unit 3 big ideas
Big idea 1 Big idea 2
- System interactions - Energetics
how would living systems function without what is the role of energy in the making
the polarity of the water molecule? and breaking of polymers?
(6.1 cells and the flow of energy in AP biology book, twelfth edition)
To maintain structural organization and carry out metabolic activities, cells and organisms need a constant supply of
energy.
energy: the ability to do work or bring about a change.
- general characteristics of life (growth/ development/ metabolism/ reproduction) require energy.
● prodocures: use light energy to produce organic nutrients.
○ The majority of life on earth depends on solar energy.
(photosynthesizing producers use energy from sunlight to create organized structure in biological molecules →
organisms that consume the producers use this potential energy, kinetically to drive their own metabolic
processes.)
❖ kinetic energy: the energy of motion
➢ mechanical energy: type of kinetic energy
■ example: when chemical energy is converted into kinetic energy
❖ potential energy: stored energy
➢ energy whose capacity to accomplish work is not being used at the moment.
➢ chemical energy: type of potential energy
■ energy stored in the bonds of chemical compounds.
● food is a form of chemical energy
laws of thermodynamics
1. the first law of thermodynamics: the law of conservation of energy
○ Energy cannot be created or destroyed, but it can be changed from one form to another.
2. the second law of thermodynamics
○ Energy cannot be changed from one form to another without a loss of usable energy.
or
○ Every energy transformation makes the universe less organized/ structured (more chaotic)
■ each energy transformation moves us close to a condition where all usable forms of
energy become heat that is lost to the environment.
■ as a result of the second law of thermodynamics → no process requiring the
conversion of energy is 100% efficient. energy is lost in the form of heat:
● heat that dissipates into the environment cannot be captured or converted to one
of the other forms of energy.
entropy: term used to indicate the relative amount of disorganization
- if the structure is ↑ organized, then it is ↓ stable.
, Jenan Taybah
Honors/ AP biology
(2021- 2023)
1
↓ organized, then it is ↑ stable.
- a reaction occurs spontaneously if it ↑ the entropy in the universe.
(6.2 metabolic reactions and energy transformations in AP biology book, twelfth edition)
all living organisms maintain their structure and function through chemical reactions.
● reactants: substances that participate in the reaction.
● products: substances that form as a result of the reaction.
● free energy: the amount of energy left to do work after a chemical reaction has occurred.
○ the change in free energy is determined by: subtracting the free energy content of the reactants
from that of the products
● metabolism: the sum of all the chemical reactions that occur in a cell. (includes spontaneous reactions and
energy requiring reactions.
○ exergonic reaction: spontaneous and released energy.
○ endergonic reactions: require an input of energy to occur.
❖ ATP: (adenosine triphosphate)
➢ ATP is composed of
■ nitrogen- containing base (adenine)
■ 5- carbon sugar (ribose)
■ 3 phosphate groups
● the 3 phosphate groups repel each other creating instability + potential energy.
● a phosphate group can easily be removed
➢ the common energy currency for cells.
➢ ↑ active the organism, ↑ demand for ATP
❖ the ATP cycle
➢ cells don’t store large amounts of ATP as ATP.
■ they regenerate it using ADP (adenosine diphosphate) + an inorganic phosphate (P).
➢ the cycle is powered by the breakdown of glucose and other bio-molecules during cellular
respiration.
➢ the cycle is not efficient (only 39% of the free energy stored in chemical bonds of glucose
molecules transform into ATP, the rest isaq1§ lost as heat)
❖ coupled reactions
➢ ATP breakdown can be coupled to endergonic reactions in a way that it minimizes the energy lost.
➢ ATP breakdown is coupled to the energy requiring reaction → both energetically favorable
and unfavorable reactions occur in the same place, at the same time.
➢ through coupled reactions ATP drives forward the energetically unfavorable processes that
must occur to create a ↑ degree of order and structure.
a cell has two main ways to couple ATP hydrolysis to an energy- requiring
ATP ADP + (P)
reaction:
1. ATP is used to energize a reactant.
2. ATP is used to change the shape of the reactant.
c + d ————> a +b
Big idea 1 Big idea 2
- System interactions - Energetics
how would living systems function without what is the role of energy in the making
the polarity of the water molecule? and breaking of polymers?
(6.1 cells and the flow of energy in AP biology book, twelfth edition)
To maintain structural organization and carry out metabolic activities, cells and organisms need a constant supply of
energy.
energy: the ability to do work or bring about a change.
- general characteristics of life (growth/ development/ metabolism/ reproduction) require energy.
● prodocures: use light energy to produce organic nutrients.
○ The majority of life on earth depends on solar energy.
(photosynthesizing producers use energy from sunlight to create organized structure in biological molecules →
organisms that consume the producers use this potential energy, kinetically to drive their own metabolic
processes.)
❖ kinetic energy: the energy of motion
➢ mechanical energy: type of kinetic energy
■ example: when chemical energy is converted into kinetic energy
❖ potential energy: stored energy
➢ energy whose capacity to accomplish work is not being used at the moment.
➢ chemical energy: type of potential energy
■ energy stored in the bonds of chemical compounds.
● food is a form of chemical energy
laws of thermodynamics
1. the first law of thermodynamics: the law of conservation of energy
○ Energy cannot be created or destroyed, but it can be changed from one form to another.
2. the second law of thermodynamics
○ Energy cannot be changed from one form to another without a loss of usable energy.
or
○ Every energy transformation makes the universe less organized/ structured (more chaotic)
■ each energy transformation moves us close to a condition where all usable forms of
energy become heat that is lost to the environment.
■ as a result of the second law of thermodynamics → no process requiring the
conversion of energy is 100% efficient. energy is lost in the form of heat:
● heat that dissipates into the environment cannot be captured or converted to one
of the other forms of energy.
entropy: term used to indicate the relative amount of disorganization
- if the structure is ↑ organized, then it is ↓ stable.
, Jenan Taybah
Honors/ AP biology
(2021- 2023)
1
↓ organized, then it is ↑ stable.
- a reaction occurs spontaneously if it ↑ the entropy in the universe.
(6.2 metabolic reactions and energy transformations in AP biology book, twelfth edition)
all living organisms maintain their structure and function through chemical reactions.
● reactants: substances that participate in the reaction.
● products: substances that form as a result of the reaction.
● free energy: the amount of energy left to do work after a chemical reaction has occurred.
○ the change in free energy is determined by: subtracting the free energy content of the reactants
from that of the products
● metabolism: the sum of all the chemical reactions that occur in a cell. (includes spontaneous reactions and
energy requiring reactions.
○ exergonic reaction: spontaneous and released energy.
○ endergonic reactions: require an input of energy to occur.
❖ ATP: (adenosine triphosphate)
➢ ATP is composed of
■ nitrogen- containing base (adenine)
■ 5- carbon sugar (ribose)
■ 3 phosphate groups
● the 3 phosphate groups repel each other creating instability + potential energy.
● a phosphate group can easily be removed
➢ the common energy currency for cells.
➢ ↑ active the organism, ↑ demand for ATP
❖ the ATP cycle
➢ cells don’t store large amounts of ATP as ATP.
■ they regenerate it using ADP (adenosine diphosphate) + an inorganic phosphate (P).
➢ the cycle is powered by the breakdown of glucose and other bio-molecules during cellular
respiration.
➢ the cycle is not efficient (only 39% of the free energy stored in chemical bonds of glucose
molecules transform into ATP, the rest isaq1§ lost as heat)
❖ coupled reactions
➢ ATP breakdown can be coupled to endergonic reactions in a way that it minimizes the energy lost.
➢ ATP breakdown is coupled to the energy requiring reaction → both energetically favorable
and unfavorable reactions occur in the same place, at the same time.
➢ through coupled reactions ATP drives forward the energetically unfavorable processes that
must occur to create a ↑ degree of order and structure.
a cell has two main ways to couple ATP hydrolysis to an energy- requiring
ATP ADP + (P)
reaction:
1. ATP is used to energize a reactant.
2. ATP is used to change the shape of the reactant.
c + d ————> a +b
