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22 terms

Zoology

mitosis+meiosis
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Mitosis
cell division in which chromosome number stays the same two cells produced from original cell
Meiosis
cell division in which chromosome number is cut in half and 4 cells produced rom the original cell
Stages of mitosis
Interphase (G1,S,G2)
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Cytokinesis
division of cytoplasm
Prophase
chromosomes fully condensed
nuclear membrane completely breaks up
centrioles migrate to opposite poles of the cell
spindle fibers form between poles
chromosomes attach to spindle fibers at centromeres
Metaphase
chromosomes align in the middle between 2 poles
Anaphase
sister chromatids separate and migrate to opposite poles
Telophase
chromosomes un-condense
nuclear membrane forms around each set of chromosomes
spindle apparatus breaks up
Gene
section of DNA that codes for protein
Homologs
alternate forms of chromosome that code for the same sets of proteins
Allele
alternative forms of a gene that codes for the same protein
Linked genes
genes that occur on the same chromosome
Dyad
sister chromatids --> 2 copies of the same chromosome
TetraD
homologs = 2 Dyads --> 4 chromosomes
Synapsis
dyads contact one another to form tetrad
Chiasmata
points of connection between non-sister chromatids in tetrad
Crossing over
exchange of DNA between non-sister chromatids at Chiasmata
- Occurs at metaphase I
- Splitting occurs at Anaphase I
Interkinesis
waiting phase, getting ready for second Meiosis
Mendel's laws
1. Segregation of Alleles
2. Independent assortment
Genotype
genetic make up in diploid organisms
Phenotype
expressed i.e. "what it looks like"
Test cross
homozygous recessive individual "aa".