Chapter 6 Flashcards
what is the ultimate source of energy for all life on earth?
the sun
what are producers and what do they do?
plants, convert electromagnetic energy from the sun to chemical energy
who are consumers and what do they do?
animals, consume plants and convert chemical energy to ATP
what do decomposers do?
break down producers and consumers for their energy
is any chemical reaction 100% efficient?
no, some energy is always lost as heat
what are the two types of energy?
kinetic and potential
what is kinetic energy?
the process of doing work, using mode
what is potential energy?
the potential to do work, storage mode
what type of energy is represented by a waterfall?
kinetic
what type of energy is represented by a dam?
potential
what determines potential energy?
position
where in relation to the nucleus is there more potential energy?
farther away, valence electrons react in oxidation reduction reactions
where is potential energy stored?
in covalent bonds
how is potential energy transferred from one molecule to another?
through oxidation reduction reactions, by creating and breaking covalent bonds
what is the 1st law of thermodynamics?
energy can’t be created or destroyed, it just changes condition
what is an example of the 1st law of thermodynamics?
the sun’s energy is converted into glucose via photosynthesis
what is the 2nd law of thermodynamics?
entropy is ever increasing, the universe is becoming more disorganized
what is entropy and what is it in chemical equations?
disorganization, denoted by S in chemical equations
what is an example of entropy?
as water changes from solid to liquid, it energy is less organized
what is free energy, and what is it in chemical equations?
the energy available to do work, G
what is enthalpy; in chemical equations?
energy contained in a molecule’s chemical bonds, H
what is the equation for free energy?
Free energy = enthalpy - (entropy x abs. temp)
G = H - TS
what is an endergonic reaction?
when the products have more free energy, G, than the reactants,
energy input is required,
reaction is not spontaneous,
ΔG is positive
what is an exergonic reaction?
when the reactants have more free energy,
energy is released,
the reaction is spontaneous
ΔG is negative
what kind of reaction needs energy input?
endergonic
what kind of reaction releases energy?
exergonic
which reaction rate increases as energy is added?
endergonic
which reaction’s products don’t contain free energy but the reaction itself releases energy?
exergonic
what is activation energy?
the energy needed to start an endergonic reaction, and can sometimes be used in exergonic reactions as well
how does activation energy work?
by destabilizing existing bonds, and by putting strain between 2 monomers to encourage hydrolysis
how does activation energy work for exergonic reactions?
by bringing things closer together for dehydration synthesis
what do catalysts do?
speed up reactions by lowering activation energy
what are catalysts?
enzymes
what is the energy currency of cells?
ATP, adenosine triphosphate
where is the energy stored in ATP?
the bonds between the phosphate groups
which phosphate bonds have the most potential energy in ATP?
the ones furthers away from the center, like the 2nd or 3rd phosphate groups
what happens when the phosphate to phosphate bond is broken in ATP?
ADP + Pi + free energy is released
where does the free energy comes from in ATP?
the covalent bonds between phosphate groups
what is ADP?
adenosine diphosphate
what is Pi
inorganic free phosphate group
what combines to make ATP, what is a byproduct, and is what kind of reaction?
ADP + Pi + free energy = ATP + water, dehydration synthesis reaction
what are enzymes?
biological catalysts
what does a catalyst do?
speed up reactions by lowering activation energy
what kind of molecule are most enzymes?
proteins
how do enzymes work?
strain bonds or pull them closer together
are all enzymes proteins?
no, some are made of RNA, involve RNA molecules, and are synthesized by RNA itself
what is a ribozyme?
RNA with enzymatic abilities
give an example of a ribozyme
ribosomes!
what 3 environmental factors affect enzyme function?
- pH
- temperature
- salinity
outside the enzyme’s functional range
do all enzymes have the same optimal conditions?
no
does cold denature an enzyme?
no, it just slows the reaction WAY down
where is pepsin found?
in the stomach
where is trypsin found?
small intestine
do pepsin and trypsin have the same optimal conditions?
no
what is a substrate?
the reactants, or material that an enzyme work with, and part of the reaction
are enzymes used up in chemical reactions?
no, they are released after the reaction for reuse
what is the enzyme’s active site?
the part of the enzyme that receives and holds the substrate
what is induced fit?
the process of the substrate coming to the active site that triggers a SLIGHT conformational change in the enzyme so it can hold and work with the substrate
what is the enzyme-substrate complex?
the closing of an enzyme around the substrate
what do inhibitors do?
decrease enzyme activity
what are the 2 types of inhibitors?
- competitive inhibitors
2. noncompetitive inhibitors
how do competitive inhibitors work?
they block the active site, so they have to COMPETE with the substrate for access
how do noncompetitive inhibitors work?
they change the enzyme’s shape so the active site is no longer available
what are inhibitors?
molecules that binds to an enzyme, and cause it to be nonfunctional by changing its shape or blocking the active site
why do enzymatic reactions level out on a chart?
you can only add so many enzymes until the substrates saturate
why do noncompetitive inhibitors slow reactions more and quicker?
it does not have to compete for the active site, it just changes the enzyme’s shape to stop function
what are allosteric enzymes?
enzymes that are active or inactive, and can be turned on or off
what do allosteric inhibitors do?
turn of allosteric enzymes
what do allosteric activators do?
turn on allosteric enzymes
what is an allosteric site?
where the allosteric inhibitor or activator binds to the allosteric enzyme
do all products come from one enzyme?
no, sometimes several enzymes are needed to complete a product
what is the advantage of several enzymes being used to complete a product?
- product of one reaction directly delivered to next enzyme, product becomes substrate
- eliminates possibility of unwanted side reactions, enzymes are lined up
- all actions controlled as a unit, like dominos, in a regulatory pathway
what is a biochemical pathway?
a series of reactions yielding a final product
what is feedback inhibition?
the product of a biochemical pathway is used to inhibit the reaction/enzyme that made it
what is the 1st product in a biochemical pathway called?
intermediate substrate A
what is the 2nd product in a biochemical pathway called?
intermediate substrate B
what is the final product of a biochemical pathway called?
end product
what happens if the concentration of final product in a biochemical pathway is too high?
the final product become an allosteric inhibitor
what happens if the concentration of final product in a biochemical pathway is too low?
the allosteric inhibitor disengages and the reaction begins again
what is metabolism?
the sum of all chemical reactions inside the cell
what is anabolism?
building reactions, require energy
what is catabolism?
breaking down reactions, release energy, “catabolism cuts”
give an example of an anabolic reaction
body BUILDers take anabolic steroids to BUILD massive muscles
what two additional molecules may be needed for enzyme activity?
cofactors and coenzymes?
what are cofactors?
usually metal ions, Mg2+, Fe2+
what are coenzymes?
non-protein organic molecules, electron donors or acceptors, vitamin A and vitamin C —> antioxidants
what is vitamin A’s role in nutrition?
it’s a fat-soluble vitamin that is necessary in ruminants for many functions including vision, bone growth, immunity, and maintenance of epithelial tissue
