BIOLOGY: Bioenergetics

• What are plants classified as in terms of nutrition?

  Autotrophs
• Why are plants called producers in food chains?

  They make their own food using light
• What type of reaction is photosynthesis?

  Endothermic reaction
• Where does most photosynthesis take place in plants?

  In the leaves
• What are mesophyll cells packed with to absorb light energy?

  Chloroplasts
• What is the role of chlorophyll in photosynthesis?

  To absorb light energy
• What are the sugars produced by photosynthesis used for?

  To make substances and release energy

  
• What are the reactants for photosynthesis?

  • Light
  • Water
  • Carbon dioxide

  
• Why is photosynthesis essential for food chains on Earth?

  It produces food for most organisms
• What factors are necessary for photosynthesis to occur?

  Light, water, and carbon dioxide
• How does light availability affect the rate of photosynthesis?

  More light increases the rate of photosynthesis

  
• Why is water not considered a limiting factor for photosynthesis?

  Plants transpire more water than needed
• What environmental factors can affect the rate of photosynthesis?

  Temperature and amount of chlorophyll

  
• How does temperature affect the kinetic energy of particles in photosynthesis?

  Higher temperature increases kinetic energy
• What happens to enzymes at higher temperatures during photosynthesis?

  They can be denatured

  
• How does light intensity affect the rate of photosynthesis?

  More light increases the rate until limited

  
• What happens to the rate of photosynthesis at low light intensities?

  It initially increases with light intensity

  
• How does carbon dioxide concentration affect photosynthesis?

  More carbon dioxide increases the reaction rate

  
• What can affect the amount of chlorophyll in plants?

  Diseases and lack of nutrients
• What is the effect of low temperature on photosynthesis?

  Reduced rate of collisions
• What is the effect of high temperatures on enzymes in photosynthesis?

  Enzymes denature and lose function

  
• What are the interactions of limiting factors in photosynthesis?

  • More than one factor can limit photosynthesis
  • Rate increases with light, temperature, and CO2
  • Factors can level off when one is limiting

  
• What does the inverse square law describe?

  The relationship between light intensity and distance

  
• How does light intensity change with distance according to the inverse square law?

  It decreases as distance increases

  
• What is the formula for calculating light intensity?

  Light intensity = 1/d

  
• Why do commercial horticulturists use greenhouses?

  • To control limiting factors of photosynthesis
  • To maximize crop yield and profit
  • To maintain optimal conditions for growth
• What are the costs associated with growing plants in greenhouses?

  Increased costs but higher crop yield
• What are the main uses of glucose produced in photosynthesis?

  • Used for respiration
  • Converted to starch for storage
  • Used to produce fats or oils
  • Used to produce cellulose
  • Combined with nitrates for amino acids

  
• When do plants respire and photosynthesize?

  Respire all the time, photosynthesize during the day
• What type of reaction is cellular respiration?

  Exothermic reaction
• What does cellular respiration release?

  Energy
• Why do organisms need energy from respiration?

  For chemical reactions, movement, and warmth
• What is the word equation for aerobic respiration?

  Glucose + Oxygen → Carbon Dioxide + Water

  
• Where does aerobic respiration primarily occur?

  In the mitochondria

  
• What is anaerobic respiration in animals?

  Incomplete breakdown of glucose into lactic acid

  
• When does anaerobic respiration occur?

  When oxygen supply is insufficient

  
• What is produced during anaerobic respiration in animals?

  Lactic acid

  
• What is fermentation in yeast?

  Anaerobic respiration producing ethanol and carbon dioxide

  
• What are the economic uses of fermentation?

  In bread and alcoholic drinks production
• Compare aerobic and anaerobic respiration.

  • Aerobic: requires oxygen, produces more energy
  • Anaerobic: no oxygen, produces less energy and lactic acid