BISC 202 Lecture Notes - Lecture 2: Sister Chromatids, Dna Replication, Mitosis
8 Dec 2018
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Dna replication does not increase the # of chromosomes (no impact on ploidy) Before replication, each chromosome consists of 1 dna molecule (1 chromatid) After replication, each chromosome consists of 2 dna molecules (2 chromatids: chromatids. During s phase, each chromosome is replicated (dna replication), the original chromosome and the new copy are called sister chromatids. Sister chromatids are united by a centromere. During cell division, sister chromatids are separated from each other: homologous chromosomes. A pair of chromosomes that have the same genes in the same loci (may have different alleles dominant and recessive) One of the pair is maternal, the other one is paternal. Humans have 46 chromosomes (2n = 46) The other pair is sex chromosome (xx female; xy male: diploid (2n) Nucleus contains two sets of homologous chromosomes (2 genomes: haploid (n) Nucleus contains only one set of chromosome (1 genome: cell cycle: Some cells stop actively dividing and enter g0 phase.
