- Endoplasmic reticulum = largest of internal membranes; composed of
phospholipid bilayer with associated proteins and a Lumen; it weaves in sheets
and tubules through the interior of the cell, creating a series of channels between
folds
- Cisternal space/Lumen → one of two of largest compartments in
eukaryotic cells
- Cytosol → fluid component of the cytoplasm containing dissolved
organic molecules such as proteins and ions
- Rough ER → dotted with small bumps called ribosomes; appears
to be composed of flattened sacs
- Golgi body/Apparatus = flattened stacks of membranes interconnected with one
another; # of stacked membranes ranges from 1 to 20 in protists, more in animal
cells, and several hundred in plant cells; Abundant in glandular cells which
secrete substances
- Chloroplasts = use light energy to generate ATP and sugars; Plant cells and
other eukaryotics organism typically contain from one to several hundred;
*ALLOWS ORGANISMS TO MAKE OWN FOOD; contains pigment chlorophyll
which gives green color
- Structure contributes to function; parts include thylakoids, Grana, Stroma,
and Inner membrane
- Internal membrane (thylakoid membrane) → continuous
phospholipid bilyer organized into flattened sacs, which are
stacked in columns (Granum); Contains chlorophyll and
other pigments for capturing light energy; contains
components to synthesize ATP by chemiosmosis;
- Photosyntheic pigments cluster together to form
photosystems → act as large antennas that gather
light energy
- Stroma → surrounding thylakoid membrane system;
semiliquid substance; houses enzymes needed to
, assemble organic molecules from CO2 using ATP coupled
with reduction Via NADPH; Calvin cycle of photosynthesis
occurs here
- Calvin cycle generates a proton gradient by electron
transport;
- Gradient used in generating ATP by chemiosmosis.
- Symbiosis = close relationship between organisms of different species that live
together
- Endosymbiosis → one cell lives inside a larger cell
- The Theory of Endosymbiosis → proposes that some of todays
eukarytoic organelles evolved as consequence of a symbiosis
arising between two cells that were originally free living; One
prokaryote was engulfed by and became a part of another cell
- Photosynthesis = the energy used by most liiving cells is captured from the sun in
this process
- CO2 + 2 H2A + light energy → (CH2O) + H2O + 2 A
H2A = Electron donor
- 1st two stages (Light-Dependent reactions) = requires light; produces O2,
NADPH, and ATP; occur in inner membrane of chloroplasts
- The third stage (Light-Independent Reactions/Carbon Fixation) =
formations of organic molecules from CO2; Takes place via a cyclic series
of reactions (Calvin Cycle); As long as ATP and NADPH ae available
reactions can occur in presence or absence of light
- Pigments = molecules that absorb light energy in the visible range; we see the
color that is reflected, not absorbed
- Two types used in green plant photosynthesis, Chlorophylls and
carotenoids
- Chlorophyll absorb photons within narrow energy ranges; two kinds,
Chlorophyll a and Chlorphyll b which preferentially absorb violet-blue and
red light; neither pigments absorb photons between 500 and 600 nm and
, instead reflects them (green)
- Chlorophyll a = main photsyntheic pigment in plants and
cyanobacteria; only pigment that can act directly to convert light
energy to chemical energy
- Chlorophyll b = acts as an accessory pigment/secondary light
absorbing pigment
- Carotenoids absorb mostly blue and green light and reflect orange and
yellow; accessory pigments
- Light exhibits properties of both wave and particles
- The wave nature of light produces an electromagnetic spectrum that
differentiates light based on wavelength; we cant see large part of
spectrum; Visible light can be divided into separate colors using a prism
- Absorption spectrum → the range and efficiency of photons molecule is
capable of absorbing; when photon strokes molecule with precise
energy needed to excite an electron, the molecule will absorb the
photon, rasing the energy level. Whether its absorbed depends on
energy level and chemical nature of molecule hit; Specific atoms can
only absorb certain photons of light
- In photosynthetic bacteria the plasma membrane itself is the phosynthetic
membrane
- Plants have two linked photosystems