7.7-8.3 Quiz Flashcards
how is energy transferred
through redox reactions, the transfer of electrons
oxidation
loss of electrons
reduction
gain of electrons
examples of redox reactions
cellular respiration, photosynthesis, etc
Redox reactions in cells involve
the transfer of a hydrogen atom, electrons progressively lose free energy through transfers
result in the formation of ATP
a series of energy transfers
NADPH is involved in
photosynthesis
what is the reduced form of FAD
FADH2
cytochromes
proteins that contain iron which accepts electrons from hydrogen and then transfers them
what is the function of enzymes
increase speed of a chemical reaction without being consumed by the reaction
what is catalase
an enzyme with the highest known catalytic rate; protects cells by destroying hydrogen peroxide
what is activation energy
the energy required to begin a reaction and break existing bonds
enzyme substrate complex
an unstable intermediate complex formed by the enzyme in order to control the reaction
enzyme + substrate –>
ES complex
ES complex –>
enzyme + product
what is an active site
a region on an enzyme where the substrate binds
induced fit
binding of substrate to the enzyme causes a change in shape of the enzyme (distorting the chemical bonds of the substrate)
two components of some enzymes
apoenzyme and a cofactor (non protein, specific metal ion; iron, copper, zinc, and manganese)
what is a coenzymes
organic non polypeptide compound the binds to the apoenzyme and serves as a cofactor (carrier molecules)
types of coenzymes
NADH, NADPH, FADH2, ATP, Coenzyme A (most vitamins)
heat and enzyme relation
enzymes are heat tolerant, arches have certain enzymes that allow them to survive extreme habitats
enzymes have an optimal pH
most human enzymes is 6 to 8
metabolic pathways
the product of one enzymes-controlled reaction serves as substrate for the next reaction
gene control
a specific gene directs synthesis of each type of enzyme
(genes can be switched on the amount of enzyme can influence the reaction)
how can rate of reaction be limited
by enzyme concentration or by substrate concentration
enzymatic reactions reactant and product relationship
the product of one reaction is the reactant for the next
feedback inhibition
enzyme regulation in which the formation of a product inhibits an earlier reaction in the sequence
allosteric site
modifies the enzyme’s activity when an allosteric regulator is bound to it , keeps the enzyme inactive equaling a functional active site
competitive inhibition
the inhibitor competes with the normal substrate for the active site of the enzyme (temporary)
noncompetitive inhibition
the inhibitor binds with the enzyme at the a site other than the active site, altering the shape of the enzyme and inactivating it
irreversible inhibition
inhibitor permanently inactivates or destroys an enzyme when the inhibitor combines with one of the enzymes functional group, either at the active site of elsewhere (poisons)
why do cells use aerobic respiration
to obtain energy from glucose (glucose oxidized, oxygen reduced)
aerobic respiration requires
O2 and nutrients are catabolized to CO2 and H2O, free energy increases
stages of aerobic respiration
glycolysis, formation of acetyl coenzyme A, citric acid cycle and electron transport and chemiosmosis
where does glycolysis take place
in the cytoplasm, making pyruvate and 2 ATP
dehydrogenations
two hydrogens are transferred to NAD+ or FAD
decarboxylation
part of a carboxyl group is removed as a molecules of CO2
preparation reaction
molecules are rearranged to undergo further dehydrations or decarboxylation
phosphorylation
transfer of a phosphate group, may be substrate level or oxidative phosphorylation
two ways ATP is produced
substrate phosphorylation and oxidative phosphorylation
substrate phosphorylation
a phosphate group is transferred directly from an organic molecules to ADP
oxidative phosphorylation
transfer of phosphate group to ADP is due indirectly to the oxidation of NADH and FADH2, and directly chemiosmosis
what stages of respiration occur in the mitochondria
formation of acetyl coA, citric acid cycle, and electron transport and chemiosmosis
glycolysis
starts with a 6 carbon and 2 ATP in, ends with 4 ATP 3 pyruvate; endergonic and exergonic reaction
glycolysis net yield
2 ATP, 2 NADH
first phase of glycolysis
input of energy; transfer of phosphate group from ATP to glucose. yields 2 G3P (high energy)
glucose + 2 ATP = 2 G3P + 2 ADP
second phase of glycolysis (energy capture)
G3P oxidized and converted to pyruvate
2 G3P + 2 NAD+ +4ADP = 2 pyruvate + 2 NADH + 4 ATP
overall glycolysis makes
2 G3P, 2 ADP, 2 pyruvate, 2 NADH, 4 ATP
stage 2 pyruvate converted to aceyl coA
pyruvate undergoes oxidative decarboxylation, NAD+ is reduced to NADH
2 pyruvate + 2 NAD+ + 3 CoA = 2 acetyl CoA + 2 NADH + 2 CO2
total end results of aerobic respiration
2 G3P, 2 ADP, 2 pyruvate, 4 NADH, 4 ATP, 2 acetyl CoA + 2 CO2
Cirtic Acid Cycle / Krebs cycle/ TCA cycle
acetyl CoA tranfers acetoyl group (2C’s) to oxaloacetate (4 C’s) to form citrate (6 C’s)
oxaloacetate + acetyl CoA == citrate + CoA
citric acid cycle net yield
6 CO2, 6 NADH
citric acid cycle products
1 ATP, 1 FADH2, 3 NADH
