Unit #2 Flashcards
Summary Equation of Photosynthesis
6 CO2 + 12 H2O + light energy -> C6H12O6 + 6 O2 + 6 H20
light
- raw material of photosynthesis
- in form of a wave, acts like both a wave and a particle
- shorter the wavelength, the higher the energy
- longer the wavelength, the lower the energy
- does not cause damage to nucleus/DNA
- excites the electrons inside of the chlorophyll
CO2
- raw material of photosynthesis
- covalently bonded
- changes from inorganic CO2 to organic carbon in the Carbon Cycle
- 408.36 parts per million of atmospheric CO2
- enters leaves through stomates and dissolves in the water that is in the cell walls of mesophyll cells, diffuses across into cytoplasm, and eventually into the storm oaf the chloroplast
Water
- raw material of photosynthesis
- only around 1% of the water absorbed by plants is used
- hydrogen bonded
Options for an excited electron
- could go back to original place
- could give off energy as hear or light
- could give off light energy=fluorescence
- could get passed to some other molecule and some every is captured in covalent bonds
chlorophyll a
- CH3, 5 oxygen atoms
- absorbance peaks=430-664nm
- embedded in thylakoid membranes and anchored by hydrocarbon tail
- found in photosynthetic eukaryotes and cyanobacteria
chlorophyll b
- CHO, 6 oxygen atoms
- absorbance peaks= 460-647nm
- embedded in thylakoid membranes and anchored by hydrocarbon tail
- found in seed plants, bryophytes, green algae, and euglenoid algae
- accessory pigment=helps harvest more wavelengths of light
carotene
- hydrocarbon chain
- accessory pigments
- β=carrots, orange, vitamin A, retinal
- found in all chloroplasts and some cyanobacteria
- some function as accessory pigments during photosynthesis, some function in photo-protection (absorbing and dissipating excess light energy)
xanthophylls
- accessory pigments
- hydrocarbon plus oxygen
- yellow (ex: corn)
phycobilins
- found in cyanobacteria and red algae
- attached to water soluble proteins
- accessory pigments
reaction-center complex
organized association of proteins holding a special pari of chlorophyll a molecules in a photosystem
light-harvesting complex
various pigment molecules (chlorophyll a, b, carotenoids) bound to proteins in a photosystem
photosystem
- embedded in membrane of a thylakoid
- harvests light
- contains reaction-center and light-harvesting complexes
- contains a primary electron acceptor
- transfers energy through pigment molecules
- contain proteins
photosystem II
-chlorophyll a, chlorophyll b, β carotene, and reaction center which all = P680
photosystem I
-250-400 molecules of chlorophyll a, chlorophyll b, carotenoids, and reaction center which all= P700
photolysis
light breaking apart a water molecule
chemiosmosis
process of a molecule moving from high concentration to low concentration based on its charge and concentration inside the cell
cyclic phosphorylation
electrons go to photosystem I, but not PSII and produces no NADPH and no O2, makes more ATP than noncyclic
noncyclic phosphorylation
process of converting ADP +Pi to ATP using the energy from sunlight, done in PSII
NADP+
cofactor, used in PSI of light reactions, with H+ can be converted into NADPH, classified as an energy carrier
NADPH
coenzyme
water movement types
- in and out of cells
- across or through tissues
- from the roots to the leaves
why water is needed for plants
- photosynthesis
- leaves are made of water
- diffusion
- cellular respiration
diffusion
net movement of molecules or atoms from a region of high concentration to a region of low concentration as a result of random motion of the molecules or atoms
osmosis
movement of water through a semipermeable membrane
facilitated diffusion
uses a protein channel, not ATP, aquaporins
active transport
needs energy from ATP, can go against concentration gradient
cotransport
takes two proteins, builds up the concentration gradient, requires ATP
water potential
- a measurement of differences in the potential energy of water
- waterfall example (top=high, bottom=low)
- in cells, gravity is not as crucial, potential comes from pressure and dissolved things
pressure potential
the total amount of pressure put on a cell by water
osmotic (solute) pressure
more stuff dissolved in the solution=higher pressure
Pascal
- SI unit of pressure, water potential is measured in
- equal to one newton
megapascal
equal to 1,00,00 pascals
turgor pressure
force within the cell pushes the membrane against cell wall
isotonic
equal net movement of water and molecules
hypertonic
more solutes outside of the cell, water will flow out, plasmolysis
hypotonic
more solutes inside of the cell, water will flow in
plasmolysis
loss of water in a cell, usually lead to death of cell, hypertonic situation
imbibition
special type of diffusion that occurs when water is absorbed y solids causing enormous increase in volume
apoplectic movement
water movement through cells by the cell walls/nonliving components of a cell only, roots
symplastic movement
water movement through cells by the plasmodesmata/living components of a cell only, roots
trans-membrane movement
water movement through cells by both living and nonliving components of a cell, roots
root pressure
- osmotic pressure in the cells of a root system that cause water to rise through the stem and to the leaves via the xylem
1. transpiration is slower at night due to higher humidity in the atmosphere and closed stomates so there’s no upward xylem flow
2. inorganic ions are actively transported out of xylem parenchyma and the ions accumulate in xylem tracked and vessels in the roots
3. water potential is lowered and water flows into the xylem producing a positive pressure in the roots, the endodermis prevents “back flow” out of the xylem
4. water and dissolved ions are pushed up the xylem
hydathodes
modified pore that exudes water droplets on leaves
guttation
the secretion of droplets of water from the pores of plants, caused by root pressure
embolism
- air bubbles caused by broken branches, insect damage, or freezing
- in large plants it can make the vessel permanently nonfunctional
bulliform cells
- large, bubble-shaped epidermal cells that occur in groups on the upper surface of the leaves of many monocots
- adaptation for dry environments when the leaves fold
Nehemiah Grew
water movement by “pumping action” by xylem parenchyma
Marcello Malpighi
water movement by capillary action
Stephen Hales
water movement by root pressure
Cohesion-Tension Hypothesis
- water moves by bulk flow driven negative pressure driven by transpiration
- proposed by Henry Horation Dixon and John Joly in 1895
- transpiration, cohesion, and adhesion of water
function of guard cells
- open and close stomate
- help regulate the rate of transpiration
- share a middle lamella at each end and are “stuck together”
Pressure-Flow Hypothesis
food moves from sources to sinks by bulk flow driven by positive pressure driven by cotransport of sucrose into and out of cells
sinks
any plant part that can’t make its own food: shoot and root apical meristems, developing fruits, cortical cells in roots, rhizomes, tubers (etc)
sources
photosynthesizing leaves or food-storage tissues like root cortical cells
C Hopkns CaFe Mighty Good
-carbon
-hydrogen
-oxygen
-potassium
-nitrogen
-sulfur
-calcium
-iron
-magnesium
these are the macronutrients (essential elements) for plants
with CHOCaFeMg; but Not always Clean. CuMn, CoZn, MoBy
-sodium
-chlorine
-copper
-manganese
-cobalt
-zinc
-molybdenum
-boron
these are micronutrients (essential elements) for plants
paper chromatography
- technique used to separate the components of a mixture
- discrete zones on the paper, solvent moves by capillary action
- polarity, electoral charges, size, and chemical attractions
spectrophotometry
- plant pigments absorb specific wavelengths of light and reflect or are transparent to others
- instrument used to detect the amount of radiant light energy absorbed by molecules
most to least polar
- b
- a
- xanthopylls
- carotene
