Cellular Respiration Flashcards
What is energy?
Energy is the ability to do work or put matter into motion
What are the different kinds of energy?
Kinetic - The energy of doing work/motion
Potential - Stored or inactive energy
Radiant - Energy that travels in waves
Electrical - The flow of charged particles
Mechanical - Energy directly involved in moving matter
Chemical - Potential energy stores in chemical bonds that is released when those bonds are broken
Heat - Kinetic energy contained in the random motion of molecules
What is entropy?
The measurement of disorder and randomness.
All energy interactions increase entropy in the universe, expenditure if heat increases randomness
What is the first law of thermodynamics?
Energy is is neither created nor destroyed, only converted from one form to another
What is the second law of thermodynamics?
Heat is a product of energy conversion
What is ATP? What is its structure?
Adenosine Triphosphate, the chemical energy stored in food (which is measured in calories) which is released during cellular respiration to make ATP in the mitochondria
What is recycled from ADP and inorganic Phosphate (Pi) via cellular respiration?
ATP
How much ATP do we use per second while at rest?
Approximately 10million
What is metabolism?
The sum of energy from all chemical reactions at a given time
What is the difference between a catabolic reaction and an anabolic reaction?
A catabolic reaction is the break down of molecules, releasing the energy stores in ATP bonds
An anabolic reaction is using ATP to synthesize larger molecules
What are the different types of chemical reactions?
Synthesis (Anabolic) - A + B —> AB
Ex. Amino acids combine to make polypeptide chain (protein)
Decomposition (Catabolic) - AB–> A + B
Ex. Glycogen converting to glucose
Exergonic, meaning energy released
Reversible - A + B <—> C + D
Ex. Bicarbonate reaction
What is an enzyme, how does it work?
An enzyme is a protein that acts as a catalyst to speed up the rate of reactions by lowering the activation energy of a reaction
What does it mean for an enzyme to be “site specific”?
Enzymes only recognize specific substrates (aka reactants) at an active site
True or False: An enzyme can only be used once
False. Enzymes can be used over and over again because they are not part of the reaction, they just change
If a protein is an enzyme it prolly ends in what suffix?
-in or -ase
What are the factors that affect enzyme activity?
Concentration - Increases in substrate or enzyme amount will increase rate of activity
Note - When all enzyme active sites are engaged a substrate has reached saturation
TEMPERATURE - Increase in temperature increases rate
pH - Every enzyme has an optimal pH
Note - There are upper limits to temperature and upper/lower limits to pH where proteins will denature
What is allosteric regulation?
Noncompetitive enzyme inhibition. An enzyme binds to a different site on a substrate or the active site is available but the enzyme cannot fit
What is Competitive Inhibition?
An enzyme binds to an active site as a substrate imposter
What is feedback inhibition?
The accumulation if an endproduct turns off a pathway.
Ex. Extra isoleucine binds to threonine deaminase to prevent more threonine being converted to isoleucine "We're good, bro"
What is the equation for cellular respiration?
Glucose + Oxygen —> Carbon Dioxide, Water, & Energy
C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP
What is the difference between oxidation and reduction reactions?
Molecules that lose electrons are oxidized, molecules that gain electrons are reduced
(Movement of electrons = movement of Hydrogen)
Ex. In CellResp Glucose is oxidized (it loses Hydrogen) and Oxygen is reduces (it gains Hydrogen, becoming water)
What are dehydrogenases and what do they use as coenzymes?
Dehydrogenases are enzymes that catalyze redox reactions by removing hydrogen
They use coenzymes called “electron carriers”, in CellResp NAD+ from niacin (Vitamin B3) becomes NADH; FAD from riboflavin (Vitamin B2) becomes FADH
What are the two mechanisms for ATP synthesis?
Substrate-Level Phosphorylation
-Enzymes transfer a phosphate group from a substrate to an ADP
-This occurs in glycolysis and Krebs cycle
Oxidative Phosphorylation
-A series of redox reactions transfers electrons from organic molecules such as proteins to oxygen atoms
-This occurs in the electron transport chain
What process produces the majority of ATP molecules?
The electron transport chain
What are the stages of cellular respiration?
1 - Glycolysis
1.5 - Facilitated Diffusion
2 - Krebs Cycle
3 - Electron Transport Chain
Describe Glycolysis
Occurs in cytosol, anaerobic reaction
6 glucose uses 2 ATP and divides into 2 three-Carbon molecules called pyruvate, each produces 2 ATP for a net harvest of 2 ATP
If oxygen is present 2NADH moves to ETC, pyurvic acid is converted to acetyl-CoA and moves to mitochondria
If no oxygen is present pyurvic acid is reduced to lactic acid, which is fermented to produce 2 ATP (this is what makes muscles feel fatigued), when Oxygen is present again lactic acid will be oxidized, become pyurvic acid in liver, and return to Krebs cycle
What happens during the facilitated diffusion step of cellular respiration?
2 pyurvates (as Pyurvic acid) created during glycolysis enters the mitochondrial matrix where it is concerted to Acetyl Coenzyme A (AcetylCoA) and enter the Krebs cycle
This profess produces 1CO2 and 1NADH
What happens during the Krebs Cycle?
In the Mitochondrial Matrix, Aerobic
2 AcetylCoA + 2ADP + 2Pi + 6NAD + 2FAD ->
4CO2 + 2ATP + 6NADH + 2FADH2
What happens during the Electron Transport Chain?
(Requires Oxygen)
Hydrogens delivered by coenzymes NAD and FAS are split into electrons and H+ ions
Each is passed down the inner membrane of the mitochondria aling a chain of proteins
Each protein cues a redox reaction until all the H are accepted by Oxygen, becoming water
This process creates the lion’s share of ATP
What is chemiosmosis?
The movement of ions across a membrane down the electrochemical gradient
The electrical energy released by electrons moving down the chain pumps H+ ions into the intermembrane space, creating a proton gradient of potential energy
This gradient drives proteins back in through ATP Synthase, and the spinning creates kinetic energy which ATP Synthases uses to catalyze the ADP + Pi –> ATP reaction
What is the metabolic pool concept?
Any organic molecule can be used in cellular respiration
What is lipolysis?
The hydrolysis of triglycerides into glycerol and fatty acids catalyzed by lipase
How are glycerol and fatty acids used in ATP production?
Glycerol is converted to glyceraldehyde phosphate, which produces 18 ATP when entering the Krebs cycle as a glycolysis intermediate
Fatty-Acid chains undergo beta oxidation, breaking the chains into 2 Carbon acetic acid fragments, which yield 54 ATP
When are ketones produced?
When Acetyl CoA production exceeds the capacity of the Krebs cycle ketones are produced and released into the blood
What is ketosis? When does it occur
The name for an increase in ketones circulating in the blood, which can be used as an energy source for skeletal and cardiac muscle.
Occurs when lipids are the primary energy source in the body, either from storage or consumption
What is ketoacidosis?
A decrease in blood and urine pH due to ketone presence
What is deamination?
Think ketosis for protein. Proteins are hydralyed into individual aminos caled proteases.
In the liver amine groups are taken out of amino acids as ammonia, which is combined withe CO2 in kidneys to produce urea, which is excreted
What are the different ways glucose is obtained?
Glycogenolysis - The breakdown of glycogen to glucose (liver, skeletal muscle)
Gluconeogenesis - the synthesizing of glucose from non-carbonydrates such as glycerol, lactic acid, or amino acid (liver, kidneys)
