Bioenergetics

• What is the independent variable in an experiment?

  Thing you purposefully change
• What is the dependent variable in an experiment?

  Thing you measure
• What is a control variable?

  Thing you keep the same
• What does "optimum" mean in the context of enzymes?

  It refers to the best working conditions
• Why might a lower temperature than optimum be chosen in industry?

  It is cheaper and requires less energy
• How should substances be prepared before mixing in an enzyme practical?

  Put in water bath for about 5 minutes
• How can we ensure more accurate results in enzyme experiments?

  By repeating results and testing smaller intervals
• What does accuracy refer to in scientific measurements?

  How close values are to the true value
• How is the rate of reaction calculated in enzyme experiments?

  By finding the gradient of the line of best fit
• What is the test for starch?

  Add iodine solution
• What color does iodine turn if starch is present?

  Blue/black
• What is the test for sugar?

  Add Benedict's reagent and heat
• What color does Benedict's reagent turn if sugar is present?

  Red/orange
• What is the test for fat (lipid)?

  Add ethanol, then water
• What should appear if fat is present in the test?

  Cloudy white emulsion
• What is the test for proteins?

  Add sodium hydroxide and copper sulfate (biuret solution)
• What color does the protein test turn if proteins are present?

  Purple
• Why should goggles be worn during enzyme practicals?

  Because iodine, Benedict's, and sodium hydroxide are irritants
• What is respiration?

  A reaction that releases energy in cells
• Where does respiration occur in cells?

  In the mitochondria
• What type of reaction is respiration?

  Exothermic reaction
• What is the equation for aerobic respiration?

  6O2 + C6H12O6 → 6H2O + 6CO2 + Energy
• Why do cells that need lots of energy have many mitochondria?

  They release lots of energy in respiration
• What does metabolism include?

  Conversion of starch, lipid formation, respiration
• How does exercise affect breathing and heart rate?

  It causes deeper breathing and increased heart rate
• What happens if more energy is taken in than used?

  Body mass increases
• What occurs during anaerobic respiration in humans?

  Glucose converts to lactic acid and energy
• What is produced during anaerobic respiration that can cause pain?

  Lactic acid
• What happens after strenuous exercise regarding heart and breathing rates?

  They slowly decrease to pay back oxygen debt
• Where is lactic acid transported after exercise?

  To the liver for conversion back to glucose
• What is fermentation in yeast cells?

  Anaerobic respiration producing ethanol and carbon dioxide
• What is diffusion?

  Spreading out of particles from high to low concentration
• How can the rate of diffusion be increased?

  By increasing temperature and surface area
• Why do plants have more stomata on the bottom of leaves?

  To reduce evaporation from direct sunlight
• What factors increase transpiration?

  Increased light, temperature, air movement, and decreased humidity
• What is a potometer used for?

  To measure water uptake in plants
• How should a potometer be set up?

  Must be airtight with no air bubbles
• What is the formula for calculating the rate of transpiration with a potometer?

  $\Pi r^2 \times \text{distance air bubble moved} / \text{time}$
• How do you count stomata on a leaf?

  Mount a leaf on a slide and observe
• What is the word equation for photosynthesis?

  Carbon dioxide + water → glucose + oxygen