Reproduction Flashcards
Interphase
G1, S, G2 –> dividing cells spend 90% of the time
chromosomes are not visible because they are in chromatin form
G0
Non-dividing cell. Simply living and carrying out functions without preparing for division
G1
Create organelles and increase size.
Restriction point: DNA is good. If DNA is damaged, cell goes into arrest (p53 protein)
S
Cell replicates genetic material
Two identical chromatids bound at centromere
G2
DNA is checked and if there is enough organelles for new cell
Molecules responsible for cell cycle
CDK are activated by cyclins. CDK-cyclin complexes phosphorylate transcription factors needed for cell cycle
Centrioles
paired cylindrical organelles responsible for organization of microtubules
centrosome
region outside nucleus that contains centrioles
Centromeres
DNA sequence on chromosome that holds sister chromatids together and attaches to kinetochore
Meiosis I
Homologous chromosomes (same number chromosome but one from dad one from mom) separate Yields haploid cells
Reductional division
Meiosis I
Equational division
Meiosis II
Prophase I
Homologous chromosomes come together and intertwine: synapsis. Forms a tetrad
What holds tetrads together?
synaptonemal complex
Crossing over
Occurs in prophase I
at the chiasma
Mendel’s second law of independent assortment
inheritance of one allele has no effect on the likelihood of inheriting certain alleles of other genes