Exam 2 Flashcards
(T/F) The presence of air spaces around the mesophyll cells in leaves helps in the absorption of light by the leaf due to refraction of light within the leaf.
TRUE
(T/F) Under low O2 conditions the CO2 compensation point for both C3 and C4 plants would both be expected to be about the same.
TRUE
(T/F) Photosynthesis and respiration each have optimal temperatures and the optimal temperature for respiration is higher than for photosynthesis.
TRUE
(T/F) The effect of temperature on net photosynthesis is the effect of temperature on total photosynthesis minus the effect of temperature on respiration and photorespiration.
TRUE
(T/F) In C3 plants, the quantum yield decreases with increasing temperature due to increased photorespiration at higher temperatures.
TRUE
(T/F) C4 plants generally have a higher internal concentration of CO2 than C3 plants and this results in lower rates of photorespiration and therefore a lower CO2 compensation point.
TRUE
(T/F) Even when light, CO2, and temperature are optimal, plant growth can be limited if the supply of water is not adequate.
TRUE
(T/F) When a plant cell expands, it is due to the fact that the water potential of the cell is more negative than that of the exterior of the cell which leads to the accumulation of water in the cell which causes the build up of turgor pressure in the cell.
TRUE
(T/F) Osmosis is the movement of water through a differentially permeable membrane to achieve an equal water concentration on both sides of the membrane.
TRUE
(T/F) Water potential and changes in water potential play a role in the movement of compounds through the phloem.
TRUE
When the water potential of the soil is less negative than the water potential of the plant, the plant will wilt.
FALSE, plant expands
When sugars move into the phloem in the leaves, the water potential becomes more negative and this causes water to move into the phloem.
TRUE
Roots elongate by taking up water and pushing through the soil, and the meristem serves to protect the tip of the root as it moves through the soil.
FALSE
When phloem cells unload sucrose, the water potential of the phloem becomes more negative and this leads to a movement of water into the phloem cells.
FALSE
Which of the following is the best explanation for why C4 plants don’t show light saturation?
a. C4 plants have both bundle sheath and mesophyll cells.
b. C4 plants are more efficient in their use of water than C3 plants.
c. C4 plants are able to continue to utilize light energy to photosynthesize even under very low CO2 levels.
d. C4 plants have the same light compensation point as C3 plants.
e. C4 plants are specially adapted to hot and dry environments.
c. C4 plants are able to continue to utilize light energy to photosynthesize even under very low CO2 levels.