Meiosis Flashcards
Background
Different parents produce combined offspring sexually
46-23 chromosomes (diploid-haploid)
2 divisions
creates 4 sperm cells for men and only 1 ovum in females
Prophase l
A diploid cell w/ chromosomes that bind to homologous chromosomes through synapsis forming a tetrad (group of 4 chromatids)
chromatids from homologous chro.cross over & replace forming verity & diff genes
Metaphase l
Homologous chrom. line up at middle and attach to opposite spindle fibers
Anaphase l
Spindle fibers separate homologous chrom. by pulling to opposite sides of cell
chrom. from each homologous pair are separate but sister chromatids are together
Telophase l
Nuclear membrane forms around chrom.
Cytokinesis splits the cell into 2 haploid cells, each with 1 pair of chrom. from homologous pair and sister chromatids
Prophase ll
Spindle fibers form in each cell
Metaphase ll
Chrom. line in the middle and attach to spindle fibers from both poles
Anaphase ll
Sister chromatids separate and move to opposite sides forming individual chrom.
Telophase ll
Spindle fibers leave and nuclear membrane forms
cytokinesis splits cells into 4 genetically diff haploid cells
Mendelian Genetics
genetic material from 2 parents blend together (wrong)
recessive trait gets masked by dominant trait
Follows laws of dominance and segregation
Law of dominance and Law of segregation
Dominant allele expressed if present
Alleles have to separate during gamete formation
Alleles
Alternate versions of genes on locus of specific chromosome
Non mendelian genetics
Incomplete dominance
Codominance
X Linked
doesn’t follow law of dominance
ID- alleles of genes mix and form a new phenotype (red and white flower results in pink)
CD- both phenotypes expressed (blood types)
X- gene found of x sex chromosome (RG colorblindness, duchenne muscular dystrophy)
Polygenism
Multiple genes on chromosomes regulate single trait (eye color based on EYCL1 on 19 or EYCL3 on 15)
