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8 Οκτ 2021 · During interphase (S phase) the DNA replicates to create two identical strands of DNA called chromatids, joined together by a narrow region called the centromere. The two chromatids that make up the double structure of a chromosome are known as ‘sister chromatids’.
15 Αυγ 2020 · Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique. The term chromosome comes from the Greek ...
Although the numbers and sizes of chromosomes vary considerably between different species (Table 4.2), their basic structure is the same in all eukaryotes. The DNA of eukaryotic cells is tightly bound to small basic proteins (histones) that package the DNA in an orderly way in the cell nucleus.
Eucaryotic DNA Is Packaged into a Set of Chromosomes. In eucaryotes, the DNA in the nucleus is divided between a set of different chromosomes. For example, the human genome—approximately 3.2 × 10 9 nucleotides—is distributed over 24 different chromosomes.
Chromosomes are structures within cells that contain a person's genes. Genes are contained in chromosomes, which are in the cell nucleus. A chromosome contains hundreds to thousands of genes. Every normal human cell contains 23 pairs of chromosomes, for a total of 46 chromosomes.
Each chromosome in one set is matched by a chromosome of the same type in the other set, so there are actually 23 pairs of chromosomes per cell. Each pair consists of chromosomes of the same size and shape, and they also contain the same genes. The chromosomes in a pair are known as homologous chromosomes.
Chromosomes are found in the nucleus of every cell of our body and are made up of DNA, tightly coiled around proteins. We have 23 pairs of chromosomes altogether, and they can only be easily observed during cell division.
