FreeNotes
The rate of photosynthesis is influenced by several factors: Light intensity: More light increases the rate of photosynthesis up to a point, beyond which the rate plateaus. Light is required to provide energy for the light-dependent reactions of photosynthesis. Carbon dioxide concentration: The higher the concentration of CO₂, the faster the photosynthesis rate, as CO₂ … Read more
The dark reactions, or Calvin cycle, occur in the stroma of the chloroplast. During this cycle, carbon dioxide is fixed by the enzyme RuBisCO and converted into a five-carbon sugar called ribulose bisphosphate (RuBP). The cycle produces glyceraldehyde-3-phosphate (G3P) using the ATP and NADPH from the light reactions. G3P is then used to form glucose … Read more
The light reactions occur in the thylakoid membranes of the chloroplast. Chlorophyll absorbs light energy, which excites electrons that are passed through an electron transport chain, producing ATP and NADPH. Water molecules are split during photolysis to release oxygen. The ATP and NADPH produced are then used in the Calvin cycle for synthesizing glucose. … Read more
ATP (adenosine triphosphate) is a molecule that stores and transfers energy within cells. It consists of an adenine base, a ribose sugar, and three phosphate groups. The energy is stored in the high-energy bonds between the phosphate groups. When one phosphate group is removed (via hydrolysis), energy is released, which can be used for cellular … Read more
This analogy refers to the specificity of enzymes. The enzyme’s active site is like a lock, and only substrates with the correct shape and chemical properties (the right “key”) can bind to the active site and initiate the reaction. For example, the enzyme amylase only catalyzes the breakdown of starch because its active site is … Read more
(a) Temperature: Increasing temperature generally increases enzyme activity up to a point, as it provides more energy for molecular collisions. However, beyond the enzyme’s optimal temperature, the enzyme can denature and lose its activity. (b) pH: Each enzyme has an optimal pH range, and changes in pH can alter the enzyme’s shape, affecting its ability … Read more
The activation energy is the energy required to initiate a chemical reaction. For a reaction to occur, reactant molecules must collide with enough energy to break bonds and form new ones. Enzymes lower the activation energy by providing an alternative pathway for the reaction with a lower energy barrier. This is achieved by binding to … Read more
An enzyme is a biological catalyst, usually a protein, that speeds up the rate of a specific biochemical reaction by lowering the activation energy. Enzymes are highly specific for their substrates, meaning they catalyze only one type of reaction or work on one specific substrate. Their characteristics include: Specificity: Each enzyme works on a specific … Read more
Extreme pH conditions can cause enzymes to denature, altering their three-dimensional structure. This change prevents the enzyme from binding effectively with its substrate, reducing or stopping the enzyme’s activity. Related Questions: Why are enzymes called biological catalysts? Name the factors affecting enzyme activity. At what pH do pepsin and trypsin enzymes act the best? … Read more
NADPH is produced in the light-dependent reactions of photosynthesis and is used in the Calvin cycle to reduce carbon dioxide into glucose. It acts as a carrier of electrons and protons, which are necessary for the synthesis of carbohydrates. Related Questions: Why are enzymes called biological catalysts? Name the factors affecting enzyme activity. At … Read more