52 terms

Bio Cellular respiration and Photosynthesis

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Fermentation
a partial degradation of sugars that occurs without oxygen
consists of glycolysis plus reaction that regenerate NAD+, which can be reused by glycolysis
-alcohol
-Lactic acid
produces 2 ATP per glucose
Aeorbic respiration
consumes organic molecules and oxygen and yields ATP
Anaerobic respiration
similar to aerobic respiration but consumes compounds other than oxygen
uses an electron transport chain with a final electron acceptor other than O2 (ex. sulfur)
redox reactions
chemical reactions that transfer electrons between reactants
oxidation
when a substance loses electrons
reduction
when a substance gains electrons
glucose, O2
During cellular respiration ________________ is oxidized and _________________ is reduced
NAD+
electrons from organic compunds are transferred to ______, a co enzyme
functions as an oxidizing agent
electron transport chain
NADH passes the electrons to ____________, passes electrons in a series of steps instead of one explosive reaction
O2 pulls electrons down the chain in an energy-yielding tumble
Glycolysis
breaks down glucose into two molecules of pyruvate
Occurs in the cytoplasm and has two major phases
--Energy investment phase
--Energy payoff phase
Occurs with or without oxygen
Net ATP of 2
citric acid cycle
In the presence of O2, pruvate enters the mitochondrion and the oxidation of glucose is completed
-pyruvate is converted to acetyl Coenzyme A
oxidative phosphorylation
accounts for most of the ATP synthesis (90%)
In the cristae of the mitochondrion
substrate-level phosphorylation
A smaller amount of ATP is formed in glycolysis and the citric acid cycle by _______________________
32
For each molecule of glucose the cell makes ___ of ATP
1 ATP, 3 NADH, and 1 FADH2
Products of the citric acid cycle when pyruvate is broken down to CO2
steps in the citric acid cycle
The acetyl group of acetyl CoA combines with oxaloacetate, forming citrate
-citrate then decomposes back to oxaloacetate
-NADH and FADH2 relay electrons to the electron transport chain
Chemiosmosis
Electron transfer in the etc causes proteins to pump H+ from the mitochondrial matrix to the inter membrane space
-The use of energy in a H+ gradient to drive cellular work
ATP synthase
uses the exergonic flow of H+ to drive the phosphorylation of ATP
when the H+ moves back across the membrane is passes through this protein
O2
Acts as the final electron acceptor in the electron transport chain after they are passed through cytochromes (proteins)
Obligated anaerobes
carry out fermentation or anaerobic repsiration and cannot survive in the presence of O2
Facultative anaerobes
They can survive using either fermentation or cellular respiration
Glucose, 2 ATP, 2 NAD+
glycolysis input
2 pyruvate, 2 ATP, 2 NADH
glycolysis output
2 pyruvate
citric acid cycle input
2 ATP, 8 NADH, 6 CO2, 2 FADH2
citric acid cycle output
Photosynthesis
the process that converts solar energy into chemical energy
chlorphyll
the green pigment with in the chloroplasts
mesophyll
where the chloroplasts are found, the interior tissue of the leaf
stomata
where CO2 enters and O2 exits
microscopic pores
thylakoids
connected sacs in the chloroplasts, stacked in columns called the grana
stroma
dense interior fluid in the chloroplasts
H2O, CO2
Photosynthesis oxidizes _____________ and reduces _______________
Light reactions
In the thylakoids
-splits H20
-Releases O2
-Reduces NADP+ to NADPH
-Makes ATP from ADP
Calvin cycle
in the stoma
forms sugar from CO2 using ATP and NADPH
carbon fixation of CO2
spectrophotometer
measures a pigment's ability to absorb various wavelengths
absorption spectrum
a graph plotting a pigment's light absorption versus wavelength
action spectrum
profiles the relative effectiveness of different wavelengths of radiation in driving a process
photosystem
consists of a reaction-center complex surrounded by light-harvesting complexes
light-harvesting complex
pigment molecules bound to proteins
transfer the energy of photons to the reaction center
primary electron acceptor
This is in the reaction center and accepts excited electrons and is reduced
Photosystem II
functions first and is best absorbing a wavelength of 680 nm
reaction center chlorophyll is called P680
Photosystem I
best at absorbing wavelength of 700 nm, chlorophyll a is called P700
Linear electron flow
the primary pathway involves both photosystems and produces ATP and NADPH using light energy
Light reaction
1) photon hits a pigment and its energy is passes among pigment molecules until it excites P680
2) the excited electron is transferred to the primary electron acceptor
3) H2O is split by enzymes and the e- are transferred from the hydrogen atoms and O2 is released
4) The electrons fall down the etc from the priamry electron acceptor of PSII to PSI, the energy released drives the creation of a proton gradient (drives ATP synthesis)
5) In PSI the transferred light energy exictes P700 which loses an electron to an electron acceptor
6) The electrons are then transferred to NADP+ to NADPH and is now ready for the Calvin cycle
cyclic electron flow
uses only photosystem I and produces ATP but not NADPH
no oxygen is released
satisfying the higher demand for ATP in the Calvin Cycle
glyceraldehyde 3-phosphate (G3P)
what is produced from the calvin cycle
takes 3 turn of the cycle fixing 3 molecules of CO2
Carbon fixation
Reduction
Regeneration of RuBP
3 phases of Calvin cycle
Photorespiration
rubisco adds O2 instead of CO2 to the Calvin cycle producing a two carbon compound
consumes O2 releases CO2 and produced no ATP or sugar
C3 plants
initial fixation of CO2 via rubisco forms a three-carbon compound
C4 plants
minimize the cost of photorespiration by incorporating CO2 into 4-carbon compounds in mesophyll cells
PEP carboxylase
Enzyme required by C4 plants to minimize photorespiration
it has a higher affinity for CO2 than rubisco does so it can fix CO2 even when concetrations are low
CAM plants
plants that open their stomata at night incorporating CO2 into organic acids
Stomata is closed during the day and CO2 is released from organic acids and used in the Calvin cycle
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