MCB 250 Exam 1 Set questions with
verified solutions
What is the Universal Tree of Life based on? - correct answer ✔✔small subunit
rRNAs
What is reverse transcription? - correct answer ✔✔using RNA to make DNA
What is catabolism? - correct answer ✔✔breaking down food to make energy
What is anabolism? - correct answer ✔✔synthesizing components of cells so they
can grow and divide
What happens with transcription and translation in prokaryotes? - correct answer
✔✔transcription and translation are simultaneous
What are the 6 primary chemical elements of life? - correct answer ✔✔carbon,
hydrogen, nitrogen, oxygen, phosphorous, sulfur
Covalent bonds result from: - correct answer ✔✔shared electrons
What are conjugated bonds in aromatic rings? - correct answer ✔✔allow electron
sharing among all the carbons
,Why do aromatic rings stack? - correct answer ✔✔clouds of electrons interact
with each other at their faces
Why are aromatic rings more stable when stacked? - correct answer ✔✔the pi-
bonds overlap and create more stability
Compounds w/ conjugated double bonds or aromatics absorb light in what range?
- correct answer ✔✔UV or visible
More conjugated double bonds means that light of ___ energy will be absorbed. -
correct answer ✔✔lower
Define a chiral molecule. - correct answer ✔✔when rotated, cannot be
superimposed on its mirror image
Define an achiral molecule. - correct answer ✔✔when rotated, molecule can be
superimposed on its mirror image
If 2 or more side groups are the same, how does it affect the superimposed mirror
image? - correct answer ✔✔they can be super imposed
What amino acid has no D or L format? - correct answer ✔✔glycine
Why does D vs. L format matter in amino acids? - correct answer ✔✔only one
form of chiral molecule is found in nature
, What does a high-energy bond refer to? - correct answer ✔✔bonds that release
significant energy when hydrolyzed
What is strength dictated by in hydrogen bond? - correct answer ✔✔bond angle
(straight is best)
Define H-bond donor. - correct answer ✔✔the hydrogen covalently bonded to an
electronegative element
Define H-bond acceptor. - correct answer ✔✔an electronegative element capable
of bonding to H
What is the change in free energy of a H-bond? - correct answer ✔✔3-7 kcal/mole
What is the deltaG for ionic bonds? - correct answer ✔✔approx 5 kcal/mol
Are ionic bonds directional? - correct answer ✔✔nope!
____ is when electron clouds attract each other weakly. - correct answer ✔✔van
der Waals forces
When do van der Waals forces become important? - correct answer ✔✔when two
large surfaces fit together (like enzymes and substrates)
Define an amphipathic molecule? - correct answer ✔✔both hydrophobic and
hydrophilic regions
verified solutions
What is the Universal Tree of Life based on? - correct answer ✔✔small subunit
rRNAs
What is reverse transcription? - correct answer ✔✔using RNA to make DNA
What is catabolism? - correct answer ✔✔breaking down food to make energy
What is anabolism? - correct answer ✔✔synthesizing components of cells so they
can grow and divide
What happens with transcription and translation in prokaryotes? - correct answer
✔✔transcription and translation are simultaneous
What are the 6 primary chemical elements of life? - correct answer ✔✔carbon,
hydrogen, nitrogen, oxygen, phosphorous, sulfur
Covalent bonds result from: - correct answer ✔✔shared electrons
What are conjugated bonds in aromatic rings? - correct answer ✔✔allow electron
sharing among all the carbons
,Why do aromatic rings stack? - correct answer ✔✔clouds of electrons interact
with each other at their faces
Why are aromatic rings more stable when stacked? - correct answer ✔✔the pi-
bonds overlap and create more stability
Compounds w/ conjugated double bonds or aromatics absorb light in what range?
- correct answer ✔✔UV or visible
More conjugated double bonds means that light of ___ energy will be absorbed. -
correct answer ✔✔lower
Define a chiral molecule. - correct answer ✔✔when rotated, cannot be
superimposed on its mirror image
Define an achiral molecule. - correct answer ✔✔when rotated, molecule can be
superimposed on its mirror image
If 2 or more side groups are the same, how does it affect the superimposed mirror
image? - correct answer ✔✔they can be super imposed
What amino acid has no D or L format? - correct answer ✔✔glycine
Why does D vs. L format matter in amino acids? - correct answer ✔✔only one
form of chiral molecule is found in nature
, What does a high-energy bond refer to? - correct answer ✔✔bonds that release
significant energy when hydrolyzed
What is strength dictated by in hydrogen bond? - correct answer ✔✔bond angle
(straight is best)
Define H-bond donor. - correct answer ✔✔the hydrogen covalently bonded to an
electronegative element
Define H-bond acceptor. - correct answer ✔✔an electronegative element capable
of bonding to H
What is the change in free energy of a H-bond? - correct answer ✔✔3-7 kcal/mole
What is the deltaG for ionic bonds? - correct answer ✔✔approx 5 kcal/mol
Are ionic bonds directional? - correct answer ✔✔nope!
____ is when electron clouds attract each other weakly. - correct answer ✔✔van
der Waals forces
When do van der Waals forces become important? - correct answer ✔✔when two
large surfaces fit together (like enzymes and substrates)
Define an amphipathic molecule? - correct answer ✔✔both hydrophobic and
hydrophilic regions
