Metabolism and Energy Flashcards
Energy
capacity to do work
First law of thermodynamics
energy does not appear out of no wear and it does not vanish
second law of thermodynamics
entropy increases spontaneously
Cell Store and retrieve energy
in chemical bonds of molecules
Reaction
the process by which such chemical change occurs
Reactants
molecules that enter a reaction
Products
molecules that remain at the reaction’s end
Free energy
amount of energy that is available to do work
endergonic
energy in
exergonic
energy out
ATP
energy carrier, accepts and release exergonic reactions and delivers endergonic reactions
ATP has ___ phosphates
3
Phosphorylation
Phosphate group transfer
ATP/ADP cycle
cycle of using and replenishing ATP
Enzymens
make specify reactions occur much faster than they would on their own
Active sites
polypeptide chains of enzymes are folded into one more active sites, pockets where substrates bind and where reactions proceed
Transition state
when substate bonds reach their breaking point and the reaction will run spontaneously to product
Closer molecules are together
more likely they will react
Cofactors
atoms or molecules that associate with enzymes and are necessary for their function
Coenzymes
vitamins
Antioxidant
neutralizes free radicals
Metabolic Pathways
any series of enzyme mediated reactions by which a cell builds, rearranges, or breaks down an organic substance
allosteric
region of an enzyme other than the active site that can bind regulatory molecules
Feedback Inhibitions
the end product of a series of enzymatic reactions inhibits the first enzyme in the series
Oxidation reduction reactions
the only way cells can capture energy from glucose is to break down the molecules in small, manageable steps.
Electron transfer chain
an organized series of reaction steps in which membrane bound arrays of enzymes and other molecules give up and accept electrons in turn
Wavelengths
the distance between the crests of two successive waves of light
Photosynthesis
harness of energy of light to build organic molecules from inorganic raw material
Pigment
organic molecule that absorbs light of specific wavelengths
Chlorophyll
most common photosynthesis pigment in plant. makes plants green
Chloroplast
specializes in photosynthesis in plant and many protists
Stroma
plant chloroplasts have two outer membranes and filled with a semifluid matrix
Thylakoid Membrane
form stacks of disks that are connected by channels. light harvester
Photosystem
groups of hundreds of pigments and other molecules that work as a unit to begin the reactions of photosystems
Light dependent reactions
the energy of light gets converted to the chemical bond energy of ATP
NADP+
accepts electons and hydrogen ions
light independent reactions
runs on energy delivered but the ATP and NADPH formed in the first stage. second stage of photosynthesis
Reactions of the firs stage of photosynthesis
convert the energy of light to the energy of chemical bonds
Photophosphorylation
any light driven reaction that attaches phosphate to a molecule
Calcin Benson cycle
builds sugars in the stroma of chloroplasts. They are light independent, they run bond energy of ATP
carbon fixation
extracting carbon atoms from an inorganic source and incorporating them into an organic molecule
Rubisco
fixes carbon by attaching CO2 to five carbon
six carbon
unstable
Plants use glucose
to make light independent reactions for other molecules
C3 plants
plants that use only the calvin benson cycle to fix carbon. sugar plants
stomata
small openings across the epidermal surfaces of leaves and green stems
opens CO2 and O2 out
photorespiration
At high O2 levels, rubisco attaches oxygen to RuBP in a pathway
C4 plants
Plants that use the additional reactions also close stomata on dry days, but their sugar production does not decline. ex. corn. dry plants
CAM plants
have an alternative carbon fixing pathway that allows them to conserve water even in regions where the daytime temperatures can be extremely high.
Autotrophs
Self nourishing organisms, harvest energy directly from environment.
Heterotrophs
Most bacteria, animals, protists, fungi. Get energy and carbon from organic molecules that have already been assembled by other organisms.
Photoautotroph
make sugars from carbon dioxide and water using the energy of sunlight
Chemoautotroph
extract energy and carbon from simple molecules in the environment
Aerobic
use oxygen
anaerobic
occur in the absence of oxygen
aerobic respirations
main pathway by which cells harvest energy from organic molecules
glycolysis
convert one six carbon molecule of glucose into pyruvate
pyruvate
molecule with a three carbon backbone
Substrate level phosphorylations
direct transfers of a phosphate group from a substrate to ADP
Krebs cycle
breaks down the pyruvate products of glycolysis
Electron Transfer Phosphorylation
third stage of aerobic reparation, occurs inside mitchocondria, flow of electrons through mitochondrial electron transfer chains ultimately results in the attachment of phosphate to ADP
Lactate fermentation
electrons and hydrogen ions are transferred from NADH directly to pyruvate
Alcoholic fermentation
Pyruvate becomes converted to ethyl alcohol. product is ethanol.
Energy inputs drive organization of molecules into units called
cells
Oxidation
loss of electrons
Reduction
gain of electrons
Photosystem II
releases energy
Pholoysis
split water by energy, oxygen is a byproduct
Noncyclic photosynthesis
photsystem I works in this
non cyclic
results in oxygen
C02 —Photosynthesis–glucose then
O2—–H2O
Glycolysis
converts one molecule of glucose into two molecules of ATP
1 glucose molecule has ___ ATP
36
glycolysis, acetyl, and krebs cycle: 2
electron transfer: 36
