cc1 - biological compounds

Question 1

four key inorganic ions in living organisms

Answer 1

magnesium ions
iron ions
calcium ions
phosphate ions

Question 2

role of magnesium in plants

Answer 2

used to produce chlorophyll

Question 3

role of iron in animals

Answer 3

found in haemoglobin + involved in transport of oxygen

Question 4

role of phosphate in living organisms

Answer 4

produces ADP + ATP

Question 5

role of calcium in living organisms

Answer 5

strengthens tissues like bones and teeth in animals + cell walls in plants

Question 6

why is water a polar molecule

Answer 6

O is more electronegative than H
O attracts electron density in covalent bond more strongly

Question 7

h bonding between water molecules

Answer 7

weak intermolecular forces of attraction form between lone pair on a O and a H on an adjacent molecule

Question 8

metabolite

Answer 8

molecule formed or used in metabolic reactions

Question 9

role of water as a metoblite

Answer 9

water is reactant in photosynthesis + hydrolysis reactions
water is product in aerobic respiration + condensation reactions

Question 10

why is waters high specific heat capacity important for organisms

Answer 10

water acts as a temp buffer, enabling endotherms to resist fluctuations in core temp+ to maintain optimum enzyme activity

Question 11

why is waters high latent heat of vaporisation important for organsims

Answer 11

when water evaporates, it has a cooling effect
important in homeostasis; organisms can lose heat through sweating + panting

Question 12

why is water an important solvent for organisms

Answer 12

water is polar universal solvent
enables chem reactions to take place in cells, transport of materials in plasma, + removal of metabolic waste

Question 13

why does water have high surface tension

Answer 13

due to ordered arrangement + cohesion of molecules at surface of water

Question 14

why is high surface tension of water important for organsims

Answer 14

enables transport of water + nutrients through plant stems and small blood vessels in body
allows small insects to ‘walk’ on water

Question 15

monosaccharide

Answer 15

simple sugar
general formula - Cn(H20)n

Question 16

examples of monosaccharides

Answer 16

ribose
deoxyribose
alpha + beta glucose
fructose
galactose

Question 17

bond between two monosaccharides

Answer 17

glycosidic bond

Question 18

disaccharide

Answer 18

molecule formed by condensation of 2 monosaccharides, forming glycosidic bond
formula - C12H22O11

Question 19

examples of disaccharides + their monosaccharide constituents

Answer 19

sucrose (glucose-fructose)
maltose (a-glucose-a-glucose)
lactose (glucose-galactose(

Question 20

polysaccharide

Answer 20

polymer of monosaccharides
formed by many condensation reactions

Question 21

examples of polysaccharides

Answer 21

starch
glycogen
cellulose
chitin

Question 22

function of starch

Answer 22

energy storage in plants

Question 23

structure of starch

Answer 23

polymer of a-glucose monomers
two forms: amylose + amylopectin
amylose: a-1,4-glycosidic bonds, unbranched
amylopectin: a-1,4- and a-1,6- glycosidic bonds, branched

Question 24

function of glycogen

Answer 24

energy storage in animals

Question 25

structure of glycogen

Answer 25

highly branched - enables rapid hydrolysis of glucose molecules

Question 26

structure + function of cellulose

Answer 26

linear polysaccharide - main component of cell walk in plants consists of many b-glucose molecules joined by b-1,4-glycosidic bonds alternate glucose materials rotated 180° allowing H bonds between parallel chains, forming myofibrils

Question 27

structure + function of chitin

Answer 27

linear polysaccharide found in exoskeleton of insects + crustaceans as well as fungal cell walls consists of many b-glucose molecules (w/ amino acid side chains) joined by b-1,4-glycosidic bonds alternate glucose molecules rotated 180° allowing H bonds between parallel chains, forming myofibrils

Question 28

how a triglyceride is formed

Answer 28

one molecule of glycerol forms ester bonds w/ 3 fatty acids via condensation reactions

Question 29

structure + function of triglycerides

Answer 29

high energy to mass ratio - energy storage, high calorific value from oxidation insoluble hydrocarbon chain - no effect on water potential of cells, used for waterproofing slow heat conductor - thermal insulation, e.g: adipose tussue less dense than water - buoyancy if aquatic animals

Question 30

phospholipid

Answer 30

formed by condensation of 1 molecule of glycerol, 2 molecules of fatty acid + a phosphate group

Question 31

structure + function of phospholipids

Answer 31

glycerol backbone attached to 2 hydrophobic fatty acid tails + 1 hydrophilic polar phosphate head forms phospholipid bilayer in water - component of cell membranes tails splay outwards - waterproofing, e.g: skin

Question 32

diff between saturated + unsaturated fats

Answer 32

saturated fats - no C double bonds, solid at room temp due to strong intermolecular forces unsaturated fats - one of more C double bonds, liquid at room temp due to weak intermolecular forces

Question 33

diff between monounsaturated fats + polyunsaturated fats

Answer 33

monounsaturated fats - contain one C double bond polyunsaturated fats - contain more than one C double bond

Question 34

low density lipoprotein

Answer 34

combination of triglycerides from saturated fats + protein block receptor sites, reducing cholesterol absorption bad

Question 35

how ldls contribute to risk of cardiovascular disease

Answer 35

high blood cholesterol level caused by ldls lead to formation of atherosclerosis plaques

Question 36

general structure of amino acids

Answer 36

amine group (-NH2) variable side chain (R) carboxyl group (-COOH) H atom

Question 37

how polypeptides form

Answer 37

many amino acid monomers join together in condensation reactions forms peptide bonds

Question 38

primary structure of a protein

Answer 38

individual sequence of amino acids

Question 39

secondary structure of protein

Answer 39

local interactions of amino acids in polypeptide chain resulting in a-helices or b-pleated sheets h bonds

Question 40

tertiary structure of protein

Answer 40

folding of protein to make 3d structure disulfide bonds ionic bonds h bonds hydrophobic interactions

Question 41

quaternary structure of protein

Answer 41

interactions of more than 1 polypeptide chain may involve addition of prosthetic groups, e.g: metal ions or phosphate groups

Question 42

structure + function of fibrous proteins

Answer 42

long polypeptide chains, folded in parallel little tertiary/quaternary structure aside from cross linkages for strength - makes then insoluble + good for structural roles

Question 43

structure + function of globular proteins

Answer 43

spherical, compact, highly folded w/ complex tertiary/quaternary structures hydrophilic r groups face out + hydrophobic r groups face in - water soluble metabolic roles, e.g: enzymes

Question 44

diff between reducing + non reducing sugar

Answer 44

reducing sugar - free aldehyde or ketone functional group so can act as reducing agent non reducing sugar - no free aldehyde or ketone functional group so cant act as reducing agent

Question 45

benedicts for reducing sugar

Answer 45

add equal volume of sample being tested + benedicts reagent heat in electric water bath at 100°C for 5 mins observe colour of precipitate formed

Question 46

+ive result for reducing sugars

Answer 46

colour change from green to yellow to orange to brown to brick red depending on quantity of reducing sugar present

Question 47

benedicts for non reducing suagr

Answer 47

+ive test for reducing sugar hydrolyse non reducing sugars w/ equal vol of dilute HCl heat in boiling water bath for 5 min retest solution w/ benedicts reagent observe colour of precipitate formed

Question 48

+ive result for non reducing sugars

Answer 48

colour change from green to yellow to orange to brown to brick red depending on quantity of non reducing sugar present

Question 49

food test used to identify proteins

Answer 49

buiret

Question 50

biuret test

Answer 50

add equal volume of sample + NaOH add few drops of dilute copper sulfate solution mix + record observations

Question 51

+ive result of biuret

Answer 51

colour change from pale blue to purple

Question 52

iodide test for starch

Answer 52

add iodine-Kl solution colour change from organe to blue-black if +ive

Question 53

emulsion test from fats + oils

Answer 53

add ethanol to sample + shake allow to settle add equal volume of water record observations

Question 54

+ive result of emulsion test

Answer 54

white cloudy emulsion forms