtubules
Protein complex
How does hte lagging strand replicate DNA?
- DNA replicated in bits called okazaki fragments
- Each fragment started by a RNA primer
- End of replication each primer converted to DNA & fragments combined by DNA ligase
Why do telomers shortedn during DNA replciaiton?
Because last RNA primer cant be converted to DNA so is lost
Whats telomere shortening associated with?
Aging related diseases
How could we counteract aging?
Sufficient concentrations of telomerase could counteract telomere shortening effectively immortalising cells
What are the 4 phases of cell division?
G1
S
G2
Mitosis
What occurs during the G1 phase?
Cell grows
Prepares precurosrs of DNA synthesis
What occurs during S phase?
DNA replication
What happens during G2?
Cell Growth
Prep for mitosis
What are the phases of mitosis?
Prophase Metaphase Anaphase Telophase Cytokinesis
What happens in prophase?
- Chormosomes condense
- Nuclear membrane dissapears
- Spindle fibres from centrioles
What happens in metaphase?
- Chromosmes align at equator
- Spindle fibres attach to kinetochore of centromer by microtubules
What happens in Anaphase?
- Sister chromatids seperate
- Move to opposite ends of cell
Telophase?
2 new diploid nuclei form
Cytokinesis?
Typically starts mid telophase
Cytoplasm seperates
