Chromosome Structure Flashcards
Are histones highly conserved proteins?
Histones are highly conserved proteins, especially H3 and H4
Why is DNA packaging important?
DNA is long; so for it to fit in the nucleus, it is important for it to be packaged properly into chromatin
What is supercoiling?
Occurs when DNA coils back on itself and when it is overwound or underwound
Describe positive supercoiling
Over-rotated in same direction as DNA coil; so left-handed supercoil compensates
Describe negative supercoiling
DNA is underwound so right-handed supercoil compensates
What is the function of centromeres in cell division?
Centromeres must attach to spindle fibers for proper segregation into daughter cells
Are centromeres heterochromatic or euchromatic?
Heterochromatic
Describe telomeres
- Provide stability for ends of chromosomes so that chromosomes are not degraded by exonucleases
- Prevent chromosomes from joining with each other at the ends due to ligase activity
- Provide proper replication of the end of chromosome