Unit 2: Cell Energy

Which molecule(s) could be represented by the circle labeled Z that is produced as an output of the mitochondria and required by the chloroplast? Select ALL that apply.

• Letter Z could be an oxygen molecule because it is produced in cellular respiration and is a reactant of photosynthesis.

• Letter Z could be a water molecule because it is produced in photosynthesis and is a reactant of cellular respiration.

• Letter Z could be a water molecule because it is produced in cellular respiration and is a reactant of photosynthesis.

• Letter Z could be a glucose molecule because it is produced in photosynthesis and is a reactant of cellular respiration.

• Letter Z could be carbon dioxide because it is produced in cellular respiration and is a reactant of photosynthesis.

Answer explanation

Carbon Dioxide is the only component that is stated correctly it is a reactant of photosynthesis and a product of Cellular Respiration.

Write balanced chemical equations showing the relationship between the two processes.

• H₂O + CO₂ ⇒ C₆H₁₂O₆ + O₂

• 6H20 + 6CO2 + sunlight ⇒ 6O2 + C6H12O6 + ATP

• 6H₂0 + 6CO₂ + sunlight ⇒ 6O₂ + C₆H₁₂O₆6O₂ + C₆H₁₂O₆ ⇒ 6CO₂ + 6H₂O + ATP

• 6H₂0 + 6CO₂ + sunlight ⇄ 6O₂ + C₆H₁₂O₆

Answer explanation

Due to the fact that its a never ending cycle between the two.

Review the schematic diagram of photosynthesis and the involvement of the chloroplast in this process. All BUT ONE choice describes what is happening in the light dependent reaction.

• Energy from sunlight is absorbed by chlorophyll.

• Water is broken down and oxygen is produced.

• Products include ATP and NADPH.

• Reactants include carbon dioxide and water.

Answer explanation

This happens in the thylakoid membranes.

Evergreen needles have a thick outer coating, called a cuticle. Predict how this provides an advantage for photosynthesis.

• The cuticle holds in more glucose.

• The cuticle helps keep the tree cooler.

• The cuticle allows them to retain more water.

• The cuticle allows for enhanced gas exchange.

Answer explanation

Cuticle is waxy and is there t retain water so the more of it the more water it retains.

Each flask also contains 200 mL of H₂0 and 2 mL of bromothymol blue. Bromothymol blue is a chemical indicator solution that changes color from blue to yellow in the presence of CO₂. The students then place a plant and fish into each flask according to the table above. Which flask(s) will turn yellow and why?

• Flask 1 & 2 because there is only one process taking place in each of these flasks so the products do not get used up.

• Flask 3 (only) because this is the only flask in which photosynthesis and cellular respiration are both taking place.

• Flask 2 (only) because the fish produce CO₂ as products of cellular respiration and do not undergo photosynthesis therefore not consuming CO₂.

• Flask 1 & 3 because these flasks contain plants that undergo photosynthesis.

Answer explanation

There is no Carbon dioxide.

During winter, what factors can reduce the rate of photosynthesis in evergreens such as pine trees? Choose ALL that apply.

• decreased carbon availability

• less sunlight

• more water availability

• increased oxygen availability

• colder temperatures

Answer explanation

The more light and warmer the more effective it will be at making glucose

The by-products of cellular respiration include

• glucose and carbon dioxide

• carbon dioxide and water

• glucose and oxygen

• energy and oxygen

Answer explanation

Both products of cellular respiration.

Which of these products is formed during the metabolic reactions of cellular respiration?

• water

• fructose

• oxygen

• glucose

Answer explanation

Carbon dioxide and water are WASTE in cellular respiration

What is the best explanation for the relationship between light intensity and the rate of photosynthesis.

• As light intensity increases, the rate of photosynthesis increases until photosynthesis reaches its maximum rate.

• As light intensity increases, the rate of photosynthesis decreases.

• As light intensity increases, the rate of photosynthesis increases as well

• Light is required for photosynthesis, but light intensity doesn't influence the rate of photosynthesis

Answer explanation

Increases until no longer affected as shown on graph