B4 Flashcards
What is Photosynthesis?
Photosynthesis is a process carried out by plants that converts carbon dioxide and water into glucose and oxygen. Sunlight is used as the energy source for the reaction.
Where does Photosynthesis take place?
Photosynthesis takes place inside chloroplasts found in plants and algae. A green chemical called chlorophyll inside chloroplasts traps the energy of sunlight.
What happens during Photosynthesis?
During photosynthesis, carbon dioxide reacts with water to produce glucose (a sugar) and oxygen.
What is the symbol equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
What effects the rate of reaction for photosynthesis (how fast the reaction is)?
Temperature, light intensity, Carbon dioxide concentration & High chlorophyll concentration
How does the Temperature effect the rate of reaction for photosynthesis?
Temperature affects the rate of photosynthesis. Increasing the temperature increases the rate of photosynthesis because more energy is provided.However, if the temperature is increased to above about 45°C, the enzymes that catalyse (speed-up) the reaction begin to denature (change shape so they do not work anymore).
This causes the rate of the reaction to fall quickly until it stops altogether.
How does Light intensity effect the rate of reaction for photosynthesis?
Light intensity affects the rate of photosynthesis.
Increasing light intensity increases the rate of photosynthesis because more energy is provided. However, if the light intensity is increased above a certain threshold, the rate of photosynthesis will not increase because another factor (such as temperature) is limiting the rate of the reaction.
How does Carbon dioxide effect the rate of reaction for photosynthesis?
Carbon dioxide concentration can affect the rate of photosynthesis. Increasing the carbon dioxide concentration increases the rate of photosynthesis.However, above a certain threshold, further increases in the carbon dioxide concentration do not increase the rate of photosynthesis because another factor (such as light intensity) is limiting the rate of reaction.
High chlorophyll concentration gives a high rate of photosynthesis.
What is Respiration?
Respiration is a reaction that supplies all the energy needed by living organisms. The reaction can be aerobic (with oxygen) or anaerobic (without oxygen). In aerobic respiration, glucose reacts with oxygen in the mitochondria of cells to give carbon dioxide, water and energy.
Anaerobic respiration happens without oxygen. Anaerobic respiration happens if:
Insufficient oxygen reaches the muscles during periods of intense activity.
There is not enough oxygen in the soil for plants.
In anaerobic respiration in animals, glucose is converted to lactic acid. The build-up of lactic acid causes stiffness after exerciseIn anaerobic respiration in plant and yeast cells, glucose is converted into ethanol and carbon dioxide. The carbon dioxide released from anaerobically respiring yeast cells is what causes bread to rise. Glucose is not broken down completely in anaerobic respiration, making it a less efficient way of transferring energy than aerobic respiration.
