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What is the first law of thermodynamics? Why is it important to cellular energetics?
The amount of energy in the universe is constant, and energy can’t be created or destroyed
-it can be transformed though
-It’s important because it says that organisms must get their energy from somewhere and that it’s never just gone, it goes somewhere else when it’s lost or used
What is the second law of thermodynamics? Why is it important to cellular energetics?
Energy is lost in the form of heat
-It says how energy is lost and why organisms constantly need to replenish their energy
-Organisms can’t retain energy forever
What is heat energy?
Energy transferred from one system to another that isn’t doing work
What is an endergonic reaction?
The products have more energy than the reactants
-absorbing energy from environment
What is an exergonic reaction?
The products have less energy than the reactants
-Break down and release energy into environment
How are endergonic and exergonic reactions linked in cellular energetics?
Both reactions occur in the process of creating and breaking down ATP
-Energy going into endergonic reaction is less than the energy that goes out during exergonic
-As ADP and Pi go through an endergonic reaction, they create ATP (energy)
-As ATP is broken down through a exergonic reaction, it releases energy by breaking the third phosphate bond creating ADP and Pi
What is the basic structure of ATP?
ATP- Adenine triphosphate
-Has 3 phosphate groups
-A ribose molecule (5 carbon sugar)
-Adenine molecule (Nitrogenous base)
How does ATP store and release energy? (What is it’s role as an energy carrier)
ATP stores energy in the bonds it has with the phosphorous, when those bonds are broken it releases energy
What is an oxidation and reduction reaction (redox)?
most energy producing paths come from these reactions
-Oxidation strips electron from atom in compound
-Reduction donates electron to compound
How does a redox reaction relate to endergonic and exergonic reactions?
A redox reaction is an example of the binding reactions of endergonic and exergonic reactions
What is the process of diffusion?
The process of transport; substances move from areas of high → low concentration until the concentration is equal
What factors influence diffusion rates?
-The extent of the concentration gradient; greater the difference of concentration, the greater the rate of diffusion
-Mass; heavier molecules are slow
-Temp; high temp increases energy → movement → increase diffusion
-Solvent density; as density increases, diffusion decreases
-Solubility; nonpolar or lipid-soluble diffuse quicker
-Surface area and thickness of plasma membrane; increased surface area increases diffusion, increased thickness decreases diffusion
-Distance; greater distance slows diffusion
What is selective permeability?
Plasma membrane allows some, but not all materials to pass through
How does selective permeability affect movement of materials across plasma membranes? (What type of molecules can pass through and which cannot)
It stops certain materials from entering
-Gases like carbon dioxide and oxygen can cross the membrane
-Some polar molecules, like water and ethanol, can pass through
-Small molecules
What is facilitated diffusion?
Materials diffuse across the plasma membrane with help from membrane proteins
-The cell facilitates/guides the diffusion process
-uses concentration gradient
-Used to bring ions or useful molecules into the cell that are needed
Difference between active transport and Facilitated diffusion?
Active transport requires energy, while facilitated transport lets the diffusion work on it’s own
-Active transport moves things against the concentration gradient
-Facilitated diffusion has proteins that create channels for molecules to diffuse/flow through
What is osmosis?
Water diffuses across the membrane to a less concentrated side
-It continues until the concentration of water is equal on both sides
-The side with more solute will still have a higher level of water
Requires NO energy
What is Active transport?
Moves substances against their concentration gradients
-requires energy as ATP
-Moves materials/molecules in and out of membrane
What is tonicity?
The measure of relative concentrates of water and solute on opposite sides of plasma membrane
What is Hypertonic?
Less water concentration and MORE solute concentration
What is Isotonic?
Equal amounts of water moving in and out of cell
-Balanced
What is Hypotonic?
Have higher concentration of water than solutes
Water>Solute
What is endocytosis and exocytosis?
ENDO cytosis means transport requiring energy to move large molecules, parts of cell, or entire cells INTO a cell
EXO cytosis is used to take material OUT of the cell, also requires energy
What is the ultimate source of energy for life on earth?
sun
How does photosynthesis convert sun energy into useable energy forms?
Photosynthetic organisms turn solar energy into chemical energy, used by other animals
-Use light reactions and Calvin cycle
6 H2O + 6CO2 → 6O2 + C6H12O6
What are the reactants in photosynthesis and what are they used for?
Carbon dioxide: Used in the Calvin cycle when Carbon is captured from the CO2 to help make sugar molecules (glucose)
Water: Used in Light reactions and split into H+ ions and e-, releasing O2 (oxygen)
What are the products in photosynthesis and what are they used for?
Glucose: made from the Calvin cycle after taking a carbon from CO2
-Goes to Cellular respiration for glycolysis
Oxygen: Made from Light reactions when they split from the Water molecules
-Goes to Oxidative Phosphorylation/ end of Electron Transport chain in Cellular respiration
What is the structure of Chloroplast?
Have a double membrane (inner and outer)
-Third membrane forms stacked thylakoids
-In chloroplasts are…
Thylakoid
Chlorophyl
Stroma
Granum
What is the function of the Thylakoid?
Form stacks like plates
-contain the pigment chlorophyll
What is the function of Chlorophyll?
Absorbs light which is responsible for it’s green color
What is the function of Stroma?
The space surrounding the thylakoids and granum
What is the function of Granum?
A stack of thylakoids
How do the influences of light (wavelength and intensity) affect photosynthesis?
The wavelengths of 425 (Blue) and 675 (Orange/Red) yield the best ATP
-HIGH intensity yields MORE ATP
What is step 1 of light dependent reactions?
(Convert solar energy to chemical energy as NADPH or ATP)
Step 1. Happens in photosystem (PSII and PSI)
-Light energy goes from Chlorophyll to Chlorophyll, until it reaches the reaction center
-When light energy hits chlorophyll A molecules in R.C. they get excited and release e- onto Carrier NADP+, making it NADPH
What is step 2 of light dependent reactions
Step 2. The reaction center of PSII takes its high energy e- to protein and electron carriers between PSI
-missing e- is replaced by low energy e- from H2O
Releases 2 e-, 2 H atoms, and 1 O atom
What is step 3 of light dependent reactions?
Step 3. As e- move through the electron chain they lose energy, and that energy moves H atoms to the thylakoid lumen and accumulate
-Electron needs re-energized, so PSI absorbs photon and oxidizes energy to send high energy e- to NADP+ to make NADPH
-PSII captures the energy to make ATP, PSI captures energy to make NADP+ to NADPH
Where does the ATP and NADPH from light dep. reactions go to?
Into the Calvin Cycle to be used in the Reduction reaction
What is a photosystem?
A Multiprotein complex
Structure: Antenna proteins with chlorophyll bound to them surround a reaction center
-First step of light dependent reactions occur here, first in Photosystem 2, then in Photosystem 1
How does an electron transport chain create ATP and NADPH in photosynthesis?
The electron transport chain is how electrons come from light energy to making ATP and NADPH
-After Light dependent reactions, Hydrogen atoms go through the ATP synthase protein that acts as a generator to add phosphate to ADP, creating ATP
What is Stage 1 of Calvin Cycle?
Fixation: Starts w/ CO2, enzyme Ribulose biphosphate carboxylase (RuBisCo) and 3 molecules of ribulose Biphosphate
(RuBP) has 5 C and 2 P
-RuBisCo catalyzes a reaction between CO2 and RuBP, making PGA (phosphoglycerate)
PGA has 3 C’s and 1 P
-each turn of cycle involves 1 RuBP and 1 CO2, making 2 PGAs
-Carbon Fixation as CO2 is “fixed” from inorganic- organic molecules
What is Stage 2 of Calvin Cycle
Reduction: ATP and NADPH turn 6 molecules of PGA into 6 molecules of phosphoglyceraldehyde (PGAL)
-For ATP, energy is released w/ loss of Phosphate atoms, turning it into ADP
-For NADPH, both energy and Hydrogen atoms are lost, turning it into NADP+
-Both molecules go back to light dep. Reactions to be reused
What is stage 3 of the Calvin Cycle?
Regeneration: For every 3 CO2 molecules, one PGAL leaves Calvin Cycle to make sugar in the cytoplasm
-Other 5 PGAL molecules made during stage 2 stay in Calvin Cycle to make RuBP
Allows system to fix more CO2
-3 more molecules of ATP are used in regeneration steps
What is the role of ATP and NADPH in photosynthesis? (Where are they made? Where are they used? What are they used for?)
Both ATP and NADPH: Made from light dependent reactions
-used in reduction stage of the Calvin cycle
-Used to turn PGA into PGAL
How are light reactions and the calvin cycle coupled?
The light reactions make ATP and NADPH, which goes to the calvin cycle and is turned into ADP and NADP+
-After calvin cycle the ADP and NADP+ go back to light cycle to make ATP AND NADPH
Why is the uptake of CO2 and release of Oxygen used to measure rates of photosynthesis?
Oxygen is the product released from photosynthesis, so the more that’s released that means the more photosynthesis that’s happening
-If more CO2 is used than you can also expect more photosynthesis to happen
What are the characteristics of Bacteria? (a major group of prokaryotes)
-Can be pathogens that cause disease in organisms
-Bacteria = prokaryote because their DNA isn’t in a true nucleus
-Described by shapes
-Photosynthetic bacteria: use sunlight for energy and fix CO2 for growth
-Non-photosynthetic Bacteria: Get energy from inorganic/organic compounds through chemosynthesis
-Cell walls contain Peptidoglycan
What are the characteristics of Archaea? (a major group of prokaryotes)
-Archaea are different than bacteria because they have different cell wall; pseudopeptidoglycan in the wall
-Archaea live everywhere
What is the metabolic diversity of bacteria and archaea?
-Very flexible, can switch from one energy source to another
-some primary producers use chemosynthesis to turn chemical energy from inorganic compounds into organic compounds that store energy
Chemosynthesis fuels the ecosystems where sunlight can’t reach
What is anaerobic respiration? (metabolism)
chemosynthesis to turn chemical energy from inorganic compounds into organic compounds that store energy
What are proteins and lipids? (metabolism)
What are the different environments that prokaryotes can live in?
They can live in all kinds of different environments, with high acidity, high temperatures, extremely low temperatures
-Halophiles: live in salty areas
-Acidophiles: live in acidic planes
-Thermophiles: Live in hot places
How are bacteria and archaea necessary for hydrothermal vent ecosystem?
Primary producers in hydrothermal vents are chemosynthetic bacteria/microbes
-They use high energy e- from the oxidation of H2S to reduce CO2, instead of the oxidation of H2O
Have similar reactions to calvin cycle for reduction of CO2 to carbohydrates
No light reaches thermal vents so the primary producers have to make energy without sunlight
What are some of the important biological and ecological functions of bacteria and archaea?
-Many are decomposers and help with the nutrient cycle by breaking down dead things
-recycle nutrients
-Carbon Fixation: turn CO2 into organic Carbon compounds
-Nitrogen Fixation: Turn atmosphere nitrogen into ammonium for plants
-Also cause lots of human illness and death
-Create climate change; carbon released is metabolized, making CO2 and Methane gas (greenhouse gases)
What are beneficial effects of bacteria/archaea on humans?
-Help with soil formation and stabilization
-Increase soil fertility
-help maintain pH
What are harmful effects of bacteria/archaea on humans?
-Can be pathogens that spread illness
-Can contaminate food
-Spoil food
-Cause foodborne illness
What is the current hypothesis of the relationship between bacteria, archaea, and eukaryotes?
Both bacteria and archaea are prokaryotes because they don’t have a true nucleus.
-Difference between
Endosymbiotic theory???
What are the characteristics of fungi?
-Eukaryotic; have a true nucleus and membrane bound organelles
-DNA comparison shows the DNA is more like animals than humans
-Don’t do photosynthesis
What is the life cycle of fungi?
-Heterotrophic
-Saprobes: Live off dead organisms
-Parasites: live off living organisms
-Most fungi are multicellular, yeast are unicellular
Have both Asexual and sexual reproduction
Asexual: Through fragmentation, cloned properties are maintained and the parent thallus (repro. organ) goes through mitosis
Sexual: Has 3 stages, can happen in homothallic or heterothallic mycelium
How do fungi sexually reproduce?
Plasmogamy (cytoplasmic fussion): 2 haploid cells fuse, leading to a dikaryotic stage
Karyogamy (Nuclear marriage): haploid nucleus fuse to form diploid zygote nucleus
Mitosis: Happens in gametangia (organs w/ different mating types) and releases spores
How do fungi obtain nutrition?
Fungi are heterotrophic
-Release enzymes outside of the cell that break down nutrients in the environment
-In fungal storage, polysaccharides are glycogen, rather than in starch in plants
-Mostly saprobes: live off dying organisms
What is the role of fungi in ecosystems?
-Key part in decomposing, have enzymes that break down cellulose and lignin in plants unlike other decomposers
-Many fungi have mutualistic relationship w/ roots, they give them water and fungi get photosynthetic products
-Lichens on roots break them down to make soil
-fungi also has mutualistic relationship with arthropods and insects
What are benefits of fungi?
-Decomposers; allow for nutrients to break down and cycle
-Some fungi are food for other animals
-control populations of pests
-many antibiotics are naturally made by fungi, which are made into drugs
What is harmful about fungi?
-Can be parasitic and hurt living things
-skin infections
-Fungi attack by colonizing and destroying tissue
-Systematic mycoses go to internal organs and treatment has serious side effects
-opportunistic mycoses attack individuals with already weak immune systems
How are proteins broken down during cellular respiration?
Proteins are hydrolyzed by enzymes in cells and turn into amino acids
-Amino Acids the pyruvate, Acetyl CoA, and Krebs Cycle
-If body is starving the Amino acids go into glucose catabolism
What is catabolism?
Breakdown of complex molecules into smaller units which release energy
How are fats broken down during cellular respiration?
Fatty acids are catabolized in the matrix of the mitochondria, turning them into acetyl groups that bind with CoA to make Acetyl-CoA, going into the Krebs cycle
-Fats break into glycerol and fatty acids
Glycerol goes into glycolysis to pyruvate
Fatty acids go into Acetyl CoA
What is the equation for photosynthesis?
Solar energy + Carbon Dioxide + Water → Carbohydrate + Oygen
6 H2O + 6CO2 → 6O2 + C6H12O6
What is the equation for cellular respiration?
Carbohydrate + Oxygen → Carbon dioxide + Water + Energy
C6H12O6 + O2 → 6CO2 + 6H2O + energy
What are the reactants of cellular respiration?
Carbohydrate (C6H12O6): comes from photosynthesis in the Calvin Cycle when it makes the glucose
Used for glycolysis to break down this 6 Carbon sugar into 2 3-Carbon sugars (pyruvate)
Oxygen (O2): Comes from light reactions in Photosynthesis when they split H2O molecules
Used in oxidative phosphorylation at end of electron transport chain to make H2O by pulling electrons through the transport chain
What are the products of cellular respiration?
Carbon Dioxide (CO2): released from the Krebs Cycle, 2 molecules per cycle
Goes to Photosynthesis in the Calvin Cycle to use the Carbon to make sugar molecules
Water (H2O): released at the end of the electron transport chain during oxidative phosphorylation
Goes to Light reactions to split and give electrons
Energy (ATP): 32 are made from Oxidative Phosphorylation, 2 are made from Glycolysis, 2 are made from Krebs cycle
What is the role of NAD+, NADH, FAD, and FADH2 in Cellular respiration?
NAD+ and FAD molecules capture electrons in the Krebs cycle, becoming NADH and FADH2 to later release them during oxidative phosphorylation in the electron transport chain
-NAD+ and FAD are electron carriers
What happens during glycolysis?
The glucose is broken down into 2 3-Carbon pyruvate and the energy from the chemical bonds is taken and put into ATP and NADH
-Purpose: To make pyruvate and release energy molecules
-occurs in cytoplasm
What are the reactants and products of glycolysis?
Glucose → 2 pyruvate + 2 NADH + 2 ATP
-4 ATP was made over the whole reaction, but 2 were used in phase 1 to change glucose
-The pyruvate continues into the mitochondrion
-ATP is released and NADH goes to oxidative phosphorylation
What happens during the oxidation of pyruvate?
If oxygen is available, aerobic cell. respiration happens and the pyruvate moves into mitochondrion
-Pyruvate (3-Carbon) turns into Acetyl group (2-Carbon) and attaches to carrier compound becoming Acetyl-CoA
Major function is to deliver 2-Carbon energy to next part
-NAD+ reduces to NADH and Co2 is released for each pyruvate molecule entering the reaction
-happens in matrix
What are the products and reactants of the Oxidation of Pyruvate?
Pyruvate → CO2 + NADH + Acetyl-CoA
-NADH goes to oxidative phosphorylation
-Acetyl-CoA is taken to the Krebs Cycle
-CO2 is released for Calvin cycle in photosynthesis
What happens during Krebs Cycle?
Acetyl-CoA enters the cycle and joins a 4 Carbon molecule, dropping it’s carrier and becoming a 6 Carbon molecule
-Releases Co2 and reduces NAD+ to NADH (becomes 5 Carbon)
-Releases CO2 and reduces NAD+ to NADH (becomes 4 Carbon)
-Changes ADP, FAD, and NAD+ before completing the loop
-Happens in Matrix of mitochondria
What are the products and reactants of krebs cycle?
Acetyl-CoA + ADP + FAD + NAD+→ CO2 + 2 ATP + FADH2 + NADH
-CO2 is created twice to break down the 6 Carbon and is released from Cell. Respiration (goes back to Calvin cycle)
-ATP is made from ADP entering the cycle (energy released)
-FADH2 is made from FAD coming from the oxidative phosphorylation (go back to O.P)
-NADH is made from NAD+ coming from oxidative phosphorylation (go back to O.P.)
Total ATP Yield: 2 ATP
What happens during Oxidative Phosphorylation?
Makes ATP using electron transport chain and chemiosmosis
-Makes 32 ATP from glucose molecule
-Happens in intermembrane space
-Phosphate is added to ADP through redox
What is Substrate Level phosphorylation?
Phosphate is added through enzymes
What are the products and reactants of oxidative phosphorylation?
NADH + FADH2 + ADP + O2 → 32 ATP +H2O
-H2O is sent to light reactions in photosynthesis
-NADH, FADH2, and ADP are all used as electron carriers to bring e- to O.P.
-32 ATP made
What are the parts of the mitochondrion?
Outer membrane (outside)
Inner membrane: membrane surrounding matrix
(electron transport chain happens along this)
Inter membrane space: area between inner and outer membrane
Cristae: Folds along the inner membrane that increase surface area of matrix (redox reactions happen here)
Matrix: Area inside the mitochondrion (Krebs cycle occurs)
What is the role of oxygen during cellular respiration?
Oxygen is used at the end of the electron transport chain in Oxidative phosphorylation to join with hydrogen molecules to make water
the oxygen comes from the light dependent reaction in photosynthesis
What is the role of water during cellular respiration?
Water is made in cellular respiration at the end of the Electron transport chain and sent to the light dependent reactions in photosynthesis
What is the source of the carbon in CO2 that’s released in cellular respiration?
The carbon comes from the 6 Carbon molecules in the Krebs cycle that are the product of a 4 Carbon plus an Acetyl group from pyruvate
-The carbon is broken off twice, making it a 5 carbon group and then a 4 carbon group to restart the cycle
What’s the difference between aerobic cellular respiration and fermentation?
Fermentation is anaerobic and doesn’t use oxygen
-Aerobic cell. respiration: Electrons go to oxygen in end (36 ATP produced)
-Fermentation: electrons go to pyruvate and it’s broken down and converts to ethanol or lactate. (2 ATP Produced)
Energy in these alcohol bonds isn’t used to make ATP, so fermentation makes way less energy.
-Fermentation is used by certain prokaryotes; obligate anaerobes: only live in environments lacking oxygen
Lactic Acid fermentation
Uses fermentation to reduce pyruvate to Lactic Acid
-Used routinely in mammal red blood cells and skeletal muscle w/ low oxygen supply (fatigued muscle)
Alcohol fermentation
Produces ethanol
-In 1st reaction, carboxyl group is removed from pyruvate, releasing CO2
-In 2nd reaction, acetaldehyde reduces to make ethanol and regenerate NAD+
Why do cells use fermentation? What are the products?
Cells use fermentation when oxygen isn’t available
-Pyruvate is broken down releasing CO2 in part of it (Alcohol fermentation)
-Small amount of ATP is made over all, 2 ATP
-Purpose: Regenerates NAD+ and allows glycolysis to happen w/out oxygen
What is the final electron acceptor in aerobic cellular respiration?
What’s the final electron acceptor in fermentation?
Aerobic: Final electron acceptor is oxygen and becomes water after accepting electrons
-Yields 36 ATP because it goes through Glycolysis (2 ATP), Krebs Cycle (2 ATP) and oxidative phosphorylation (32 ATP)
Fermentation: Final electron acceptor is pyruvate at the end of glycolysis (2 ATP)
-Yields 2 ATP because it only goes through glycolysis and would require oxygen to continue past this stage
How do varying conditions affect respiration rates in yeast?
-Don’t need oxygen to survive, but it helps them grow faster
-More sugar gives them more to nutrients to feed off of and increases respiration rates
-High temperature kills yeast
What is the purpose of cellular respiration?
Cellular respiration makes a crap ton of ATP (36 ATP when aerobic) and all that energy is used throughout the body
-Also helps create the reactants in Photosynthesis to release oxygen and glucose
What is the relationship between cellular respiration and photosynthesis?
Cellular respiration produces the reactants for photosynthesis, and photosynthesis produces the reactants for cellular respiration
-It’s a cycle that just keeps going when the chloroplasts get light energy
How does an atom of carbon get from Glucose to being released as CO2 in the Krebs cycle?
Glucose is split into 2 3-Carbon Pyruvate
Pyruvate turns into Acetyl-CoA through oxidation of pyruvate
Acetyl-CoA drops the CoA as it enters into Krebs Cycle as a 2 Carbon molecule
2 carbon molecule joins a 4 carbon molecule in the krebs cycle and becomes 6 Carbon molecule
6 carbon molecule reduces NAD+ to NADH and loses carbon in CO2, becoming 5 carbon molecule
5 Carbon molecule reduces NAD+ to NADH and loses another carbon in CO2, becoming 4 carbon molecule
Is the electron transport chain needed to track a carbon atom?
No, electron transport chain only shows flow of electrons and production of energy, as well as the end making a molecule of water
-Carbon only goes from glucose to Krebs cycle
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