Mitosis and Meiosis

nucleus

large, membrane bound organelle housing (most) genetic material of a cell

DNA

a double stranded nucleic acid that contains the genetic information for cell growth, division, and function

chromosome

a threadlike structure of DNA and its associated proteins

gene

a linear segment of DNA that provided coded instructions leading to the expression of hereditary traits

homologous chromosomes

chromosomes in a (diploid) organism that carry the same genes on them but might have different versions of that gene (alleles)

allele

alternative forms of a gene found and expressed along the same location on a chromosome

karyotype

the distinctive appearance of all the chromosomes in a cell, including the number and types of chromosomes present

ploidy

number of complete chromosome sets present in a cell 

mitosis

process that makes new cells that are genetically identical to the starting cell

cell cycle

sequence of chromosomal replication and cellular division in a eukaryotic cell

G1

cells performing their functional roles and the decision is made whether to divide or not

S phase

where DNA is replicated (chromosomes are replicated)

G2

quality control that checks if cell is ready to continue into M

meiosis

a division in which the amount of chromosomes is reduced by half and produces four genetically different cells

prophase I

where homologous pairs of sister chromatids are joined at tetrads and when crossing over occurs between non-sisters

possible arrangments of homologs

2^n

metaphase I

where chromosomes independently assort in the center of the cell

anaphase

where chromosomes are brought apart into chromatids in mitosis or chromosomes are separated in meiosis I 

telophase

when nuclear envelope reappears and cell begins cleaving into two different cells