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What is fertilization?
Union of female and male gametes
What is crossing over?
The process in which homologous chromosomes exchange portions of their chromatids during meiosis
What is the outcome of Meiosis I in terms of cell number and ploidy?
2 haploid cells
What separates in Anaphase II of Meiosis II?
Sister chromatids
What is the outcome of Meiosis II in terms of cell number and ploidy?
4 haploid cells
What are the differences between mitosis and meiosis?
Four haploid cells instead of two diploid cells, only occur in sex cells, daughter cells are genetically different, reduction in chromosome number, two divisions
What is nondisjunction?
The failure of homologs or sister chromatids to separate. Results in a cell with extra or missing chromosomes.
When in Meiosis is nondisjunction most likely to take place?
Anaphase I or II
What is the purpose of meiosis?
Reduce the amount of genetic information in the resulting gametes by 1/2
In what types of cells does meiosis occur?
Reproductive cells
How much genetic information does the resulting organism have from fertilization?
Full genetic information
What is ploidy (haploid, diploid, octoploid)?
How many copies of a chromosome is in a cell. Diploid cells, for example, have 2 copies of each chromosome.
What is a genotype?
The genetic makeup of an organism
What is a phenotype?
The physical characteristics of an organism
What is an allele?
Different forms of a gene
An individual having two different alleles for a given gene is said to be what?
Heterozygous
An individual having the same alleles for a given gene is said to be what?
Homozygous
A trait that only requires one allele to be expressed is what?
Dominant
A trait that requires two alleles to be expressed is what?
Recessive
What process has to take place prior to cell division?
Replication of DNA
What is the purpose of crossing over?
Increases genetic diversity
In what phase does crossing over occur?
Prophase I
What separates in Anaphase I of Meiosis I?
Replicated homologous chromosomes
