Concept 8.1: An organism’s metabolism transforms matter and energy

Flashcards from Concept 8.1 of Pearson's Campbell Biology, Twelfth Edition.

First Law of Thermodynamics

Law that states that energy can be transferred or transformed, but not created or destroyed

• Demonstrated through energy use by living things

Second Law of Thermodynamics

Law that states that energy transfer or transformation increases universal entropy

• Demonstrated through the conversion of energy to heat by living things through inefficienies in conversion

Metabolism

The totality of an organism’s chemical reactions

• Arises from orderly interactions between molecules

Metabolic pathway

Pathway where a specific molecule is altered in a series of steps to produce a product, catalyzed by enzymes

Enzyme

A macromolecule that speeds up a specific reaction

Catabolic pathway

Metabolic pathway that releases energy by breaking down complex molecules into simpler compounds

• Seen through cellular respiration breaking down glucose with O₂

• Allows for energy use by anabolic pathways

• Described as “downhill”

Anabolic pathway

Metabolic pathway that consumes energy by building up complex molecules from simpler ones

• Seen through the synthesis of protein from amino acids

• Uses energy from catabolic pathways

• Described as “uphill”

Energy

The capacity to cause change or do work, existing in various forms

• Living cells must transform energy from one form to another to do the work of life

Kinetic energy

Energy associated with motion

• Moving objects impart motion to other matter

Thermal energy

The kinetic energy associated with random movement of atoms or molecules

• One object to another is called heat

• Light is another type, done through photosynthesis

Potential energy

Energy that matter possesses because of its location or structure

• Possessed due to the arrangement of electrons in bonds between atoms

Chemical energy

Potential energy available for releaes in a chemical reaction

• Glucose has more of this as it is released during catabolism

Thermodynamics

The study of energy transformations in a collection of matter

Isolated system

A system that is unable to exchange energy or matter with its surroundings, as in a vacuum-sealed drink bottle

Open system

A system that is able to transfer energy and matter between the system and its surroundings, as in organisms that absorb energy and release heat and waste

Spontaneous processes

Processes that increase the entropy of the universe without energy input, happening at varying rates

• Balances out anabolic reactions that build up molecules through the breakdown of molecules in catabolic reactions for heat and small molecules

Nonspontaneous processes

Processes that decrease entropy and require an input of energy

• Seen through anabolic reactions amongst amino acids to proteins

• Balanced by the catabolic breakdown of organized form of matter