32. Nutrient assimilationnew

32. Nutrient assimilationnew - Absorption Ingestion...

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1 Nutrient Assimilation - Taking Up the Right Stuff 1. We’ll use clickers today 2. Circulation systems HW due on Friday Photosynthesis Ingestion Absorption Each Fundamental Process of Life Universal physical and chemical principles Common genomic toolkit from LUCAC places design constraints on provides certain opportunities for provides molecular solutions for can evolve for Unity of Life Diversity of Life Ecological roles Organismal strategies Different cells, tissues, & organs selection pressures and/or Unique Gas Exchange and Circulatory Systems in Different Multicellular Lineages 1. No specializations for gas exchange and circulation in unicellular organisms - passive diffusion only 2. Independent origins of gas exchange and/or circulatory systems in various multicellular animal and plant lineages 3. Physicochemical constraints (Fick’s Law and Hagen- Poiseuille equation) operating on convergent structures Nutrient Assimilation - Taking Up the Right Stuff Photosynthesis Ingestion Absorption Deep molecular homologies underlie all nutritional strategies
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Nutrient assimilation - Unity of Life Definition - the uptake of non-gaseous molecules from the environment into the cell Common features with gas exchange - 1) Transmembrane process dependent on surface area 2) Passive diffusion down chemical (concentration) gradients for a few molecules (such as water), but not true for most nutrient molecules at most times Big Steps in the Origin of Life Origin of information processing/replication system Origin of metabolism for generating small organic molecules and larger polymers Origin of bioenergetics Origin of lipid membranes defining the boundary of life – the challenge of impermeable membranes F Fig 6.8 Gases - high permeability -> do not require transport proteins Nutrients - low permeability -> require selective transport proteins Gas exchange vs. nutrient assimilation/osmoregulation Nutrient assimilation and osmoregulatory/excretory systems exhibit deep molecular homologies • Homologous transport proteins operating in modern organisms • Carry out nutrient assimilation and osmoregulation/excretion • Evolved in pre-LUCAC organisms. amino acids
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This note was uploaded on 02/01/2012 for the course BSCI 207 taught by Professor Higgins during the Spring '08 term at Maryland.

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32. Nutrient assimilationnew - Absorption Ingestion...

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