Chromosomes

For my students =)

Those of you who still have problems on understanding What is a CHROMOSOME, this post is for you. Do read and try to understand. Enjoy!

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-A chromosome is found in the nucleus of all cells (except RBC, since they do not have nucleus)

-Chromosomes are made up of a long, linear DNA molecule which in turn is made up of many sets of genes : it is the genetic material that all organisms inherit from their parents

-A DNA molecule is usually very long & consists of hundreds & thousands of genes

-G1 phase : cell does its normal everyday job. Each chromosome contains only a single molecule of DNA where it is not condensed & appear like thread-like structures called chromatin

-S phase : synthesis of DNA occurs. Replication of DNA in nucleus. Duplication will result in sister chromatids

-Within a sister chromatid, it contains a DNA double helix

-G2 phase : cell gets ready for mitosis

-When cell division begins, chromatins will condense, coil up, compact & thicken, thus making them easily seen under the light microscope. In the middle, it has a narrow region called the centromere

-DUring mitosis, this 2 sister chromatids will finally separate during anaphase & each will become an independent daughter chromosome