Chapter 7 Energy and Nutrient Relations Flashcards
(81 cards)
What kind of organisms use carbon dioxide as a carbon source and inorganic chemicals such as hydrogen sulfide as the source of their energy?
Chemosynthetic Autotrophs
______ wavelengths of light, such as infrared light, carry ______ energy than shorter wavelengths of light, such as UV light.
long ; less
longer wavelengths have ____ energy
less/little
What type of solar radiation is called photosynthetically active?
visible light
Organisms that lack a membrane-bound nucleus are called _____
prokaryotes
Number of photons striking square meter of surface each second
photon flux density
Within the range of PAR, plants ABSORB mainly ______ wavelengths of light.
blue and red
Within the range of PAR, plants EMIT mainly ______ wavelengths of light.
green
ATP & NADPH act as what to make sugar?
electron donor
Which of the following is not true concerning the effects of infrared light on living things?
It decreases the motion of whole molecules that comprise living things.
Which of the following are true of visible light?
- It makes up about 42% of the total energy of solar radiation at sea level.
- It has sufficient energy to power photosynthesis.
C3 photosynthesis ______.
refers to the conversion of RuBP (enzyme) to a 3-carbon acid called PGA
In ______
photosynthesis, there is a relatively low rate of carbon dioxide uptake. One reason for this is that the enzyme RuBP carboxylase has a low affinity for carbon dioxide
c3
During photosynthesis, photosynthetic pigments absorb photons of light and immediately transfer the energy to ______.
electrons
The two mechanisms that help to reduce high levels of photorespiration in plants are _______ photosynthesis and ________ photosynthesis.
Crassulacean Acid Metabolism (CAM)
C4 Photosynthesis
Ultraviolet light is highly energetic and can break
_______ bonds in the organic molecules that compose living things.
covalent
PEP carboxylase ______.
catalyzes the reaction between carbon dioxide and phosphoenol pyruvate (PEP)
Carbon fixation in a plant that does C3 photosynthesis refers to ______.
the process where carbon dioxide is incorporated into a 3 carbon organic acid
In plants doing C4 photosynthesis, the four-carbon acids initially produced diffuse into
_________ they can be converted to three-carbon acids and carbon dioxide.
bundle sheath
To minimize the effects of photorespiration, plants concentrate the gas called
________ by using C4 or CAM photosynthesis.
carbon dioxide (co2)
Because PEP carboxylase has a high affinity for carbon dioxide, C4 plants are able to ________ the concentration gradient between the atmosphere and in the inside of their cells. This also allows them to have ________ stomata open, which conserves water.
increase
less
CAM photosynthesis ______.
is found among epiphytes in the canopies of forests
is found in plants in arid and semiarid environments
One limitation of CAM photosynthesis is ______.
carbon dioxide typically enters cells only during the night, reducing carbon availability
Which of the following is NOT true concerning C4 photosynthesis?
PEP carboxylase fixes carbon dioxide into a 4-carbon acid in the bundle sheath cells.
TRUE ANSWERS
C4 plants do better than C3 plants in hot, dry, light intense environments.
Sugars and starches are produced in the bundle sheath cells.
Carbon dioxide is concentrated in the bundle sheath cells.