LACL4

Question 1

what are the water volume ratios in ICF and ECF?

Answer 1

ICF: 2/3
ECF: 1/3

Question 2

why is water a polar molecule?

Answer 2

• O is more electronegative than H so attracts electrons of the covalent body towards it
• H bonding occurs (in any NOF Cl molecules)

Question 3

what is meant by something being electronegative?

Answer 3

attracts/ gains electrons

Question 4

what is meant by something being electropositive?

Answer 4

tending to lose electrons

Question 5

is DNA parallel or anti-parallel?

Answer 5

anti-parallel

Question 6

when is H bonding strongest?

Answer 6

when 3 atoms involved lie in a straight line (e.g. in DNA)

Question 7

where does H bonding occur in DNA?

Answer 7

between bases of two strands

Question 8

what type of bond is H bonding?

Answer 8

intermolecular force (covalent)

Question 9

are molecules that form H bonds water-soluble?

Answer 9

yes; since they are polar

Question 10

what are some examples of water soluble (hydrophillic) molecules?

Answer 10

• sugars
• alcohols
• aldehydes
• ketones
• compounds with N-H group

Question 11

what happens to solute-solute H bonding when it dissolves in water?

Answer 11

replaced with energetically favourable solute-water H bonding

Question 12

do O=O and O=C=O have polarity?

Answer 12

no (they are symmetrical and linear, even spread of electronegativity)
therefore, on their own they don’t dissolve in water

Question 13

what protein carries O2 around the body?

Answer 13

haemoglobin protein complex

Question 14

what carries/ transports CO2 around the body?

Answer 14

bi-carbonate (CO2 is converted to carbonic acid which dissociates and with bicarbonate diffuse into ISF and plasma where it’s used as a buffer

Question 15

what happens to water molecules when hydrophobic alkyl chains are present (e.g. hydrophobic tail)?

Answer 15

• highly ordered H2O molecules form “cages” around hydrophobic chains
• “the hydrophobic effect”

Question 16

what happens to water molecules when enzyme reacts with substrate?

Answer 16

water molecules are distorted (disorder); not fixed

Question 17

what happens to water molecules when enzyme and substrate are NOT reacting?

Answer 17

water molecules are ordered and lined up around each enzyme and substrate

Question 18

what is hydrophobic effect?

Answer 18

hydrophobic molecules arrange themselves in water so as to minimise disruption of H bonding among surrounding water molecules

• energetically stable
• water cage formed around the lipid
• ordering of water
• low entropy

Question 19

what happens to water molecules when there are CLUSTERS/GROUPS of lipids?

Answer 19

only lipid portions at the edge of the clusters force ordering of water so fewer H2O molecules are ordered
- entropy increases (reduces SA so more water moves freely as it cannot bind)

Question 20

what is an amphipathic molecule?

Answer 20

contain both hydrophobic and hydrophillic parts (e.g. phospholipids)

Question 21

what is a liposome?

Answer 21

phospholipids arranged in a sphere which enclose a water droplet, especially formed to carry drugs or other substances to tissues

Question 22

where are hydrophobic and hydrophillic regions found on a protein?

Answer 22

hydrophobic; on the inside, contains nonpolar side chains

hydrophillic; on the outside, contains polar side chains

Question 23

is energy needed to fold proteins?

Answer 23

No; proteins fold naturally due to presence of R groups (amino acid properties)

Question 24

what transports hydrophobic lipids from small intestine to other body parts?

Answer 24

chylomicron

Question 25

what makes up chylomicrons?

Answer 25

• triglycerides
• phospholipids
• cholesterol
• proteins

Question 26

why do fats need to be transported by chylomicrons?

Answer 26

they don’t dissolve in water

Question 27

does water dissociate?

Answer 27

yes to H+ and OH-

Question 28

what is the ion product equation for water?

Answer 28

Kw= (H)(OH) ^-14 mol/L

Question 29

as Ph increases, what happens to pOH?

Answer 29

decreases

Question 30

what do acidic solutions have in terms of H and OH ions?

Answer 30

high H

low OH

Question 31

what do basic solutions have in terms of H and OH?

Answer 31

high OH

low H

Question 32

pH +pOH =

Answer 32

14 ALWAYS

Question 33

are weak acids and bases fully or partially dissociated?

Answer 33

partially

Question 34

are strong acids and bases fully or partially dissociated?

Answer 34

fully

Question 35

what is a proton donor and proton acceptor?

Answer 35

proton donor= acids

proton acceptor = bases

Question 36

what is a conjugate acid-base pair?

Answer 36

a proton donor and corresponding proton acceptor combined

Question 37

what is a buffer?

Answer 37

solution of a weak acid/base and one of its salts

Question 38

the smaller the pKa value…

Answer 38

the stronger the acid

Question 39

what is the purpose of a buffer?

Answer 39

when small amounts of acid and alkalis are added, it doesn’t change the pH by a lot

Question 40

what is the Henderson-Hasselbatch equation used for?

Answer 40

working out the amount of weak acid or conjugate base you have in a given system
(calculating how the pH of a physiological solution responds to changes in either conjugate acid or base)

Question 41

what molecule acts as a buffer in the blood?

Answer 41

HCO3 (bicarbonate); without it pH levels would fluctuate wildly if cellular acids enter the circulation (e.g. lactic acid)