BI110 Lecture Notes - Lecture 11: Metabolic Pathway, Transfer Rna, Chromosome
Bi110 lesson 11
ribosomes
705
705
805
membrane-enclosed organelles
absent
absent
present
membrane lipids
ester-linked
ester-linked
ester-linked
peptidoglycan in cell wall
present
absent
absent
methanogenesis
absent
present
absent
temperature tolerance
up to 90oC
up to 120oC
up to 70oC
common attributes for all life forms
1. lipid molecules assemble to form a bilayer that contains the cell
2. a genetic system based on DNA
3. a system of information transfer: DNA → RNA → protein
4. a system of protein assembly using mRNA and tRNA using ribosomes to polymerize the
amino acids
5. reliance on proteins as the major structural and catalytic molecule
6. use of ATP as the molecule of chemical energy
7. the breakdown of glucose by the metabolic pathway of glycolysis to generate ATP
gene transfer
1. vertical gene transfer
● inheritance from one generation to the next 2. horizontal gene transfer
● movement of genetic material between unrelated organisms
• ○ introduces genes from one species into another
• ○ can occur through viral infection or endosymbiosis
• ○ evolutionary advantageous
• ○ does not change evolution of gene transfer
• ● some protein-coding genes once located in the chloroplast or mitochondrial genomes
relocated to the nuclear genome
• ● following the transcription of these genes, translation occurs in the cytosol before
proteins import into the mitochondrion or the chloroplast
• ● mitochondria evolved from an aerobic bacterium that was engulfed by an anaerobic
achaean, transforming it into a eukaryotic cell
• ● over time, many genes on the mitochondrial chromosome were transferred to nuclear
chromosomes
• ● later, in the history of life, photosynthetic bacteria were engulfed by eukaryotic cells
• ● the engulfed photosynthetic bacteria evolved into chloroplasts, which are responsible
for
photosynthesis in algae and plants
