Cellular Energy Transformations Flashcards
1st Law of Thermodynamics:
Energy is neither created or destroyed
2nd Law of Thermodynamics:
hen energy changes form the entropy(disorder) of the surroundings increases.
Why are the laws of thermodynamics important to cellular energy?
the energy transformations of life are subject to them!
What is energy coupling?
When exergonic reactions fuel endergonic reactions
What does exergonic mean in regards to metabolic reactions?
metabolic reactions that release energy
What is free energy and why is it important?
-Free energy is energy release from endergonic reactions, and it is important because it also provides energy to endergonic reactions
-this is an example of energy coupling
What law of thermodynamics does energy coupling connect to?
First law: energy is neither created nor destroyed
How does ATP provide energy?
It powers cellular work (or the energy TRANSFER) by coupling exergonic reactions to endergonic reactions
-I
What is transport work?
moving substances across membranes
What is chemical work?
providing the activation energy for enzyme-catalyzed reactions
Why is ATP the main energy intermediate in the biosphere
- consumers and producers store energy in the bond between ADP and another phosphate group, which forms ATP
-Use for temporary energy storage by all organisms.
-Cells release energy by breaking these bonds and can restore energy by reforming them. - A more efficient energy source than glucose because glucose must be broken down.
What is creatine phosphate and how is it related to the energy making process within the cell?
Creatine phosphate is a compound that gives up its phosphate to ADP so that ADP can be recharged into ATP. This allows it to be used for immediate energy needs because it allows the body to create ADP more effectively and efficiently.
What is ATP synthase and how is it related to the synthesis of ATP?
-ATP synthase is an enzyme that lowers the activation energy of the phosphorylation of ATP, or the combination of ADP and phosphocreatine into ATP/
What is the synthesis of ADP and ATP also called, and what kind of reaction is it considered?
anabolism (phosphorylation)
What is the atp/adp cycle and what is it an example of ?
he catabolism of ATP into ADP and a phosphate group
and The anabolism of ATP from ADP and phosphocreatine
- energy coupling
-ATP is being “recharged”
In what layer of the leaf does photosynthesis occur and why?
the mesophyll layer, because it is the only layer that contains chloroplasts
How do plants acquire the carbon dioxide and water needed to perform photosynthesis?
The acquire water throug htheir roots and carbon dioxide through their stomata.
What are the two intermediate reactions that photosynthesis can be broken down into?
Photolysis(Light Dependent:Catabolic)
Calvin Cycle(Light Independent:Anabolic)
What is the calvin cycle?
A light independent, anabolic, and anaerobic reaction that is part of photosynthesis
Is photosynthesis aerobic or anerobic
anaerobic, because it uses carbon dioxide, not oxygen!
What are the steps of the calvin cycle and what is it’s purpose
Uses the ATP and hydrogen from photolysis, along with absorbed CO2 from the atmosphere, to form glucose. ATP is stored in these glucose bonds.
-this glucose is then stored as starch in the plant, and is the unused during cellular resipration.
What are the steps of photosynthesis in order
photolysis, calvin cycle?
When do plants use cellular respiration or photosynthesis?
Plants use cellular respiration when they are not able to photosynthesize to meet their energy needs.
Plants use photosynthesis constantly, and then use cellular respiration to break down this glucose and meet their immediate energy needs. Excess glucose is stored as starch in the structural body of the plant.
How do heterotrophs use cellular respiration and how
Heterotrophs use cellular respiration to meet their immediate energy needs. They break down glucose in food that they consume into ATP, which stores energy in the chemical bond between ADP and a Phosphorus group.
-only yields 2 atp
- The excess LACTIC ACID is broken down and stored in the liver and kidneys. DOES NOT YIELD ENERGY
-When oxygen isn’t available, heterotrophs use alcoholic and lactic acid fermentation.
What are the pros and cons of anaerobic vs aerobic respiration?
Aerobic respiration requires oxygen and produces more ATP, while anaerobic respiration does not require oxygen and produces less ATP.
summarize aerobic cellular respiration
The complete process of breaking down glucose in the presence of oxygen, producing carbon dioxide, water, and ATP. This process involves glycolysis, Acetyl CoA formation, the Krebs Cycle, and the electron transport chain.
What are the steps of aerobic cellular respiration
This process involves glycolysis, Acetyl CoA formation, the Krebs Cycle, and the electron transport chain.
What is the alternate definition of free energy?
Energy available to do work in a chemical reaction.
Creatine Phosphate
A molecule that provides a phosphate group to ADP, converting it back to ATP. This allows cells to restore energy in ATP bonds, and therefore, use more energy. This is used for immediate energy needs.
What do autotrophs do with excess energy? What do heterotrophs do with excess energy?
-autotrophs store excess energy as starch, build biomass, and reflect sunlight they are not able to absorb. PLANTS DO NOT GIVE OFF EXCESS ENERGY AS HEAT.
-heterotrophs give off excess energy as heat.
what is Phosphorylation and what is it used in?
-The process of adding a phosphate group to a molecule., used in converting ADP to ATP
-this is used in cellular respiration. More specifically, in photolysis, the Krebs Cycle, and the electron transport chain
What two molecules combine to form ATP?
-phosphocreatine and ADP
What are the reactants and products of photosynthesis
reactants: water, carbon dioxide, light energy
products: glucose, oxygen
What is photolysis and how does it work?
-photolysis is the first stage of photosynthesis. In this stage, energy from sunlight excites the electrons in water, causing them to split, releasing oxygen.
-**PHOTOLYSIS CREATES A SMALL AMOUNT OF ATP, BECAUSE ATP POWERS ALL CELLULAR WORK-THIS ATP THEN MOVES ONTO THE CALVIN CYCLE **
The hydrogen ions in water then bond to NADP, an electron carrier, and ATP, are later used in the Calvin cycle
How does the Calvin Cycle work
-The calvin cycle is an aerobic reaction that is the final step of photosynthesis. IN this stage carbon dioxide, ATP, and NADPH synthesize glucose.
-the chemical energy in the ATP (Which is created in photolysis, because sunlight provides the chemical energy need for adp and p to bond.) becomes stored in the chemical bonds in glucose.
-ADP is also broken down to provide energy during this reaction, providing the ADP and P needed in PHOTOLYSIS.
-this reaction is sped up by rubisco, specifically the absorbtion of carbon dioxide
-when the hydrogen ions are released from NADPH to form glucose, the NADP “electron carrier” can be reused, thus securing photosynthesis as a cycle.
What is RUBISCO and what is it used in?
the enzyme and incidentally the most abundant protein in the world responsible for lowering the activation energy of the calvin cycle
Chloroplast
Chloroplasts are organelles inside mesophyll cells that are the main site for photosynthesis
Accessory pigments
Pigments other than chlorophyll that absorb different wavelengths of light not absorbed by chlorophyll
ex: caretenoids
When plants stop making chlorophyll, the colors of the accessory pigments are unmasked/become visible
What wavelength is reflected light, and why do plants reflect light?
-If light is not immediately absorbed by the chloroplast, it is reflected by other objects in the environment
When light “bounces back”, it does so at a longer wavelength (red)
What is the relationship between wavelength and ATP production?
Shortest wavelengths produce the greatest excitation of electrons
More excited electrons = more ATP
electron carrier
A compound that can accept a pair of high energy electrons and transfer them, along with most of their energy, to another molecule.
electron transport chain
Series of eelectron carrier proteins that shuttle high energy electrons during ATP generating reactions.
- used to pump H+ ions across the mitochondria.
What factors affect photosynthesis
-temperature
-light intensity
-water availablility.
What pigments have the shortest wavelengths? what about the longest?
-blues have the shortest, reds have the longest.
What is ATP synthase and when is it used in cellular respiration?
-an enzyme that enzyme which lowers the activation energy of phosphorylation of ADP. This occurs during many stages of cellular respiration. DOES NOT OCCUR DURING PHOTOSYNTHESIS, BECAUSE PHOTOSYNTHESIS DOES NOT PRODUCE ATP
What stage of cellular respiration produces the most ATP
-the electron transport chain, produces about 30
How does alcoholic fermentation work?
-carried out by yeast, produces ethyl alcohol and CO2
How does lactic acid fermentation work?
pyruvic acid is converted to lactic acid
What substance in photosynthesis is both a product and a reaction
H2O, enters in liquid form, leaves as water vapor
How do the products of photosynthesis leave the leaf?
-water and CO2 leave through the stomata, glucose leaves through the central vein.
What is glucose classified as?
both matter AND energy!
metabolism
processes carried out to acquire and use energy
Where do the stages of cellular respiration occur in the cell?
glycolysis-cytoplasm
-krebs cycle- mitochondria
-electron transport chain-mitochondria
what are C4 plants and what are some examples
Plants that have evolved a mechanism to minimize photorespiration by using a four-carbon compound to initially fix carbon dioxide before it enters the Calvin cycle.
-this is often in environemt
photorespiration and why does it occur?
photorespiration is cellular respiration in the presence of oxygen. This is because rubisco, an enzyme that speeds up the calvin cycle, has an affinity for oxygen when it is exposed to it, and absorbs it into the plant because it then binds to it instead of carbon dioxide. This makes photosynthesis difficult or impossible to execute.
-photorespiration reduces the pants energy, because it causes the plant to “cannibalize” itself, and cellular respiration produces less energy than photosynthesis.
-this often happens when there Is a density of plants, because then a lot of oxygen is released. It also occurs when there is a lack of CO2 and at high temperatures
CAM plants
Plants that avoid water loss by opening their stomata at night to take in carbon dioxide, and store it so it can be used during the day for photosynthesis.
- like C4 plants, they also use a 4 carbon molecule in the carbon fioxation/ (absorption) stage of the calvin cycle.
ex: succulents and cacti
What are C4 pants and how are they different from CAM plants?
-C4 plants use an alternate route of carbon fixation ( using 4 carbons) so the plant can avoid absorbing oxygen, and thus initiating photorespiration.
EX: Grasses: Corn and Sugarcane)
What is the difference between CAM and C4 plants?
-C4 plants don’t close their stomata to preserve water
-CAM plants preserve water, C4 plants avoid oxygen
How many steps in cellular respiration produce ATP and how much ATP do they produce?
3/4 (glycolysis produces 2 ATP, krebs cycle produces 2 atp, electron transport chain produces 26-30 atp)
How many steps in photosynthesis produce ATP?
NONE!
What is the chemical equation for photosynthesis?
6CO2+6H2O+sunlight/chemical energy—>C6H12O6+6O2
What is the chemical equation for cellular respiration?
6O2+C6H12O6–> ATP+ 6CO2+6H2O
How many molecules of oxygen are absorbed in cellular respiration, and at what step are these molecules absorbed?
the electron transport chain
How many molecules of CO2 are produced during the Krebs cycle?
4
How much carbon dioxide is released during cellular respiration, and during what step does this occur?
- 2O2, during the formation of acetyl coA
how many molecules of water are absorbed during photosynthesis and during what stage does this occur?
-H2O, during photolysis
How many molecules of carbon dioxide are absorbed during photosynthesis and during which step does this occur?
6CO2, it is absorbed during the calvin cycle
how much oxygen is released during photosynthesis and during which step?
6O2, during photolysis
is photosynthesis endergonic or exergonic and why?
-photosynthesis is an endergonic reaction because it requires an input of energy (sunlight) , and then stores the energy in the bonds of glucose.
-Therefore, it absorbs energy
is cellular respiration endergonic or exergonic? Why?
Cellular respiration is an exergonic reaction because it releases energy as ATP as it breaks down glucose
Why aerobic cellular respiration more advantageous to organisms?
The waste byproducts of aerobic respiration are simpler (CO2), and are easier to break down. THis means that it takes less energy to break them down, as opposed to fermentation, where the waste products must be broken down by the body and don’t produce any energy.
Therefore, more energy is available to recharge ATP from ADP and Creatine Phosphate
As a result of this higher efficiency, aerobic organisms can be more complex, active and have longer-life spans.
How are accessory pigments used during photosynthesis?
- electrons of the accessory pigments are passed on to chlorophyll, exciting its electrons. As chlorophyll is the most abundant, this splits water into oxygen ( which is released, ) and hydrogen ions, which are picked up by NADP+ to move into the next cycle.
What is the charge of NADP
positively charged (NADP+)
What is the charge of NADH?
positively charged (NADH+)
How many hydrogens does NAD+ pick up
