Water - hydrogen bonds Flashcards
Where did the first cells evolve?
Watery environment - deep oceans close to hydrothermal vents in the Earth’s crust
How did cells evolve?
Water & solutes trapped within a membrane, chemical reactions began occuring
Why is liquid water important for life processes?
Allows dissolved molecules to move around - can easily collide and reacti with each other
What are the key functions of hydrogen bonding? (list 6)
- dissolving of solutes in water
- the cohesion and adhesion of water molecules
- base-pairing between the two strands of DNA
- structure - part of secondary & tertiary structures in proteins, bonds between strands of cellulose and collagen give molecules tensile strength
- interactions between mRNA and tRNA during protein synthesis
- surface effects on membranes between polar phosphate groups and water
How is water composed?
One oxygen atom covalently bonded with two hydrogen atoms.
Explain the charge of water
Electrically neutral as a whole.
Polar molecule due to uneven sharing of electrons - called a dipole.
Weak positively charged region on the hydrogen atoms, weak negatively charged region on the oxygen atom.
Why do hydrogen bonds form between water molecules?
As a result of the polarity of water. Hydrogen bonds form between the positive and negatively charged regions of adacent water molecules.
How strong are hydrogen bonds
Weak - constantly breaking and reforming.
When large numbers are present they form a strong structure.
What is hydrogen bonding?
Weak electrostatic attractive forces between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another molecule.
