Molecular Biology test exam
questions and answers graded A+
what are redox reactions? - ANS✅✅the transfer of one or more electrons
what is oxidation? - ANS✅✅the loss of electrons from one substance (reducing agent); go from a
reduced form to an oxidized form by losing H+ and electrons that are then get picked up an acceptor
what is reduction? - ANS✅✅the addition of electrons to another substance (oxidizing agent); go
from an oxidized form to a reduced form by picking up h+ and electrons ; coenzymes
what is substrate phosphorylation? - ANS✅✅mode of ATP synthesis; specific chemical reaction of
bond rearrangements of phosphate group make a high energy phosphate which can be transferred
from a substrate to ADP to make ATP; don't get a lot of ATP this way
what is gylcolysis? - ANS✅✅occurs in the cytosol; begins degradation process by breaking glucose
into two molecules of pyruvate; has two phases; net total of 2 ATP generated per pyruvate; 2
substrate level phosphorlaytion;
what are the two steps of glycolysis? - ANS✅✅phase 1- energy investment - ATP is used to keep
glucose inside the cell, to activate it for entrance into pathway, and to provide a phosphate for
future high energy phosphate; start with a C6 and end with 2 3C; use 2 ATP- glucose is
phosphorlated
phase 2- happens twice; make 4 ATP; NAD+ takes H+ away so that a phosphate can come in
(substrate level)- generate 2NADH+; lose 2 water to move P to then make ATP -> substrate level -->
makes pyruvate (2)
what happens to the pyruvate after glycolysis? - ANS✅✅enters the mitochondria by a membrane
transport protein; converted to acetyl CoA by COO- is left as CO2, then 2 carbon fragment is oxidized
to make acetic acid (ion), then NAD+ takes the electrons (makes 2 total NADH+), the CoA attaches to
acetate- now it can enter the Krebs cycle
what is the citric acid cycle (Krebs cycle) - ANS✅✅occurs in the mitochondria cytosol and
membrane; breakdown of glucose to CO2 is completed; 2 substrate level phos; 2 ATP made; 6
NADH+ made- made when the carbon structure is oxidized - either release CO2 (4 total) or
regenerate acceptor; 2 FADH+ made - after ATP is made, oxidizes; 2 oxidative decarboxylation
, what is oxidative decarboxylation? - ANS✅✅when a molecule of CO2 is lost; happens when
electrons and hydrogen ions are also lost
what are the two halves of the Krebs cycle? - ANS✅✅first half- to completely metabolize the
glucose; acceptor adds acetyl CoA to make a 6 carbon structure (lose and add water), oxidize carbon
structure (lose 2 NADH+ and 2CO2_ - makes 5 C structure- oxidized (2 NADH+ and 2 CO2) - make 4 C-
now lost all 6 carbons from glucose
second half - regenerate acceptor- substrate level phosphorlatyion (make 2 ATP), make 2 FADH+ -
add water, NAD+ oxdizes Cstructure makes NADH+, acceptor generated
what are the fates of pyruvate and what are the products of each fate? - ANS✅✅1) ehtanol-
makes 2 ATP
2) lactate- 2 ATP
3) acetyl CoA
what is oxidative phosphorylation? - ANS✅✅a mode of ATP synthesis that has two processes:
electron transport chain and chemiosmosis; uses NADH and FADH made in previous steps to make a
lot of ATP; has a - delta G; series of redox couples;
what is the electron transport chain? - ANS✅✅a collection of molecules embedded in the inner
membrane of the mitochondira; 4 protein complexes; building a proton gradient by electrons are
being transported down the chain - electrons come from NADH+ and FADH+ which get reoxidzed -
complexes take those electrons- electrons in IV make join with H+ ad 1/2O2 to make water;
electrons pumped into mito intermembrane space; - delta G; to make potential energy to make ATP;
transport proteins pump H+ out
what is chemiosmosis? - ANS✅✅ATP synthesis powered by the flow of H+ back across the
membrane- powers ATP generation- the energy generated is used to make ATP because of - delta G
to do work; makes about 26 or 28 ATP
what happens when there is a lack of oxygen? - ANS✅✅then no water is made and IV will then
block all other processes from occuring, so less ATP is made- metabolism shuts down; lactic acid
fermentation keeps glycolysis going even with lack of oxygen so some ATP is made- only a short
amount of time because toxic
how many ATP are made at the end of cellular respiration? - ANS✅✅30 to 32 ATP
questions and answers graded A+
what are redox reactions? - ANS✅✅the transfer of one or more electrons
what is oxidation? - ANS✅✅the loss of electrons from one substance (reducing agent); go from a
reduced form to an oxidized form by losing H+ and electrons that are then get picked up an acceptor
what is reduction? - ANS✅✅the addition of electrons to another substance (oxidizing agent); go
from an oxidized form to a reduced form by picking up h+ and electrons ; coenzymes
what is substrate phosphorylation? - ANS✅✅mode of ATP synthesis; specific chemical reaction of
bond rearrangements of phosphate group make a high energy phosphate which can be transferred
from a substrate to ADP to make ATP; don't get a lot of ATP this way
what is gylcolysis? - ANS✅✅occurs in the cytosol; begins degradation process by breaking glucose
into two molecules of pyruvate; has two phases; net total of 2 ATP generated per pyruvate; 2
substrate level phosphorlaytion;
what are the two steps of glycolysis? - ANS✅✅phase 1- energy investment - ATP is used to keep
glucose inside the cell, to activate it for entrance into pathway, and to provide a phosphate for
future high energy phosphate; start with a C6 and end with 2 3C; use 2 ATP- glucose is
phosphorlated
phase 2- happens twice; make 4 ATP; NAD+ takes H+ away so that a phosphate can come in
(substrate level)- generate 2NADH+; lose 2 water to move P to then make ATP -> substrate level -->
makes pyruvate (2)
what happens to the pyruvate after glycolysis? - ANS✅✅enters the mitochondria by a membrane
transport protein; converted to acetyl CoA by COO- is left as CO2, then 2 carbon fragment is oxidized
to make acetic acid (ion), then NAD+ takes the electrons (makes 2 total NADH+), the CoA attaches to
acetate- now it can enter the Krebs cycle
what is the citric acid cycle (Krebs cycle) - ANS✅✅occurs in the mitochondria cytosol and
membrane; breakdown of glucose to CO2 is completed; 2 substrate level phos; 2 ATP made; 6
NADH+ made- made when the carbon structure is oxidized - either release CO2 (4 total) or
regenerate acceptor; 2 FADH+ made - after ATP is made, oxidizes; 2 oxidative decarboxylation
, what is oxidative decarboxylation? - ANS✅✅when a molecule of CO2 is lost; happens when
electrons and hydrogen ions are also lost
what are the two halves of the Krebs cycle? - ANS✅✅first half- to completely metabolize the
glucose; acceptor adds acetyl CoA to make a 6 carbon structure (lose and add water), oxidize carbon
structure (lose 2 NADH+ and 2CO2_ - makes 5 C structure- oxidized (2 NADH+ and 2 CO2) - make 4 C-
now lost all 6 carbons from glucose
second half - regenerate acceptor- substrate level phosphorlatyion (make 2 ATP), make 2 FADH+ -
add water, NAD+ oxdizes Cstructure makes NADH+, acceptor generated
what are the fates of pyruvate and what are the products of each fate? - ANS✅✅1) ehtanol-
makes 2 ATP
2) lactate- 2 ATP
3) acetyl CoA
what is oxidative phosphorylation? - ANS✅✅a mode of ATP synthesis that has two processes:
electron transport chain and chemiosmosis; uses NADH and FADH made in previous steps to make a
lot of ATP; has a - delta G; series of redox couples;
what is the electron transport chain? - ANS✅✅a collection of molecules embedded in the inner
membrane of the mitochondira; 4 protein complexes; building a proton gradient by electrons are
being transported down the chain - electrons come from NADH+ and FADH+ which get reoxidzed -
complexes take those electrons- electrons in IV make join with H+ ad 1/2O2 to make water;
electrons pumped into mito intermembrane space; - delta G; to make potential energy to make ATP;
transport proteins pump H+ out
what is chemiosmosis? - ANS✅✅ATP synthesis powered by the flow of H+ back across the
membrane- powers ATP generation- the energy generated is used to make ATP because of - delta G
to do work; makes about 26 or 28 ATP
what happens when there is a lack of oxygen? - ANS✅✅then no water is made and IV will then
block all other processes from occuring, so less ATP is made- metabolism shuts down; lactic acid
fermentation keeps glycolysis going even with lack of oxygen so some ATP is made- only a short
amount of time because toxic
how many ATP are made at the end of cellular respiration? - ANS✅✅30 to 32 ATP
