BIO EXAM 3 (Photosynthesis & Respiration)
Cellulosic ethanol
Only a few microbes have enzymes to break bond in cellulose
The immediate next energy-rich state formed with energy provided by electrons flowing through the mitochondrial electron transport chain is
a proton gradient
What can be consumed and go through cellular respiration
all substances (proteins, carbs, fats) can go thru cellular respiration
Slow-twitch oxidative fibers
(with many mitochondria and myoglobin for oxygen storage) use oxidative respiration - is slower, but produces much more ATP energy -Fat stored in these fibers, or mobilized from fat cells, is broken down in glycolysis and the citric acid cycle in the mitochondrion. NADH shuttles filled with electrons deliver electrons to the mitochondrial electron transport chain and support production of lots of ATP. *extract a lot of energy from glucose, use fat as a long-lasting energy source, act over extended periods, make a lot of ATP, not able to operate without oxygen
carbon cycle
-CO2 is used to make sugar molecules, sugars can be used to form proteins, lipids, etc. -when plants are eaten by consumer, the carbon in the plant is now in the consumer -decomposers break down materials, and incorporate carbon in to their own bodies -CO2 is returned to atmosphere through cellular respiration
Carbon conversion reactions:
-Conversion of CO2 to sugar=[HCOH] takes place in the chloroplast stroma fluid -Conversion of sugar=[HCOH] to CO2 takes place in the mitochondrial matrix fluid
Glycolysis
-Glucose enters the cytosol where glycolysis takes place and generates two pyruvates from glucose. -The pyruvate formed from glucose through glycolysis in the cytosol enters a mitochondrion and is converted to another molecule that enters the citric acid cycle -If oxygen is present, glucose can be burned completely in the mitochondria for highest ATP energy yield. If not, fermentation occurs.
A healthy gut excludes oxygen
-Gut microbes normally perform fermentation and grow slowly (not much oxygen in gut) -Antibiotic treatment and some chronic gut conditions can increase oxygen levels in the gut. -This can allow microbes like E. coli, Salmonella, and others to switch to aerobic respiration to spin out of control. -As long as these microbes are unable to take off, they are harmless. They only become pathogenic when gut conditions are disrupted.
Cellular Respiration overview step by step
-High-energy electrons + protons are extracted from C-H bonds in glycolysis and citric acid cycle and transferred to the electron shuttle NADH -NADH delivers these high-energy electrons to the electron transport chain to make a lot of ATP -The citric acid cycle extracts high-energy electrons until all carbon atoms of the original sugar molecule have been turned into CO2 -NADH drops high-energy electrons into the electron transport chain. Oxygen picks up electrons at the end of the chain, adds 2 H+ and forms H2O with polar bonds & tightly held electrons. Oxygen is the terminal electron acceptor of the electron-transport chain. (Without oxygen as the terminal electron acceptor, ATP levels drop quickly and we die) -The energy of electrons running through the electron transport chain is used to build a proton gradient. This gradient is then utilized to produce a lot of ATP (about 32 ATP).
Hemoglobin's O2 binding capacity
-Muscle releases CO2 from cellular respiration into the blood fluid; this CO2 decreases hemoglobin's O2 binding capacity -Hemoglobin releases O2 to the muscle; CO2 is taken away from the muscle by the blood fluid. -Lungs release CO2 into the air. -The drop in CO2 concentration in the blood fluid increases hemoglobin's O2 binding capacity. -O2 inhaled by the lungs binds tightly to hemoglobin.
Calvin Cycle reactions in stroma of chloroplast (Photosynthesis)
-The calvin cycle uses the NADPH, ATP, CO2 from the light reaction to form carbs 1. CO2 fixation: CO2 is attached to RuBP in a reaction creating 2 3PGs 2. CO2 reduction: 6 NADPH & 6 ATP energize the reduction. 3PG ---> G3P (carb). ADP and NADP+ return to thylakoid. Net gain of 1 G3P to form glucose 3. Regeneration of RuBP: ATP combines G3Ps to form RuBP -This cycle has to run 6 times for a net gain of 6 Carbon molecules
The mitochondrial uncoupling protein
-consists of a proton channel portion but does not have a turbine for making ATP -Protons (H+) flow through the uncoupling protein channel along their concentration gradient without making ATP. -All energy is released as heat. -Even though no ATP is produced, glycolysis and citric acid cycle will continue to run and energy is released as heat
When a pathogen is present...
-our beneficial gut microbes send a signal to our mitochondria to produce superoxide as a lethal weapon. -this is an O2 molecule that gets just one electron, and gets angry and destroys the pathogens and cancer cells
Oxygen in photosynthesis
-oxygen is a by-product of photosynthesis -oxygen is formed from water -oxygen formed in the chloroplast could be used in the mitochondria of the same cell -leaves require light to produce oxygen
Oxygen
-ozone layer (O3) formed from O2 -O3 shields against intense ultraviolet radiation
Fast-twitch glycolytic fibers
-store energy as glycogen and have few mitochondria -quick but does not provide much ATP energy -Two ATP are formed from each glucose in glycolysis, and that is all the ATP these fibers can form. Pyruvate is converted to lactate using electrons and H+ from NADH. The NAD+ produced that way is able to support additional rounds of glycolysis and ATP production. *acting quickly, cant extract a lot of energy, not able to use fat as an energy source, not being able to use oxygen
Brown fat cells
-turn ALL of the energy from food into heat -produce heat in newborns, small mammals in cold climates, & hibernating animals. -Brown fat cells have many mitochondria and use an uncoupling protein to uncouple electron transport from ATP formation to generate only heat and no ATP at all.
Soil microbes provide
-water & nutrients -defense against pests & pathogens -Plants secrete carbohydrates into the soil as food for the microbes.
What happens in the electron transport chain?
1. High-energy electrons from food are fed into the electron transport chain 2. Electrons in the electron transport chain give up energy to build a proton gradient of H+ from low concentration in the matrix to high concentration in intermembrane space. This is done in 3 spaces or proteins 3. Utilization of the proton gradient energizes ATP formation by the ATP synthase turbine H+ flows from high concentration in space between membranes to low H+ concentration in the matrix (facilitated diffusion)
Light reactions in a thylakoid of a chloroplast (Photosynthesis)
1. Sunlight energizes electrons of chlorophyll that are continuously replaced by electrons from water (water splits) 2. Energized electrons flow through the electron transport chain; their energy is used to move H+ from low H+ in stroma to high H+ inside thylakoids (gradient) 3. H+ flow from high concentration within thylakoids to low H+ concentration in the stroma--specifically in the ATP synthase--creates an additional Phosphate, turning ADP to ATP 4. The energized electrons and a Hydrogen molecule are used to reduce NADP+ to NADPH -The light reactions provide ATP and NADPH to the Calvin cycle.
Flow of energy through ecosystem
1. sunlight enters ecosystem and is absorbed by grass (producer) 2. cow (consumer) eats grass and the chemical energy from this food is used to power the cows body functions 3. energy leaves the system as heat
Aerobic vs Anaerobic Respiration
Aerobic Cellular Respiration With Oxygen= Glycolysis + Citric Acid Cycle + Electron Transport Anaerobic Respiration Without Oxygen = Fermentation Glycolysis + lactic acid or alcohol production
Electrons and shells
After absorbing the energy of a photon of sunlight, the electron has enough energy to jump up to this higher shell. This energized electron is now ready to leave the atom and create an electrical current. The energized electron can leave its atom and flow from the solar cell into a wire or from chlorophyll into the electron transport chain of the light reactions
cellular respiration formula
C6H12O2 + 6O2 ------> 6CO2 + 6H20 + Energy (ATP)
Equation
CO2 + H2O +sun's energy --> C6H12O6 + O2
Summary of Cellular Respiration
Energy-rich electrons are extracted from sugar in glycolysis and the citric acid cycle, picked up by NADH, and shuttled over the electron transport chain. Oxygen picks up electrons at the end of the electron transport chain and forms water. The energy given up by the electrons is used to produce ATP
Sunlight energizes electrons that pass into an electron transport chain where they help move protons (H+) from low to high concentration. The electrons are loaded onto (NADP+) at the end of the photosynthetic electron transport chain.
Electrons flowing down the electron transport chain help move protons from low concentration in the stroma to high concentration in the inner thylakoid space. After dropping off the protons, the electrons receive a second boost from sunlight in the NADPH-producing photosystem that loads electrons onto NADP+.
GI & GL
Glycemic Index (GI) = rapidity of conversion of glucose Glycemic load (GL) = GI x amount of food consumed High GL = chronic elevated blood glucose
C4 plants
Grasses discussed as biofuel crops for cellulosic ethanol production -C4 plants don't open pores as widely: Lose ~275 g H2O per g CO2 fixed -C4 plants possess an additional step that fixes CO2 very efficiently even when internal CO2 concentrations are low, however, this step costs extra ATP energy -
Role of hemoglobin
Hemoglobin in the blood stream transports O2 inhaled by the lungs to body cells; hemoglobin then transports the CO2 waste produced by the body cells back to the lungs to be exhaled
Glucose levels
High GL diet: • Increases blood glucose levels Physical inactivity: • Diminishes glucose uptake into the muscles Psychological stress: • Releases glucose from fat cells and then increases appetite... • Diminishes glucose uptake into the muscles Genetics: • Slow transporters for glucose uptake into the muscles
The role of H2O and CO2
Hydrogen bonding allows water to travel up through the tree trunk until it leaves the tree through leaf pores that open to take in CO2
Electrons thru cellular respiration
In cellular respiration, electrons are extracted again from sugars and dropped into another electron shuttle, NADH, that takes these electrons to another electron transport chain where electrons give up energy to make ATP for cellular work. At the end of the electron transport chain of cellular respiration, the electrons combine with O2 and H+ to water again, which completes this electron circuit of life
Heat
In every step of the food chain, much energy is lost as heat especially when endothermic livestock is involved -Eating from lower on the food chain, producers, is more energy-efficient
Glycolysis & fermentation without oxygen
Lactic acid fermentation (forms lactic acid) -Muscle cells under anaerobic conditions -Some yeasts (fungi) & some bacteria Alcohol fermentation (forms ethanol) -Some yeasts (brewer's yeast and baker's yeast) & some bacteria
Light reaction formula
Light + H2O ---> ATP + NADPH
Light reactions
Light energy from the sun and water enter the chloroplast. Light reactions take place in the green thylakoids and produce the energy carrier ATP, the electron shuttle NADPH, and oxygen gas (O2) as a byproduct.
Electrons thru photosynthesis
Photosynthesis extracts electrons from water, energizes these electrons and moves them into an electron transport chain. At the end of the electron transport chain, these electrons are dropped into the electron shuttle NADPH that takes them to where they are needed to convert CO2 to C-H bonds in sugars. Electrons flowing through the electron transport chain give up energy that is used to make ATP to power sugar formation.
Bonds involved
Polar bonds (H2O & CO2) are converted to non polar bonds (C-H & O2)
The role of CO2 and O2
Pores on the leaf's outer surface let carbon dioxide enter and oxygen exit the leaf
Calvin cycle
Primary function: to synthesize a simple sugar (G3P) from carbon dioxide Carbon dioxide enters the chloroplast and is converted to sugars in the Calvin Cycle in the stroma (the fluid-filled space around the thylakoid membranes). ATP and NADPH power sugar production in the Calvin Cycle. Used-up ATP becomes ADP and a phosphate group and NADPH turns into NADP+, all of which return to the light reactions to be recycled again to ATP and NADPH. Carbon dioxide bonds with tightly held electrons is converted to sugar bonds with lossely held electrons in the Calvin cycle
C3 plants
Rapidly growing tree hybrid poplar discussed as another new biofuel crop -C3 plants open pores more widely: Lose ~450 g H2O per g CO2 fixed
Electron flow along electron transport chain is powered by what
Solar energy creates electron flow along a biological electron transport chain, which powers production of ATP and energized electrons & H for C-H bonds
These activate pathways that store energy as fat..
Sugars, starches, saturated fats, low fruit & veggies
How CO2 is created
The byproducts of burning C-H bonds with O2 are H2O and CO2
Overview + equation of Respiration
The outputs of photosynthesis, (sugar and oxygen) are used in cellular respiration mainly for the purpose to create ATP for producers and consumers. Other outputs of respiration are CO2 and H2O used in photosynthesis -As we inhale oxygen and eat food, CO2 is exhaled C6H12O6 + O2 ---> ATP + CO2 + H2O
How Oxygen is made
Through Photosynthesis -Without O2, multi-celled organisms (that depend on aerobic respiration) would not have arisen and life would be only single celled
CO2 levels
Winter increases and summer decreases due to changes in photosynthetic activity.
Effects of Cyanide or carbon monoxide
block O2 from picking up electrons from the transport chain. -The chain fills up with electrons, and NADH has no place to drop off its electrons. -No empty NAD+ is available to pick up electrons from the citric acid cycle. The cycle stops running.
thylakoid membranes, inner mitochondria membrane, electron transport
building a gradient, use to make ATP
Outer cell membrane
building a gradient, using ATP
Usage of carbs produced in calvin cyle
cellular respiration in the mitochondria or is used to form storage carbohydrate starch in a storage organ like a potato, or is used to form the structural carbohydrate cellulose that forms plant cell walls.
Metabolism
highly dynamic and highly responsive to the organism's environment
Sucrose
major carbohydrate in sugar cane & sugar beet; only 1 step to split sucrose into hexoses (for conversion to ethanol) -Sucrose is easy to convert to hexoses. -Seven harvests of cane before replanting is necessary. -Cane waste is burned for power & heat. -Still: food versus fuel conflict
Starch
major storage carbohydrate in corn grains or potato tubers Starch is easy to digest to hexoses. -HOWEVER: Annual crop, high input of fertilizer (produced with fossil fuels); only small portion of plant mass used -Huge food versus fuel conflict: Price of corn has more than tripled over the last decade
oxidative phosphorylation
making atp in the electron transport change using oxygen
Which consumes ATP
only the calvin cycle
Where is NADPH PRODUCED?
only in electron transport in the light reactions
What is needed to form water in mitochondria?
protons electrons oxygen a place for oxygen to bind to the inner mitochondrial membrane
Electron transport chains & ATP synthase turbines location
the inner thylakoid membranes and inner mitochondrial membranes.
Advantages of photosynthetic algae & bacteria
• can be grown in areas not suitable for plant growth • some can be grown in brackish water or saltwater • some release their energy-rich products, making energy-intensive harvesting unnecessary
