AAMC FL 2 Flashcards
Which amino acid’s side chain is frequently encountered at the active site of metalloenzymes?
Histidine. Active sites of metalloenzymes resemble the five-membered imidazole rings associated with histidine.
Absorption of ultraviolet light by organic molecules always results in what process?
Excitation of bound electrons
Increasing the polarity of the eluting molecule will increase its affinity for the stationary phase and (increase or decrease) the elution time?
Increase the elution time. Decreased retention factor.
The half-life of a radioactive material is the time it takes for half of all the radioactive nuclei to decay into (daughter or radioactive) nuclei?
Daughter nuclei which may or not also be radioactive.
Why must the person either lean forward or slide their feet under the chair in order to stand up?
To keep the body in equilibrium while rising
Aromatic side chains absorb in the near UV region of the electromagnetic spectrum, which has longer wavelengths, and hence lower energy, than peptide bonds.
Aromatic side chain has more closely spaced energy levels.
What type of curves indicate cooperative processes?
Sigmoidal curves (S-shaped)
A decrease in oxidation number is a reduction or an oxidation?
Reduction
G-C base pairs form (stronger or weaker) pi-stacking interactions than A-T base pairs.
Stronger. Most thermal stability. Increase in melting temperature in GC-rich DNA
The lone pair of electrons in ammonia allows the molecule to act as a Lewis (acid or base) in water.
Lewis base that donates the electron pair in forming a covalent interaction.
When K is greater than 1,
the reaction’s deltaG is negative and the reaction is spontaneous.
The Lewis acid-base interaction between a metal cation and an electron pair done is known as a ___ bond?
Coordinate covalent bond
In DNA, sugar-phosphate backbones form the (interior or exterior) of the double helix.
Exterior
Bonds between identical atoms are likely to be the (least or most) polar ?
Least polar
Negative focal length = diverging lens. What type of image do it form?
Virtual and reduced images of objects situated at distances larger than the focal length.
Protein secondary structure is represented by repeated patterns of hydrogen bond between
the backbone amide protons and carbonyl oxygen atoms.
Ubiquitination targets a protein for ____ by a proteasome.
Degradation
Posttranslational modification of proteins such as histone acetylation is analyzed by what type of blotting?
Western blotting (SNOW DROP)
The brain is derived from what germ layer?
Ectoderm (central nervous system)
The tips of an antibody are the what type of regions?
The variable regions (specific for a particular antigen)
Dependency ratio
The number of economically dependent members of the population (too young or too old) to the number of economically productive members (working-age 16-85)
