BiochemistryLesson 1 of 5 in the course Microbial Metabolism

Cellular Metabolism: Energy Transfer and Enzyme Regulation

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Metabolism connects the chemical reactions that sustain life. This lesson introduces metabolic pathways and explains how organisms obtain carbon and energy.

Metabolism is the sum of all chemical reactions inside a cell. These reactions commonly occur in stepwise, interconnected sequences called metabolic pathways. A pathway’s product may become the next reaction’s starting material, allowing a cell to transform matter and manage energy in a coordinated way.

All flashcards

What is metabolism?
The sum of all chemical reactions occurring inside a cell.
What is an exergonic reaction?
A reaction that releases energy, which may be captured and used by the cell.
How do anabolism and catabolism differ?
Anabolism uses energy to build complex molecules from simpler ones. Catabolism breaks complex molecules down and releases energy.
What distinguishes autotrophs from heterotrophs?
Autotrophs use inorganic carbon such as CO2CO_2 to make organic compounds. Heterotrophs obtain carbon from organic compounds.
What is a chemoheterotroph?
An organism that obtains energy from chemical compounds and uses organic compounds as its carbon source.

Quiz questions

  1. In a redox reaction, what happens when a molecule is oxidized?Answer: It loses electrons to another molecule.
  2. Which reduced electron carrier is especially important in anabolism and photosynthesis?Answer: NADPH
  3. How can ATP provide energy for cellular work?Answer: Breaking a phosphate bond releases transferable energy.
  4. Where does a competitive inhibitor bind to reduce an enzyme’s activity?Answer: At the active site, where it competes with the substrate.
  5. What is feedback inhibition in a metabolic pathway?Answer: A pathway product reduces the activity of an earlier enzyme.

Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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