Flashcards in Chapter 2 Deck (59):
What is metabolism?
Catabolism - break down of foods into molecules and frees up energy for anabolism
Anabolism - uses molecules to build bigger molecules, uses energy from catabolism to do so
What is the 2nd law of thermodynamics?
entropy in an isolated system must remain the same or increase but it cannot decrease
How do cells get energy to decrease entropy?
From food and/or the sun
some of this is released as heat
What is the first law of thermodynamics?
energy cannot be created or destroyed but converted from one form to another
How is heat used in a cell?
It is used to drive reactions in anabolism
always coupled with reactions that increase order (decrease entropy)
How many stages are in photosynthesis?
What is the waste product of the first stage?
What happens in the first stage of photosynthesis?
sunlight is captured in stored in chemical bonds of small carriers.
Oxygen is a waste product
What happens in the second stage?
the small energy carriers are used to drive carbon fixation (the process to make sugar from carbon dioxide and water)
What is the net result of photosynthesis?
Light energy + CO2 +H2O -> sugars + O2 + heat energy
What is the net result of respiration?
sugar + O2 -> CO2 +H2O
What is oxidation?
addition of oxygen atoms
removal of electrons
oxidation number increases
what is Reduction?
Removal oxygen atoms
oxidation number decreases
addition of electrons
when does carbon form a polar covalent bond?
when it forms a bond with a more electronegative atom
Cl, O, S
Carbon becomes more positive than it usually would
When is a reaction energetically favored?
when it is a spomtaneous reaction (goes downhill)
Whatis activation energy?
the energy needeed to start a chemical reaction
What is an catalyset
an enzyme that lower the activation energy of a given reaction
increases he rate of a reaction
What does a enzyme bind to in a living cell?
What is the active site of an enzyme?
a groove that only one selective enzyme could fit
What motions caused by heat energy that make rapid binding possible?
Vibrations of a covalantly linked molecule
Rotation help bbring all of these surfaces together `
What is the reaction rate ofr the binding of a enzyme-substrate complex depended upon?
It is depended upon the substrate concentration. because substrates move faster
What will happen wit poorly fitted enzyme-substrate complex?
they will dissociate quicker. the themal energy willl cause the bonds to break
How are energetically unfavorable reactions in a cell that build order and require energy is acheived?
They are coupled with energtically favored (spontaneous) reactions that release energy
What is Gibbs free energy?
the amount of work that can be extracted from a system
measure the amount of disorder
What is gibbs free energy depended upon and what is the formula?
1) if the reaction is energetacally favored at standard conditionds
2) the concentrations of those reacations
delta G = delta G(knot) + 0.616Ln concentration of [products]/[reactants] delta G = delta G (knot) + 1.42 log concentration [products]/[reactants]
When does Delta G = delta G (knot)
when the concentration of the product and reactants are equal log1 = 0
What is delta G at equilibrium?
What is the equalibrium constant?
K = [products]/[reactants]
What is delta G (knot) equal to at equilibrium?
since Delta G = 0 at equilibrium, Delta G (knot) =
what changes the equilibrium constant by factor of 10?
every 1.4 kcal/mole (5.9 kJ/MOLE)
how can sequential delta G Knot reactions be calculated?
If reactions are happening in a sequential manner than an unfavorable reaction can be driven by a favorable. the Delta Gknot are additive.
What are activated carrier molecules used for?
To carry bond energy
energy is transferred to carrier molecules to carry that energy to places of need
What are some Activated bond energy carriers that carry energy from one place to another?
they are called coenzymes
What role do enzymes play in energy transfer in cells?
they couple favorable reactions to unfavorable reactions in the generation of a carrier molecule
Which activated molecule is most abundant in the cell?
ATP (Adenosine triphosphate)
The phosphate group is hydrolyzed to release the bond energy between ADP and inorganic Phosphate
what do the bond energy stored in ATP do in the cell?
moves molecules in & out the cell
drives un favorable reactions
joins to molecules together
What are the roles of NADH (nicotinamide adenine dinucleotide) and NADPH (nicotinamide adenine dinucleotide phosphate)?
They serve as electron (H-) and (H+) carriers. they are both in reduced form.
Why does NADPH readily gives up its electrons?
it is an effective reducing agent because the nicotine ring achieves a more stable state without the electrons (same reason that ATP gives up a phosphate group)
What does the phosphate distiguish NADPH from NADH?
The extra phosphate group has no effect on the ability to transfer electrons.
it is there so both NADH and NADPH can transfer to a whole different set of molecules.
What kind of reactions do NADH and NADPH mainly do in the cell?
NADH - intermediate in the catabolize high energy molecules into ATP
NADPH - intermediate to anabolize high energy molecules
What is the ratio of NAD+ to NADH in the cell and why?
NAD+ is kept high compared to NADH
to keep NAD+ plentiful as a oxidizing agent
What is the ratio of NADP+ to NADPH in the cell and why?
NADPH is kept high compared to NADP+
NADPH is kept plentiful as a reducing agent
What is Acetyl coenzyme A?
It is a n activated Carrier molecule.
Coenzyme A carries an acetyl group which is used to add two carbons in the catabolic pathway of glucose.
What does main group of carrier molecules serve as?
They save as ways for specific enzymes to recognize that molecule.
Why does the main portion of most carrier molecules contain Nucleotide (mostly adenosine)?
because early life forms my have used RNA molecules to catalyze reactions. The nucleotides are thought to made it easier for RNA to bind to them
what is the group that is carried in the high energy linkage in ATP?
What is the group that is carried in the high energy linkage in NADH, NADPH and FADH2?
electrons and hydrogens
What is the group that is carried in a high energy linkage for Acetyl CoA?
What is the group that is carried in the high energy linkage in Carboxylated biotin?
What is the group that is carried in the high energy linkage in S-Adenosylmethionine?
What is the molecule that is carried in the high energy linkage in Uridine diphosphate glucose?
How are the building of macromolecules coupled to the hydrolyzes of ATP?
B-OH + ATP -> B-O-PO3 +ATP
A-H + B-O-PO3 -> A-B + Pi
Proteins and polysaccharides are more complicated
How can ATP be altered to produce more mole/kcal?
In some reactions hydrolysis of ATP to ADP-Pi produces -11 to -13 kcal/mole delta G
to get more energy ATP is broken into AMP & PiPi
then PiPi is broken up to produce a change of -26 kcal/mole delta G
What are the two types of condensation reactions?
What is head polymerization?
The reactive bond that is needed for the condensation reaction is on the end of the growing polymer.
Each monomer carries the bond needed for the next addition of a monomer
what is tail polymerization?
Each monomer carries a high energy bond for its own addition
What macromolecules use the tail polymerization method for synthesis?
What macromolecules use the head polymerization method for synthesis?