Each human cell contains 23 pairs of chromosomes (23 x 2 = a total of 46 chromosomes).

Females have a chromosome pair of XX.

Males have a chromosome pair of  XY.  

Both male and female cells contain one X chromosome.   

The first 22 chromosomes are called autosomes, which means they are not sex chromosomes. Typically, one chromosome comes from the mother, and the other chromosome comes from the father.  The 23rd pair determines the gender of the offspring.  

This means:  

Females get one X chromosome from their mother and one X chromosome from their father.  (XX chromosome pair)             

Males get one X chromosome from their mother and one Y chromosome from their father.   (XY chromosome pair)

Therefore, we can say that If a father donates an X chromosome during reproduction, the offspring will be a girl (XX).  If a father donates a Y 
chromosome during reproduction, the offspring will be a boy (XY). 

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​an exchange of genetic material between homologous chromosomes during meiosis



​crossing over 


​having more than two sets of chromosomes

polyploid​


a mature haploid male and female cell, otherwise known as the reproductive cells, which unite during fertilization to produce a zygote​


a single set of unpaired chromosomes from either parent, which equals 23 chromosomes instead of from both parents, which equals 46 chromosomes​
gametes ​



haploid

a eukaryotic organism that contains two sets of chromosomes (one set from each parent), which equals 46 chromosomes​



​diploid

the mode of reproduction where an offspring is produced from a single parent​


​the mode of reproduction where an offspring is produced from two parents


asexual reproduction​

​sexual reproduction  


​the product of reproduction


​offspring 


any cell of a living organism except for the reproductive cells​


the region of the chromosome where the two sister chromatids are joined​


somatic cell ​


centromere ​

a fertilized egg formed by the union of a female gamete and a male gamete​


zygote ​


​the pairing of homologous chromosomes from each parent at the beginning of meiosis


​a set of chromosomes having genes in the same order, one received from each parent


synapsis ​


homologous chromosomes ​


​one of the two strands of an identical chromosome joined by a centromere during early cell division


chromatid​


​a collection of threadlike structures that move and separate the chromosome during cell division


substance that forms chromosome and made up of proteins, RNA, and DNA​


spindle fibers ​


chromatin​


a cylindrical cell structure that is made up of nine triplets of spindle fibers and found in most animal cells during cell division​
centriole ​

​the dividing of a cell that creates four daughter cells where the new cells contain half the number of chromosomes of the parent cell
​the dividing of a single cell that creates two identical cells where the new cells contain the same number of chromosome and genetic material as the original cell


meiosis ​


​mitosis 


a mature female reproductive cell; unfertilized egg​



ovum​

the initial stage of cell division where chromosomes shorten and thicken and can be seen as two chromatids, the spindle, containing spindle fibers is formed in opposite ends of the cell, and the nucleus membrane disappears​

​the second stage where chromosomes with help from the spindle fibers move to the center of the cell to be separated


prophase ​


​metaphase 

​the mature motile male sex cell by which the ovum is fertilized


spermatozoa ​

​the division of cytoplasm that creates two daughter cells at the end of cell division


​cytokinesis


the stage in cell division where the two chromatids are separated by the spindle fibers and pulled to opposite ends of the cell​


  anaphase ​

​the final stage in cell division where the chromosomes are now separate at the poles, a nucleus develops around each of the chromosomes, and two daughter cells are created


telophase 




Science:  Mitosis and Meiosis - Flashcards
Use the flashcards to help you memorize the following terms and definitions. Then try the worksheets shown on the Science Homepage. Once you are ready to quiz yourself, click the Quiz link.