Biology Unit 3 Flashcards
Cellular Respiration
C6H12O6 + O2 —–> Co2 + H20 + Energy Intermediate
Cellular Respiration is high in areas with mitochondria. Liver, Muscles and Nerves.
Glucose is being oxidized to Co2. Oxygen is being reduced to water.
Nerves can only use glucose as its energy source so it is important that we have enough glucose to break down.
Cellular Respiration Energy
27-29 ATP + Heat (Heat is used for temperature regulation)
Cellular Respiration is a Exergonic Reaction with a Delta G of -686kal/mol. (Opposite of Photosynthesis G= 685 kal/mol)
How is glucose broken down?
Glucose is broken down in many steps using many different enzymes/redox/coenzymes in order to achieve full amount of ATP
NAD
You only need a small amount of NAD because you can reuse them. NAD+ is reduced to NADH and NADH is oxidized to NAD.
In its reduced state it is holding energy
Glucose Breakdown
Glucose going to be broken down (Glycolysis) in both eukaryotes and prokaryotes.
Glycolysis: Simple Overview
Process that happens in the cytoplasm of all cells. It breaks down Glucose into 2 pyruvate and generates ATP in the process
Transition Reaction Process: Simple Overview
Both pyruvates are going to be oxidized. Energy is going to be stored in NADPH and 2 carbons are released as CO2.
Citric Acid Cycle (Krebs Cycle): Simple Overview
Happen in the mitochondrial matrix.
Electron energy is stored as NADH+H and FADH2.
4 carbons are released as Co2
Mitochondrial Diseases
Mutations in mitochondrial DNA can affect the cells energy demand. If this energy demand is not met it can ultimately be fatal. This effects the brain, muscles and nerves
Oxidative Phosphorylation
Extracts energy from NADH+H and FADH2. Generates 23-25 ATP using the ETC and ATP synthase
Glycolysis
Nerves can only use glucose as an energy source so it is very important.
Has a energy investment phase and a energy harvesting phase.
Glucose phosphorylation requires an enzyme at each step
Energy Investment
Glucose needs to be activated by 2 ATP. The phosphates from ATP get transferred to Glucose to phosphorylate it and ATP turns to ADP. Glucose phosphorylated is fructose diphosphate. In the state glucose is now irreversible since it is changed.
Fructose Diphosphate (6 carbons) is split into 2 G3Ps at the cleavages. G3P is a 3 carbon molecule.
G3P
Is a 3 carbon molecule with a Aldehyde, Alcohol and Phosphate group.
Aldehyde= H-C=O
Alcohol= C-OH
Energy Harvesting
G3P is changed to pyruvate. Since this is a oxidation (G3P sends 2 electrons and protons to NAD), 2NAD is converted to 2NADH+H. 2ADP are changed to 2ATP by a substrate level phosphorylation (G3P phosphate goes on the ADP).
Feedback Inhibition with Glycolysis
Since ATP is produced, if there is enough ATP present it will bind to Phosphofructokinase (PFK) and inhibits the rest of glycolysis. Well ATP levels fall the inhibition is going to be removed (not binding).
Oxygen and Glycolysis
If oxygen is available then the pyruvates will continue to go to the Krebs Cycle, if there is no oxygen then they run anaerobically.
Substrate Level Phosphorylation
Phosphate from substrate is attached to ADP to make ATP
Glycolysis Formula
C6H12O6 + 4 ADP + 2 ATP+ 2 NAD + 4P ——> 2 Pyruvate + 4 ATP + 2 NADH + 2 ADP
Transition Reaction
Pyruvate enter mitochondrial matrix through Hydrogen / Pyruvate Symporter (Co transport, secondary transport and symport).
Pyruvate gets decarboxylated and turns into a acetyl group (2 carbons). Co enzyme A is added to the acetyl group. = Oxidations
So, NAD+ —> NADH (times 2)
Pyruvate + coA —-> acetylcoA + co2 (times 2)
Co2 gets transported out of mitochondria and goes out the lungs
Krebs (Citric Acid) Cycle
Occurs in the mitochondrial matrix.
Acetyl CoA splits and CoA is transported back to the transition reaction. Acetyl combines to oxaloacetate (c4) to make citrate (c6). Citrate is decarboxylated to c5 while NAD+ is reduced to NADH. Co2 is released. c5 is decarboxylated to c4 and NAD is reduced to NADH. Co2 is released and ADP gets phosphorylated by a substrate phosphorylation to ATP. c4 molecule is called succinate. Succinate gets oxidized to fumarate and FAD gets reduced to FADH2. Fumarate then gets oxidized to make oxaloacetate.
Competitive Inhibition: Oxaloacetate and succinate act in competitive inhibition on succinate dehydrogenase. If there is a lot of oxaloacetate then it will bind to succinate dehydrogenate and slow down the Krebs cycle. If there is more succinate then it will bind and the Krebs cycle will continue to go on.
2 Oxaloacetate + 2 Acetyl CoA + 6 NAD + 2ADP + 2FAD —-> 2 Oxaloacetate + 2 CoA + 6 NADH + 2ATP + 2FADH +4Co2
Does the Krebs cycle use oxygen?
No but it has to be present for it to run
Oxidative Phosphorylation
The process in which ATP is formed using energy from NADH and FADH2 to oxygen by a series of electron carriers
Location of Oxidative Phosphorylation
In Eukaryotes: The cristae of the mitochondria
In Prokaryotes: The plasma membrane
A series of carrier molecules
Pass energy rich electrons across an array of proteins and cytochromes
Cytochromes
Are respiratory molecules with complex carbon rings with metal atoms in the center
Electron Transport System
The fate of hydrogens: Hydrogens from NADH+H gets oxidized to NAD and their electrons flow down the ETC
Energy Yield per Glucose Molecule
In the cytoplasm: Glycolysis is going to generate 2 ATP and 2 NADs.
In the Matrix: Transition reaction produces: Co2 and 2 NAD
Krebs: Generates 6 NADH, 2 ATP, 4CO2 and 2 FADH
Substrate Level Phosphorylation (before ECT) makes 4 ATP
ETC generates around 23-25 ATP
30% of energy from a glucose molecule is used to make ATP
When you are on a diet
You loose more metabolic water and breathe out more Co2
Poisons to Cellular Respiration (3 types)
- Block the ETC
- Respiratory Protein
- Uncoupler
Poisons that Block the ETC
- Rotenone
- Cyanides
Rotenone’s: Attach to the first protein in the ETC and block the transport of electrons so water or ATP is not produced. They are kill pests, insects and fish
Cyanides: Attach to cytochrome C. Inhibit the movement of electrons so no generation of ATP
Poisons: Respiratory Proteins
- Oligomycin’s / Malachite Greens
Block ATP Synthase. So everything is normal but H+ cannot diffuse through ATP synthase so no ATP production
Poisons: Uncouplers
- DNP (Dinitrophenol)
Makes H+ leaky so the concentration gradient. ETS continues but there is no ATP production
Dinitrophenol is used in people who go to the gym to increase their metabolic rate but this can be lethal.
Metabolic Pool
Carbohydrates, Fats and Proteins can be used to make energy in cellular respiration
Catabolism= Breakdown
Proteins and Nitrogenous Wastes
Proteins can be broken down to amino acids which contain amine groups. These amine groups then contain nitrogen which are called nitrogenous wastes.
- Ammonia- The most toxic
- Urea- (Used by humans) More energy expensive than ammonia but uses less water to get rid of
- Uric Acid- (Seagulls) Most energy expensive but takes the smallest amount of water to get rid of
In humans: We turn amino acids into urea through the Krebs cycle backwards which is called the Urea Cycle. Urea can then be exported through our urine.
Different R-Groups of amino acids can be processed differently and enter respiratory pathways at different sites
Fats
- Glycerol
- Fatty Acids
Glycerol: G3P can be converted into pyruvates
Fatty Acids: Carbon and hydrogen chains that become Acetyl CoA.
Related Processes to the Metabolic Pool
Glycogenesis: Production of Glycogen (Storage form of glucose)
Glycogenolysis: Break down of glycogen
Lipogenesis: Production of lipids. Caused by access carbohydrates that pyruvates and acetyl coA can be used to make fatty acids and stored fats
Lipolysis- Break down of lipids
Gluconeogenesis- Production of glucose from something other than carbohydrates. Fats and proteins turned into glucose and is done in the liver.
Metabolic Pool Overview
Proteins: Contain Amino Acids that can be used as pyruvate, acetyl CoA and in the citric acid cycle
Fats: Glycerol can be used as pyruvate. Fatty Acids can be used in acetyl CoAs.
Are Fermentation and Anaerobic Respiration the same thing?
NOO
Anaerobic Respiration uses a ETC pathway where fermentation does not
Fermentation is a anaerobic pathway
When Oxygen is Limited:
Hydrogens have no acceptors. NADH and FADH cannot be oxidized so they turn into free radicals. Glycolysis stops since there is no NAD
2 Things Organisms will do when there is no oxygen
- Anaerobic Respiration (Only done in prokaryotes)
- Fermentation
Anaerobic Respiration: Donate their electrons to a different receptor. Often Sulfur, Sulfate or Nitrate.
Fermentation: “Anabolic Pathway”- Runs without oxygen. Used for a quick burst of ATP but it is not sustained very long. Provides NAD so glycolysis can keep running
Zymology
The study of fermentation. Louis Pasteur is the first zymologist and you use this in alcohol fermentation.
Anerobic Respiration
Uses a different electron acceptor. Sulfate, Sulfur or Nitrate. This regulates the carbon, sulfur and nitrogen cycles. Still uses the ETC and ATP synthase.
- Is less efficient
-Is used in prokaryotes
2 types of Fermentation
- Lactic Acid fermentation 2. Alcoholic Fermentation
Lactic Acid Fermentation
Used in animal, bacterial (lactobacillus. yogurt and cheese) and fungi.
Pyruvate is reduced to Lactic Acid in the presence of lactate dehydrogenase. Then NADH is oxidized to NAD which is used to resupply glycolysis.
This Lactic Acid is then sent to the liver in order to make ATP in the Cori Cycle.
Drawbacks: A build up of Lactic Acid could disrupt your pH balance. Lactic Acid is going to accumulate.
Misconception: Lactic acid doesn’t cause cramps that is due to the oxygen debt build up in your muscles.
Alcoholic Fermentation
Used in yeast cells (Fungus). Used for bread and alcohol.
Pyruvate is decarboxylated to acetaldehyde and is then reduced to ethanol. NADH gets oxidized to NAD to resupply glycolysis by pyruvate dehydrogenase.
Ethanol and CO2.
Cori Cycle
Lactic acid turned into ATP in liver when O2 is present. Lactate is broken down to acetyl-CoA and metabolized.
Efficiency of Fermentation
2.1 efficiency compared to 29%. You have to repay off your oxygen debt.
Primary Metabolism
Involves the break down of nutrients in order to give building blocks and ATP. Dealing with the production of ATP. Catabolism= Breaking down
Secondary Metabolism
Synthesis of molecules that are not essential for cell structure or growth. They enhance survival and reproduction.
Common in Plants. Animals include the slow moving ones.
Important for: Defense, Attractions Protection and Competition. And for biopharmaceuticals
Categories
- Phenolics 2. Alkaloids 3. Terpenoids 4. Polyketides
Phenolics
Antioxidants with intense smells and flavors. Antioxidants help stabilize free radicals. Includes Flavonoids: Vanilla and Chocolate
Anthocyanins: Strong Pigment
Tannins and Lignin’s: Upset gi track
Alkaloids
Basic. Bitter Tasting molecules for defense.
Come from amino acid cursors. Include Caffeine, Nicotine, Capsaicin (spicy), Cocaine. Depressants: Morphine
Terpenoids
Biggest category of second metabolites. Intense smells and colors. Precursor for photoreceptors. Attractive. Mint, Cinnamon, Steroid Hormones
Polyketides
Chemical Weapons. Antibiotics (penicillin). Tetrodotoxin- Blue ringed octopus. Pufferfish. Conotoxin- Cone snail
Shuts off nervous system and provide pain relief
Before Division cells..
Grow, duplicate their organelles and replicate their DNA
Two Major Stages of cell cycle
Interphase (90%) and Mitosis (10%)
Why do we need the cell cycle?
Growth, cell replacement (from wounds) and Asexual Reproduction
Which cells do not divide and which divide frequently
Nerve, Skeletal + Cardiac Muscles cells do not divide
Red Blood Cells, Bone Marrow and Platelets regularly divide because they have a definite lifespan