Cell Cycle & Cell Death Flashcards
where is DNA sequestered?
Nucleus
what is the largest organelle in the cell?
nucleus
how many subunits make up the nuclear pore complex?
8 large subunits
what are the 4 zones of the nucleolus? What do each do?
fibrillar center - contain rRNA genes - 13,14,15,21,22
fine fibrillar / nuclear organizer center - transcription of rRNA genes
granular region / pars granulosa - initial ribosome assembly
chromatin assocated with nucleolus - looks like heterochromatin
what makes up a nucleosome?
DNA + histone
what is euchromatin (appearance + activity)?
less condensed
more transcriptionally active
what is heterochromatin (appearance and activity)?
more condensed
less transcriptionally active
what are the specialized sequences that make up a chromosome?
centromere
telomere
replication origin
what is a centromere?
o centric heterochromatin, persistence throughout interphase, hold sister chromatids together, site of kinetochore formation
what is a telomere?
at the end of the chromosome
allows chromosome to be replicated
what is found in interphase?
G1, S, G2
what is found in mitosis?
karyokinesis
cytokinesis
what is the longest, most variable phase in the cell cycle?
G1/Gap 1
what are the 2 checkpoints in the G1 phase? what do they use?
G1 DNA damage checkpoint - p53 Check
G1 restriction checkpoint (look at size, environment)- retinoblastoma protein (Rb)
what happens during the S phase? What does S phase mean?
new sister chromatids are formed
DNA synthesis/replication
what is the checkpoint in S phase?
S DNA damage checkpoint
what happens in the G2 phase?
cell prepares for division
what are the checkpoints in the G2 phase?
unreplicated DNA checkpoint
G2 DNA damage checkpoint
what are the two checkpoints in the M phase?
spindle assembly checkpoint
chromosome segregation checkpoint
what does the spindle assembly checkpoint do?
prevents premature entry into anaphase
what does the chromosome segregation checkpoint do?
prevents cytoinesis until separation of chromosomes
what are the stages of karyokinesis?
prophase prometaphase metaphase anaphase telophase