Sept 25 Flashcards
How is DNA compacted in prokaryotes vs eukaryotes?
Prokaryotes is less compact in a nucleoid, eukaryotes is much more compact in nucleus
Haploid or diploid and what shap fo chromosomes for prokaryotes and eukaryotes?
Prokaryotes is single circular chormosome, haploid. Eukaryotes is haploid or diploid, multiple linear chromosomes
What happens to the number of chromosomes, ploidity, genome size, gene density as complexity of organisms increases?
They all increase, except gene density decreases
What makes up the space for the reason that multicellular organisms have a lower gene density?
Have longer intergenic sequences, so more introns, repetitive DNAs,
What are genome wide repeats?
They are sequences repeated a lot
What are regulatory regions in DNA? what are the 3 main products?
Encode for functional RNA, not protein. MicroRNA, ShortinterferingRNA, ribosomalRNA
What is a kinetochore?
It is a protein complex that forms on centromeres, it captures spindles during chromosome segregation
What is a centromere?
It is a DNA sequence that has highly repetitive sequences, needed for kinetochore formation
What is the telomere cap made of?
TG rich cap
What function do telomeres have?
To protect frequent DNA recombination and degradation
What is a downside of frequent DNA recombination that telomeres prevent?
More recombination means more dsDNA breaks so more mutations
What are key points in the cell cycle when huge chromosomal topological changes occur?
From G1 to S phase, get DNA replication, then G2 to mitosis has chromosome condensation
What is the purpose of gap phases in cell cycle?
To check that previous phase is complete and to prep for next phase of cell cycle
What holds sister chromatids together following DNA replication?
Cohesin
What protein helps pacage DNA into chromosomes condensed?
Condensin
