Lecture 7-8 Flashcards
What is retina and what it contains on human eyes?
The retina is located at the back of human eye and it contains photorecptors cells which convert photons into electrical info.
What are two types of photoreceptors?
Rod photoreceptors cells (light intensity) and cone photorecptor cells (color vision)
What is photoisomerizaiton?
As light triggers a chanfe in molecular configuration on opsin protein.
what is phototransduction?
It’s the process by which light detected by photoreceptor cells is converted to electrical impulses before these impulses are then sent to the brain.
What is coulomb’s law?
Fe=kq1q2/r^2
What forces are included in intramolecular force?
ionic bond, covalent bond, and metallic bond
What is electronegativity?
The tendency of an atom to attract a shared pair of electrons
What is metallic bonds?
A type of covalent bonding specifically occurs between atoms of metals. Valence electrons are free to move through the lattice.
What is Lennard-Jones Potential?
Describes the potential energy of interaction between two nonbonding atoms or molecules based on their distance of seperation.
What is the smaller attractive term in LJ potential?
London dispersion force
What is the sigma value in L-J potential?
Van der Waals radius.
What is short range forces?
Short range forces tend to be repulsive. It happens when the centers of molecules are separated by three angstroms or less.
What is long range force?
AKA Van der Waals forces. It happens when three angstrom range are attractive.
What is intermolecular force responsible?
Surface tension, friction, viscosity, and differences between behaviour of gases.
What are three types of Van der Waals forces?
Dipole-dipole, interactions between dipoles and induced dipoles, LDF
What is disulfide bonding?
A covalent bond derived from the oxidation of two S-H group
What’s the difference between intramolecular and intermolecular disulfide bridge?
Intra: stabilize the tertiary structure
Inter: stabilize the quaternary structure
What is capillary action?
It only occurs when adhesive forces are stronger than cohesive forces.
What is surface tension?
It’s the result of cohesive forces between liquid molecules at an interface. It leads to surface film.
What is surfactant?
It’s the compound which lower surface tension by disrupting intermolecualr forces at the interface.
What is self-assembly?
It’s a process in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local interactions among the components themselves without external direction.
What the condition that self assenbly would occur?
- it’s a spontaneous process.
- The product of self-assembly is more thermodynamically stable. The Gibb’s free energy must be less thatn zero, a net gain in entropy.
What is super-hydrophobicity?
A result of micro- and even nano-structured patterns. When contanct angle is larger than 90 deg.
How to quantifying hydrophobicity?
γSG= γSL+ γLGcosa
