3- Chapter 3 Flashcards
What are the 7 chemical elements that predominate in living systems?
(In order of highest percentage in cells to least)
Carbon 50% Oxygen 25% combined with hydrogen (same amounts) Hydrogen Nitrogen Phosphorus Sulfur Selenium All cells require carbon and nitrogen
What are growth factors?
What are trace metals?
Growth factors are organic micronutrients
Vitamins
Some amino acids
Trace metals are cofactors of certain enzymes
Iron
What is simple transport?
What is group translocation?
What are ABC transport systems?
3 basic mechanisms of active transport in prokaryotic cells
Simple- only uses a transmembrane protein
Group- uses a series of proteins in a transport event (phosphotransferase system)
ABC- uses 3 components, substrate binding protein, transmembrane transporter, ATP hydrolyzing protein
Can be used in gram negative and positive bacteria and archaea
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How do simple transporters and group translocation differ?
Group translocation chemically modifies the transported substance and an energy rich organic compound drives the transport event rather than a proton motive force
What are chemotrophs and it’s two sub categories?
Chemotrophs are organisms that conserve energy from chemicals
Chemoorganotrophs use organic chemicals like glucose or acetate
Chemolithotrophs carry out chemolithotrophic reactions where inorganic compounds can be oxidized like hydrogen iron and other compounds or elements
What are heterotrophs and autotrophs?
Heterotrophs- obtain carbon from one or another organic compound
Chemoorganotrophs
Autotrophs- use carbon dioxide as its carbon source
Chemolithotrophs and phototrophs
What is free energy?
What is exergonic and endergonic?
The energy available to do work
G
Exergonic- release of free energy with negative G
Endergonic- requires free energy and G is positive
Calculate free energy by subtracting the reactants free energy from the products free energy
(C+D) - (A+B)
What is activation energy?
What are catalysts?
Minimum energy require to start reaction
Catalysts help facilitate a reaction by lowering activation energy without affecting he reaction itself (only affect rate of reaction)
Enzymes are the major catalyst made of proteins
What’s the difference between prosthetic groups and coenzymes?
Prosthetic groups bind tightly to their enzymes
Coenzymes are loosely and transiently bonded to enzymes
Both non protein molecules that participate in catalysis but are not substrates
What is oxidation vs reduction?
Oxidation removes an electron
Reduction adds an electron
Page 82 review
How does NAD+ and NADH relate to redox reactions?
NAD+ is a very common redox coenzyme
NADH is a good electron donor since it carries 2 electrons and 2 hydrogen’s and NAD+ is a week electron acceptor
What is adenosine triphosphate?
Energy rich phosphate compound ATP
Consists of ribonucleoside adenosine bonded to three phosphate molecules (page 85 picture)
Free energy released is -32kj/mol
What is coenzyme A?
Contains energy rich thioester bonds and hydrolysis of these bonds give sufficient free energy to be coupled to the synthesis of an energy rich phosphate bond
Important in energetics of anaerobic microorganisms (fermentation)
What is fermentation and respiration?
Fermentation- anaerobic catabolism in which organic compounds donate and accept electrons so redox balance is achieved without need of external electron acceptors
Respiration is aerobic or anaerobic catabolism where an organic or inorganic electron donor is oxidized with O2 or another compound
What is glycolysis?
What is substrate level phosphorylation?
Series of reactions in which glucose is oxidized to pyruvate
Contains 2 redox reactions
2 ATP in and 4 ATP out for each molecule of glucose fermented
SLP- a process by which the energy rich phosphate bond on the organic compound is transferred directly to ADP to form ATP from the compounds produced from glycolysis
3 stages of glycolysis?
Stage 1 is preparatory and consumes ATP and uses no redox reactions
Stage 2 redox reactions occur, energy is conserved 2 molecules of pyruvate are formed
Stage 3 redox balance is achieved and fermentation products are formed
What are the two redox reactions in glycolysis?
The first reduces NAD+ to NADH
The second is where inorganic phosphate is also turned to organic form
What is the total ATP breakdown for aerobic respiration? (Glycolysis and citric acid cycle?
2 net ATP is produced through glycolysis and substrate level phosphorylation then oxidative phosphorylation in glycolysis can produce another 6 for a 8 ATP total
In citric acid cycle, 2 GTP (ATP) is produced from substrate level phosphorylation then another 28 ATP from oxidative phosphorylation
For a total of 30 ATP
Added up its 38 ATP total
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What goes in to the citric acid cycle and what comes out?
2 pyruvate, 8 NAD+, 2 GDP, and 2 FAD go in
6 CO2, 8NADH (24 ATP), 2 FADH2 (4 ATP), and 2 GTP (2 ATP) come out
What two major roles do the citric acid cycle and glycolysis have in common?
- Glucose respiration coupled to energy conservation
2. Biosynthesis of key metabolites
What is the glyoxylate cycle?
Functions to replenish oxaloacetate used for biosynthesis and becomes active when acetate is used as an electron donor
What are the oxidation reduction enzymes that participate in electron transport?
NADH dehydrogenases- NADH bonds then the 2e- and 2H+ are transferred to a flavoprotein
Flavoproteins- accepts 2e- and 2H+ and oxidizes and passes 2e- on
Iron-sulfur proteins- nonheme
Cytochromes- contain heme groups use Fe for oxidation and reduction
In small non protein electron carriers there is quinones- small hydrophobic redox molecules, can move within membrane
How does electron transport chain work?
How is proton motive force created?
2 electrons and 2 protons enter the electron transport chain when NADH is oxidized to NAD+
H+ ions from H2O are pushed to the outer surface of the membrane while the OH- is pushed inside the cell which creates inner and outer membrane charge differences and this creates the proton motive force which energizes the membrane
How much energy is released per NADH that is oxidized in the electron transport chain?
220 kJ of energy released
-220
How does the proton motive force generated from electron transport chain actually drive ATP synthesis?
Pmf creates torque in the large membrane protein complex that synthesizes ATP
The complex is called ATP synthase
Oxidative phosphorylation forms ATP from respiratory electron flow
What is anaerobic respiration?
Electron acceptors other than O2 support respiration in many bacteria and archaea
Some electron acceptors include NO3->NO2
Fe3+ -> F2+
How do chemoorganotrophs differ from chemolithotrophs in terms of electron donors?
Chemolithotrophs are autotrophs that oxidize an inorganic electron donor and use carbon dioxide as carbon source
Chemoorganotrophs are heterotrophs and therefore use organic compounds as carbon sources
Use glycolysis and citric acid cycle and electron transport chain
What is anabolism?
The biosynthesis of informational macromolecules (proteins and nucleus acids
What is gluconeogenesis?
When a cell is growing on other carbon compounds besides hexose, glucose must be biosynthesized by phosphoenolpyruvate
What is pentose phosphate pathway?
Major pathway for protein production
Glucose is oxidized to CO2, NADPH, and rubulose 5-phosphate
Pentose forms from ribulose 5 phosphate
Important to pentose metabolism and produces many other important sugars in the cell
What are amino acid families?
Groups of structurally related amino acids that share several biosynthetic steps
Which are purines and which are pyrimidines?
Purines- adenine and guanine
Pyrimidines- thymine, cytosine, and uracil
How are fatty acids formed?
Constructed two carbons at a time, each C2 unit originates from the 3 carbon compound malonate
