Bio Stuff

Bio Stuff - Lecture 2: Chapter 10 Chromosomes, Mitosis,...

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I. Eukaryotic Chromosomes A. Genes cell’s informational units, made of DNA DNA- collectively called the organism’s genome. [contains hundreds or even thousands of genes] [ human Genome Project humans have about 25k genes that code for proteins] An individual’s genome is organized into informational units called genes, which control the activates of the cell and are passed on to its descendants B. Chromatin Consists of long, thin threads that are somewhat aggregated, giving them a granular appearance. During cell division, the chromatin fibers condense and the chromosomes become visible as distinct structures C. Chromosomes –“colored bodies” carriers of genetic information in eukaryotes lies within the cell’s nucleus D. Histone small, positively charged (basic) proteins that bind to the negatively charged DNA Contains certain proteins that facilitate chromosome packaging. Positive charge because they have a high proportion of amino acids with basic side chains E. Nucleosome histone (protein) bead wrapped in DNA organized into coiled loops held together by non-histone scaffolding proteins each nucleosome bead contains a set of 8 histone molecules this forms a protein core around which the double-stranded DNA winds The DNA surrounding the histone consists of 146 nucleotide pairs Another segment of DNA, about 60 nucleotide pairs long, links nucleosome beads Functions like tiny spools, preventing DNA strands from becoming tangled. Scaffolding Proteins : are non histone proteins that help maintain chromosome structure Condensin : group of proteins that are required for chromosome compaction 1. DNA wrapped around histone proteins to form Nucleosome.
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2. Nucleosome are compacted into chromatin fibers which are coiled into looped domains 3. The looped domains are compacted, ultimately forming chromosomes Cell cycle : stages through which a cell passes from one cell division to the next are collective Consists of two main phases, inter-phase and M phase M phase: involves two main processes, mitosis and cytoinesis. Mitosis, process involving nucleus, ensures that each new nucleus
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This note was uploaded on 11/19/2011 for the course 101 101 taught by Professor Alla during the Fall '09 term at Rutgers.

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Bio Stuff - Lecture 2: Chapter 10 Chromosomes, Mitosis,...

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