Chapter 11 Flashcards
Gametes
haploid reproductive cells (eggs and sperm)
Somatic cells
nonreproductive cells
Somatic and germ-line cells are ________.
diploid
Zygote
diploid (2n) cell resulting from fusion of male and female gametes
Fertilization (syngamy)
fusion of gametes to form a new cell
Asexual reproduction
single individual is the sole parent and passes all copies of its genes without fusion of gametes
Asexual reproduction gives rise to a _______
clone
Mitosis has ____ round(s) of division and ____ round(s) of genome replication
2; 1
Synapsis
homologous chromosomes becomes closely associated
Synaptonemal complex
joins paired homologous
Crossing over (genetic recombination)
homologues exchange chromosomal material
Chiasmata
sites of crossing over
Metaphase I
- pairs of homologues chromosomes align on metaphase plate
- both chromatids of one homologue are attached to kinetochore microtubules
- each homologue is attached to microtubules connecting to opposite poles
Anaphase I
- Each pair of homologous chromosomes separates (sister chromatids remain attached)
- Homologues move toward opposite poles
Prophase II
New spindle forms, nuclear envelope breaks donw
Metaphase II
Kinetochores bind to sister chromatids -> migrate to the metaphase plate
Anaphase II
- Cohesion complex joining centromeres is destroyed
- Sister chromatids separate, pulled to opposite poles
Telophase II
Nuclear envelope reforms around daughter chromosomes
Cytokinesis forms _____ daughter cells
haploid
What are the four distinct features of meiosis?
- Homologous pairing and crossing over
- Sister chromatids remain connected and segregate together during anaphase I
- Kinetochores of sister chromatids are attached to the same pole in Meiosis I and different pole in Meiosis II
- DNA replication does not occur between the two meiotic divisions
If the number of c’somes was not reduced prior to gamete formation, what would happen to the number of c’somes within the zygote?
If the number of chromosomes were not reduced prior to gamete formation (i.e., if meiosis did not occur), the number of chromosomes in the zygote would double.
During Meiosis I, paired _____________ align on the metaphase plate.
Homologous chromosomes
During Meiosis II, paired _____________ align on the metaphase plate.
sister chromatids
Daughter cells at the end of Telophase I are haploid
True
Gametes are __________________ and somatic cells are ___________________
Haploid, diploid
Daughter cells at the end of Telophase II are haploid
True
