Photosynthesis Flashcards
The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.
Photosynthesis
It is essential for the growth and survival of autotrophic organisms, as well as for providing oxygen to the atmosphere
Photosynthesis
Ancient civilizations,
such as the _____ and
________, noted that
plants appeared to “eat”
air and sunlight.
Greeks and Egyptians
conducted experiments and concluded that water was the source of a plant’s increased mass.
Jan Baptista Van Helmont
- conducted experiments with a variety of gases, including “dephlogisticated air” (now known as oxygen).
- observed that plants exposed to sunlight
released a gas that could relight a burning candle, which we now recognize as oxygen.
Joseph Priestley
- get their energy from “eating others”
- consumers of other organisms
- consume organic molecules
Heterotrophs
- get their energy from “self”
- get their energy from sunlight
- use light energy to synthesize organic molecules
Autotrophs
- consumers
- animals
- fungi
- most bacteria
Heterotrophs
- producers
- plants
- photosynthetic bacteria
Autotrophs
What does the plant obtain to complete photosynthesis?
Sunlight, Carbon dioxide, Water, Nutrients
What does it mean to be a plant?
- collect light energy
- store light energy
- need to get building block atoms from the environment (CHONPS)
- produce all organic molecules needed for growth (Carbohydrates, proteins, lipids, nucleic acids)
- double membrane
- stroma
- thylakoid sacs
- grana stacks
Chloroplast
H+ gradient build up within thylakoid sac
Chlorophyll & ETC in thylakoid membrane
sheathed with an upper and lower epidermis. The exposed
surfaces of the epidermal cells are coated with a cuticle.
Leaf
are located between the two epidermal layers and are consequently identified as mesophyll (meso, middle; phyll, leaf)
tissues.
Photosynthetic tissues
tissue generally consists of one to three layers of palisade mesophyll cells.
Upper photosynthetic
are elongated, cylindrical cells with the long axis perpendicular to the surface of the leaf.
Palisade cells
are the smallest unit of light.
Photons
The light emitted from the sun contains photons in a wide spectrum of wavelengths, called the
Electromagnetic spectrum
Photosynthetic
organisms use only a
short portion of the
electromagnetic
spectrum called
Visible light
are green because they absorb light wavelengths in red & blue and reflect green back out
Chloroplast
Carbon dioxide and water are converted into
_____________ and ____________, driven by the energy of sunlight captured by chlorophyll and other pigments.
Glucose and oxygen
molecules are taken in from the surrounding
environment.
Carbon dioxide
This is absorbed by chlorophyll
and other pigments in the
chloroplasts.
Water
a simple sugar, is the
primary product of
photosynthesis and serves as
an energy-rich molecule for the
cell.
Glucose
is released as a
byproduct of photosynthesis
and is released into the
atmosphere.
oxygen gas
- convert solar energy to chemical energy
- ATP
Light reactions
uses chemical energy (NADPH & ATP) to reduce carbon dioxide to build sugars
Calvin cycle
act as light-gathering “antenna complex”
Photosystems
2 photosystems in thylakoid membrane
Photosystem II and Photosystem I
The key to the photosynthetic electron transport chain is the
presence of two large, multimolecular, pigment-protein complexes
known as
Photosystem I
These two photosystems operate in series linked by a third multiprotein aggregate called the
Cytochrome complex
The effect of the chain is to extract low-energy electrons from water
and, using light energy trapped by chlorophyll, raise the energy level
of those electrons to produce a strong reductant
NADPH
-The bulk of the chlorophyll in the photosystem functions
as
antenna chlorophyll
The association of chlorophyll with specific proteins forms a number of different
chlorophyll-protein (CP) complexes
consist of accessory
pigment molecule and chlorophyll – the molecules that
absorb the photons of light.
photosystems
consists of two chlorophyll-proteins (CP) known as CP43 and CP47.
Photosystem II
it is the longest-wavelength, thus the lowest-energy-absorbing
chlorophyll in the complex.
energy sink
is the site of the primary photochemical
redox reaction, it is here that light energy is actually converted to chemical energy.
reaction center chlorophyll a
