Biochemistry

Question 1

Chemical Fundamentals

Answer 1

Living things are composed of matter

Definition: Matter is anything that has mass and occupies space

Question 2

Atom

Answer 2

Smallest unit of matter composed of:

• protons
• neutrons
• electrons

Question 3

Isotopes

Answer 3

elements of an atom with the same number of protons but different number of neutrons
ex. carbon, a major constituent of living organisms has 3 isotopes ie. C12, C13, C14
C12=most abundant
C14=least abundant

Question 4

Radioisotopes

Answer 4

isotope that decays or decomposes into smaller atoms, subatomic particles of energy.
ex. C14 is radioactive breaks down to N14
Definition: Half-life is the time it takes for one half of the nuclei in a radioactive sample to decay

Question 5

Uses of Radioisotopes

Answer 5

Radiometric dating

nuclear medicine for diagnosis and treatment

Question 6

Two main types of chemical bonding

Answer 6

Intra-molecular forces (forces WITHIN the molecules)

Inter-molecular forces (forces BETWEEN molecules)

Question 7

Intra-molecular forces

Answer 7

Two types:

Ionic bonds, and covalent bonds

Question 8

Ionic bond

Answer 8

bond between atoms that have lost or gained electrons and have become charged

Question 9

Ions

Answer 9

Charged atoms

Question 10

Cation

Answer 10

Ion that is negatively charge

Question 11

Anion

Answer 11

ion that is negatively charged

Question 12

Covalent bond

Answer 12

bonds formed when atoms share one or more pairs of valance electrons
They can be either polar or non-polar

Question 13

Electronegatively

Answer 13

measure of an atom’s ability to attract a shared electron pair when it is participating in a covalent bond
ex. En for noble gases is 0

Question 14

Symmetrical molecules

Answer 14

Bonds are all polar are nonpolar

Question 15

Asymmetrical molecule

Answer 15

are non polar if all the bonds are non polar, and they are polar if at least one bond is polar

Question 16

Inter-molecular bonds

Answer 16

chemical bonds between molecules
weaker then intramolecular bonds
THREE TYPES:
London dispersion forces
Dipole-dipole forces
Hydrogen bonds

Question 17

London dispersion forces

Answer 17

weakest bond, they exist between all molecules. Only forces between noble gases and non polar molecules

Question 18

Dipole-dipole forces

Answer 18

hold polar molecules together

Question 19

Hydrogen bonds

Answer 19

forms between a partial positive charged H atom with a partially negative charged O,N and F atom in another molecule
This bond is the strongest and most biologically significant, and responsible for many unique properties of water

Question 20

Water

Answer 20

Very important to life. Without we wouldn’t exist
All organisms have water
Ex. control body temp, keep eyeballs moist, lubricate joints

Question 21

Water properties

Answer 21

• colourless, odourless, and tasteless
• can exist as a solid, liquid, and gas in temp range found on earth
• chemical composition H2O
• It’s polar due to - polar bond & asymmetrical shape

Question 22

Water the versatile solvent

Answer 22

• more substances dissolve in it
• Most chemicals of biological interest dissolve in water
  ex. NaCl dissolve in water
  NaCl is an ionic compound, it dissociates in water i.e breaking of the ionic bond
  Polar molecules = dissolve in water

Question 23

Hydrophobic molecules

Answer 23

non-polar molecules that are not strongly attached to water

Question 24

Hydrophilic molecules

Answer 24

polar or charged molecules that are strongly attracted to water

Question 25

Miscible

Answer 25

describes liquids that dissolve into one another

ex, ethanol (alcohol in beverages) and ethylene glycol (alcohol in antifreeze) = miscible in water

Question 26

Immiscible

Answer 26

describes liquids that form separate layers instead of dissolving into one another
ex. oil and gas = immiscible with water