Ch 6 and Ch 8 Flashcards
metabolic pathways
produce energy through chemical ractions
catabolic pathways
degrade complex molecules, break their bonds for energy
anabolic pathways
build complicated molecules, consume energy and store in the bonds
bioenergetics
how energy flows through living systems
kinetic energy
moving energy that can produce work, when molecular bonds are broken
chemical potential energy
resting energy that is being stored, when molecular bonds are created and energy is stored in them
isolated system
can’t exchange energy with its surroundings
open system
exchanges energy with its surroundings
why cells are open systems
they absorb light and chemical energy, release heat and metabolic waste
first law of thermodynamics and biology
byproducts of cell metabolism increase entropy
free energy change
free-energy is what does the work when temperature and pressure are uniform, responsible for spontaneous changes
free energy and reactions
in order for the reaction to be spontaneous, the change in free energy must be negative; free energy tells us if a reaction can occur spontaneously this way
exergonic
when change in free energy is negative and spontaneous reactions can occur; the change in G is the maximum amount of work the spontaneous reaction can do
endergonic
absorbs free energy from the environment; when change in free energy is stored and positive
metabolism and equillibrium
living things must always be an open system that is in disequillibrium
cellular work
is powered by ATP and the progression of exergonic and endergonic reactions; the hydrolysis of ATP produces heat and proteins use energy to do work
work that proteins can do when given energy from ATP
chemical work, transport work, mechanical work
protein chemical work
if the change in free energy of the chemical relationship is less than the energy from the ATP, the chemical relationship’s bonds are broken
protein transport work
ATP changes the shape of the proteins so it can bind to other molecules,transports solutes through the transport proteins
ATP/ADP cycle
starts as ADP, adds a phosphate and produces water; when need energy, breaks bond of third phosphate, releases energy, and becomes ADP again
protein mechanical work
ATP changes the shape of the proteins so it can bind to other molecules, makes motor proteins move
role of enzymes
speeds up hydrolysis and bonding of chemicals as a catalyst; reusable
activation energy and chemical reactions
to break bonds it requires a certain amount of energy called activation energy; frequently the activation energy is absorbed as thermal energy
activation energy and enzymes
enzymes lower the amount of activation energy required by making the reaction occur more easily
enzyme specificity
enzymes only react with their designated substrate like a puzzle piece
induced fit model
as substrate approaches the enzyme, the enzyme moves around the substrate to make a snug fit and catalyze better
how enzymes lower the required activation energy
provides a template for molecules to fit together, stretches the bonds so easier to break, optimal reaction environment
how to increase the digestion of substrates with enzymes
must add more enzymes to increase rate (assuming correct pH and temperature)
enzymes and temperature/pH
each enzyme has an optimal pH and temperature, outside of that it doesn’t do its job well or eventually denatures
enzyme cofactors
perform crucial catalyst functions alongside the enzyme
enzyme inhibitors
competitive inhibitors look like the substrate and clog the enzyme; noncompetitive inhibitors impede reactions while bound elsewhere to the enzyme
allosteric regulation
uses reversible enzyme inhibitors to block enzymes when need to lower the metabolism of a substrate
cooperativity of an enzyme
when an enzyme has multiple sites for reactions, when one substrate locks in to a site, more are attracted to the other sites
feedback inhibition
when an enzyme is over catalyzing the end product of the catalyst reaction will stay inside the enzyme to block further reactions
autotrophs
make own food
heterotrophs
consume products made by other organisms
mesophyll
the tissue in the interior of the leaf that contains chloroplast
stomata
cells on the exterior of the leaf where CO2 and oxygen are exchanged
stroma
the inner liquid of the chloroplast, held in by an inner and outer chloroplast membrane
thylakoid
membrane system where chlorophyll is embedded, stacks of thylakoids are called grana, and the inside of a thylakoid is hollow called the thylakoid space
chlorophyll
found in membrane of thylakoid, green pigment that absorbs light for photosynthesis
photosynthesis equation
6CO2 + 6H2O + Light —> C6H12O2 + 6O2
two stages of photosynthesis
light reactions and calvin cycle
light reactions
photosystem two and one. splits water to stabilize PSII electrons while H+ powers ATP synthase and PSII electrons stabilize PSII electrons. bonds NADPH. O2 is released
calvin cycle
uses energy from ATP and NADPH to take the CO2 and make the organic glucose
carbon fixation
when CO2 is used to make an organic molecule
light wavelength and light energy
the shorter the wavelength, the higher the energy; violet has the shortest wavelength and red has the highest
absorption spectra
show how a pigment absorbs each wavelength
action spectrum
shows rate of photosynthesis for different wavelengths; doesn’t totally match absorption spectra due to accessory pigments’ role; needs spectrophotometer
the pigments of plants
chlorphyll a is the primary pigment, chlorophyll b is the accessory pigment, accompanied by carotenoid accessory pigments
accessory pigment roles
absorb other wavelengths to photosynthesize, but not as effectively as the primary pigment would
structure of a photosystem
chlorophyll absorb light and excite electrons that eventually excite the special pair of chlorophyll a molecules that send electrons to the primary electron acceptor
where the light reactions occur
in the photosystems nested in the thylakoid membrane, thylakoid space and stroma
where the calvin cycle occurs
the stroma
parts of the chloroplast
mesophyll cells: where chloroplasts are; stomata is where water and CO2 are intaked
chemiosmosis
the process of H+ protons moving across a gradient to make ATP in photosynthesis and in cellular respiration
needed materials for light reactions
water, ADP, chlorophyll A, light, cytochrome complex, ATP synthase, NADP+ reductase, NADP+, protons
needed materials for calvin cycle
RuBP, CO2, rubsico enzyme, 9 ATP, 6 NADPH
light reactions products
H+, ATP, NADPH, oxygen gas
calvin cycle products
one G3P molecule, ADP, NADP+
photorespiration
when CO2 stops coming in the leaf and rubisco fixes oxygen gas rather than co2 to start calvin cycle
problems with photorespiration
uses ATP instead of making it, decreases output by releasing organic molecules as CO2
chemoautotrophs
make own energy from thermal energy, under water near thermal vents
examples of photosynthesis autotrophs
bacteria, protists, plants, NOT fungi
how water gets to chloropyll
from roots to xylem, through adhesion and cohesion, gets to the vain of leaf
how CO2 gets into the cell
the cells on the surface absorb water and buckle to make a hole (aka the stomata) for the CO2 to enter
cytochrome complex
carrier proteins for electrons
why leaves turn red/brown
chlorophyll stops being made, so the secondary pigments that have always been there are now needed to photosynthesize and red/brown is reflected
C3 vs C4
C3 is regular photosynthesis; C4 opens stomata quickly and periodically during the day; photosynthetic layers are closest to veins to be close to water; stores CO as an acid
C4 vs CAM
CAM only opens at night and stores CO2 at night so doesn’t have to open the stomata, then uses CO2 in light reactions during the day
carbon fixation three stages
carbon fixation, reduction, regeneration
