EXAM 1 Flashcards
Silent Mutation (definition and consequence)
D: Change in nucleotide sequence that does not change the amino acid specified by a codon
C: No change in phenotype; neutral with respect to fitness
Missense Mutation (definition and consequence)
D: Change in nucleotide sequence that changes the amino acid specified by codon
C: Change in primary structure of protein; may be beneficial, neutral, or deleterious
Nonsense Mutation (definition and consequence)
D: Change in nucleotide sequence that results in an early stop codon
C: Leads to mRNA breakdown or a shortened polypeptide; usually deleterious
Frameshift Mutation (definition and consequence)
D: Addition or deletion of a nucleotide
C: Reading frame is shifted, altering the meaning of all subsequent codons;
almost always deleterious
How does the structure of a protein determine its function?
Through shape and interactions
REMEMBER (proteins)
Molecular interactions influence protein structure and function
An enzyme…
decreases the activation energy of a reaction but has no effect on free energy
What is ∆G?
∆G is change in Gibbs free
energy between products and reactants; any energy that is readily available to use
Exergonic
releases energy, spontaneous (favors products)
Endergonic
requires input of energy for the reaction to proceed, nonspontaneous (favors reactants)
REMEMBER (spontaneous)
Spontaneous reactions are not necessarily fast.
Refer to Figure 1:
- Is this reaction exergonic or endergonic?
- Will this reaction proceed spontaneously Why or why not?
- Since ∆G is negative, the reaction is exergonic.
- This reaction will proceed spontaneously because it is exergonic and favors the formation of products.
Refer to Figure 2:
- What is activation energy (Ea)
- How does Ea affect the rate of a reaction?
- How does an enzyme increase the rate of a reaction?
- Activation energy is the kinetic energy required to reach the high-energy transition state.
- The higher the Ea, the slower the reaction.
- An enzyme brings substrates together and lowers the activation energy.
REMEMBER (enzyme)
An enzyme has NO EFFECT on ∆G
Refer to Figure 3:
- Which reactions are coupled in this figure?
- How does the coupled reaction differ from
the uncoupled reaction?
- A + B –> AB (uncoupled) and ATP –> ADP + Pi
- The coupled reaction is exergonic and spontaneous.
Which of these nucleotides, AMP
or ATP, could be added to a growing RNA
chain?
ATP
Initiation (concerning enzyme action)
Binding of substrates in a specific orientation
Transition (concerning enzyme action)
Lowering of activation energy
Termination (concerning enzyme action)
Release of products (which have a lower affinity for the active site)
Competitive Inhibition
The regulatory molecule binds to the active site, inhibiting the substrate from doing so.
Allosteric Regulation (activation)
The regulatory molecule binds to another part of the enzyme and changes its shape, making the active site available for the substrate to bind to.
Allosteric Regulation (inhibition)
The regulatory molecule binds to another part of the enzyme and changes its shape, making the active site unavailable for the substrate to bind to.
Allele
Different DNA sequence
Gene
DNA sequences
Environment
Inputs of information flow
Phenotype
Output of information flow
Fitness
Reproductive success
At a molecular level, what makes an allele
dominant or recessive?
gene products
Why is DNA a good molecule for storing
information?
DNA is more stable than RNA
REMEMBER (directionality)
Nucleic acids have directionality (AKA polarity)
Nonpolar covalent bond
Electrons are shared equally between the two atoms (placed halfway).
Polar covalent bond
Electrons are not shared equally, so partial charges exist.
REMEMBER (non-polar bond)
Energy input is needed to build molecules
with non-polar bonds.
NONPOLAR NOTE
Nonpolar bonds have higher potential energy than polar bonds.
HYDROPHOBIC NOTE
Molecules or regions of a molecule that are composed primarily of nonpolar
bonds are hydrophobic.
HYDROPHILIC NOTE
Molecules or regions of a molecule that are composed primarily of polar bonds
are hydrophilic.
