Topic 4 Core questions - Bioenergetics Flashcards
State the word equation for photosynthesis.
Carbon dioxide + water -> glucose + oxygen (light above the arrow)
State the balanced chemical symbol equation for photosynthesis
6CO₂ + 6H₂O -> C₆H₁₂O₆ + 6O₂
Is photosynthesis an endothermic or exothermic reaction?
Endothermic
What energy transfer occurs in photosynthesis?
Light energy to chemical energy
Where does photosynthesis occur in a plant or algal cell?
Chloroplasts
What are chloroplasts filled with?
Chlorophyll
What is the function of chlorophyll?
Captures light energy
Name the three factors which affect the rate of photosynthesis.
Temperature, light intensity, carbon dioxide concentration
What is the formula for the inverse square law (for light intensity)?
light intensity∝1/distance²
Describe how the inverse square law applies to light intensity and distance.
The intensity of light is inversely proportional to the square of the distance from the light source.
E.g. if you halve the distance, the light intensity will be 4 times greater
What does the inverse square law mean in practice when considering how plants grow?
When the light is moved twice as far from the plant it will receive a quarter of the energy
Why can’t a commercial grower of plants just increase all three limiting factors of photosynthesis to maximum levels to obtain optimum growth?
Light, temperature and CO2 all cost money to supply – a balance between expenditure and income must be struck for a profit to be made
Name the ways glucose produced in photosynthesis is used in plants.
Used for respiration
Converted into insoluble starch for storage
Used to produce fat or oil for storage
Used to produce cellulose which strengthens the cell wall and/or used to produce amino acids for protein synthesis.
What else, other than glucose, do plants need to produce proteins?
Nitrate ions
Where are mineral ions absorbed from and through which plant organ?
From the soil, through the roots
What is aerobic respiration and where does it occur in cells?
Respiration WITH oxygen, in the mitochondria
What is anaerobic respiration and where does it occur in cells?
Respiration WITHOUT oxygen, in the cytoplasm
Is respiration an endothermic or exothermic reaction?
Exothermic
State the balanced symbol equation for aerobic respiration.
C₆H₁₂O₆ + 6O₂ -> 6CO₂ + 6H₂O
glucose + oxygen -> carbon dioxide + water
State the word equation for anaerobic respiration in animal cells.
Glucose -> lactic acid
State the word equation for anaerobic respiration in plant and yeast cells.
Glucose -> ethanol + carbon dioxide
Which transfers more energy, aerobic or anaerobic respiration?
aerobic respiration
How have humans used our understanding of anaerobic respiration in plant and yeast cells in manufacturing?
Production of bread and alcoholic drinks
Name three physical ways in which the human body reacts to an increased demand for energy.
increased heart rate, increased breathing rate and increased breathing volume
