Enzymes
Draw and label the basic structure of an enzyme
enzyme
active site
allosteric site
List and describe 3 factors that can affect the function of an enzyme.
3 factors that can affect the function of an enzyme are temperature, pH, and chemicals. For temperature, up to a certain point increased temperature can increase enzyme activity; too high can denature. Enzymes function best at a certain pH so when an enzyme is out of its normal pH range, it is unable to function properly since hydrogen bonds in the enzyme will break and change the shape of an enzyme, and shape determines function. Chemicals can inhibit enzyme activity by blocking that enzyme or stopping production of that enzyme.
Plants are primary producers, what does that mean?
Plants are referred to as primary producers because they produce their own food and are the ultimate sources of organic compounds for all heterotrophs.
In which organelle does photosynthesis take place? More specifically, where does each stage of photosynthesis take place?
Photosynthesis takes place in the chloroplast. The light dependent reactions take place in the thylakoid membranes and the Calvin Cycle takes place in the stroma.
What is the overall reaction of cellular respiration?
C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O + energy (ATP and heat)
Describe how enzymes are able to "speed up" reactions.
They lower the activation energy (the initial energy needed to start the reaction). They do this by brining substrates close together/in the right position, changing the shape of the substrate,
How does competitive inhibition differ from noncompetitive inhibition?
In competitive inhibition the inhibitor competes for binding at the active site. In noncompetitive inhibition, the inhibitor binds at an allosteric site.
How do enzymes affect activation energy?
Enzymes affect activation energy by lowering it so that reactions can occur faster.
What is the purpose of each phase of the Calvin cycle?
Carbon fixation attaches CO2 to RuBP (via rubisco) to incorporate carbon into an organic compound called 3-PGA. In reduction, ATP and NADPH are used to convert 3-PGA into G3P, which is a reduction reaction. In regeneration, the remaining G3P molecules regenerate RuBP, which allows for more CO2 entering the cycle to be fixed.
What happens to the pyruvate that is produced via glycolysis?
The pyruvate enters the mitochondria and is oxidized into Acetyl CoA.
True or False: enzymes are consumed by reactions.
False; enzymes are not consumed by reactions
True or false: denaturing of an enzyme is irreversible
False, sometimes it can be reversed if the primary structure of the protein is still intact and conditions are returned to normal
Differentiate between autotrophs and heterotrophs.
Autotrophs produce their own food from their surroundings whereas heterotrophs live off of other organisms since they are unable to make their own food.
Fill in the blanks: the electrons derived from splitting water are used for the synthesis of ____ and ___
ATP; NADPH
What is the purpose of the citric acid cycle?
The citric acid cycle turns Acetyl CoA into citrate and releases CO2 while creating more ATP (energy) and more NADH and FADH2 (electron carriers).
A cell utilizes an allosteric enzyme to regulate a multi-step biosynthetic pathway via feedback inhibition. Which characteristic best distinguishes an allosteric regulator from a simple competitive inhibitor?
allosteric regulators permanently form covalent active site bonds
alter enzyme conformation
If a mutation occurs on DNA that codes for an enzyme, what is most likely to happen?
If a mutation occurs on a segment of DNA that codes for an enzyme, the enzyme may lose function since the mutation will cause a change in the enzyme’s shape and therefore a change in the function.
How does the structure of ATP allow it to store and release energy?
When the bonds between the second and third phosphates break, this releases energy (this release of energy is due to the lowering of free energy and not from the bond itself—but this is out of scope for the course). When ATP is hydrolyzed, the bond breaks, energy is released, and the free phosphate transfers the energy by phosphorylating other molecules, turning them into reactive intermediates.
Why does photorespiration occur?
In hot, dry climates stomata close. This leads to less CO2 coming in leaves and a buildup of oxygen. Rubisco can bind to oxygen instead of CO2, using ATP and not producing sugar.
What is the difference in how much ATP can be produced through aerobic respiration vs anaerobic respiration and fermentation?
In aerobic respiration, 30-32 ATP are created per glucose molecule whereas in anaerobic respiration, only 2 ATP molecules are created per glucose.
True or False; In some reactions, the end product can act as an inhibitor to an early enzyme in the same pathway
True
Predict what would happen to a cell exposed to an irreversible inhibitor like cyanide.
If a cell was exposed to an irreversible inhibitor like cyanide, the enzymes in the cell would not be able to function. Therefore, cellular processes would not be able to occur. Since cyanide is an irreversible inhibitor, the enzymes will be blocked forever and the cell would not fulfill its necessary functions and would eventually die.
Try creating a flow chart that traces the flow of energy through your body. What products increase entropy of you and your surroundings?
food in
co2 out
heat out
kinetic energy out
Products that increase the entropy of you and your surroundings are heat, CO2, H2O…
Knowing about light and its importance to plants, create an explanation for why leaves change color in fall.
Leaves change color in the fall because the days become shorter and there is less sunlight. This causes the leaf cells to stop producing a lot of chlorophyll, which means that other pigments including carotenoids will be absorbing the light and they absorb at other wavelengths
How does fermentation produce alcohol and lactic acid?
Alcohol: After glycolysis, the 2 pyruvate are converted into 2 acetaldehyde after CO2 is released and then 2 NADH are used to create 2 ethanol.
Lactic acid: After glycolysis, the 2 pyruvate are directly reduced by NADH to form 2 lactate.