before a cell can replicate, a variety of chemical reactions must take place. these reactions are collectively called:

the sum of all the chemical reactions in a cell

energy requiring

the most abundant element

comprises about 50% of a cell's dry weight

prokaryotes that are able to use CO₂ as their sole source of carbon

the second most abundant element, comes in 2 forms: organic and inorganic

mostly is in inorganic form

energy sources used by bacteria:

organotrophs (heterotrophs) and lithotrophs (autotrophs)

energy sources used by bateria:

organic (chemoorganotrophs) and inorganic (chemolithotrophs)

free energy (G)

the change in free energy at standard conditions (ph 7, 25 C, reactants 1M)

if negative then the reaction will proceed with the release of free energy that can be conserved as ATP (exergonic)

if positive the reaction requires energy to proceed (endergonic)

= products - reactants

a substance that lowers the activation energy of a reaction, thereby increasing the rate of reaction

facilitate reactions but are not consumed or transformed by the reaction

do not affect the energetics or the equilibrium of a reaction; only affect the SPEED at which reactions proceed

AKA speed of a reaction

determined by energy of activation

at high temperatures, reactions will go fast but not feasible in living cells

____ determines direction for reactions as they proceed to equilibrium, while the speed at which those reactions occur is determined by ____ that in cells is lowered by enzymes that result in increased reaction velocity

the catalysts of biological systems

highly specific, catalyzing only a single type or class of a reaction (ensures that none of the substrate is diverted to nonproductive side-reactions. no wasteful by products are formed)

in enzyme catalyzed reactions, the enzyme (E) temporarily combines with the reactant or substrate (S) forming ____

substrate binds to the enzymes active site with weak bonds (hydrogen bonds, hydrophobic interactions, van der waals forces)

as the reaction proceeds, the product (P) is released and the enzyme (E) returns to its original form

E+S → ES → E+P

involves the removal of an electron(s) from a substance

LEO

the electron donor

the addition of an electron(s)

GER

the electron acceptor

the tendency for substances to vary in becoming oxidized or reduced

unit used: volts (V)

tells what direction the reaction goes

represents the same atom on each side of the arrow in the half reactions

oxygen almost always electron acceptor

 hydrogen almost always electron donor

represents a range of reduction potentials for redox couples from the most negative at the top to the most positive at the bottom

top (reduced) has the greatest tendency to donate electrons and the bottom (oxidized) has the greatest tendency to accept electrons

the difference in potential between 2 substances is expressed as ΔE₀'

farther the electrons drop from a donor before being caught by an acceptor the greater the amount of energy released (ΔE₀' proportional to ΔG₀')

oxidized(more positive)/reduced(more negative)

the greater the difference in redox potential (ΔE₀') between the pair, the greater the amount of energy available in the oxidation-reduction reaction

ΔE₀'= E₀' (oxidizing agent) - E₀' (reducing agent)

ΔG= -nFΔE₀'

reduced member that is more negative will donate to the oxidized pair that is more positive

fueling

degradative metabolism, exergonic, oxidative, -ΔG

provides: energy (from ox. of energy source in a complete redox reaction), C skeletons (12 intermediates), and reducing power (ex. NADH + H) for the cell

spontaneous

involves the chemical modification of macromolecules, their transport of pre-specified locations in their cell, and their association to form cellular structures (envelope, appendages, nucleoid, polysomes, inclusions, and enzyme complexes)

the hundreds of biosynthetic reactions grouped into functional units, each consisting of from one to a dozen sequential reactions that produce one or more building blocks

may be linear, branched, or interconnected; each pathway is controlled en bloc

invloves those reactions which use the C skeletons to make subunits of the macromolecules

12 key intermediated, ATP, NADPH₂ (i.e. the products of fueling) → building blocks

conserves the chemical energy released in redox reactions (conserved for cell functions)

these compounds function as the energy source to drive energy-requiring reactions in the cell

attaches phosphate groups via oxygen atoms

not all are energy rich

substrate level phosphorylation and oxidative phosphorylation

electron transport mediated synthesis of ATP. mechanism involves Mitchell's chemiosmosis and generation of proton motive force

the presence of a series of membrane associated electron carriers arranged in order of increasingly more positive E₀'

an alternation in the chain of electron only and electron plus proton carriers

the generation of a proton motive force as a result of charge seperation across the membrane, acidic_out and alkaline_in

involves glucose oxidation to pyruvate and the donation of hydrogen atoms (H + e) from NADH + H to pyruvate or a derivative of pyruvate

only 1 oxidation producing NADH and 2 SLP to make ATP

uses 2 ATP to start pathway, produce 2 more at 2 SLP steps above: 2 net ATP produced

rate is fast because little energy made

no oxygen, so no Krebs (TCA)

no ATP from OP. NADH is used to re-reduce pyruvate or a derivative

EM pathway/gycolysis = good example

uses oxygen as a terminal (external) electron acceptors

pyruvate (3C) is oxidized to acetyl-coA (2C) which enters Krebs/TCA by condensing with the 4 C oxacetate to produce citric acid

4 moles of NADH and 1 mole FADH₂ are produced per pyruvate

since there are 2 pyruvates per starting glucose, this produces 30 net APT

when the 2 SLP ATP are added from the EM pathway and NADH goes to electron transport to produce 3X2=6 more. these add to the 30 to give 38 total ATP per prokaryotic cell

the complex that converts the proton motive force into ATP

consists of F₁ and F₀

F₀ proton conducting channel

-ab₂c₁₂: channels protons across membrane. proton movement drives rotation of c proteins, generating a torque transmitted to F₁by the gamma/ep subunits causing conformational change in beta subunits

F₁ multisubunit headpiece located on cytoplasmic side of membrane that catalyzes synthesis of ATP

-alpha₃beta₃gamma ep delta

biological oxidation in which the terminal electron acceptor is usually an inorganic molecule (external) other than oxygen

uses oxidative phosphorylation for ATP synthesis

some of the electron acceptors used include nitrate, sulfate, and carbon dioxide

when CO₂ is used as an electron acceptor, the resulting product is either methane or acetic acid, depending on the organism involved. much if not all the methane produced in our gut, by cows or in swamps is produced by this process

alpha-ketoglutarate→ glutamate family

oxaloacetate→ aspartate family

pyruvate→alanine

glucose-6-P→ribose-5-P→ribose-5P→ribonuceotides + NADPH→ deoxyribonucleotides + NADP

????

an orderly increase of all the major chemical constituents of an organism

not necessarily an increase in total mass because that may be due to accumulation of cellular reserve material

normally results in cellular multiplication except in the special case of coenocytic (multinucleated) organisms

in a multicellular organism cellular multiplication results in an increase in size of the individual. in unicellular organisms, it leads to an increase in the number of individuals

the most common means of unicellular microbial reproduction

expresses the fact that 2 cells have arisen from one cell

usually involves an equal partitioning of material (DNA, proteins, etc)

cells elongate to approximately twice their length and then form a partition that eventually separates cell into 2 cells

septum results from invagination (inward growth of cytoplasm). membrane and cell wall from opposing directions

generation time

the time required for the population to double (doubling time)

when a microbial population is innoculated into fresh medium, growth usually does not take place immediately, but only after a period of time

occurs because for growth to occur in a particular culture medium, the cells must haev a complete complement of enzymes for synthesis for the essential metabolites not present in that medium

the pattern of population increase where the number of cells doubles during each unit of time period

if plot log#s v. time= straight line

synchranous= stepwise

# v. time= curve

when cells are no longer able to find the nutrients needed, the cells can die

exponential, but slower than the growth exponential rate

in a tube or flask, with limited nutrients, exponential growth cannot occur indefinately

occurs primarily because: as essential nutrient of the medium is used up, waste by product of the organism builds up to an inhibitory level

there is no net increase or decrease in cell number but many cell functions can continue

1. nonhalophile

2. halotolerant

3. halophile

4. extreme halophile

1. psychrophile

2. mesophile

3. thermophile

4. hyperthermophile