Studied by 8 people
How do enzymes work?
Enzymes lower activation energy, converting reactants into products more efficiently
How can scientists increase enzyme reaction rates?
By increasing temperature, enzyme concentration, or substrate concentration
What slows down enzymatic reactions? Name 3 factors
Low temperature, pH imbalance, inhibitors
What is denaturation, and what causes it?
Denaturation is the loss of an enzyme’s shape due to high temperature or extreme pH
Compare the first and second laws of thermodynamics
The first law states energy cannot be created/destroyed (e.g., ATP formation); the second law states energy disperses/disorganizes (e.g., heat loss)
Compare catabolic and anabolic reactions
Catabolic breaks down molecules to release energy; anabolic builds molecules, requiring energy
Compare endergonic and exergonic reactions
Endergonic absorbs energy (e.g., photosynthesis); exergonic releases energy (e.g., cellular respiration)
Identify if the following are endergonic or exergonic: Building ATP
Endergonic
Identify if the following are endergonic or exergonic: Breaking down ATP
Exergonic
How is ATP made?
Through cellular respiration or photosynthesis
What happens in the light dependent reactions?
Light starts the reaction, producing ATP and NADPH in the thylakoid membrane
What happens in the light independent reactions?
CO2 is used to form glucose in the stroma
What is the overall photosynthesis reaction?
6CO2 + 6H2O + light → C6H12O6 + 6O2
Which organisms perform photosynthesis?
Plants, algae, and some bacteria
How are Photosystems II and I different?
Photosystem II absorbs shorter wavelengths; Photosystem I prefers longer wavelengths
What happens in glycolysis?
Glucose is split into pyruvate, producing ATP in the cytoplasm
Describe the Kreb’s Cycle
Acetyl CoA is oxidized to produce ATP, NADH, and FADH2 in the mitochondria
What occurs in oxidative phosphorylation?
ATP is formed as electrons are transferred in the mitochondrial membrane
What happens if oxygen is absent?
Anaerobic respiration; in animals, it leads to lactic acid fermentation; in yeast, alcohol fermentation
Compare ectotherms and endotherms with examples
Ectotherms rely on external heat (e.g., reptiles); endotherms generate internal heat (e.g., mammals)
What is photosynthesis?
Photosynthesis is the process by which plants, algae, and some bacteria use sunlight to convert carbon dioxide and water into glucose and oxygen
Where does photosynthesis occur in a plant cell?
Photosynthesis occurs in the chloroplasts of plant cells
What are the two main stages of photosynthesis?
The two main stages are the light
What occurs during the Calvin Cycle?
The Calvin Cycle uses CO2, ATP, and NADPH to produce glucose
Where does the Calvin Cycle take place?
It takes place in the stroma of the chloroplast
What is carbon fixation in the Calvin Cycle?
Carbon fixation is the process of converting CO2 into an organic molecule (glucose) during the Calvin Cycle
What is the overall equation for photosynthesis?
6CO2 + 6H2O + light → C6H12O6 + 6O2
What are photosystems, and what are their roles in photosynthesis?
Photosystems I and II are protein complexes in the thylakoid membrane that capture light energy to drive electron transport
What role does water play in photosynthesis?
Water is split during the light
What colors of light do chlorophyll and accessory pigments absorb?
Chlorophyll absorbs blue and red light; accessory pigments absorb other wavelengths such as green, yellow, and orange
What is the purpose of NADPH in photosynthesis?
NADPH carries high
What is cellular respiration?
Cellular respiration is a process by which cells break down glucose and other molecules to produce ATP, releasing energy
Where does cellular respiration occur in eukaryotic cells?
Cellular respiration occurs in the mitochondria
What are the three main stages of cellular respiration?
The three main stages are glycolysis, the Krebs Cycle, and oxidative phosphorylation (electron transport chain)
What is glycolysis, and where does it occur?
Glycolysis is the first stage of cellular respiration, breaking down glucose into pyruvate in the cytoplasm
What are the products of glycolysis?
The products are 2 ATP, 2 NADH, and 2 pyruvate molecules
What happens to pyruvate after glycolysis if oxygen is present?
Pyruvate enters the mitochondria and is converted to Acetyl
What happens to pyruvate in the absence of oxygen?
Pyruvate undergoes fermentation, producing lactic acid in animals or ethanol and CO2 in yeast
What is the Krebs Cycle, and where does it occur?
The Krebs Cycle (Citric Acid Cycle) is a series of reactions in the mitochondrial matrix that produces ATP, NADH, FADH2, and CO2
What are the reactants and products of the Krebs Cycle?
Reactants: Acetyl
What is the purpose of NADH and FADH2 in cellular respiration?
NADH and FADH2 carry high
What is oxidative phosphorylation?
Oxidative phosphorylation is the final stage of cellular respiration, where electrons from NADH and FADH2 are transferred through the electron transport chain, creating ATP
Where does oxidative phosphorylation occur?
It occurs in the inner mitochondrial membrane
How does the electron transport chain produce ATP?
The chain uses energy from electrons to pump protons across the membrane, creating a gradient that drives ATP synthase to generate ATP
What is the role of oxygen in cellular respiration?
Oxygen is the final electron acceptor in the electron transport chain, forming water as a byproduct
What is the overall equation for cellular respiration?
C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
How are photosynthesis and cellular respiration related?
Photosynthesis produces glucose and oxygen used in cellular respiration, while cellular respiration produces CO2 and water used in photosynthesis
This organelle uses photons to carry out electron transfer and subsequent carbohydrate production
Chloroplast
What is the balanced formula for respiration?
C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
This is the most efficient type of cellular respiration that includes both substrate level and oxidative phosphorylation
Aerobic Respiration
Identify this molecule
ATP
What are the products of anaerobic respiration in plants/animals?
2 ATP, Ethanol/Lactic Acid
Name the 3 stages in the complete oxidation of glucose
Glycolysis, Krebs Cycle, Electron Transport Chain
Give an example of an ion that uses an ATP pump
Na+, K+, H+
How many ATP are produced by substrate level phosphorylation (NOT ETC)?
4 (2 in glycolysis + 2 in Krebs)
This is the reactant that allows the Krebs Cycle to begin (the product of pyruvate oxidation)
Acetyl CoA
What are 2 products of Photosystem II?
Oxygen (O2), H+ or ATP
Where does the Calvin Cycle take place?
The stroma of the chloroplast
How many ATP are produced by oxidative phosphorylation?
28 to 34
This is the final electron acceptor in the electron transport chain during respiration
Oxygen (O2)
Where do light
dependent reactions take place?
Name the two molecules that donate ions to the electron transport chain in the mitochondria
NADH, FADH2
What is the reactant of the transition reaction (between glycolysis and Krebs)?
Pyruvic acid
What are the 3 reactants of the light
independent reactions?
What does chlorophyll do in the photosynthetic process?
Absorbs/captures light (photons), receives electrons from water, transfers electrons
If there is an increase in NADPH at the end of photosystem I, what happens?
The cyclic pathway begins
Explain how temperature can affect enzymatic activity
Increased temperature can increase collisions and thus enzymatic rates; too much heat leads to denaturation, causing the enzyme to change shape and stop working. Decreased temperature reduces collisions and decreases enzymatic rates
Which part of aerobic respiration produces the greatest amount of ATP energy?
The electron transport chain
What is the balanced equation for photosynthesis?
6CO2 + 6H2O + sunlight → C6H12O6 + 6O2
What process converts pyruvate to lactic acid?
Anaerobic respiration (specifically lactic acid fermentation)
Chemiosmosis refers to…
Movement of H+ ions down the concentration gradient through ATP synthase
How much NADH does one round of the Krebs Cycle produce?
6
Which respiration process is least efficient?
Fermentation (anaerobic respiration)
Location of glycolysis
Cytosol/cytoplasm outside the mitochondria
The organelle responsible for ATP production
Mitochondria
What effect does a lack of oxygen have on glycolysis?
None
What happens during competitive inhibition?
Another chemical competes for the enzyme’s active site, decreasing enzymatic efficacy
During what part of photosynthesis is water split? What is it split into?
Photosystem II; split into H+, O2, and electrons
What type of reaction is the following: ATP + H2O → ADP + Pi + chemical energy
Hydrolysis, catabolic, exergonic
What is it called when an enzyme’s shape changes due to a chemical attaching to it away from the active site?
Allosteric inhibition/non
Why is the energy of an endothermic reaction always more than its exothermic counterpart?
Some energy is lost to heat
Dehydration synthesis is what type of reaction?
Anabolic, endergonic
What are the 2 steps of the light
dependent reaction (in order)?
When electrons and hydrogens are added to a molecule, what has happened to the molecule?
It has been reduced
When a molecule loses electrons, we say it has been _____
Oxidized
A molecule that stabilizes the active form of an enzyme
Activator (coenzyme or cofactor)
Note 
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