C.13 - Meiosis Flashcards
Zygote
The fertilized egg (union of gametes) and has one set of chromosomes from each parent.
Produces somatic cells by mitosis and develops into an adult
Diplonitic - Animal
Gametes are the only animal haploid cell; Produced by meiosis (undergoes no further cell division before fertilization) Gametes fuse forming diploid zygote, divide by mitosis resulting in multicellular organism.
Haplodiplontic- Plants and Some Algae
An alternation of generations which includes both a diploid and haploid multicellular stage
Haplontic- Fungi and some protists
The only diploid stage is the single-celled zygote (There is no multicellular diploid stage). Each haploid cell grows by mitosis into a haploid multicellular organism
Somatic Cells
Non-reproductive cells with two sets of chromosomes ( 2x23=46 total)
Gametes
Reproductive cells (sperm and eggs) that have half as many chromosomes as somatic cells
Asexual reproduction
One parent produces genetically identical offspring by mitosis
Sexual reproduction
Two parents give rise to offspring that have unique combinations of genes inherited from the two parents
Karyotype
An ordered display of the chromosomes pairs from a cell
Homologous Chromosomes
The two chromosomes in each pair. They are the same length and shape and carry same gene
Sex Chromosomes
Determine the sex of the individual, are called X and Y. Human females have a homologous pair of X chromosomes and Human males have one X and one Y chromosome
Autosomes
The remaining 22 pairs of chromosomes, excluding sex chromosomes
Diploid cell (2n)
Has two sets of chromosomes. For humans, the diploid number is 46 (2n = 46)
Haploid (n)
A gamete (sperm or egg) contains a single set of chromosomes. For humans, the haploid number is 23 (n = 23) Each set of 23 consists of 22 autosomes and a single sex chromosome
Sister Chromatids
A sister chromatid refers to the identical copies (chromatids) formed by the DNA replication of a chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said to be ‘one-half’ of the duplicated chromosome.
