2.1.2

Question 1

polar molecule definition

Answer 1

a molecule with regions of negativity and regions of positivity

Question 2

why is water polar

Answer 2

contains hydroxyl groups, oxygen is negative and hydrogen is positive

Question 3

why is water more dense than ice

Answer 3

due to hydrogen bonds the molecules freeze further apart

Question 4

properties/ characteristics of water and causes (4)

Answer 4

stable habitat temperature (high specific and latent) solvent (polar), coolant (absorbs energy easily), transport medium (adhesive and cohesive)

Question 5

define capillary action

Answer 5

water rising up a narrow tube against gravity

Question 6

why do pond skaters float

Answer 6

the cohesion of water on water creates surface tension

Question 7

carbohydrate definition

Answer 7

C H O & sometimes modified at SER

Question 8

monosaccharides (3)

Answer 8

fructose, alpha glucose, beta glucose

Question 9

uses of carbohydrates

Answer 9

energy source
energy store
structural (chitin, cellulose)

Question 10

maltose is made of _

Answer 10

alpha glucose x2

Question 11

sucrose is made of _

Answer 11

fructose + alpha glucose

Question 12

lactose is made of _

Answer 12

beta glucose + galactose

Question 13

cellulose is made of _

Answer 13

beta glucose x2

Question 14

difference between ribose and deoxyribose? (structure and function)

Answer 14

structure - deoxyribose loses an O on C2
function - deoxyribose is DNA, ribose is RNA, ATP, NAD and ribonucleic acid

Question 15

starch is made of _

Answer 15

amylose (1,4) and amylopectin (1,4 and 1,6) so branched
mainly plants

Question 16

why is starch useful

Answer 16

theyre better storage as:
less soluble
more compact
branched

Question 17

test for proteins

Answer 17

biuret test, blue to lilac

Question 18

test for starch

Answer 18

iodine, yellow to black

Question 19

test for lipids

Answer 19

water, ethanol, shake, clear to white emulsion at top

Question 20

test for reducing sugars

Answer 20

grind, water, Benedicts and heat, blue to red depending on concentration, qualitative unless colorimeter

Question 21

test for non-reducing sugars

Answer 21

same as reducing but add HCl and heat to boil

Question 22

glycogen summary

Answer 22

alpha glucose, more compact and easier to add/ remove as more branches, mainly animal

Question 23

cellulose summary

Answer 23

alternating beta glucose so straight chain, adds to microfibrils then macro then fibres which cross for hydrogen bonding strength in cell wall

Question 24

cholesterol summary

Answer 24

sterol group
one OH, 4 carbon rings
amphipathic
compartmentalisation, used in bile/ steroids, controls fluidity and stabilises membrane

Question 25

phospholipid summary

Answer 25

1 glycerol + 1 hydrophyllic phosphate head + 2 hydrophobic fatty acid (sometimes kinked if unsaturated) tails forms bilayers for membranes or micelles

Question 26

unsaturated vs saturated fats

Answer 26

unsaturated has C=C which causes them to kink and be liquid at room, mainly plants, can be mono or poly unlike saturated which has none and is mainly animals

Question 27

triglyceride sumary

Answer 27

1 glycerol + 3 fatty acids -> triglyceride + 3 water forms ester bond

Question 28

lipid summary and uses (6)

Answer 28

large non-polar macromolecule consists of C H O used for energy source and store insulation (therm+elec) buoyancy protection

Question 29

inorganic cations and uses (5)

Answer 29

Ca - NIT, bones and teeth H - pH, translocation K - NIT, stomata opening Na - NIT, kidney function NH4 - production of nitrate ions

Question 30

inorganic anions and uses

Answer 30

PO4 - DNA, ATP, membranes, nucleic acid, bones OH - pH determinant Cl - amylase cofactor, chloride shift HCO3 - blood pH, CO2 transport NO3 - nitrogen for plants

Question 31

roles of lipids

Answer 31

energy source (ester bond) energy store (solid, insoluble) insulation (electrical, thermal) buoyancy protection/ cushioning

Question 32

peptide bond summary

Answer 32

condensation reaction amino bonds to carboxylic C(=O) - N(H) - C water forms covalent

Question 33

polypeptide structure

Answer 33

primary - amino acid sequence secondary - alpha helix and beta pleated sheets, hydrogen bond tertiary - globular/ fibrous and prosthetic quaternary - 2+ protein subunits

Question 34

bonds in tertiary and quaternary (5)

Answer 34

peptide hydrogen ionic hydrophobic/phillic interactions disulfide

Question 35

globular protein summary

Answer 35

compact, soluble, spherical solubility as R group orientation, helps with transportation

Question 36

haemoglobin summary

Answer 36

2 alpha and 2 beta globins with prosthetic haem groups (reversible O2 reaction) found in erythrocytes

Question 37

catalase summary

Answer 37

enzyme 4 different proteins with prosthetic haem group breakdown H2O2 into H2O and O2

Question 38

insulin summary

Answer 38

hormone lower blood glucose produced in pancreas quaternary

Question 39

fibrous enzyme summary

Answer 39

insoluble, long, little/ no tertiary organised/ repetitive structure

Question 40

collagen summary

Answer 40

three helixes joined by covalent cross links high mechanical strength found in connective tissue

Question 41

keratin summary

Answer 41

varying number of disulfide bonds change flexibility found in hair, skin and nails

Question 42

elastin summary

Answer 42

strong, flexible, extensible found in muscle fibres joined by covalent cross links stretch and recoil

Question 43

difference between alpha and beta glucose

Answer 43

beta up (alternates) alpha bottom

Question 44

difference between ribose and deoxy

Answer 44

deoxy - NO OH on C2 (ribose has)

Question 45

how to identify amino acids

Answer 45

thin layer chromatography, compare known to unknown

Question 46

chromatogram spray for amino acids

Answer 46

ninhydrin

Question 47

chromatography depends on...

Answer 47

molecule size, polarity (R group) and solubility in solvent

Question 48

parts of a chromatogram

Answer 48

origin solvent front known amino acids unknown amino acids

Question 49

Rf formula

Answer 49

distance by solute/ distance by solvent

Question 50

chromatography controls/ details

Answer 50

gloves, prevent sweat & a.a. contamination capillary tubes to place small droplets pencil line solvent below origin

Question 51

chromatography phases

Answer 51

stationary and mobile silica gel in stationary then organic solvent