BIOA01H3 Lecture Notes - Gamete, Sister Chromatids, G2 Phase
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BIOA01H3 Full Course Notes
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Structure: double helix, twisted ladder, coiled in chromosomes. Function: to contain all of the instructions for life. Dna inside chromosomes, inside the nuclei of the cell. Nucleotide: phosphate + deoxyribose + nitrogenous base pair. Base pairs: pairs of nitrogenous bases, always pairs at and cg. Gene: segment of dna that encodes instructions for protein. Rna retrieves instructions from dna and takes it out to make protein. Dna twists on itself -> twists with histone (beads) -> histones twist to make chromatid. 1 pair sex chromosomes (that define your sex, male xx, female xy) Each pair is homologous same instructions but different messages. Not all living things have the same number of chromosomes. Centromere: middle region of chromosome, attracts spindle fibers. N: haploid: # of unique chromosomes -> human is 23. Chromosome -> (before mitosis, copies in s phase) -> called sister chromatids when centromere is added. Homologs: single chromosomes that are similar but not the same to another homolog.