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Metabolism

Overview

  • Metabolism: step by step process by which cells take nutrients from their environment and convert them into sufficient components to double their mass and then become 2 cells

  • All the biochemical reactions that take place in the cell are called its metabolism

    • Each step is coordinated by a specific enzyme

  • Catabolic Pathways

    • Breakdown cellular components

    • Exergonic

  • Anabolic Pathways

    • Synthesis cellular components

    • Endergonic

    • Must be coupled to exergonic reaction

Function of Metabolism

  1. Synthesis and Division

  2. Reproduction

    • Making more cellular materials

    • Requires the production of starting materials

5 Metabolic Tasks Necessary For A Cell To Synthesize All Other Cellular Components

  1. Bringing nutrients into the cell

  2. Catabolism: converting nutrients into a group of organic compounds which serve as a starting point to synthesize all other cellular components

    1. 12 precursor metabolites

    2. ATP

    3. Reducing power ie:  NADH

  3. Biosynthesis

    • Making small molecules the cell needs

  4. Polymerization

    • To form macromolecules

  5. Assembly

Catabolic Reactions

  • Breakdown of reactants

  • Used for recycling building blocks

  • Used for energy to drive endergonic reactions

    • Energy stored in intermediates such as ATP, NADH

Anabolic Reactions

  • Biosynthetic reactions

  • Make large macromolecules or smaller molecules not available from food

  • Require energy inputs from intermediates (NADH or ATP) to drive reactions

Two Ways to Make ATP

  1. Substrate-level Phosphorylation (one to one tradeoff)

    • Enzyme directly transfers phosphate from one molecule to another molecule

  2. Chemiosmosis (many molecules of ATP per molecule of glucose)

    • Energy stored in an electrochemical gradient is used to make ATP from ADP and Pi

Redox Reaction

  • Electron removed from one molecule is added to another

  • Oxidation: removal of electrons

  • Reduction: addition of electrons

NADH

  • Electrons removed by oxidation of organic molecules are used to create energy intermediates like NADH

  • NAD+  Nicotinamide adenine dinucleotide

  • NADH useful in two ways:

    • Releases a lot of energy when oxidized that can be used to make ATP

    • Can donate electrons during synthesis reactions to energize them

Metabolism

Overview

  • Metabolism: step by step process by which cells take nutrients from their environment and convert them into sufficient components to double their mass and then become 2 cells

  • All the biochemical reactions that take place in the cell are called its metabolism

    • Each step is coordinated by a specific enzyme

  • Catabolic Pathways

    • Breakdown cellular components

    • Exergonic

  • Anabolic Pathways

    • Synthesis cellular components

    • Endergonic

    • Must be coupled to exergonic reaction

Function of Metabolism

  1. Synthesis and Division

  2. Reproduction

    • Making more cellular materials

    • Requires the production of starting materials

5 Metabolic Tasks Necessary For A Cell To Synthesize All Other Cellular Components

  1. Bringing nutrients into the cell

  2. Catabolism: converting nutrients into a group of organic compounds which serve as a starting point to synthesize all other cellular components

    1. 12 precursor metabolites

    2. ATP

    3. Reducing power ie:  NADH

  3. Biosynthesis

    • Making small molecules the cell needs

  4. Polymerization

    • To form macromolecules

  5. Assembly

Catabolic Reactions

  • Breakdown of reactants

  • Used for recycling building blocks

  • Used for energy to drive endergonic reactions

    • Energy stored in intermediates such as ATP, NADH

Anabolic Reactions

  • Biosynthetic reactions

  • Make large macromolecules or smaller molecules not available from food

  • Require energy inputs from intermediates (NADH or ATP) to drive reactions

Two Ways to Make ATP

  1. Substrate-level Phosphorylation (one to one tradeoff)

    • Enzyme directly transfers phosphate from one molecule to another molecule

  2. Chemiosmosis (many molecules of ATP per molecule of glucose)

    • Energy stored in an electrochemical gradient is used to make ATP from ADP and Pi

Redox Reaction

  • Electron removed from one molecule is added to another

  • Oxidation: removal of electrons

  • Reduction: addition of electrons

NADH

  • Electrons removed by oxidation of organic molecules are used to create energy intermediates like NADH

  • NAD+  Nicotinamide adenine dinucleotide

  • NADH useful in two ways:

    • Releases a lot of energy when oxidized that can be used to make ATP

    • Can donate electrons during synthesis reactions to energize them

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