Review questions Flashcards
how is asexual reproduction and sexual reproduction different?
asexual utilizes mitosis and sexual utilizes meiosis
what are examples of asexual reproduction?
mitotic division of unicellular organisms
budding of multi cellular organisms
regeneration of pieces of organisms
list the phases of meiosis
interphase - same as mitosis
S-phase
meiosis
what are the stages of meiosis?
two nuclear divisions
four haploid cells
what happens during meiosis 1
reduction division
separation of homologous chromosomes
results in 2 haploid cells
list the phases of meiosis 1
prophase
metaphase
anaphase
telophase
what are the results of meiosis 1 and meiosis 2?
meiosis one results in 2 haploid cells
meiosis 2 results in 4 haploid cells
prophase 1
condensation of chromatin nucleoli disappear spindle formation nuclear envelope breaks down pairing of homologous chromosomes and crossing over
metaphase 1
bivalents align at spindle equator
spindle fibers attach to one kinetochore from each chromosome
chromosome alignment is random
anaphase 1
homologous chromosomes are separated
move to opposite poles
composed of two sister chromatids
Telophase 1
chromosomes arrive at poles
nuclear envelope form
cytokinesis produces two haploid cells
Meiosis 2
Separation division
separation of sister chromatids
results in four haploid cells
what may be separated from meiosis by short interphase
meiosis 2
prophase 2
very brief, similar to prophase of mitosis
chromosomes condense
nuclear envelope breaks down
spindle apparatus forms
metaphase 2
chromosomes align on metaphse plate, half as many
Anaphase 2
sister chromatids are separated, becoming daughter chromosomes
telophase 2
chromosomes reach poles, decondense and nuclear envelopes form
results in four haploid cells with variable allele combinations
what happens after telophase 2
cytokinesis
how does gametogenesis result in males and females?
males - results in four haploid sperm cells
females - results in one haploid egg cell and three polar bodies
what do eggs require in gametogenesis
eggs often require development phase during meiosis
