Chapter 3
During glycolysis of a single glucose molecule , how many ATP are produced by substrate-level phosphorylation
4 Four ATP are produced by substrate-level phosphorylation, though two of those will be "invested" early in glycolysis.
Fatty acids and some amino acids are converted directly into
Acetyl CoA
If an electron and a hydrogen lon are removed from a structure during a chemical reaction , the structure is said to have been
Oxidized
What is the molecule that enters the citric acid cycle ?
acetyl coenzyme A
Negative feedback control of multienzyme complexes works by the end product
decreasing its own production by inhibiting the complex allosterically.
Enzymes are
proteins
What is the net number of ATP molecules that can be produced from the oxidation of a glucose molecule under anaerobic conditions?
2
The net result of a single glycolysis run is the formation of
2 NADH and 2 ATP
How many ATP are produced using the energy from each NADH ?
3 Three ATP are produced by the energy from each NADH.
Total ATP produced from one glucose molecule is 38. Why is the net value only 30 ?
ATP is used to bring pyruvate and NADH into the mitochondrion from the cytosol.
If an enzyme is inhibited by a substance that binds away from the active site , this substance must be a ( n )
Allosteric inhibitor
How is negative feedback control of multienzyme complexes turned off ?
As the product concentration decreases, the complex is no longer inhibited.
Which of the following correctly represents the mechanism of enzyme function ?
E + S -> E-S -> E-P -> E + P
Pyruvate undergoes oxidation when it loses electrons to
NAD+
Which of the following best describes the reduction of the coenzyme NAD * ?
NAD+ + H -> NADH
If an enzyme is inhibited by a substance that binds away from the active site , this substance must be a ( n )
Substrate
Which of the following is a common feature of electron carriers ?
They can be reversibly oxidized and reduced.
A hydrogen atom consists of
a proton and an electron
As concentration of substrate is increased in a reaction catalyzed by an enzyme , the reaction rate will stop increasing once saturation is reached because
all enzymes are actively engaged in a reaction.
Building glycogen from glucose molecules is an example of
anabolism
The breaking of old chemical bonds and forming of new ones is called a
chemical reactions
Reactions that release energy are called
exergonic reactions
An ATPase enzyme breaks down ATP into ADP and phosphate using water in the reaction . This enzyme is in the enzyme class
hydrolase
The optimum temperature for most enzymes is around body temperature . If the body temperature is slightly elevated , what effect will this have on enzymatic reactions
increased reaction rates
During a fever , the body increases in temperature , which will affect internal chemical reactions by
increasing kinetic energy of the reactants, helping them overcome the activation energy.
Maltase is an enzyme that breaks down maltose . If a maltase enzyme has just completed catalyzing the decomposition of maltose , then
it is available to catalyze the same reaction with another maltose molecule.
Which of the following molecules is produced , along with the oxidation of NADH , when oxygen levels are limited ?
lactate
Under anaerobic conditions , the end - product of glycolysis is converted to
lactic acid
Cells obtain energy by food molecules such as glucose .
oxidizing
In smooth muscle , the contractile protein myosin is activated by myosin light chain kinase ( MLCK ) . Based on its name , how does MLCK activate myosin ?
phosphorylates myosin
During the intermediate stage , pyruvate dehydrogenase catalyzes the formation of acetyl coenzyme A from coenzyme A and
pyruvate
Which of the following is a product of glycolysis
pyruvate
Which of the following binds to the active site of an enzyme ?
substrate
DNA polymerase is an enzyme that binds DNA but is unable to bind RNA . This best displays the enzyme characteristic of
substrate specificity
