Unit 3 Cellular Energetics Flashcards
What are enzymes and what is their role?
proteins that have a tertiary shape that must be maintained
Enzymes speed up biochemical reactions by lowering activation energy requirements.
How is enzyme structure related to enzyme function?
The structural characteristics of an enzyme make the enzyme very reaction specific.
What determines whether a substrate can interact with an enzyme?
The shape and charge of the substrate must be compatible with the active site of an enzyme for a reaction to occur.
What happens to an enzyme after the completion of a reaction?
Enzymes are not consumed by the reaction. Enzymes are reused. (not chemically changed)
what is a substrate?
a molecule that interacts with an enzyme
How do enzymes facilitate chemical reactions in cells?
Enzymes are biological catalysis that facilitate chemical reactions in cells by lowering activation energy requirements.
What is activation energy in a chemical reaction?
Activation energy is the initial energy required for a reaction to occur.
What does it mean for an enzyme to be denatured?
Denaturation of an enzyme occurs when the protein structure is disrupted, eliminating the ability to
catalyze reactions.
Explain how the cellular environment affects enzyme activity.
Environmental pH can alter the efficiency of enzyme activity, including through the disruption of hydrogen bonds that provide enzyme structure. Can lead to the enzyme becoming denatured
Higher environmental temperatures increase the speed of movement of molecules in a solution,
increasing the frequency of collisions between enzymes and substrates and therefore increasing the
rate of reaction.
Decreasing temperature outside the optimum range will result in slowed reaction rates but will not denature
How do changes in enzyme concentrations affect the rate of reactions?
Increased enzyme concentration increase reaction rate. Decreased enzyme concentration will decrease reaction rate.
How do changes in substrate and product concentrations affect the rate of reactions?
Increasing substrate concentration will initially increase reaction rate. Substrate saturation will not result in a continued increase in reaction rate. Reaction rate will remain constant if substrate saturation levels are maintained.
How do competitive inhibitors affect enzyme activity?
The competitive inhibitor binds to the active site and changes shape to prevent the substrate from binding there. reaction can’t perform.
How do noncompetitive inhibitors affect enzyme activity?
noncompetitive inhibitors bind to a different site on the enzyme; attaches itself to another part of the enzyme, thereby changing the overall shape of the site for the normal substrate so that it does not fit as well as before, which slows or prevents the reaction taking place.
What do living things use chemical energy for?
Living things use the chemical energy stored in molecular bonds of macromolecules and ATP to perform necessary life functions.
How is energy efficiently transferred in a biological pathway?
Pathways in biological systems are sequential (preform or used in a sequence) to allow for a more controlled and efficient transfer of energy.
Explain what happens in photosynthesis.
what are the products? where does it occur?
occurs in the chloroplast
(light dependent)
light is absorbed by the chloroplast, electrons become excited, passes them through the thylakoid membrane the movement of the electrons form ATP water splits into
h +ions and oh releasing oxygen 2 atp are formed and h+ions attach to nadp to form carrier molecules Nadph
During the light independent reaction (Calvin cycle) carbon dioxide binds to a 5-carbon molecule making it an unstable 6-carbon molecule which quickly breaks down into a stable 2-3-carbon molecule some make glucose some restart the cycle, 2 ATP formed and NADH and FAHD, are produced.
What is the photosynthesis equation?
What is the cellular respiration equation?
CO2 +H2O + sunlight→ C6H12O6 + O2.
C6H12O6 + O2 → CO2 + H2O
What is the function of the electron transport chain?
The electron transport chain allows for the efficient transfer of energy from electrons to a proton gradient.
What is the role of NADH and FADH,?
NADH and FADH carry electrons to the E.T.C
How does the electrochemical / proton gradient power ATP synthase?
what are the protons and where do they come from?
Protons flow down their concentration gradient into the matrix through the membrane protein ATP synthase, causing it to spin (like a water wheel) and catalyze conversion of ADP to ATP.
H+ ions and they come from photosynthesis
What is the importance of decoupling during respiration?
When decoupling occurs during cell respiration, heat is released and can be used for thermoregulation.
What processes do all forms of life use to produce ATP?
All living things use fermentation and cellular respiration to produce ATP.
How is an electrochemical/proton gradient formed
during cell respiration?
As the electrons pass through the
ETC, an electrochemical gradient of protons (hydrogen ions) is established across the internal
membrane (the matrix)
What is the purpose of glycolysis?
To break down glucose to form 2 molecules of pyruvate, 2 ATP and NADH. h+ ions are picked up and transported to the etc.
