Midterm 1 Flashcards
(12 cards)
Why does NH3 dissolve completely in water?
NH3 has a net dipole which means water is able to interact with it and create a hydration sphere
Which biomolecules rely on hydrogen bonds?
Nucleic acid; nitrogenous bases uses hydrogen bonds to weakly bond to the complementary base
What are the 4 properties of water that are due to hydrogen bonding?
- Make liquid water cohesive and adhesive
- Moderate temperature changes by absorbing/releasing energy
- Make ice less dense than water
- Allow water to be a universal solvent
What is a practical example of waters cohesive principles in nature?
- High surface tension which is good for some organisms
2. Is what allows water to travel up the xylem of trees and other plants
How is water able to moderate temperature changes?
Hydrogen bonds in water are the reason for it’s High cohesive properties, this gives water a high specific heat which means it can absorb alot of energy and release alot of energy with very little change in it’s own temperature; thus moderating the temperature on earth
How is ice less dense than liquid water?
When water is in liquid form the hydrogen bonds between water molecules are constantly breaking and reforming ; meaning that when the bonds are broken, water molecules can be quite close together. In contrast when water is in solid form, ice, the hydrogen bonds between water molecules are fixed and thus do not allow water to come close together. Liquid water is closer together; thus meaning there are more molecules in a given space than solid water, When theres more of a substance in a given area, we can say that, that substance is more dense, therefore liquid water is more dense than solid water
What makes water such a great solvent?
It’s a polar molecule, capable of solvation spheres
What are 4 non-covalent bonds important to biomolecules?
- Hydrogen bonding
- Van der waals
- Ionic bonding - charge charge
- Hydrophobic forces
What is an example of charge-charge bonding?
Electrostatic interaction between Na+ and Cl-
What is a hydrophobic interaction?
Non-polar molecules in an aqueous solution associating with each other rather than water
What makes hydrophobic interactions different from electrostatic interactions?
Hydrophobic interactions aren’t due to an intrinsic attraction to each other but rather a increase in entropy that comes from having as few highly organized solvent spheres as possible
What are 3 reasons that the rate of diffusion is slower inside the cell?
- Cytoplasm has higher viscosity because of dissolved solutes; like navigating through a bunch of bodies in a crowd
- Charged molecules bond transiently to each other; like your scarf catching on someones button in a crowd
- Collisions with other molecules; like people in a crowd pushing
