CH 6 SG Flashcards
Kinetic energy
energy of motion - Heat energy/entropy (ex: mechanical energy)
The first law of thermodynamics
• (conservation of energy)
• (energy cannot be created or destroyed)
Calorie (cal)
the amount of energy that can raise the temperature of 1 gram (g) of water by 1°C.
• Food calories are kilocalories, equal to 1,000 calories.
How does ATP function as an energy currency?
(via phosphate transfer) storing and releasing energy through the breaking and reforming of bonds between its phosphate groups
How do enzymes catalyze chemical reactions?
(by lowering the energy of activation barrier/speeding up the process) by binding to reactant molecules (called substrates) at a specific site on their structure called the active site - alternate term INDUCED FIT
Why is an enzyme’s shape an important factor in how an enzyme binds to its substrate?
the active site is a unique, complementary shape designed to fit the specific substrate
Properties of enzymes
• Are usually proteins
• Speed up chemical reactions, often by a million-fold or more
• Act on one or a few specific substrates
• Remain unchanged by reactions
• Are reused over and over, catalyzing the transformation of many substrate molecules
• Are sensitive to temperature
• Are sensitive to their chemical environment/pH and salt concentration
• May need the assistance of special cofactors (for specific ions or molecules)
• Has inhibitors (specific ions or molecules)
• Are tightly regulated w/in the cell
Examples of enzyme inhibitors
-Aspirin (Cyclo-Oxygenase/Non Steroidal Anti-inflammatory Drug (NSAID))
-Cyanide (Cytochrome oxidase/Inhibits respiratory chain)
-Fluoride (Enolase/Inhibits Glycolysis)
Potential energy
stored energy - Chemical energy (ex: food)
Heat
energy transferred between substances at different temperatures, flowing from hotter to colder bodies
entropy
(increasing) a constant input of energy maintains life’s organization
chemical energy
potential energy stored in the bonds between atoms and molecules in chemical compounds
How does thermodynamics relate to biological systems?
(Explain the energy transformations) metabolism, maintaining life’s complexity, and the constant need for energy inputs, all while governed by the laws of conservation of energy and the increase of entropy
How does calorie compare to food Calories (kcal)?
a “food calorie” (or Calorie with a capital C) being equivalent to a kilocalorie (kcal)
phosphate transfer
a chemical reaction that moves a phosphate group from one molecule to another
Catabolic reactions
Metabolic process that breaks down large molecules into smaller ones; catabolic metabolism
Anabolic reactions
Chemical reaction in which smaller molecules (monomers) are combined to form, larger molecules, polymers; anabolic metabolism
catalyze chemical reactions
the chemical process of adding a substance called a catalyst to speed up a reaction, or lower the temperature or pressure required to start it
energy of activation (barrier)
(energy that must be added in order for molecules to react with one another) the minimum amount of energy required to activate atoms or molecules for chemical transformation or physical transport
You can think of a cell as a machine that continuously and efficiently performs a variety of functions, such as…
‒ movement,
‒ energy processing, and
‒ production of various products.
Cells control their chemical environment using
‒ energy,
‒ enzymes, and
‒ the plasma membrane
Energy
is defined as the capacity to cause change
The second law of thermodynamics
• (energy conversions are not 100% efficient, and they increase the entropy of universe)
• Cost of organization is energy
Metabolism
is the total of all chemical reactions in an organism (Living cells require two main types of metabolism-anabolic/catabolic)
Free energy(∆G)
is the amount of energy
available.
• The change in free energy after a reaction is calculated by subtracting the free energy of the reactants from that of the products
(A negative ∆G means that a reaction will go forward)
Exergonic reactions
are spontaneous and release energy.
• (∆G is negative).
Endergonic reactions
require an input of energy.
• (∆G is positive).
Mechanical energy
We convert chemical energy into a type of kinetic energy (walking)
substrate
(certain reactant molecule) the surface or material on which an organism lives or grows, or the substance an enzyme acts upon to initiate a chemical reaction
Oxidation
is the loss of electrons (rusting/exposed to air)
Reduction
(the gain of electrons) is the gain of hydrogen atoms.
•Gain of electrons.
The terms also apply to covalent reactions involving hydrogen atoms (e− + H+ ).
cofactors
(Non-protein assistant required by an enzyme in order to function, (metal ions) (others are coenzymes)) Inorganic ions such as copper, zinc, or iron
coenzymes
(Non-protein, organic molecule that aids the action of the enzyme to which it is loosely bound) (Organic nonprotein cofactors)
•NAD+, FAD, and NADP+.
•Vitamins are often components of coenzymes.
