Enzymes
What is the role of enzymes in biological reactions?
What is: enzymes act as catalysts to speed up chemical reactions, by lowering the activation energy required
What is the primary structure of a biological membrane?
Answer: The primary structure of a biological membrane is a phospholipid bilayer with embedded proteins.
What are the two main stages of photosynthesis?
Answer: The two main stages are the light-dependent reactions and the Calvin cycle (light-independent reactions).
What is cellular respiration?
Answer: Cellular respiration is the process by which cells convert glucose into ATP, utilizing oxygen in aerobic conditions.
Describe the lock-and-key model of enzyme action.
The lock-and-key model suggests that the enzyme (lock) has a specific shape that fits a specific substrate (key), facilitating the reaction.
Describe the fluid mosaic model of cell membranes.
Answer: The fluid mosaic model describes the membrane as a dynamic structure where lipids and proteins can move laterally, creating a mosaic appearance.
What is the role of chlorophyll in photosynthesis?
Answer: Chlorophyll absorbs light energy, primarily from the blue and red wavelengths, to drive the photosynthetic process.
Name the three main stages of cellular respiration.
Answer: The three main stages are Glycolysis, the Krebs cycle (Citric Acid Cycle), and the Electron Transport Chain.
What factors can affect enzyme activity?
Answer: Factors include temperature, pH, substrate concentration, and the presence of inhibitors or activators.
What is the difference between passive and Active transport across membranes?
Answer: Passive transport does not require energy and moves substances down their concentration gradient, while active transport requires energy to move substances against their gradient.
Write the overall equation for photosynthesis.
CO2 + H20 = CH2O + 02
Describe the role of mitochondria in cellular respiration.
Answer: Mitochondria are the powerhouses of the cell, where the Krebs cycle and Electron Transport Chain occur, producing ATP from glucose.
Explain the term "enzyme specificity."
Answer: Enzyme specificity refers to the ability of an enzyme to select and catalyze only one specific substrate or a group of closely related substrates.
How do membrane proteins contribute to cell signaling?
Answer: Membrane proteins act as receptors or channels that facilitate communication between cells and their environment, allowing for signal transduction.
How does carbon dioxide concentration affect the rate of photosynthesis?
Answer: Increased carbon dioxide concentration generally increases the rate of photosynthesis up to a certain point, after which other factors may become limiting.
What is the difference between aerobic and anaerobic respiration?
Answer: Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration occurs without oxygen and produces less ATP along with by-products like lactic acid or ethanol.
What is the significance of enzyme co-factors and co-enzymes?
Answer: Co-factors and co-enzymes are non-protein molecules that assist enzymes in catalyzing reactions, often required for activity.
Discuss the role of cholesterol in cell membranes.
Answer: Cholesterol helps to stabilize membrane fluidity and integrity, making membranes less permeable to very small water-soluble molecules that might otherwise pass freely through.
Explain the significance of the Calvin cycle in the context of photosynthesis.
Answer: The Calvin cycle converts carbon dioxide into glucose using the ATP and NADPH produced in the light-dependent reactions, making it essential for energy storage in plants.
Discuss the role of NADH and FADH2 in cellular respiration.
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Answer: NADH and FADH2 are electron carriers that shuttle electrons to the Electron Transport Chain, where their energy is used to produce ATP.