biological molecules Flashcards

Question

ammonium chemical symbol

Answer 1

regulation of blood pH, involved in transport of CO2 involved in ATP formation in photosynthesis and respiration

Answer 2

needed for production of nitrates by nitrifying bacteria production in deamination of amino acids

Answer 3

nerve transmission and muscle contraction cofactor in blood clotting (prothrombin to thrombin) bone formation

Answer 4

nerve transmission affects reabsorption of water in kidney

Answer 5

nerve transmission in guard cells as part of opening mechanism in stomata

Answer 6

absorbed by root hair cells used as source of nitrogen in plants to make amino acids

Answer 7

bone formation, component of phospholipids component of ATP and nucleic acids

Answer 8

regulation of blood PH involved in transport of CO2

Answer 9

cofactor for amylase enzyme chloride shift in RBC

Answer 10

regulation of blood pH

Answer 11

a molecule that has an uneven charge distribution (partial positive and negative charges which do not cancel out)

Answer 12

hydrogen bonds

Answer 13

covalent bond

Answer 14

electropositive

Answer 15

electronegative (bc greater pull on electron)

Answer 16

liquid at room temp density changes solvent for polar molecules water & non-polar molecules reactions cohesion & surface tension high specific heat capacity high latent heat of vaporisation water is a reactant

Answer 17

the hydrogen bonds between H2O molecules make it more difficult for them to escape and become a gas

Answer 18

provides a habitat e.g. lakes, rivers, seas be a major component of tissues be a reactions medium for chemical reactions be an effective transport medium e.g. blood

Answer 19

cooling of water allows maximum number of hydrogen bonds to form so water molecules space out to allow this and water expands as it breezes. Therefore ice is less dense than water and floats. This creates currents.

Answer 20

the currents created allow circulation of water. a layer of ice will float to the top of water and insulate a pond against extreme temperatures, decreasing heat loss so aquatic organisms have a stable environment ice floats so provides land for terrestrial animals

Answer 21

water molecules cluster around charged parts of solute molecules or ions and keep them apart bc water is polar

Answer 22

molecules can move around in solvent and react together molecules and ions can be transported when dissolved good for removal of water e.g. urea in urine

Answer 23

they are pushed together, allowing hydrophobic reactions to occur

Answer 24

tertiary structure of proteins to form phospholipid bilayer to form

Answer 25

water can form hydrogen bonds with the hydrophilic groups of the amino acids in these proteins

Answer 26

water molecules are attracted together as a result of hydrogen bonds

Answer 27

at the surface of water, water molecules are all hydrogen bonded to the water molecules beneath, giving the surface of the water the ability to resist force applied to it

Answer 28

columns of water are pulled up xylem in the transpiration stream insects e.g. pond skaters can walk on water jellyfish keep shape in water because molecules not easily compressed so this gives jellyfish support

Answer 29

HIGH : 4.2 kJ of energy required to raise the temp of 1kg of water by 1C

Answer 30

hydrogen bonds restrict movement of water molecules and therefore a large amount of energy is needed to raise the temperature

Answer 31

water does not warm up or cool down easily (high thermal stability) water keeps a stable temperature, giving aquatic organisms a stable environment in which to live gases remain soluble in water e.g. oxygen for aerobic respiration of organisms

Answer 32

as water molecules are held together by hydrogen bonds, relatively large amounts of heat energy are needed for water to evaporate. this energy helps the molecules to break away form each other

Answer 33

helps keep temperature stable cools organisms e.g. mammals sweating and plants' perspiration

Answer 34

hydrolysis reactions e.g. digestion (catabolic) raw material of photosynthesis (anabolic)

Answer 35

aquatic organisms can photosynthesise

Answer 36

monosaccharides= single sugars (short chains or ring) e.g. glucose disaccharides= double sugars e.g. maltose polysaccharides=many sugars joined together (branched/unbranched chains) e.g. glycogen

Answer 37

(CH2O)n n=between 3 and 9

Answer 38

soluble in water because of polar -OH group insoluble in non-polar solvents tastes sweet

Answer 39

shows number of each atom

Answer 40

shows arrangement of atoms

Answer 41

molecules with the same molecular formula but different structural formulae e.g. alpha and beta glucose

Answer 42

energy source component of (monomer for) glycogen and starch (energy stores)

Answer 43

energy source component of cellulose (provides structural support to cells)

Answer 44

H on bottom

Answer 45

component of RNA component of ATP

Answer 46

two OH groups at bottom

Answer 47

component of DNA

Answer 48

OH group bottom left H bottom right

Answer 49

carbonyl group

Answer 50

hydroxyl group

Answer 51

aldehyde group

Answer 52

it is polar so makes glucose/ other molecules soluble in water

Answer 53

freely soluble in water therefore soluble in blood plasma and can be transported to cells for uptake

Answer 54

transport chemical reactions temperature control support movement reproduction

Answer 55

sexually reproducing organisms sometimes use water to bring gametes together for fertilisation in mammals the foetus develops in a water-filled sac, which provides physical and thermal stability bryophytes release antherozoids (male gametes) in moist conditions, which use flagella to swim to oospheres(female reproductive cells) by chemotaxis.

Answer 56

nastic movements (do not involve growth towards a stimulus) depend on osmotic flow of water e.g. open/close of flowers or the snap of a Venus fly trap organisms such as earthworms and leeches use hydrostatic skeletons to move around. longitudinal and circular muscles contract against the watery fluid of the coelom

Answer 57

plants gain turgidity, which is essential to maintain the maximum surface area, so maximum light is absorbed for maximum photosynthesis and for maintenance of aerial plant parts for increased seed dispersal water filled tissues contribute to skeletal support. organisms with hydrostatic skeletons need water for the fluid in the coelom against which muscles can act for aquatic organisms, water provides support through buoyancy and pressure

Answer 58

high SHC so water acts as an essential buffer for organisms maintaining a constant body temp for enzyme-controlled reactions to work at optimum temp & regulate metabolism high latent heat of vaporisation means heat is released when water evaporates, which is a cooling mechanism to keep a stable temp water remains liquid over a huge temp range, which is essential for metabolism and useful for aquatic organisms which avoid freezing

Answer 59

combination of thermal stability & solvent properties make water an ideal environment for them reactions. all enzyme reactions of photosynthesis, respiration, excretion e.t.c. occur in solution

Answer 60

photosynthesis hydrolytic reactions e.g. digestive enzymes when digesting starch, proteins, lipids

Answer 61

uptake of minerals by plants from soil across root hair cells transpirations stream water-based movement of sugars and amino acids in phloem occur in solution many essential metabolites dissolve completely e.g. glucose, amino acids, vitamins and minerals larger molecule such as proteins are transported as colloids transpiration stream held together by cohesion and adhesion (mols bind to side of xylem); these give rise to capillarity in tubes of small diameter low viscosity so flows easily e.g. in xylem

Answer 62

large number of carbon-hydrogen bonds

Answer 63

all transport fluids in animals are water-based e.g. blood plasma and cytoplasm many essential metabolites dissolve completely e.g. glucose, amino acids, vitamins and minerals larger molecule such as proteins are transported as colloids low viscosity so flows easily

Answer 64

formed by 2 monosaccharides combing together in a condensation reaction, forming a glycosidic bond

Answer 65

C12H22O11 (2 hexoses subtract H2O)

Answer 66

taste sweet soluble in water because of the polar -OH group some are reducing sugars (donate electrons) e.g. maltose, lactose, cellulose some are non-reducing sugars e.g. sucrose

Answer 67

maltose sucrose lactose cellubiose

Answer 68

formed from 2 alpha glucose molecules

Answer 69

found in germinating seeds where it is broken down into glucose for respiration

Answer 70

non-reducing and therefore less reactive

Answer 71

alpha glucose and fructose

Answer 72

how plants transport their sugar in translocation less reactive as it is a non-reducing sugar

Answer 73

beta galactose and alpha glucose

Answer 74

sugar found in milk

Answer 75

2 beta glucose molecules

Answer 76

formed as an intermediate during cellulose production

Answer 77

glycogen synthase

Answer 78

glycosidic

Answer 79

2 hydroxyl (-OH) groups line up alongside each other. one combines with a hydrogen atom of the other to form a water molecule. this allows an oxygen bridge to form between them this forms a disaccharide

Answer 80

a water molecule is used to split the disaccharide during digestion by providing a hydroxyl group (-OH) and a hydrogen (H), which help the glycosidic bond to break

Answer 81

a chemical species that 'donates' an electron to an electron recipient , reducing the recipient. it is oxidised

Answer 82

a substance that 'accepts' or 'receives' an electron from a reducing agent, therefore oxidising it. it is reduced.

Answer 83

loss of hydrogen gain of oxygen loss of electrons

Answer 84

gain of hydrogen loss of oxygen gain of electrons

Answer 85

all monosaccharides are reducing sugars some disaccharides are reducing sugars

Answer 86

any sugar containing a hemiacetal is a reducing sugar

Answer 87

it tests positive with Benedict's solution (blue to orange/brick red)

Answer 88

copper (II) sulfate

Answer 89

an insoluble brick-red precipitate is formed

Answer 90

copper ions are reduced by the sugar by gaining electrons from it as a result, copper (II) oxide is produced Cu 2+ gains an electron to become Cu + reducing sugar is oxidised to form a carboxylic acid

Answer 91

positive or negative result tells us if a particular substance is present

Answer 92

tells us how much (concentration) of a substance is present

Answer 93

involving less than quantitative accuracy e.g. could have estimated concentration by comparing colour change with the colour change of a known concentration

Answer 94

wear eye protection if you get chemicals in your eyes, flush for 20 minutes with eye wash wash any chemical off skin

Answer 95

add 5cm Benedicts reagent and stir with glass rod heat in water bath at 80C for 9 minutes positive result= green/yellow/orange/brick-red precipitate negative= blue semi-quantitative

Answer 96

dip strip in solution and compare with calibration card testing urine of diabetics pos= shows 1000mg/dl neg= shows 0mg/dl

Answer 97

carry out a normal reducing sugar test (negative with sucrose, so proves absence of RS) take sample and boil with 1cm HCl with antibumping granules and point away from yourself cool solution add sodium hydrogen carbonate powder to neutralise carry out reducing sugar test again (positive with sucrose to prove presence of non-RS)

Answer 98

a disaccharide can be hydrolysed into constituent monosaccharides by boiling with hydrochloric acid this frees up 'reducing groups' e.g. sucrose id hydrolysed into glucose and fructose (both RS)

Answer 99

glucose: positive for both, and the same colour for both sucrose: negative for RS, positive for NRS mixture: positive for RS, larger positive result for NRS (if both brick red, w/ no visible difference, filter and measure mass of ppt or use colorimeter on supernatant)

Answer 100

ensures all sugar reacts withe the benedicts reagent therefore mass of ppt is proportional to conc of glucose, ensuring calibration curve is accurate

Answer 101

not all the sugar present in the juice will be glucose most fruit juice also contain high conc of fructose fructose will react with the Benedicts to give a greater mass of ppt therefore when interpolating from the glucose calibration curve, the estimate is for the conc of RS,not an accurate estimate for the conc of glucose

Answer 102

the absorbance of orange light by the supernatant little glucose present= high absorbance reading (low transmission reading)(very blue, lots of unreacted Cu2SO4) high conc of glucose= low absorbance reading (high transmission reading)(no colour, little unreacted Cu2SO4)

Answer 103

total volume wanted/ conc of stock solution x conc wanted

Answer 104

vol. of glucose solution (0.5cm) vol. of Benedicts(5cm) temp of WB (80C) time in WB (9 mins) type of filter paper(fine grade) colour of filter in colorimeter (orange or red) same solution used to 0 colorimeter (distilled water)

Answer 105

avoid spills stir before filtering (less ppt left in tube) wash out tube and pour washings through filter use same quality-fine grade filter paper record mass of filter paper at start dry filter paper to constant mass

Answer 106

a bond formed between 2 monosaccharides by a condensation reaction

Answer 107

polymers which consist of hundreds/thousands of monosaccharides joined together by condensation reactions, resulting in the formation of glycosidic bonds

Answer 108

made up of one type of monosaccharide only e.g. starch, cellulose, glycogen, callose

Answer 109

made up of more than one type of monosaccharide e.g. hyaluronic acid

Answer 110

hold glucose molecules in chains, so individual molecule can be removed easily glycogen and starch are compact glycogen and amylopectin are branched polysaccharides are insoluble

Answer 111

individual molecules can be removed in hydrolysis reactions when required so the rest of the chain can remain if not needed

Answer 112

it makes them dense granules so they don't occupy a large amount of space

Answer 113

they are more compact offers chance for lots of glucose molecules to be snipped off by hydrolysis at the same time when lots of energy is required quickly

Answer 114

glucosidase

Answer 115

they are large macromolecules and the regions which could form hydrogen bonds with the water are hidden away inside the molecule

Answer 116

they can be stored without dissolving, so will not change the water potential of the cell or affect osmosis

Answer 117

alpha glucose

Answer 118

amylose amylopectin

Answer 119

alpha glucose

Answer 120

1,4-glycosidic bonds

Answer 121

an amylose helix because a coil is a more compact shape 6 glucose molecules per turn hydrogen bonds hold helix together

Answer 122

alpha glucose

Answer 123

amylopectin is branched and shorter

Answer 124

1,4-glycosidic bonds in the chains 1,6-glycosidic bonds between chains

Answer 125

main chain forms a spiral joined by hydrogen bonds

Answer 126

amylose helix becomes entangle din amylopectin to form very large starch grains

Answer 127

chloroplasts, seeds and storage organs (e.g. tubers)

Answer 128

animals = liver and muscle cells fungi

Answer 129

1,4-glycosidic bonds in main chain 1,6-glycosidic bonds connecting branches

Answer 130

glycogen tend to be even more branches and compact but have shorter 1,4 chains so less tendency to coil

Answer 131

alpha glucose

Answer 132

glucose is released more quickly

Answer 133

beta glucose every other beta glucose is rotated 180 degrees

Answer 134

1,4-glycosidic bonds between beta glucose molecules hydrogen bonds between (-OH) groups of molecules hydrogen bonds between cellulose straight chains which run in parallel to each other

Answer 135

stops the molecule spiralling so they are held in straight chains

Answer 136

increased stability

Answer 137

many microfibrils held in bundles by hydrogen bonding make up macrofibrils

Answer 138

typically has several layers of fibres running in different directions, giving a high tensile strength other polysaccharides such as pectins cross link with cellulose fibres to create the cell wall's glue-like matrix structure

Answer 139

very high tensile strength because of glycosidic and hydrogen bonds can withstand large turgor pressure in cells (due to osmosis) so the cell won't burst supports plant (hydrostatic skeleton) freely permeable (bc of space between macrofibrils) so water and solutes can reach the plasma membrane insoluble because its a large macromolecule can be reinforced with other substances to support or waterproof, such as lignin and Suberin arrangement of macrofibrils determines the growth and change of cell shape e.g. guard cells

Answer 140

humans don't produce cellulase so cannot break down cellulose therefore it is the fibre of our food

Answer 141

yes, ruminants e.g. cows have symbiotic bacteria Ian their stomachs which digest cellulose

Answer 142

carbon, hydrogen and oxygen

Answer 143

higher proportion of hydrogen compared to oxygen

Answer 144

most common= triglycerides e.g. fats and oils derivatives e.g. phospholipids, waxes, steroids (cholesterol)

Answer 145

esters of fatty acids and alchohol

Answer 146

insoluble in water, soluble in organic solvents e.g. ethanol high in energy

Answer 147

because they are non-polar

Answer 148

34kJ/g carbs= 17kJ/g

Answer 149

they are rich in C-H bonds

Answer 150

carboxyl (carboxylic) acid group -COOH

Answer 151

example of a fatty acid saturated because it contains the maximum number of hydrogens and no double C-C bonds

Answer 152

fatty acid with one or more carbon double bond, causing a kink in the chain linoleic acid

Answer 153

poly= more than 1 carbon double bond mono= only 1 carbon double bond

Answer 154

double bonds make fatty acids melt more easily (lower MPs) so they are more likely to be liquid at room temperature

Answer 155

saturated: butter, lard unsaturated: oils e.g. sunflower oil

Answer 156

by joining a glycerol molecule to 3 fatty acid molecules. each fatty acid molecule joins via a condensation reaction

Answer 157

esterification

Answer 158

energy source energy store insulation buoyancy protection

Answer 159

ester bonds can be hydrolysed to form glycerol and 3 fatty acids, which can be used in respiration to release more energy than the respiration of sugars respiration of a lipid produces more water than that of carbohydrates

Answer 160

they store fat in their humps and respire it to release lots of water

Answer 161

insoluble so can be stored without affecting the water potential of cells high energy density

Answer 162

about twice as much

Answer 163

they have a greater proportion of hydrogen atoms compared to carbohydrates they have lots of C-H bonds

Answer 164

heat insulator= whales have blubber (adipose tissue) which decreases heat loss to the surroundings electrical insulator= fatty myelin sheath around some neurones speeds up conduction of impulses

Answer 165

fat is less dense than water, so it allows aquatic organisms to keep afloat e.g. frogs

Answer 166

fat around delicate organs e.g. kidneys acts as a shock absorber

Answer 167

lipid derivatives e.g. Suberin

Answer 168

large alcohols attached to fatty acids (larger than triglyceride)

Answer 169

in the waxy cuticle to prevent water loss

Answer 170

lipid derivatives made from triglycerides

Answer 171

a condensation reaction between and OH group on a phosphoric acid molecule (H3PO4) and one of the three -OH groups on the glycerol forms an ester bond

Answer 172

one of the fatty acids on a triglyceride is replaced by a phosphate group

Answer 173

phosphate group= polar and hydrophilic bc of -OH group rest of molecule is non-polar and hydrophobic

Answer 174

they may form a layer with heads in the water and tails sticking up or may form micelles (heads facing outwards and hydrophobic tails facing inwards)

Answer 175

phospholipids form a bilayer- tails pointing inwards (hydrophobic so move away from water and interact with each other) and heads pointing outwards ( hydrophilic so move towards water extracellularly and intracellularly)

Answer 176

increased stability because the phospholipids are free to move in the layer but will not flip sides semi permeable so small and non-polar molecules can move through the tails

Answer 177

small and non polar molecules (lipid soluble / hydrophobic0 e.g. oxygen, steroid hormones

Answer 178

interactions between shorter tails are weaker, maintaining fluidity by making the membrane less rigid

Answer 179

unsaturated fatty acid tails have 'kinks' so cannot pack as closely together, maintaining fluidity by making the membrane less rigid

Answer 180

a steroid alcohol (because of hydroxyl group) consists of 4 carbon based rings

Answer 181

all cells, but mainly in the liver because it is used to synthesise bile

Answer 182

in the membrane called stigma sterol

Answer 183

its hydroxyl group in hydrophillic and aligns towards the phosphate heads the remainder of the molecule is hydrophobic and associates with the phospholipid tails

Answer 184

the bilayer

Answer 185

regulates and maintains fluidity of the membrane makes up steroid hormones and vitamin d

Answer 186

at high temps it stabilises the membrane and raises the melting point at low temps it intercalates between the phospholipids and prevents clustering

Answer 187

testosterone, oestrogen, aldosterone, cortisol

Answer 188

hydrophobic (lipid soluble) so can pass across membranes into cells

Answer 189

carbon, hydrogen, oxygen, nitrogen (and sometimes phosphorus and/or sulfur)

Answer 190

amino acids joined by peptide bonds

Answer 191

the sequence of bases in DNA

Answer 192

essential must come from diet non-essential can be made

Answer 193

essential component of cell membranes all enzymes are proteins (specific shape important) antibodies are proteins haemoglobin (oxygen-carrying pigment) collagen keratin (hair) form structural component of animals e.g. muscle (actin and myosin)

Answer 194

act as carriers and pores for active transport and FD

Answer 195

attack and destroy invading micro-organisms

Answer 196

adds strength to many tissues including bones and artery walls

Answer 197

amino group NH2 carboxyl group COOH hydrogen atom H

Answer 198

by the R group

Answer 199

H in glycine

Answer 200

a compound with no overall electric charge, which contains separate parts which are positively and negatively charged

Answer 201

carboxyl group acts as an acid amino group acts as a base means that amino acids can act as buffers

Answer 202

a substance that helps to resist large changes in pH

Answer 203

OH, C=O or N-H some are positively charged and some are negatively charged

Answer 204

arginine proton/H+ acceptor e.g. NH2 + -> NH3 +

Answer 205

aspartic acids proton/H+ donor e.g. COOH -> COO-

Answer 206

the amino and carboxyl group can ionise amino group accepts a hydrogen ion to become NH3 + carboxyl group donates a hydrogen ion to become COO-

Answer 207

condensation peptidyl transferase enzymes

Answer 208

one amino acid loses a hydroxyl group from its carboxylic acid group the other amino acid loses a hydrogen atom from its amino group the C atom of the first amino acid bonds with the N of the second amino acid 1 O and 2 H atoms removed to form water (condensation)

Answer 209

2=dipeptide many-polypeptide

Answer 210

on ribosomes

Answer 211

biuret test (mixture of sodium hydroxide and copper sulphate)

Answer 212

egg white protein purple layer at the interface. after shaking, uniformly purple (positive result)

Answer 213

blue layer at the interface. after shaking uniformly blue (negative test)

Answer 214

a test for peptide bonds colour formed by a complex between the nitrogen atoms in the peptide chain and the Cu2+ ions

Answer 215

4 but not all proteins have all layers

Answer 216

a characteristic and specific 3D shape

Answer 217

sequence of amino acids held together by peptide bonds

Answer 218

completely alter the properties of the protein e.g. sickle cell anaemia: 1 amino acid substitution in haemoglobin

Answer 219

folding of amino acid chain into alpha helix or beta pleated sheet du to hydrogen bonding between amino acids.

Answer 220

weak on their own many together are strong

Answer 221

folding of the secondary structure to a form a precise (specific) 3D shape.

Answer 222

ionic, disulphide, hydrogen, hydrophobic/hydrophillic

Answer 223

a protein which is made up of 2 or more polypeptide chains.

Answer 224

ionic, disulphide, hydrogen , hydrophobic/hydrophillic

Answer 225

polypeptide chains coil into a helix with 36 amino acids per 10 turns of the helix. helix is held together by hydrogen bonds

Answer 226

a primarily electrostatic force of attraction between an electropositive atom (with a slight positive charge) e.g. hydorgen and a more electronegative atom (with a slight negative charge) e..g nitrogen or oxygen

Answer 227

polypeptide chains fold into a zigzag structure, where one chain folds over on itself, producing a beta pleated sheet. held together by hydrogen bonds

Answer 228

when alpha coils and beta pleats start to fold, along with the areas of straight chains of amino acids, this forms the tertiary structure. very specific 3D shape due to bonds between amino acids which lie close to each other.

Answer 229

between different types of R groups

Answer 230

ionic bonds

Answer 231

hydrophilic interacting with each other or the water in the cytoplasm

Answer 232

hydrophobic interact with each other away from the water in the cytoplasm

Answer 233

how the multiple polypeptides are arranged and held together to make the complete molecule(if it is made up of more than one polypeptide chain)

Answer 234

hydrogen (H2) is removed disulfide bond forms between R groups of cysteine amino acids very strong covalent bond

Answer 235

electrostatic attraction between oppositely charged R groups fairly strong can be broken by changes in pH

Answer 236

relatively weak, but many form a strong hold between amine and carbonyl groups between hydroxyl R groups between other polar R groups changes in pH or high temperature can break them

Answer 237

some of the amino acids that make up proteins have nonpolar groups and are therefore hydrophobic. these have a strong tendency to associate with one another inside the interior of the folded protein to avoid water molecules

Answer 238

hydrophobic R groups point inwards hydrophilic R groups point outwards and hydrogen bond with water: this makes proteins soluble

Answer 239

repetitive regular sequence of amino acids

Answer 240

long parallel polypeptide chains crosslinked (bonded e.g. H bonds) at intervals to form long fibres helical

Answer 241

stable structure are therefore strong and unreactive

Answer 242

support and structural functions

Answer 243

collagen (found in skin and arteries) elastin (found in skin, arteries and alveoli) keratin (found in hair, nails, scales)

Answer 244

irregular amino acid sequence

Answer 245

folded into a spherical shape

Answer 246

relatively unstable structure

Answer 247

easily soluble because hydrophilic groups point outwards

Answer 248

metabolic functions

Answer 249

enzymes (must be soluble to function) some hormones e.g. insulin (must be soluble to function, travels in blood) haemoglobin (carries oxygen in blood) myoglobin (stores oxygen in muscle cells)

Answer 250

not composed of monomers/ repeating subunits

Answer 251

higher ratio of unsaturated to saturated fat less (overall lipid/fat) less/no saturated fat more unsaturated fatty acids

Answer 252

globular spherical range of amino acids hydrogen bonds, hydrophobic interactions yes; haem group quaternary structure held together by H bonds and hydrophobic interactions. 4 polypeptide chains yes, soluble binds to O2, CO2, CO and H+ (therefore acts as buffer) transports O2 and CO2 in the blood in red blood cells

Answer 253

globular spherical range of amino acids hydrogen and disulfide bonds not conjugated quaternary structure held together by disulphide bonds. 2 polypeptide chains yes soluble binds to receptors on muscles and liver regulates BGL (decreases it) produced in pancreas, travels in blood plasma

Answer 254

globular spherical 327 amino acids, most of which are acidic so aren't affected by stomach acid disulphide and hydrogen bonds not conjugated no quaternary structure; only 1 polypeptide chain yes soluble protease enzyme breaks down proteins to peptides stomach

Answer 255

fibrous fibre 1000 amino acids-long helices. glycine every 3rd amino acid, repetitive covalent and hydrogen bonds not conjugated insoluble no high tensile strength, so prevent artery walls from bursting artery walls, bones, tendons, skin

Answer 256

fibrous fibre cysteine (disulphide bond) disulfide and hydrogen bonds not conjugated insoluble no strong, inflexible and waterproof so acts as barrier skin, hair, nails, hoofs, scales

Answer 257

fibrous fibre range of amino acids covalent crosslinks, hydrophobic interactions, hydrogen bonds not conjugated insoluble no gives strength and elasticity to skin and alveoli because it can stretch and recoil artery walls, skin, bladder, alveoli

Answer 258

transports oxygen from the lungs to respiring cells

Answer 259

RBCs; each RBC contains 280 million molecule of Hb

Answer 260

globular, made up of 4 tightly packed polypeptide chains 2 identical alpha globin chains and 2 identical beta globin chains

Answer 261

hydrophobic R groups face inwards; the interactions hold the molecule in a precise 3D shape hydrophilic R groups point outwards to maintain solubility

Answer 262

each polypeptide has 8 or 9 sections of a helix each polypeptide has a haem group, which is permanent but not made of protein (a prosthetic group) therefore it is a conjugated protein

Answer 263

porphyrin (polymorphyin) group. it is a flat structure with an iron ion (Fe 2+) at the centre. this gives its colour ham group binds reversibly with a molecule of O2

Answer 264

Hb+4(O2)<->Hb(O2)4 haemoglobin+oxygen<->oxyhaemoglobin from a dark purplish colour to a bright red colour ->oxygen associates with Hb to form Hb(O2)4. (loading) <- oxyhemoglobin dissociates to form Hb and O2 (unloading)

Answer 265

disulphide bonds, alpha helices beta pleated sheets

Answer 266

has a specific 3D shape, which is important for binding to complementary receptors

Answer 267

insulin binds to a tyrosine kinase receptor on its target cells in the liver and muscles it has a specific shape that is complementary to the target receptor this leads to other signalling events within the cells, leading to a decrease in BGL

Answer 268

an experiment is valid if it is suitably designed to answer the question i.e. variables have been controlled

Answer 269

the bonds contain energy, which is released when they are broken by respiratory enzymes H/OH groups can form H bonds with water so galactose is soluble and can move within the cell AVP

Answer 270

covalent bond involves the sharing of electrons between 2 atoms H bond= electrostatic attraction between electropositive H atom and an electrongeative atom

Answer 271

property of R group gives AA its properties e.g. determines what bonds it forms and whether it faces in/out

Answer 272

polypeptide translated at ribosomes= linear sequence of amino acids protein= more than 1 chain of amino acids with a complex shape

Answer 273

flexibility increases with decreasing disulfide bonds hair is more flexible than nails

Answer 274

signalling molecules e.g. hormones; control body systems by binding to receptors bind to and carry molecules around the body AS correct, specific shape for substrate so digest food

Answer 275

prevents bursting of artery walls by allowing them to withstand high pressure in tendons, bones, cartilage, connective tissue

Answer 276

colorimeter measures absorbance/transmissioon of light by a coloured slution more conc solution= more light absorbed/less light transmitted or compare to data table of known concentration

Answer 277

carboxyl group and hydrocarbon chain

Answer 278

1 or more C=C double bonds cause kink/bend in tail cannot pack closely together cannot form more H bonds lower MP

Answer 279

BOTH have dual hydrophobic/philic characteristics BOTH make up plasma membrane DIFFERENCE sterols are complex alcohol molecules, phospholipids are lipids

Answer 280

high proportion of glycine means chains can lie close to each other crosslinks between molecules are staggered to avoid weak points

Answer 281

provides mechanical strength (high tensile strength) due to covalent bonds liking triple helix molecules together flexible insoluble

Answer 282

v strong molecule (lots of disulphide bonds: degree of these determines flexibility) insoluble mechanical protection waterproof (prevents entry of waterborne pollutants)

Answer 283

strong and can stretch and recoil without breaking insoluble

Answer 284

alveolar walls: allows them to stretch during inhalation and recoil during exhalation to expel air

Answer 285

amylose= coiled, cellulose has no coiling alternate molecules flipped 180 in cellulose but monomers are same orientation in amylose alpha 1-4 glycosidic bonds in amylose, beta 1-4 glycosidic bonds in cellulose amylose is granular whereas cellulose is fibrous H bonds within molecule of amylose, H bonds between adjacent molecules of cellulose

Answer 286

high tensile strength H bonds can form between adjacent fibres

Answer 287

reactions medium (e..g metabolic) transport medium ionic compounds separate and dissolve in it can dilute toxic substances can take in gases e.g. O2