Concept 8.1: An organism’s metabolism transforms matter and
energy
Metabolism is the totality of an organism's chemical reactions,
providing insights into energy utilization, growth, and homeostasis.
It is an emergent property of life, highlighting the complexity and
organization required for orderly molecular interactions.
Metabolism arises from specific interactions between molecules,
regulated by enzymes, substrates, and products.
Metabolic Pathways
Metabolism is a network of intersecting pathways where molecules are
altered in defined steps to produce specific products.
Enzymes catalyze these metabolic pathways and are regulated to
balance supply and demand, similar to traffic lights controlling traffic
flow.
Metabolism manages the material and energy resources of the cell.
Catabolic pathways break down complex molecules, releasing energy.
Anabolic pathways build complex molecules from simpler ones,
consuming energy.
Cellular respiration is a major catabolic pathway that breaks down
glucose and other fuels to produce energy.
Anabolic pathways involve the synthesis of complicated molecules
from simpler ones, such as amino acids and proteins.
Catabolic and anabolic pathways are interconnected, allowing for the
flow of energy.
Forms of Energy
Energy is the capacity to cause change and is important for doing work
and rearranging matter.
Energy exists in various forms, including kinetic energy, thermal
energy, and light energy.
, Potential energy is energy that matter possesses due to its location or
structure.
Chemical energy refers to the potential energy available for release in
a chemical reaction.
Catabolic pathways release energy by breaking down complex
molecules.
Energy can be converted from one form to another, such as from
chemical energy to kinetic energy.
Organisms are energy transformers, deriving chemical energy from
light energy absorbed during photosynthesis.
The Laws of Energy Transformation
Thermodynamics is the study of energy transformations in matter.
A system refers to the matter under study, while the surroundings refer
to everything outside the system.
An isolated system cannot exchange energy or matter with its
surroundings, while an open system can.
Organisms are open systems that absorb energy (e.g., light or
chemical energy) and release heat and waste products.
The First Law of Thermodynamics states that energy can be transferred
and transformed, but not created or destroyed (principle of
conservation of energy).
The Second Law of Thermodynamics states that during energy
transformations, some energy is converted to thermal energy and
released as heat, becoming unavailable to do work.
Thermal energy can only be put to work when there is a temperature
difference.
In a living cell, heat generated during a chemical reaction simply
warms the organism.
The second law of thermodynamics: Every energy transfer or
transformation increases the entropy of the universe. Entropy is a
measure of molecular disorder or randomness. The more randomly
arranged a collection of matter is, the greater its entropy.
energy
Metabolism is the totality of an organism's chemical reactions,
providing insights into energy utilization, growth, and homeostasis.
It is an emergent property of life, highlighting the complexity and
organization required for orderly molecular interactions.
Metabolism arises from specific interactions between molecules,
regulated by enzymes, substrates, and products.
Metabolic Pathways
Metabolism is a network of intersecting pathways where molecules are
altered in defined steps to produce specific products.
Enzymes catalyze these metabolic pathways and are regulated to
balance supply and demand, similar to traffic lights controlling traffic
flow.
Metabolism manages the material and energy resources of the cell.
Catabolic pathways break down complex molecules, releasing energy.
Anabolic pathways build complex molecules from simpler ones,
consuming energy.
Cellular respiration is a major catabolic pathway that breaks down
glucose and other fuels to produce energy.
Anabolic pathways involve the synthesis of complicated molecules
from simpler ones, such as amino acids and proteins.
Catabolic and anabolic pathways are interconnected, allowing for the
flow of energy.
Forms of Energy
Energy is the capacity to cause change and is important for doing work
and rearranging matter.
Energy exists in various forms, including kinetic energy, thermal
energy, and light energy.
, Potential energy is energy that matter possesses due to its location or
structure.
Chemical energy refers to the potential energy available for release in
a chemical reaction.
Catabolic pathways release energy by breaking down complex
molecules.
Energy can be converted from one form to another, such as from
chemical energy to kinetic energy.
Organisms are energy transformers, deriving chemical energy from
light energy absorbed during photosynthesis.
The Laws of Energy Transformation
Thermodynamics is the study of energy transformations in matter.
A system refers to the matter under study, while the surroundings refer
to everything outside the system.
An isolated system cannot exchange energy or matter with its
surroundings, while an open system can.
Organisms are open systems that absorb energy (e.g., light or
chemical energy) and release heat and waste products.
The First Law of Thermodynamics states that energy can be transferred
and transformed, but not created or destroyed (principle of
conservation of energy).
The Second Law of Thermodynamics states that during energy
transformations, some energy is converted to thermal energy and
released as heat, becoming unavailable to do work.
Thermal energy can only be put to work when there is a temperature
difference.
In a living cell, heat generated during a chemical reaction simply
warms the organism.
The second law of thermodynamics: Every energy transfer or
transformation increases the entropy of the universe. Entropy is a
measure of molecular disorder or randomness. The more randomly
arranged a collection of matter is, the greater its entropy.
