Chapter 10 Study Guide Flashcards
Meiosis
what is a gene and where is it located
coded info in the form of hereditary units, located in the nucleus of cells on chromosomes
During meiosis, diploid cell divides ___ to form ___ which reduces chromosomes by a ___
twice, 4 haploid nuclei, half
what is created in haploid nuclei
new allele combos (not identical)
gamete formation packages the ___ into ____
haploid chromosomes into reproductive cells
___ merges haploid gametes from 2 parents to new diploid cell with ___________
fertilization, half it chromosomes from each parent
chromosomes
made up of long strands of DNA
x and y chromosomes
determines their sex (xx women, xy male)
homologous chromosomes
pair of chromosomes from different parents, genes in the same order
autosomes
other chromosomes not sex)
diploid cell
any cell with two chromosomes
haploid cell
cells w/ single set of chromosomes
difference in germ cells and gametes
germ cells undergo meiosis to produce sperm and egg;
gametes are mature sperm and eggs that are directly involved in fertilization
somatic cells
all cells that are not reproductive
difference in sexual and asexual reproduction
asexual: one parent, genetically identical to parent, through binary fission, budding, etc
sexual two parents, genetic info taken from both parents, not identical,
what occurs during prophase 1 in meiosis
2 pairs of homologous chromosomes (4 sister chromatids) perform crossing over (no longer identical) nuclear membrane disappears
Metaphase 1
homologous chromosome pairs come to the middle, and connect to spindle fibers
Anaphase 1
move to opposite poles, homologous pair separate to opposite sides
Telophase 1
nuclear membrane begins to reform, 2 haploid daughter cells are formed, each have their own set of chromosome
Prophase 2
Separate haploid daughter cells, no DNA replication, nuclear envelope breaks down in each daughter cel, chromatin condenses into chromosomes again
Metaphase 2
in both daughter cells, chromosomes align, microtubules attach to the kinetochores of each chromosome
Anaphase 2
sister chromatids separate and become chromosomes, move towards opposite sides of the cell, resulting in 4 haploid daughter cells that each contain a single copy of each chromosome
Telophase 2
nuclear membranes reform around chromosomes, cell divides via cytokinesis, which created 4 haploid daughter cells that contain half the number of chromosomes as parent cell
which stages of meiosis are responsible for all children not looking the same?
Prophase 1 only because it includes crossing over
Describe the end result features of meiosis
4 haploid daughter cells with their own set of chromosomes half the amount of each parent cell, with unique combinations of alleles
crossing over
takes place during prophase 1, homologous chromosomes exhange DNA segments to create variety
independent assortment
alleles of different genes segregate independently from one another, each allele inherited from a gene does not influence which allele it can receive for another gene.
random fertilization
process during sexual reproduction, any sperm cell can randomly fuse with any egg cell from a female
describe 3 way meiosis differs from mitosis
mitosis produces 2 identical daughter cells, meiosis 4 nonidentical haploid daughter cells are produced
meiosis involves 2 distinct cell divisions mitosis has one
meiosis reduces the chromosome number by a half to create haploid gametes, mitosis maintains the diploid chromosome number in daughter cells
