Reproduction: Meiosis (HY) Flashcards
what cells undergo mitosis and what cells undergo meiosis? Are the off-spring cells identical in mitosis and meiosis?
- somatic cells undergo mitosis, and germ cells undergo meiosis
- 2 identical daughter cells from mitosis; 4 non-identical gametes from meiosis
Meiosis I results in what type of cell division?
reductional division
homologous chromosomes are separated and form haploid daughter cells
what are homologous chromosomes? How many pairs of homologous chromosomes are in humans?
homologous chromosomes are a pair of chromosomes, one from each parent
23 homologous pairs of chromosomes in humans
Meiosis II and mitosis result in what type of cell division?
equational division
sister chromatids are separated
what is the difference between homologous pairs of chromosomes and sister chromatids?
a pair of homologous chromosomes are separate and different (one is maternal and one is paternal), but sister chromatids are identical DNA strands connected at a centromere
what is the difference between meiosis prophase I and mitosis prophase?
In meiosis prophase 1, homologous chromosomes undergo synapsis.
what occurs during synapsis?
chromatids of homologous chromosomes undergo crossing over at the chiasma (point of contact) and exchange DNA
what is a tetrad during prophase I?
a homologous pair of chromosomes with a chiasma during synapsis
also a synaptic pair; consists of four chromatids/two pairs of sister chromatids/
which of mendel’s laws does synapsis explain?
mendel’s second law of independent assortment
inheritance of one allele does not affect the inheritance of another
what is the synaptonemal complex?
holds together a pair of homologous chromosomes during synapsis
what’s the difference between meiosis metaphase I and mitosis metaphase?
In meiosis metaphase I, chromosomes are lined up at metaphase plate across from one another and are attached by only one spindle fiber
what’s the difference between meiosis anaphase I and mitosis anaphase?
In meiosis anaphase I, disjunction/segregation occurs: homologous pairs of chromosomes separate
Disjunction/segregation explains which of mendel’s laws?
Mendel’s first law of segregation (Punnet Square)
allele pairs segregate during gamete formation and randomly unite upon fertilization
what’s the difference between meiosis telophase I and mitosis telophase?
the number of chromosomes
In mitosis telophase, each daughter cell nucleus is diploid. In meiosis telphase I, each daughter cell nucleus is haploid.
What’s the main similarity and difference between meiosis II and mitosis?
Similarity: sister chromatids are being separated
Difference: parent and daughter cells are haploid in meiosis II but are diploid in mitosis
