Chapter 10 Notes Flashcards
Metabolism total of a chemical reactions in the cell and is divided into two parts, called:
catabolism and anabolism
contribute to cycling of elements in ecosystem
microbial metabolism
synthesis of complex molecules
chemical work
take up of nutrients, elimination of wastes and maintenance of ion balances
transport work
cell motility and movement of structures within cells
mechanical work
a science that analyzes energy changes in a collection of matter called a system (e.g., a cell)
thermodynamics
total energy in universe remains constant,
however, energy may be redistributed either within a system or between the system and its surroundings
first law of thermodynamics
Physical and chemical processes proceed in such a way that the disorder of the universe increases to the maximum possible
second law of thermodynamics
amount of disorder in a system
entropy
amount of heat energy needed to raise 1 gram of water from 14.5 to 15.5°C
calorie
units of work capable of being done by a unit of energy
joules
1 cal of heat is equivalent to ___ J of work
4.1840
Expresses the change in energy that can occur in chemical reactions and other processes
free energy and reactions
if delta G is negative
reaction is spontaneous
if delta G is positive
reaction is non spontaneous
- free energy change
- unit of energy available to do work
delta G
-change in enthalpy (heat content)
delta H
- temp in kelvin
- change in entropy
T
chemical equilibrium
delta S
Free energy change defined at standard conditions of:
concentration, pressure, temperature, and pH
standard free energy change at what pH?
7
Exergonic reactions
Delta G degrees is negative
reaction proceeds spontaneously
endergonic reactions
Delta G degrees is positive
reaction will not proceed spontaneously
The Energy Currency of the Cell
ATP
__ breakdown of high energy ATP is coupled with __reactions to make them more favorable
exergonic, endergonic
ATP is said to have a HIGH what?
phosphate transfer potential
it readily sends a __ ___ to other molecules
phosphate group
other molecules have higher phosphate transfer potential than __
ATP
ATP = __ and the phosphate from those molecules
ADP
Located in plasma membranes of chemoorganotrophs in bacteria and archaeal cells
electron carriers
Electron carriers located in internal mitochondrial membranes in ___ cells
eukaryotic
main electron carriers located in plasma membranes of ___ in bacteria and archaeal cells
chemoorganotrophs
NAD means
nicotinamide adenine dinucleotide
NADP means
nicotinamide adenine dinucleotide phosphate
FAD, FMN, coenzyme are all
additional electron carriers
use iron to transfer electrons
cytochrome
example of Nonheme iron-sulfur proteins
ferrodoxin
in biochemical pathway__ can be linked together to form pathways
enzymes
in biochemical pathway, Pathways can be varied in what shapes?
linear
cyclic
Branching
biochemical Pathways often __ or __ into each other
overlap or feed
biochemical pathways are dynamic pathways can be
used to monitor changes in __ levels (flux)
metabolite
Carry out reactions at physiological conditions so they proceed in a timely manner
enzymes
Enzymes speed up the rate at which a reaction proceeds toward its final ___
equilibrium
- high specificity for the reaction catalyzed and the molecules acted on
- substance that increases the rate of a reaction without being permanently altered
protein catalysts
reacting molecules
substrates
substances formed by reaction
products
protein component of an enzyme
Apoenzyme
nonprotein component of an enzyme
cofactor
energy required to form transition-state complex
activation energy
How enzymes lower Ea
- By increasing concentrations of substrates at active site of enzyme
- By orienting substrates properly with respect to each other in order to form the transition-state complex
Enzyme activity is significantly impacted by
- substrate concentration
- pH
- temperature
Rate increases as [substrate] increases or decreases?
increases
No further increase occurs after all enzyme molecules are saturated with __
substrate
loss of enzyme’s structure and activity when temperature and pH rise too much above optima
denaturation
when it comes to enzyme inhibition, __ ___ directly competes with binding of substrate to active site
competitive inhibitor
- binds enzyme at site other than active site
- changes enzyme’s shape so that it becomes less active
noncompetitive inhibitor
__ and __ discovered that some RNA molecules also can catalyze reactions
Thomas Cech and Sidney Altman
Thomas Cech and Sidney Altman discovered that some RNA molecules also can catalyze reactions, some examples of that are:
- catalyze peptide bond formation
- self-splicing
- involved in self-replication
Important for conservation of energy and materialsq
regulation of metabolism
When it comes to regulation of metabolism, Maintenance of metabolic balance despite changes in ___
environment
When it comes to the regulation of metabolism, there are three major mechanisms:
- metabolic channeling
- regulation of the synthesis of a particular enzyme (transcriptional and translational)
- direct stimulation or inhibition of the activity of a critical enzyme (post translational)
Differential localization of enzymes and metabolites
metabolic channeling
differential distribution of enzymes and metabolites among separate cell structures or organelles
compartmentation
can generate marked variations in metabolite concentrations
compartmentation
when it comes to Post-Translational Regulation of Enzyme Activity, Two important reversible control measures are:
- allosteric regulation
- covalent modification
Reversible on and off switch
Covalent Modification of Enzymes
covalent modification of enzymes, Addition or removal of a __ group (phosphate, methyl, adenyl
chemical
Inhibition of one or more critical enzymes in a pathway regulates entire pathway
feedback inhibition
catalyzes the slowest or rate-limiting reaction in the pathway
peacemaker enzyme
Feedback Inhibition:
- Each end product regulates its own branch of the ___
- Each end product regulates the initial ___ enzyme
pathway, peacemaker
different enzymes that catalyze same reaction
isoenzymes
