Exam Four: Part Four Flashcards
what is METABOLISM?
CHEMICAL PROCESS that occurs within all living things to MAINTAIN LIFE
ex. converting food into energy
use of NUTRIENTS (sources of energy/molecular building blocks)
PROCESSING:
- we break them down to help RELEASE ENERGY to be stored in their chemical bonds
- creation of certain BUILDING BLOCKS to build MACROMOLECULES needed for life
what are ENZYMES?
all of the work being done inside the cell is being done by ENZYMES:
- energy is required for a REACTION to proceed
- helps BREAK OLD chemical bonds of reactants
- forms NEW chemical bonds in the product
they are CATALYSTS;
- LOWER THE ENERGY OF ACTIVATION
- INCREASE THE REACTION RATE–chemical reactions occur more frequently and we get more product
- NOT PERMANENTLY CHANGED
(always RECYCLED)
definition of REACTION RATE + ACTIVATION ENERGY
REACTION RATE:
the FREQUENCY of COLLISIONS with SUFFICIENT ENERGY to make a PRODUCT depends on the NUMBER OF REACTANTS with ENOUGH ENERGY
- needs ENOUGH ENERGY
- WITH PROPER ORIENTATION
= REACTION
ACTIVATION ENERGY:
MINIMUM ENERGY required to start a reaction
what is an ENZYME’S STRUCTURE?
most enzymes are PROTEINS
- encoded with GENETIC MATERIAL
- transcribed into mRNA
- after, then translated into a protein!
PROTEIN – is FOLDED and MODIFIED
through the TERTIARY STRUCTURE/3-D SHAPE
- no shape. no reaction
ACTIVE SITES:
- POCKET where substrate fits and reaction occurs
- very SPECIFIC, only binds to a specific molecule
SUBSTRATES:
substances are affected by the enzyme at the active site
how do we NAME ENZYMES?
substrate + chemical reaction type + “ase”
- substrate - sucrose
- reaction - breaks down sucrose to glucose and fructose
- name - sucrase
what are Co-FACTORS and CO-ENZYMES?
sometimes ENZYMES need a second - NON-PROTEIN COMPONENT to work
- needed both for enzymes to function
COFACTORS:
- made from MINERALS (Zn, Mg, or Fe)
COENZYMES;
- anything made of an ORGANIC MOLECULE
- made from VITAMINS or NUCLEOTIDES
what are two IMPORTANT COENZYMES?
Nicotinamide adenine dinucleotide [NAD+]
& Nicotinamide adenine dinucleotide phosphate [NADP+]
- functions as ELECTRON CARRIERS
- both DINUCLEOTIDES
COENZYME A [CoA]
- important role in METABOLISM
what are some ENVIRONMENTAL EFFECTS on ENZYME ACTION?
- TEMPERATURE
- pH
- SUBSTRATE CONCENTRATION
describe ENZYME ACTION
ENZYMES are EXTREMELY EFFICIENT:
- can catalyze reactions up to 10 BILLION TIMES faster than w/o enzyme
- can react with 1-10,000 substrate molecules per second
what is TURNOVER NUMBER?
the MAXIMUM NUMBER of substrate molecules that can be processed by enzymes into product in ONE SEC for a given enzyme concentration
- where the enzyme is FULLY SATURATED WIHTHIN SUBSTRATE
describe TEMPERATURE and its effect on ENZYME ACTION
- OPTIMUM TEMPERATURE:
- the temperature at which the MAXIMUM REACTION RATE is achieved
- (most optimal at 35-40 degrees C)
- the temperature at which the MAXIMUM REACTION RATE is achieved
- TEMPERATURE IS LOWER THAN OPTIMUM
- reactions may SLOW OR STOP–INACTIVE
- LESS MOVEMENT within the reaction
- TEMPERATURE IS HIGHER THAN OPTIMUM
- proteins are DENATURED = irreversibly inactivated by heat (even if the temperature is lowered)
describe pH and its effects on ENZYME ACTION
- OPTIMUM pH
- most function best at NEUTRAL pH 7.0
- TOO ACIDIC
- too many HYDROGEN MOLECULES may be collected within the ACTIVE SITE
- cannot bind effectively to SUBSTRATE
- too many HYDROGEN MOLECULES may be collected within the ACTIVE SITE
- TOO ALKALINE
- can also result in DENATURATION
- exceptions;
- STOMACH enzymes; pH 1-2
- LIVER enzymes; pH 9-10
describe SUBSTRATE CONCENTRATION and its effect on ENZYME ACTION
- SUBSTRATE CONCENTRATION:
if HIGH
- SATURATION:
- substrate CONTINUOUSLY fills the active site of the enzyme
- MAXIMAL REACTION RATE
if LOW;
- NORMAL condition
- many INACTIVE molecules at any given time
- SLOWER REACTION RATE
**Increasing concentration does not AFFECT REACTION RATE
what is REGULATION?
- an enormous amount of energy and resources are dedicated to metabolic pathways
- cells have to REGULATE THE ACTIVITIES of the enzyme very precisely
USAGE OF METHODS;
- COMPETITIVE INHIBITION
- ALLOSTERIC INHIBITION
- ALLOSTERIC ACTIVATION
what is an INHIBITOR?
a MOLECULE that attaches to the enzyme and INTERFERES with its ability to do its JOB
describe COMPETITIVE INHIBITION
- where the INHIBITOR COMPETES with the SUBSTRATE for the enzyme’s ACTIVE SITE
TWO TYPES:
REVERSIBLE COMP. INHIBITION
- competition can be OVERCOME by increasing SUBSTRATE CONCENTRATION
- inhibitor can leave
*SULFA DRUGS–type of REVERSIBLE INHIBITOR
IRREVERSIBLE COMP. INHIBITION
- increasing the SUBSTRATE CONCENTRATION DOES NOT OVERCOME the inhibitor
*example–PENICILIN (prevents synthesis of BACTERIAL CELL WALLS–kills BACTERIA–modifies PEPTIDOGLYCAN SYNTHESIS)
