Chapter 7: Meiosis
meiosis
a form of cell division that divides the nucleus, so it halves the number of chromosomes when forming specialized reproductive cells
tetrad
a group of two chromosomes that twist around each other form a _________
fragmentation
a multicellular individual breaks into several pieces that many later develop into complete individuals by growing their missing parts
asexual reproduction
a single parent passes copies of all of its genes to each of its offspring and there is no fusion of gametes
budding
a type of asexual reproduction in which new individuals spilt off from existing ones
clone
an offspring that is genetically identical to its parent
synapsis
another name for crossing-over
F
asexual reproduction evolved from sexual reproduction (T/F)
Meiosis I involves the separation of pairs of homologous chromosomes; Meiosis II involves the separation of the two chromatids that make up chromosomes
explain the difference between meiosis I and meiosis II
1
how many ovums (eggs) does meiosis produce?
4
how many sperm cells does meiosis produce?
13
if the diploid number of an organism is 26, the number of chromosomes in the gametes produced through meiosis would be 13
F
in meiosis and cytokinesis, one diploid cell divides to produce two haploid cells (T/F)
spores
in plants, meiosis results in haploid ________
Prophase I
in which stage of meiosis does crossing-over happen?
T
independent assortment occurs when each pair of homologous chromosomes segregates (separates) independently (T/F)
Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II
list the stages of meiosis in the order that they occur
T
many species of protists form diploid cells in response to stress in the environment (T/F)
T
meiosis and the joining of gametes generate genetic variation in offspring (T/F)
oogenesis
the process by which gametes are produced in female animals
spermatogenesis
the process by which sperms are produced in male animals
binary fission
the type of asexual reproduction that occurs in prokaryotes
asexual reproduction
the type of reproduction that produces clones`
sexual reproduction
two parents each form gametes, which fuse to form offspring
undifferentiated sperm cells are produced by meiosis, and become sperm by changing in form and developing tails
what is the difference between undifferentiated sperm cells and sperm?
crossing-over
when two homologous chromosomes exchange reciprocal portions of DNA during prophase I (beginning of meiosis)
in a male cell, the cytoplasm distributes equally when dividing, so there are four haploid cells. in a female cell, the cytoplasm distributes unequally, so only one out of four survives
why does meiosis produce four sperm cells but only one ovum (egg)?