Chapter 10
Photosynthesis
specialized molecular complexes in chloroplasts capture light energy from the sun and convert it to chemical energy that is stored in sugar and other organic molecule is called photosynthesis.
chloroplasts
P;ants amd other photosynthetic organisms contain cellular organelles called chloroplast.
Autotrophs
Self-feeders; they sustain themselves without eating anything derived from other living beings. Produce organic molecules from CO2 and other inorganic raw materials obtained from the environment.
Heterotrophs
Obtain organic material by second major mode of nutrition. Unable to make their own food, they live on compounds produced by organisms (hetero-other). they are biosphere's consumer.
Mesophyll
The tissue in the interior of the leaf.
Stomata
microscopic pores
Stroma
A chloroplast has two membranes surrounding a dense fluid called stroma.
Thylakoid
Suspended within the stroma is a third membrane system, made up of sacs called thylakoid, which segregates the stroma from the thylakoids space inside these sacs.
Chlorophyll
Green pigment that gives leaves their color, resides in the thylakoid membrane choroplast.
light reaction
the photo part of photosynthesis
NADH+
Light absorbed by chlorophyll drives a transfer of the electrons and hydrogen ions from water to an accepter called NADP+
NADPH
The light reactions use use solar energy to reduce NADPH+ to NADPH by adding a pair of electrons along with H+.
Photophosphosphorylation
The light reactions also generate ATP, using chemiosmosis to power the addition of a phosphate group ADP, a process called Photophosphorylation.
Carbon fixation
incorporation of carbon into organic compounds known as carbon fixation.
Light
Light is a form of energy known as electromagnetic energy, also called electromagnetic.
wavelength
The distance between the crests electromagnetic waves is called wavelength.
primary electron acceptor
a molecule capable of accepting electrons and becoming reduced.
Photosystem (PSII) and Photosystem (PSI)
They were named in order of their discovery, but photosystem II functions first in the light reaction.
linear electron flow
Electromagnetic spectrum
Visible light
Photons
Spectrophotometer
Absorption
Chlorophyll A
Chlorophyll B
Action Spectrum
Carotenoids
light-harvesting complex
consist of various pigment molecules bound to proteins.
hydrogen carbon that are various shades of yellow and orange because they absorb violet and blue-green light.
photosynthesis, which profiles the relatives effectiveness of different wavelengths of radiation in driving the process.
The accessory pigment and separate group of accessory pigment called carotenoids.
the key light-capturing pigment that participates directly in the light reactions.
A graph plotting a pigments light absorption versus wavelength is called absorption spectrum.
The ability of a pigment to absorb various wavelength of light can be measured with an instrument called spectrophotometer.
The mode of light as wave explains many of light's properties, but certain respects light behaves as though it consist of discrete particles called photons.
The radiation is known as visible light because it can be detected as various colors by the human eye.
The entire range of radiation is known as electromagnetic spectrum.
it occurs during the light reactions of photosynthesis.
cyclic electron flow
Photoexcited electrons can take an alternative path called cyclic electron flow.
Calvin cycle
similar to the citric acid in that a starting material is regenerated after molecules enter and other exit cycle.
Glyceraldehyde 3-phosphate
the carbohydrate produced directly from the Calvin cycle is not glucose.It is actually a three-carbon sugar.
Phase 1: Carbon fixation
The calvin cycle incorporates each CO2 molecule, one at a time, by attaching it to a five carbon sugar name ribulose biophosphate.
Phase 2: reduction
receives an additional phosphate group from ATP, becoming 1,3-biosphoglycerate.
Phase 3: Regenration of CO2 acceptor (RuBP)
complex series of reactions, the carbon skeletons of five molecules of G3P are are rearranged by the last steps of the Calvin cycle into three molecules of RuBP.
Photorespiration
conditions within the leaf favor an apparently wasteful process called photorespiration.
C3 Plants
Calvin cycle enzyme that adds CO2 to ribulose bisphosphate, because the first organic product of carbon fixation is a three-carbon compound, 3-phosphoglycerate.
Photorespiration
Peroxisomes and mitochondria within the plant cell rearrange and split this compound, releasing CO2.
Bundle-sheath cells
arranged into tightly packed sheaths around the veins of the leaf.
PEP carboxylase
The first step is carried out by an enzyme present only in mesophyll cells called PEP carboxylase.
Crassulaccean metabolism
after the plant family crassulaceae, the succulents in which the process was first discovered.
CAM plants
store the organic acids they make during the night in their vacuoles until morning, when the stomata close.