·The nucleus(细胞核)of a nondividing cell(interphase分裂 间期)is filled with a diffuse(弥散)material called Chromatin(染色质)，so called because early microscopists（显微镜学家)found that it stained(染色) brightly with certain dyes(染料). 摘自：Lehninger,3rd,p35 11
11 • The nucleus (细胞核) of a nondividing cell (interphase分裂 间期) is filled with a diffuse（弥散）material called Chromatin（染色质）, so called because early microscopists（显微镜学家） found that it stained（染色） brightly with certain dyes（染料）. 摘自:Lehninger, 3rd, p35
。Chromatin(染色质)consists of DNA and proteins bound tightly together and is the substance of the chromosomes(染色体)，which do not condense (凝缩)and become individually visible until the cell is ready to divide. 丹世 y状道 0厂可#- 1
12 • Chromatin （染色质） consists of DNA and proteins bound tightly together and is the substance of the chromosomes （染色体）, which do not condense （凝缩） and become individually visible until the cell is ready to divide
·Nucleolus(核仁)is a specific region of the nucleus (细胞核)in which DNA is located.Before mitosis (有丝分裂)，the double-helical DNA of the chromatin is replicated,then in the first phase (期，阶段)of mitosis the chromatin fibers（纤 维)condense into discrete（分立的)bodies (chromosomes),each consisting of two identical chromatids(染色单体). 13
13 • Nucleolus (核仁) is a specific region of the nucleus (细胞核) in which DNA is located. Before mitosis （有丝分裂）, the double-helical DNA of the chromatin is replicated, then in the first phase （期，阶段） of mitosis the chromatin fibers（纤 维） condense into discrete（分立的） bodies (chromosomes), each consisting of two identical chromatids （染色单体）
In the first phase of mitosis the chromatin fibers condense into chromosomes. Mitosis 分裂间期 有丝分裂 hase transition Interphase prophase prometaphase metaphase anaphase telophase cytoldnass M PHASE INTERPHASE DNA moication Chromatin 染色质 Chromosome 染色体 (diffused) (condensed) 14
14 In the first phase of mitosis the chromatin fibers condense into chromosomes. 分裂间期 有丝分裂 染色质 染色体
Mitotic chromosome Chromatid -600nm in diameter) Chromosomes consisting of two identical chromatids 15
15 Chromosomes consisting of two identical chromatids