Meiosis Flashcards
Where are chromosomes located in the cell?
The nucleus
Structure of chromosomes
Centromere, Chromatids, and Histones*
What is the significance of chromosomes in cell division.
They carry DNA
Difference between haploid and diploid number
Diploid refers to a double set of chromosomes while haploid refers to a single set.
When does Meiosis take place?
It takes place during the formation of gametes in animals or in the spores in plants.
Where does Meiosis take place?
It takes place in the reproductive system of an organism.
Why does Meiosis take place?
Meiosis is important as it ensures that all organisms produced by sexual reproduction have the correct amount of chromosomes.It also promotes genetic variation through means of recombination thus sustaining the process of evolution.
Process of DNA replication
The double helix unwinds. The weak hydrogen bonds break and the two DNA strands unzip. Free floating nucleotides in the nucleoplasm build a complementary DNA strand onto each of the original two strands.
Bivalent
A bivalent is one pair of chromosomes in a tetrad.
Chromosomal Abnormalities
These occur when meiosis does not occur properly thus, changes in the chromosome number may occur.
Aneuploidy
A condition that results in the chromosome number being either one more or one less than the diploid number.
Are Trisomy 21 and down syndrome the same thing?
Yes
What is a Karyotype?
The complete diploid set of chromosomes, arranged according to their size, shape and number in homologous pairs within a somatic cell of an organism.
How to work with them
The human Karyotype has 22 ordinary chromosomes (autosomes) while the 23rd pair determines sex (gonosome) with Women bearing an XX gonosome and men having an XY gonosome. Thus, the chromosome composition of a female is: 44 + XX while male is: 44 + XY
Non-disjunction
When a chromosome does not split correctly into two chromatids during Meiosis (Meta-Anaphase)
