chapter 10: photosynthesis Flashcards
what is an autotroph?
an organism that produces its own food using light, water, or carbon dioxide
what is a heterotroph?
an organism that cannot produce its own food, instead they eat other plants/animals for energy
how did fossil fuels develop?
they formed from remains of organisms that died hundreds of millions of years ago
what is photosynthesis and why is it important?
the conversion of light energy to chemical energy that is stored in sugars, photosynthesis is important because it is critical or the existence of the vast majority on life on Earth
what are the parts of a leaf? where does gas exchange occur?
gas exchange occurs on the stomata
what are the parts of a chloroplast?
outer membrane, inner membrane, thylakoid membrane, grana, lumen, and stroma
what is CO2 being reduced to during the process of photosynthesis?
sugars (glucose)
why is photosynthesis considered an endergonic reaction?
photosynthesis is endergonic because plants cannot initiate the process until they absorb light energy (energy is needed)
what are the two major phases of photosynthesis? what comes in and goes out?
- light reactions: inputs are sunlight, water, ADP, NADP+ and its outputs are ATP, NADPH, and O2
- dark reactions (Calvin cycle): inputs are ATP, NADPH, and CO2 and its outputs are ADP, G3P, and NADP+
what is the source of electrons in the light reaction? what is the waste product?
water provides electrons for light reactions, oxygen is the waste product
what is NADP+ and NADPH?
NADP+: the oxidized form that acts as an electron carrier
NADPH: the reduced form that temporarily stores energized electrons produced during the light reactions
which phase of photosynthesis does not require light?
Calvin cycle (dark reactions)
what is visible light?
the portion of the electromagnetic spectrum that can be detected by the human eye
what is a photon?
light energy that behaves as if it were a particle
what is a pigment?
substances that absorb visible light
why do plants look green to our eye?
light absorbs every other color and only reflects green out
ground state vs excited state
- when electrons are in a ground state, they have lower energy and are more stable
- when electrons are in a excited state, they have more energy and are not stable
how does a pigment molecule excite an electron?
when electrons in the pigment absorb energy, the energy move the electrons to an excited state
what is a photosystem?
light capturing units, consisting of a reaction center complex surrounded by numerous light-harvesting complexes
what is photosystem II?
a light capturing unit in a chloroplast’s thylakoid membrane (contains two molecules of P680 chlorophyll a)
what is photosystem I?
a light capturing unit in a chloroplasts thylakoid membrane (contains two molecules of P700 chlorophyll a)
where does the light reaction take place in chloroplasts?
the thylakoid
what is noncyclic (linear) electron flow? what is produced?
- a route on electron flow during the light reactions of photosynthesis that involves both photosystems I and II
- produces ATP and NADPH
how does energy move around from electron to electron in a photosystem?
through the electron transport chain
