Show Menu

Chromosomal Basis of Heredity Cheat Sheet by

biology     genetics     meiosis     heredity     chromosome

Meiosis I

Prophase I
Chromo­somes condense, homologous pairs align, syna­psis (precise alignment, ensires 1 copy of each gene in a daughter cell). Synapsed set called a tetrad (4 chroma­tids). Then, cros­sin­g-o­ver occurs (exchange of chromosome segments between pairs of homol­ogous chromo­somes, or nonsister chroma­tids). Chia­sma forms, visible structure from crossover. X and Y chromo­somes pair and synapse thru terminal ends (PARs).
2N
Metaphase I
Nucleoli and envelope broken down, centroiles w/ spinde entern­uclear area, kinet­echore microt­ubules attach to sister kineto­chores, tetrads align at metaphase plate.
2N
Anaphase I
Chromo­somes of tetrad separate (now dyad­s). Sister chromatids remain attached at centro­meres. DNA content is halved.
2N-N
Telophase I
Spindles dissas­emble, cytoki­nesis forms two hapl­oid cells.
N
 

Meiosis

Meiosis II

Prophase II
Chromo­somes condense and spindles form, kineto­chores attach to tubules..
Metaphase II
Alignment on metaphase plate.
Anaphase II
Centro­meres separate, daughter chromo­somes (still haploid) pulled to opposite sides.
Telophase II
Chromo­somes decond­ense, nuclear envelope forms, cytoki­nesis. Four haploid cells produced, each with one chromosome from each homologous pair.
 

Meiosis Results

Generates haploid nuclei with half the number of chromo­somes found in diploid cell. (2N -> N) Diploid number restored in fertil­iza­tion.
Inde­pendent assortment of genes paternal and maternal chromo­somes have an equal chance of aligning on one side of metaphase plate.
Number of chromosome arrang­ements is 2n-1, n= # chromo­somes pairs (haploid number).
Number of chromosome combin­ations resulting from indep­endent assort­ment is 2n (number of different gamet­es).
Number of kinds of genotypes is 3n.

Ploidy

Haploid
ONE copy of each chromo­some. (N)
Diploid
TWO copies (homol­ogues) of each chromo­some. (2N)
Homologous pairs
Same gene loci, structure, and pair during meiosis.

Genes

Allele
Altern­ative forms of a single gene on the same locus that determine the same trait, but can produce different phenot­ypes.

Download the Chromosomal Basis of Heredity Cheat Sheet

1 Page
//media.cheatography.com/storage/thumb/pokemonsz_chromosomal-basis-of-heredity.750.jpg

PDF (recommended)

Alternative Downloads

Share This Cheat Sheet!

Like this cheat sheet? Check out our sponsors!

Readable.io is a collection of tools to make your writing better. More readable content means higher conversion rates and better reader engagement. Measure website and document readability, measure keyword density and more!

Click Here To Get Started!

 

Comments

TME520 TME520, 01:26 19 Oct 17

Informative cheat sheet, well worth reading. It would be easier to understand if you included a short dictionary.

Add a Comment

Your Comment

Please enter your name.

    Please enter your email address

      Please enter your Comment.

          Related Cheat Sheets

          Meiosis Cheat Sheet
          AP Biology Unit 7: Genetics Cheat Sheet