Biology 172 Exam 1; Lecture 1: Basic Chemistry

What is hydrophobicity?

This term refers to the property of a molecule to repel water, making it insoluble. While repelling water, non polar molecules stick together.

What are polar covalent bonds?

These bonds occur when electrons are shared unequally between atoms resulting in a partial negative and partial positive charge.

What are non polar covelant bonds?

These bonds are bonds where electrons with similar electronegitivities share bonds equally.

What are Hydrogen bonds?

These bonds form between 2 polar molecules due to partial positive and negative charges.

What are Ionic bonds?

These bonds are strong bonds between oppositely charged ions, causing for full loss or gain between atoms.

What is van der Waals interaction

Occurs between nonpolar molecules, has transient charge in these non polar molecules. The bonding here is weak.

What is a solvent?

Where substances easily dissolve.

The tendency of water molecules to stick to each other is___and the tendency of water molecules to stick to other surfaces is___.

Cohesion; Adhesion

How do acids on the PH scale work?

They increase hydrogen ions and decrease PH.

How do bases on the PH scale work?

They decrease hydrogen ions and increase PH.

How do buffers work on the PH scale?

Buffers minimize hydrogen ion changes and keep the PH stable.

Why are Archaea and Eukarya more closely related to each other than Bacteria and Eukarya?

The tree of life shows these two as having a more recent relationship between each other.

What is the relationship between polar vs n-p covalent bonds and

electronegativity and electron sharing?

Both polar and non polar covalent bonds share electrons, polar bonds have unequal electron sharing and occur between atoms with different electronegativity, while non polar has equal electron sharing and occurs between atoms with similar electronegativity.

How do covalent bonds compare in strength to ionic bonds?

Ionic bonds are less stable and weaker than covalent bonds

Why does oil separate from water?

The hydrophobic effect of the oil when interacting with water; water has a polar charge while oil has a non polar charge.

Why is water good at solubilizing many molecules?

The molecular polarity of water allows for this as well as strong hydrogen bonding between other polar molecules resulting in dissolving of polar substances.

Which molecule can water solubilize or dissolve ?

sea salt

Water molecules have

partial charge