Theory:

Points to Remember:
Bivalent: A pair of homologous chromosomes before their duplication in meiosis. It is also called diad.
 
Cell division: The three types of cell division that occur in animal cells are amitosis (direct division), mitosis (indirect division) and meiosis (reduction division).
 
Centromere: A structure present in between the chromosomal arms of chromosomes to which the mitotic and meiotic spindle microtubules are attached. It is called kinetochore or primary constriction.
 
Chiasma: The point of contact and interchange between chromatids of two homologous chromosomes.
 
Chromatids: One of the two identical longitudinal halves of a chromosome share a common centromere with a sister chromatid.
 
Chromosome: They are elongated rod-like structures formed during nuclear division. They represent the physical sites of nuclear genes, which are arranged in linear order. Every species has a characteristic number of chromosome.
 
Crossing over: Process in which genes are exchanged between non-sister chromatids of homologous chromosomes.
 
Diploid: An individual or cell having twocomplete sets of chromosomes.
 
Haploid: An individual or cell having a single complete set of chromosome.
 
Homologous chromosome: Chromosomes are occurring in pairs, one derived from each of the two parents. Each member of such a pair is the homolog of the other.
 
Interphase: It is the longest resting phase of the cell between two cell divisions.
 
Synapsis: Pairing of homologous chromosomes occurring in prophase -I of meiosis.
 
Tetrad: Four haploid cells arising from meiosis formed from four associated chromatids during synapsis.
 
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Animal cell cycle