Wk 1: Atoms and Elements

Question 1

Explain the relationship between biochemistry and life

Answer 1

• Living cells are chemical engines: function at constant temp and pressure, energy derived from sun
• Living cells exchange energy woth environment: always in flux
• Chemical processes within biological system are defined by biochemistry

Question 2

Describe how biochemistry relates to chemistry and biology

Answer 2

Question 3

What are the essential bioelements?

Answer 3

CHNOPS
- atoms arrange into biomolecules and compounds via chemical rxns

Question 4

what are the essential biomolecules?

Answer 4

1. Lipids and fatty acids: energy reserves and cell membranes
2. Carbs (sugars): energy sources
3. Amino acids: subunits of proteins. Structural components of cells and runs cellular functions
4. Nucleotides (DNA and RNA): code for making proteins and carriers of cellular energy

Question 5

Why are these biomolecules essential?

Answer 5

• Monomers form bonds creating polymer chains (polymerisation)
• Lipids are not true polymers (not built from monomers)

Question 6

Explain atomic structure, atomic numbers, atomic mass

Question 7

Structure and characteristics of atoms

Answer 7

• Mostly empty space
• Nucleus: protons and neutrons
• Electrons orbit
• Atoms are neutrally charged

Question 8

Explain the atomic model

Answer 8

• Bohr atomic model shows electrons in rings around nucleus
• Quanta: discrete energy levels where electrons exist

Question 9

Describe electron shells

Answer 9

• Each shell holds different amount of e- (2,8,18,32,50)
• Valence shell: outermost shell
• Valence e-: outermost electrons
• Shells are quantised energy states
• Shells contain electron orbitals

Question 9

Define mass

Answer 9

• Mass of proton: 1 amu
• 1/12th of a carbon atom

Question 10

What are isotopes

Answer 10

• Atoms with same no protons but different no. neutrons
• Can be stable or unstable
• Unstable isotopes emit radiation as they decay (useful for diagnostic imaging like CT scans)

Question 11

Calculating true aromic weight

Answer 11

multiply the percentage by atomic mass and adding results together

Question 12

Describe moles

Answer 12

• Avogadro’s Constant = 6.02 x 10^23
• • 1 mole = 6.02 x 1023 atoms of Carbon-12

Question 13

Describe ions

Answer 13

• formed by gain/loss of e- in valence shell
• Cations and anions

Question 14

Describe atomic orbitals

Answer 14

• Orbitals define electron filling and configuration, thus atom reactivity

Question 15

Filling orbitals

Answer 15

• Orbitals are ranked as s, p, d, f
  (nucleus outward; lowhigher energy)
• Any orbital orientation can only hold max 2 electrons
• s has 1 orientation (2 e-)
• p has 3 orientations (6 e-)
• d has 5 orientations (10 e-)
• f has 7 orientations (14 e-)
• Filling is based on energy levels

Question 16

Who made the periodic table

Answer 16

• Dmitri Mendeleev (1834-1907)
• Organised known elements by
  increasing atomic weight
• Noticed certain sets of properties recur periodically
• Rearranged elements with recurring sets of properties in the same column

Question 17

Periodic table arrangement

Answer 17

• Periods are rows and groups are columns
• Atomic no. and weight increases from left to right and top to bottom

Question 18

Electron filling and the periodic table

Answer 18

• Periods (rows) show which shell is filling
• Electrons given/taken or shared to obtain stable config (valency of 8)