Exam 1 SG questions - Part 3 Flashcards
Define metabolism and compare and contrast the differences between anabolism and
catabolism.
- Metabolism is how a cell uses nutrients to generate energy and ultimately stay alive
- Anabolism: how body uses ATP, synthesis reactions in a body
- Catabolism: break down of chemical substances to make ATP
What is the definition of life?
- Metabolism - transformation of energy through anabolism/catabolism
- reproduction - ability to produce new individual organisms
Distinguish enzyme and substrate; describe the mechanism of enzyme action in relation to activation energy and active site.
Enzyme is used to break down substrate or speed up a chemical process
Activation energy: enzyme lowers the activation energy needed to start a reaction
Active site: puzzle piece where substrate or reactant fits into/binds with enzyme
List and explain the factors in influencing enzyme activity and explain enzyme nomenclature.
- Enzyme nomenclature: ends with suffix -ayse, name of substrate it breaks down + ase
- Enzyme activity is changed by temp, pH, and concentration. Temp increase leads to enzyme activity increase
List and provide examples for ways in which ATP is generated during metabolism.
Aerobic:
* citric acid cycle (2 ATP)
* electron transport chain (36 ATP)
* cellular respiration in total (40 ATP)
* Net ATP generated during cellular respiration (38 ATP)
Anaerobic:
* Glycolysis (4 ATP made/2 ATP used during process)
Explain oxidation-reduction and its importance in metabolism, picking out compounds oxidized or reduced.
- Oxidation: losing electrons (hydrogens), binding with oxygen
- Reduction: gaining electrons (hydrogens), binding with hydrogens
- Carbon oxidized: O=C=C (CO2)
- Carbon reduced: methane gas (CH4) - mosty energetic
- They yield energy through the transfers of these electrons (valence electrons)
how are molecules related to the potential creation of energy
Molecules with more hydrogen have the higher potential to create energy because it has more electrons which are capable of creating energy.
Name and explain the nutritional factors among organisms for carbon and energy.
One of the main nutritional factors utilized for energy is glucose to product ATP, however proteins and fats can also be utilized.
* Glucose –> pyruvate in Glycolysis
Define fermentation and describe what happens in glycolysis, beginning with substrate and explaining by-products, final products and energy gain. Give examples of fermentation.
- Glycolysis: 6C glucose –> 3Cpyruvate (x2), anaerobic, creates 4 ATP but nets 2 ATP
- In the presence of oxygen, pyruvate moves on to the citric acid cycle.
- W/o oxygen, through fermentation, pyruvate turns into lactic acid in animals and ethanol in yeast. Lactic acid can turn back into pyruvate once the cells find oxygen again.
- End products: CO2 waste, 2 ATP, and lactic acid or ethanol
Compare aerobic and anaerobic respiration with fermentation in general terms of energy yield and final electron acceptors
- Anaerobic respiration: no oxygen, glycolysis generates 2 ATP.
- Aerobic respiration: needs oxygen, citric acid cycle and electron transport chain. Final electron receptor is oxygen and yields lots of energy (38 ATP)
- Anaerobic Fermentation: In animals pyruvate becomes lactic acid. In yeast, pyruvate becomes ethanol.
Compare the citric acid cycle to fermentation in terms of reactants, products and by-products, energy yields and conditions required for these reactions to occur
Citric Acid:
Reactants: pyruvate to acetyl COA
Products: 6 NADH, 2 FADH2, 2 ATP
Byproducts: 4 CO2 waste
Fermentation:
Reactants: pyruvate
Products: lactic acid or ethanol
Byproducts: co2 with ethanol
Explain the purpose of the electron transport chain, describing chemiosmosis.
- ETC: takes hydrogen from NADH and FADH2 and creates proton gradient along chain (which then is converted into ATP through chemiosmosis)
- Chemiosmosis: energy from proton gradient is used to create ATP
- Uses ATP Synthase to catalyze the reaction of adding a phosphate to ADP to turn it into ATP (diphosphate into triphosphate)
Be able to explain the purpose of glycolysis, prep step, citric acid cycle, and electron transport system
- Glycolysis: glucose to pyruvate
- Prep step: pyruvate to acetyl CoA
- Citric Acid Cycle: oxidizing Acetyle CoA to release hydrogens that can be transported to ETC in NADH/FADH form
- ETC uses electrons and hydrogen gradient to generate ATP with ATPase
Know the roles of oxygen, ATP synthase, NAD, and FAD in cellular respiration.
Oxygen: terminal electron acceptor
ATP synthase: enzyme that adds a phosphate to ADP to form ATP
NAD: cellular respiration hydrogen shuttle
FAD: citric acid cycle hydrogen shuttle
What are the end products of glycolysis, prep step, citric acid cycle, and ETC?
Glycolysis: 3C pyruvate (x2), synthesizes 4 ATP, uses 2 ATP, Nets 2 ATP
Prep Step: Pyruvate to Acytl CoA (x2), 2CO2 produced
Citric Acid Cycle: acetyl COA (x2) fully oxidized to form - 2 CO2 as waste, 6 NADH, 2 FADH2, 2 ATP
Electron Transport: 6 H2O and 34 ATP total
Total numbers: 38 net ATP, 6 H2O, 6 CO2, 10 NADH, 2FADH
