week 3 friday Flashcards
asexual reproduction
offspring are genetically identical (to eachother and the parent) and come from a single parent organism
sexual reproduction
two parent organisms necessary, genetically distinct + unique offspring due to recombination (crossing over)
germ - line cells
cells that become gametes (sex cells)
undergo mitosis and MIEOSIS, pass genetic information to next generation
somatic cells
all non germ-line/gemete cells
undergo mitosis but not mieosis
changes CAN happen in these cells genetic material during transcription etc but doesnt get passed onto next generation
polyploidy
many copies of homologous chromosomes (ex. 8n)
sister chromatids
identical at the nucleotide/sequence level (DNA replication)
2 sister chromatids make up a chromosome
homologous chromosomes
chromosomes that pair up with eachother during meiosis, not the same sequence (alleles) but same chromosome (genes)
2 sister chromatids make up one chromosome, in homologous chromosomes there are 4 sister chromatids
meiosis
cell division in two parts, halfing the ploidy (2n to n in humans)
meiosis 1
the reduction division (homologous chromosomes are seperated)
meiosis 2
the equational division (sister chromatids are seperated)
same thing as mitosis just starting with halpoid (n) cells
mitosis vs meiosis (1)
mitosis:
sister chromatids lined up and seperated
meiosis (1):
homologous chromosomes lined up and seperated
independent assortment
homologous chromosomes attach to microtubules at random (dad on top, mom on bottom or vice versa is equaly as possible)
contributes to genetic diversity (>8 million combos)
recombination
aka crossing over
homologous chromosomes pair and form synapses in which the chromosomes swap parts of their genetic information which massivly increases genetic diversity
what happens in early profase of mieosis
homologous chromosome pair with eachother (synapses), 4 chromosomes each with 2 sister chromatids
what happens in late profase of mieosis
spindle forms + nuclear envelope starts to degrade (still 4 chromosomes each with 2 sister chromatids)