AP Bio Unit 3 - Enzymes and Cellular
Respiration Complete Solutions
Explain how increasing substrate concentration affects the reaction rate. - ANSWER-
Increasing substrate concentration also increases the rate of reaction to a certain
point. Once all of the enzymes have bound, any substrate increase will have no
effect on the rate of reaction, as the available enzymes will be saturated and working
at their maximum rate.
Explain how increasing enzyme concentration affects the reaction rate. - ANSWER-
Increasing enzyme concentration will speed up the reaction, as long as there is
substrate available to bind to.
LESS enzymes = SLOWER reaction rates because there will be less opportunities
for substrates to collide with active sites
MORE enzymes = FASTER reaction rate because there will be more opportunities
for substrates to collide with active sites
Competitive Inhibitors - ANSWER-- They can bind to the active site
- Molecules can bind reversibly or irreversibly to the active site of the enzyme
- Competes with the normal substrate for the enzymes' active site
If inhibitor concentrations exceed substrate concentrations reactions are slowed. If
inhibitor concentration are considerably lower than substrate concentrations,
reactions can proceed normally
If inhibitor binding is irreversible, enzyme function will be prevented. If inhibitor binds
reversibly, enzymes can regain function one inhibitor detaches.
Non-Competitive Inhibitors - ANSWER-- They bind to enzymes and change enzyme
activity
- Enzymes can have regions other than the active site to which molecules can bind,
called the allosteric site
- Do not bind to the active site but to the allosteric site
- Binding causes conformational shape change and prevents enzymes functions
because the active site is no longer available
- Reaction rate decreases
- Increasing substrate cannot prevent effects of noncompetitive inhibitor binding
Non-Competitive Inhibition - ANSWER-Non-competitive inhibition is when the
inhibitor inhibits the enzymatic reaction whether or not the substrate is bound to it. It
can bind to a site other than the active site and can be allosteric.
Allosteric Inhibition - ANSWER-Allosteric inhibition is the type of enzymatic
regulation where the inhibitor binds to a site other than the active site
, What is the main source of energy input for living systems? - ANSWER-As all living
systems require a constant input of energy, SUNLIGHT is the main energy input for
living systems
Autotrophs - ANSWER-Capture energy from physical sources (like sunlight), or
chemical sources and transform that energy into energy sources usable by all cells.
During every energy transformation process, some energy is unusable, often lost in
heat.
What is the 2nd law of thermodynamics? - ANSWER-1.) Every energy transfer
increases the disorder of the universe
2.) Living cells are not at equilibrium; there is a constant flow of materials in and out
of the cell
3.) Cells manage energy resources by energy coupling. 4.) Energy-releasing
processes drive energy-storing processes
5.) Life requires a highly ordered system and does not violate the second law of
thermodynamics
Energy-Coupling - ANSWER-The cell management of energy resources. When
energy is released, it drives an energy-storing process.
Sequential Reactions - ANSWER-Allow for more controlled and efficient transfer of
energy.
For example, pathways in biological systems are sequential
And in chemical pathways, the product of one reaction can serve as a reactant in a
subsequent reaction
Photosynthesis - ANSWER-The biological process that captures energy from the
Sun and produces sugars. During photosynthesis, chlorophyll captures the energy
from sunlight and converts it into high-energy electrons. These high energy electrons
are used to make a proton gradient and reduce NADP+ to NADPH.
How did photosynthesis change Earth's early atmosphere? - ANSWER-Prokaryotic
photosynthesis by organisms, such as cyanobacteria, was responsible for the
production of oxygen in the atmosphere.
- Photosynthetic pathways are the foundation of eukaryotic photosynthesis
Pigments - ANSWER-Light-absorbing molecules that are used in light-absorbing
reactions to capture light energy. They transform said light energy into chemical
energy.
This chemical energy is then temporarily stored as the chemical bonds of carrier
molecules called NADPH.
Light-dependent reactions also produce other energy storing molecules called ATP.
What happens to the NADPH and ATP produced by the light-dependent reactions? -
ANSWER-ATP and NADPH transfer stored chemical energy to power the production
of organic molecules in another pathway, called the Calvin cycle.
Respiration Complete Solutions
Explain how increasing substrate concentration affects the reaction rate. - ANSWER-
Increasing substrate concentration also increases the rate of reaction to a certain
point. Once all of the enzymes have bound, any substrate increase will have no
effect on the rate of reaction, as the available enzymes will be saturated and working
at their maximum rate.
Explain how increasing enzyme concentration affects the reaction rate. - ANSWER-
Increasing enzyme concentration will speed up the reaction, as long as there is
substrate available to bind to.
LESS enzymes = SLOWER reaction rates because there will be less opportunities
for substrates to collide with active sites
MORE enzymes = FASTER reaction rate because there will be more opportunities
for substrates to collide with active sites
Competitive Inhibitors - ANSWER-- They can bind to the active site
- Molecules can bind reversibly or irreversibly to the active site of the enzyme
- Competes with the normal substrate for the enzymes' active site
If inhibitor concentrations exceed substrate concentrations reactions are slowed. If
inhibitor concentration are considerably lower than substrate concentrations,
reactions can proceed normally
If inhibitor binding is irreversible, enzyme function will be prevented. If inhibitor binds
reversibly, enzymes can regain function one inhibitor detaches.
Non-Competitive Inhibitors - ANSWER-- They bind to enzymes and change enzyme
activity
- Enzymes can have regions other than the active site to which molecules can bind,
called the allosteric site
- Do not bind to the active site but to the allosteric site
- Binding causes conformational shape change and prevents enzymes functions
because the active site is no longer available
- Reaction rate decreases
- Increasing substrate cannot prevent effects of noncompetitive inhibitor binding
Non-Competitive Inhibition - ANSWER-Non-competitive inhibition is when the
inhibitor inhibits the enzymatic reaction whether or not the substrate is bound to it. It
can bind to a site other than the active site and can be allosteric.
Allosteric Inhibition - ANSWER-Allosteric inhibition is the type of enzymatic
regulation where the inhibitor binds to a site other than the active site
, What is the main source of energy input for living systems? - ANSWER-As all living
systems require a constant input of energy, SUNLIGHT is the main energy input for
living systems
Autotrophs - ANSWER-Capture energy from physical sources (like sunlight), or
chemical sources and transform that energy into energy sources usable by all cells.
During every energy transformation process, some energy is unusable, often lost in
heat.
What is the 2nd law of thermodynamics? - ANSWER-1.) Every energy transfer
increases the disorder of the universe
2.) Living cells are not at equilibrium; there is a constant flow of materials in and out
of the cell
3.) Cells manage energy resources by energy coupling. 4.) Energy-releasing
processes drive energy-storing processes
5.) Life requires a highly ordered system and does not violate the second law of
thermodynamics
Energy-Coupling - ANSWER-The cell management of energy resources. When
energy is released, it drives an energy-storing process.
Sequential Reactions - ANSWER-Allow for more controlled and efficient transfer of
energy.
For example, pathways in biological systems are sequential
And in chemical pathways, the product of one reaction can serve as a reactant in a
subsequent reaction
Photosynthesis - ANSWER-The biological process that captures energy from the
Sun and produces sugars. During photosynthesis, chlorophyll captures the energy
from sunlight and converts it into high-energy electrons. These high energy electrons
are used to make a proton gradient and reduce NADP+ to NADPH.
How did photosynthesis change Earth's early atmosphere? - ANSWER-Prokaryotic
photosynthesis by organisms, such as cyanobacteria, was responsible for the
production of oxygen in the atmosphere.
- Photosynthetic pathways are the foundation of eukaryotic photosynthesis
Pigments - ANSWER-Light-absorbing molecules that are used in light-absorbing
reactions to capture light energy. They transform said light energy into chemical
energy.
This chemical energy is then temporarily stored as the chemical bonds of carrier
molecules called NADPH.
Light-dependent reactions also produce other energy storing molecules called ATP.
What happens to the NADPH and ATP produced by the light-dependent reactions? -
ANSWER-ATP and NADPH transfer stored chemical energy to power the production
of organic molecules in another pathway, called the Calvin cycle.
