NATS 1675 Lecture Notes - Lecture 17: Endoplasmic Reticulum, Messenger Rna, Nuclear Membrane
14 Aug 2016
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Adenine (a) and guanine (g) are double-ringed purines. Cytosine (c), thymine (t), and uracil (u) are single-ringed pyramidines. In dna, a pairs with t and g pairs with c. U is found in rna and is paired with a in place of t. Bases include a, u, c, and g. Mrna messenger rna: transcription part of dna in nucleus trna transfer rna, translation into protein cell rrna ribosomal rna, part of ribosome. Found bound to the endoplasmic reticulum and free floating in the cytoplasm. Cells (body cells) that have 46 (2n) paired chromosomes are called diploid. Cells (sex cells) that have only 23 (n) unpaired chromosomes are called haploid. Chromosomes contain both dna and associated proteins (collectively called chromatin) Chromosomes that are dividing are made up of two identical parts called sister chromatids. The sister chromatids are held together at a region called the centromere. G1 stage cell doubles its organelles; cell grows in size.
