Documento en PDF, traducido, modificado y actualizado por Gustavo Toledo C. para ser usado en 1º medio. es muy didáctico, se incluye un set de 16 preguntas de selección múltiple, basadas en el texto y, además se incluye un hipervínculo a una animación de Jay Phelan, autor del texto del 2012, What is life, a guide to biology, 2ª edición.
14. Chequee sus conocimientos. Preguntas de selección multiple basadas en el texto. Pueden revisar esta
animación que se complementa con el texto.
http://bcs.whfreeman.com/phelan2e/default.asp#712649__748687__
1. A green plant will grow if given nothing more than:
a) water, light, and carbon dioxide.
b) water, light, and oxygen.
c) carbon dioxide.
d) oxygen.
e) oxygen and carbon dioxide.
2. The actual production of sugars during photosynthesis takes place:
a) within the outer membrane of the chloroplast.
b) within the stroma, inside the thylakoids of the chloroplast.
c) within the stroma, outside of the thylakoid, but still inside the chloroplast.
d) just outside the chloroplast, within the mitochondria.
e) within the thylakoid membrane of the chloroplast.
3. The leaves of plants can be thought of as "eating" sunlight. From an energetic perspective this makes sense because:
a) light energy, like the chemical energy stored in food molecules, is used inside plants to do work.
b) both light energy and food energy can be converted to kinetic energy without the loss of heat.
c) the carbon-oxygen bonds within a photon of light release energy when broken by the enzymes in chloroplasts.
d) the carbon-hydrogen bonds within a photon of light release energy when broken by the enzymes in chloroplasts.
e) photons are linked together by hydrogen bonds which release energy when striking the surface of a leaf.
4. A molecule of chlorophyll increases in potential energy:
a) when it binds to a photon.
b) when one of its electrons is boosted to a higher-energy excited state upon being struck by a photon of light.
c) when it loses an electron.
d) only in the presence of oxygen.
e) none of the above. The potential energy of a molecule cannot change.
5. Photosynthesizing plants rely on water:
a) to provide the protons necessary to produce chlorophyll.
b) to concentrate the beams of light hitting a leaf, focusing them on the reaction center.
c) to replenish oxygen molecules that are lost during photosynthesis.
d) to replace electrons that are excited by light energy and passed from molecule to molecule down an electron transport chain.
e) to serve as a high-energy electron carrier.
6. During photosynthesis, which step is most responsible for a plant's acquisition of new organic material:
a) the "building" of NADPH during the Calvin cycle.
b) the excitation of chlorophyll molecules by photons of light.
c) the "plucking" of carbon molecules from the air and affixing of them to organic molecules within the chloroplast.
d) the loss of water through evaporation.
e) the production of ATP during the light reactions.
7. During C4 photosynthesis:
a) plants utilize less ATP when producing sugar.
b) plants are able to continue producing sugars even when they must almost completely close their stomata to reduce water loss during hot days.
c) plants are able to generate water molecules to cool their leaves.
d) plants are able to reduce water loss by producing more rubisco.
e) plants are able to produce sugars without any input of carbon dioxide.
15. Photosynthesis: The ''Photo'' Reactions
8. What is the main purpose of photosynthesis?
a. to release oxygen into the atmosphere
b. to make sugars for food
c. to harvest energy from carbon dioxide
d. to harvest energy from glucose
9. When a chlorophyll molecule absorbs light, exciting an electron, the chlorophyll molecule
a. releases kinetic energy.
b. gains potential energy.
c. releases a photon.
d. returns to its resting state.
10. From where do replacement electrons for chlorophyll a come?
a. the sun
b. the electron vacuum
c. thylakoid pigments
d. water molecules
11. What is the outcome of the flow of protons across the thylakoid membrane into the stroma?
a. the capture of photons from sunlight
b. the release of oxygen atoms from water molecules
c. the generation of ATP from the difference in proton concentration
d. the excitement of electrons to higher energy levels
12. Why must plants get water for photosynthesis to occur?
a. Water provides energy for making sugars.
b. Water is necessary for cellular respiration.
c. Water replaces electrons used during the "photo" reactions.
d. Water keeps plant cells hydrated.
Photosynthesis: The ''Synthesis'' Reactions
13. What links the "photo" reactions with the "synthesis" reactions?
a. light energy from the sun
b. ATP and NADPH
c. the electrons from water
d. carbon dioxide from the air
14. What is the function of rubisco?
a. Rubisco provides energy for the Calvin cycle.
b. Rubisco releases oxygen from water molecule.
c. Rubisco removes carbon dioxide from air and binds it to an organic molecule.
d. Rubisco converts sunlight energy to chemical energy.
15. What is regenerated in the Calvin cycle?
a. carbon dioxide
b. the organic molecule
c. rubisco
d. water
16. Why does feeding sugar to cut flowers keep them alive longer?
a. Sugar prevents the growth of bacteria.
b. Sugar makes cellular respiration unnecessary.
c. Sugar replaces the electrons lost in the first photosystem.
d. Sugar provides an energy source for cellular processes.