CAS BI 203 Study Guide - Midterm Guide: Semipermeable Membrane, Transfer Rna, Intron
16 Nov 2016
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Document Summary
Fundamental principles: cell has a life of its own, cells are dynamic, living units, Cells are complex little bags of organic molecules: outer boundary is flexible, outer boundary is semi permeable. ~ 20 micrometers (size) inside contains a vast array of organic molecules: proteins, lipids, carbohydrates. Dna is the same in every cell in our body. Rna is not the same in every cell in our body (different mrna, different proteins, different cell make up) Difference between prokaryotic cell and eukaryotic: cytoplasmic organelles (present in eukaryotic, absent in prokaryotic, chromosomes (prokaryotic circular dna, multiple linear dna molecules in eukaryotic) Advantage of compartments: enable cells to compartmentalize gives order and efficiency. Fundamental features are characteristic of almost every cell type. All present day cells are descendants from a common primordial ancestor. Time scale of evolution: first prokaryotes: ~ 4 billion years, oxidative metabolism and photosynthesis: ~ 3 billion years ago.
