Lecture 4: Molecules, energy, and Biosynthesis Flashcards
____ - diverse group of water-insoluble
biological molecules;
Lipids
energy stores
fats
Major components of membrane
phospholipids and sterols
Addition of 3h2o to triglyceride results to what products??
Glycerol and fatty acids
_ polyhydroxy aldehydes and ketones with the general formula of (CH2O)n
Carbohydrates
examples of monosaccharide sugars
- Glucose
- Galactose
- fructose
- ribose
- 2-deoxyribose
examples of disaccharide sugars
- sucrose
- lactose
____ – most complex and most abundant
organic molecules containing at least one
carboxyl group and one amino group.
Proteins
____ carries coded information,
arranged into genes
DNA
DNA carries coded information,
arranged into ____
genes
_____ instrumental in translating the coded message of DNA into sequences of amino acids during synthesis of protein molecules
RNA
difference between DNA and RNA ?
2’ H in DNA , 2’ OH in RNA
The process of increasing the rate of
reaction with the use of a catalyst.
Catalysis
____ - any substance that increases rate
of reaction upon addition to a certain
reaction .
Catalyst
____ catalyst of biochemical reactions (biological catalysts)
enzymes
___ neither used up in the reaction nor do they appear as reaction products
- are proteins of very specific amino acid
composition and sequence
Enzymes
Substrate + enzyme (enzyme substrate complex) = ______
Product + enzyme
enzymes can be denatured and precipitated with ____, ____, ____
salts, solvents, and other reagents
____ catalyze all the synthetic and metabolic
reactions of the cell
- allows for a faster speed of reaction
- increases the reaction rates by means of
lowering the energy of activation
Enzymes
enzymes increases the reaction rates by means of _______
lowering the energy of activation
- the kinetic energy required to bring the
reactants into position to interact. - measured as the number of calories required to bring all the molecules in a mole of reactant at a given temperature to a reactive (or activated) state.
Activation energy/free energy of activation
How do enzymes hasten the reaction?
enzymes lowers the activation energy
___ each enzyme is specific for a certain substrate (reactant molecule)
enzyme specificity
___ highly specific nature of most enzymes arises from the close and complementary fit between enzymes and substrate in a special portion of the enzyme surface.
- where the substrate can fit like a lock-and-key mechanism
Active site
- enzyme molecule is made up of one or more peptide chains folded to form a more or less globular protein of a specific conformation
Enzyme Specificity
two types of enzyme model
- lock-and-key model
- Induced-fit model
____ – catalytic potency
of an enzyme
enzyme activity
_____ – number of reactions catalyzed per second by the enzyme
Turnover number
enzymatic reaction
- substrate interacts with the active site of the
enzyme - forming an enzyme-substrate complex (ES)
- product separates from the enzyme
- free enzyme can form an ES complex with a
new substrate molecule
Factors affecting enzyme activity
- Temperature and reaction rates
- pH
The higher the temp., the higher the average molecular velocity, the higher the number of molecular collision per unit, the higher the probability of successful interaction of the reactant molecules.
as their velocities ____, the molecules
possess higher kinetic energies and thus are
more likely to react upon collision.
increase
Drop in __ exposes more positive sites on an enzyme for interaction with negative groups on a substrate molecule
pH
rise in ____facilitates the binding of positive groups
on a substrate to negative sites on the enzymes.
pH
enzyme require ___ for activity
cofactor
____ - small organic molecules that act as cofactors
coenzyme
____ – enzyme minus its cofactor; cannot function without its cofactor/coenzyme
Apoenzyme
Cofactor (coenzyme, prosthetic group or metal ion) + apoenzyme =
holoenzyme
Six major classes of enzymes
- Oxidoreductase
- Transferase
- Hydrolase
- Lyase
5.Isomerase
6.Ligase
Type of reaction of oxidoreductase
Oxidation-reduction
Type of reaction for tranferase
group transfer
Type of reaction for hydrolayses
Hydrolysis reactions (transfer of functional groups to water)
Type of reaction for lyases
Addition or removal of groups to form double bonds
Type of reaction for isomerases
isomerization
Type of reaction for ligase
Ligation of two substrates at the expense of ATP hydrolysis
The rate at which an enzymatic reaction proceeds depends on the concentrations of substrate, product, and active enzymes
Mag lesser ang substrate as time goes by habang ga taas ang ma produce na product
________- Used in the living cell as a means of controlling enzymatic reactions
Enzyme inhibition
Two types of enzyme inhibition
- competitive inhibition
2.noncompetitive inhibition
_____ -Caused by molecules that react directly with the active site of the enzyme
Competitive Inhibition
_____-Øcan be reversed by an increase in substrate concentration
Competitive inhibition
The competitive inhibition can be reversed by ___
increasing the substrate concentration
Ømost competitive inhibitors are ______
substrate analogs
Caused by molecules that bind to a region(s) of the enzyme outside the active site
Non-competitive inhibition
Caused by molecules that bind to a region(s) of the enzyme outside the active site
Non-competitive inhibition
_____ reversed by dilution or removal of the inhibitor
Non-competitive inhibition
Chemical structure of noncompetitive inhibitors typically _____ from that of the substrate.
differs
Regulation of Metabolic Reactions
- Control of Enzyme Synthesis
- Control of Enzyme Activity
- Certain conditions that reduce protein synthesis generally
- regulated at the molecular level by modulation of the rate of transcription of the gene encoding it (DNA is packaging; rate at which RNA is translated into proteins)
Øenzymes are only synthesized when needed
Control of Enzyme Synthesis
it is regulated by modulator molecules (interact with a part of the enzyme molecule )
Control of Enzyme Activity
_____- - alters the tertiary structure of the enzyme thus changing the conformation of the active site
allosteric site
interaction of the end product occurs in the allosteric site, making the end product an _____
allosteric inhibitor
- several cat-ion cofactors act as allosteric activators for some enzymes
enzyme activation
Two kinds of energy- yielding metabolic pathways in animal tissues:
. 1. aerobic metabolism
2. anaerobic metabolism
____ -food molecules are
completely oxidized to carbon dioxide and water by molecular oxygen; energy yield is far greater
Aerobic metabolism
_____ - – food molecules are oxidized incompletely to lactic acid (lactate); absence of oxygen
anaerobic metabolism
