BIOL 200 Week 2 Reading Quizzes
How many phosphate groups does an "activated nucleotide" have?
3
What is the secondary structure of nucleic acids?
A double helix of anti parallel strands
A polymer of nucleotides is called...
A nucleic acid
ATP, the molecule used in many reactions in a cell, is...
A nucleotide and ribonucleotide
We say that ATP hydrolysis (its breakdown) is "coupled" to drive endergonic reactions. This means...
A part of ATP must form a chemical bond with another reactant molecule
Potential energy stored in the bonds of a molecule is also called...
Chemical energy
Is ATP a catalyst?
No
Which of the following can be found as "helpers" of certain enzymes in cells? (Choose ALL correct answers)
inorganic ions (such as Mg2+ and Fe2+) organic molecules (such as NADH) derivatives of vitamins
Which of the following are TRUE regarding an active site of an enzyme? (Choose ALL correct answers)
it contains R-groups atoms within the active site interact with substrate molecules its structure can change after it binds to reactant
Which of the following is the best definition of a "transition state" intermediate?
it is an unstable (high energy) "mash up" of reactants
Which of the following is a source of the activation energy needed to reach the transition state intermediate? (choose the ONE best answer)
kinetic energy of molecules that is converted to chemical bond energy after collision
Imagine an enzyme in which the one of the substrates is glucose. Which of the following interactions is most likely going to form between R-groups of the enzyme's active site and the substrate? (Choose the ONE best answer)
Hydrogen bond
Which are functions of the molecule you answered for #8?
Information storage and catalysis
Why is the molecule you answered for #8 more versatile? (Why does it have more functions?)
It can adopt more structures (due to its diverse tertiary structures)
In this reaction, how is enthalpy or potential energy (H) of the molecules changing? (Choose ONE answer) C6H12O6+ 6O2—>6CO2 + 6H2O
Decreasing (number of nonpolar bonds decreases)
Changes in free energy are related to both enthalpy and entropy. Which equation best represents this?
DeltaG=deltaH-TdeltaS
When a catalyst is provided for a reaction, which of the following is decreased?
E of A (the activation energy of the reaction)
When a reaction releases heat, the reaction is...
Exothermic
Is this statement true or false? If a reaction is spontaneous, then it will always occur very quickly.
False
In this reaction, how is entropy (S) of the system changing? (Choose ONE answer) C6H12O6+ 6O2—>6CO2 + 6H2O
It is increasing (number of molecule increases)
Adenosine triphosphate (ATP) can be hydrolyzed to become ADP and inorganic phosphate. It has a deltaG of -7.3 kcal/mol. This reaction... (Choose ALL correct answers)
It's spontaneous, exergonic, and releases energy.
The best definition of catalysis is:
Making a reaction more likely to proceed
What is the name of the bond that connects nucleotides?
Phosphodiester bond
Which has a wider variety of functions in the cell?
RNA
We told you that the reaction LaTeX: Glu + NH_{3} \longrightarrow Gln + H_{2}O G l u + N H 3 ⟶ G l n + H 2 O (let's call it reaction 1) was an endergonic reaction. However, LaTeX: Glu~P + NH_{3} \longrightarrow Gln + Pi G l u P + N H 3 ⟶ G l n + P i (reaction 2) is exergonic. Which of the following are true? (Choose ALL correct answers)
Reaction 2 can occur in cells The reactants of reaction 2 have more Gibbs free energy (G) than the products of reaction 2 Glu~P has higher G than Glu
If you look at a single nucleic acid strand, the end with a free phosphate group (not part of a phosphodiester bond) is considered...
The 5' end
Looking at figure 8.9, which of the following is true? (Choose ALL correct answers)
The coupled reaction is spontaneous, and the uncoupled reaction is not. In the coupled reaction, one of the reactants is phosphorylated, but not in the uncoupled reaction.
What is the best description of "entropy"?
The disorder of a system
Consider the reaction LaTeX: R + S \longrightarrow (Transition State Intermediate) \longrightarrow T + U R + S ⟶ ( T r a n s i t i o n S t a t e I n t e r m e d i a t e ) ⟶ T + U Which has the highest relative free energy (G)? (Choose ONE answer)
The transition state intermediate
True or False: Long, weak bonds (like those found in non-polar C-H bonds) have higher potential energy than short, strong bonds (like those found in polar O-H bonds).
True
A single nucleotide contains (Choose ALL correct answers)
at least one phosphate group a ribose or deoxyribose a nitrogenous base
After an enzyme catalyzes a reaction, what is usually the situation?
the enzyme can be used again to catalyze the same reaction
What two ways do catalysts help with reactions?
they help reduce the activation energy they help molecules interact in a precise orientation
