BLG 143 Lecture Notes - Lecture 7: Peroxisome, Leucine, Nuclear Membrane
25 Oct 2017
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7. 1 bacterial and archaeal cell structures and their functions. According to morphology, species fall into 2 broad categories: prokaryotes lack a membrane bound nucleus, eukaryotes have such a nucleus. According to phylogeny or evolutionary history there are 3 domains: bacteria, archaea, eukarya. Most bacterial species have a single, circular chromosome that consists of: large dna molecule contains information, small number of proteins provide structural support. Gene: a segment of dna that contains information for building an rna molecule or a polypeptide. To fit into the cell, the dna double helix coils on itself with the aid of e(cid:374)z(cid:455)(cid:373)es to for(cid:373) the highl(cid:455) (cid:272)o(cid:373)pa(cid:272)t (cid:862)super (cid:272)oiled(cid:863) stru(cid:272)ture: bacterial chromosomes are found in the nucleoid (in centre of cell). In addition to large chromosomes, bacteria may contain plasmids contain genes but are physically independent of the main cellular chromosome: these genes help cells adapt to unusual circumstances. Ribosomes: complex structures consisting of rna molecules and proteins.
