Chromosomes and Cell Division Flashcards
What is a telomere?
DNA at the end of the chromosome, solution to the end replication problem
What is the end replication problem?
Telomeres get shorter through generations
Eroded DNA part is added back on to the telomere using RNA template
What is a centromere?
Repeated satellite DNA around the centre of a chromosome
Location of kinetochore
What is the function of the kinetochore?
Protein complex that forms tubules for spindle attachment via microtubules
What occurs during the S stage of interphase?
DNA replication
What occurs during the G1 stage of interphase?
Cell growth
What occurs during the G2 stage of interphase?
Cell preparing to divide
Give two types of extragenic DNA
Satellite DNA
Minsatellite DNA
(repeat after a different number of base pairs)
What is a histone?
A protein that that DNA wraps itself around to form a chromatin fibre
What is a nucleosome?
A solenoid structure formed when histone/DNA complexes are further packaged
Give the three types of chromosome structure in terms of p arm and p arm lengths
Metacentric - p=q; central centromere
Submetacentric - p
Describe how a karyotype is obtained?
- blood sample removed of RBCs
- culture medium added
- incubation
- colchioine added (pauses mitosis via microtubule inhibition)
- WBCs removed
- hypotonic saline added
- spread/fix/photograph
What is FISH?
Fluorescent in situ hybridation
To look at chromosome sequence using different probes
Name three types of FISH probes
Centromeric - chromosome number
Telomeric - subtelomeric rearrangements
Whole Chromosome - dyes to highlight repeated sequences
Describe X-inactivation in female mammals
One X strand is randomly inactivated in the uterus
Prevents expression of double X characteristics
