Chemical bonds Flashcards
What is an isotope?
It is an element that has same numbers of protons but different number of nuclei
(Two isotopes have same number of protons but different number of nuclei)
Why are mass numbers not whole numbers?
Because elements have different isotopes
How can we determine stability of an isotope?
An isotope with more neutrons is often unstable
Polar bond vs. Non-polar bond
- Polar bond: electrons are not shared equally
- Non-polar bond: electrons are shared equally
What is a hydrogen bond?
A special type of polar bond between partial positive and negative charges of two water molecules
Why does ice float?
Liquid water is denser than ice because ice forms a crystal lattice
What is behind Van der Waals interaction?
Van der Waals is due to transient dipoles - the weakest IMF
How can you tell a strong acid vs a weak acid?
- A strong acid dissociates completely in solution
- A weak acid does not completely dissociate
Both donate H+ ions
Strong Base vs Weak base
A strong base completely dissociates in solution
A weak base only partially dissociates
Both accept H+ in solution and release OH-
How does a buffer work?
Buffers make overall solution resistant to pH change
This is because they react with both acids and bases
What are the three main functional groups?
- Hydroxyl OH-R
- Amino R-N-/-H
- Carboxyl R-Cā/-O, OH
What is the advantage of biochemical unity?
WE can obtain energy from eating and digesting other organisms
What is polymerization?
The bonding together of monomers!
What is condensation?
The formation of a polymer linked by covalent bonds
Release one water molecule for each monomer added
Requires energy input (anabolic)
What is Hydrolysis?
The breaking of a covalent bond with help of water
Water in, monomer out
Catabolic; releases energy
How many amino acids are there?
20
What starts an amino acid and what ends an amino acid?
- Amino acid starts with an amino
- Ends with Carboxyl group
What are the two steps of protein folding?
- Hydrogen bonds form within the polypeptide backbone
- Fold to an Amino Acid or a B pleated sheet
Explain the characteristics of Proline?
Proline is an amino acid that fits into neither alpha helix or B pleated sheet.
This is due to a ring preventing free rotation of the N-C bond because N lacks a hydrogen.
It is often the last amino acid of an alpha helix
