BIO10 Lecture Notes - Dna Replication, Sexual Reproduction, Karyotype
Document Summary
The instructions for making cell parts are encoded in the dna, so each new cell must get a complete set of the dna molecules. Dna must be copied or replicated before cell division. Each new cell will then have an identical copy of the. All eukaryotic cells store genetic information in chromosomes. Human body cells have 46 chromosomes or 23 identical pairs. Each chromosome is composed of a single, tightly coiled dna molecule. Chromosomes can"t be seen when cells aren"t dividing and are called chromatin. Dna is tightly coiled around proteins called histones. Duplicated chromosomes are called chromatids & are held together by the centromere. A picture of the chromosomes from a human cell arranged in pairs by size. Asexual reproduction involves a single cell dividing to make 2 new, identical daughter cells. Mitosis & binary fission are examples of asexual reproduction.