chemical elements and biological molecules Flashcards

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1
Q

ion definition

A

charged atom or molecule that has lost or gained electrons

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2
Q

inorganic meaning

A

doesn’t contain carbon atoms

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3
Q

magnesium function

A

Mg2+
- chlorophyll production
- lack = chlorosis

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4
Q

iron function

A

Fe2+
- part of haemoglobin
- lack = anaemia

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5
Q

calcium function

A

Ca2+
- component of bones, teeth
- strengthens tissues and plant cell walls
- form nerve signals

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6
Q

phosphate function

A

Po4 3-
- component of DNA, RNA
- forms ATP

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7
Q

water properties

A
  • dipole
  • polar
  • universal solvent
  • high specific heat capacity
  • high latent heat of vaporisation
  • high cohesion
  • metabolite
  • transparent
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8
Q

how is water a dipole

A
  • has slightly +/- charged ends
  • numerous hydrogen bonds between water molecules = strong
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9
Q

how is water polar

A
  • 2 (+) charged H, 1 (-) charged O
  • covalently bonded
  • unequally charged
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10
Q

how is water a universal solvent

A
  • water is a dipole so attracts charged molecules
  • dissolves polar / charged molecules
  • O2/CO2 can dissolve
  • can act as a transport medium, water flows
  • dissolves more than any other liquid
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11
Q

how does water have a high specific heat capacity

A
  • many H bonds mean lots of energy is required to increase its temp
  • reduces fluctuations = stable aquatic environments
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12
Q

how does water have a high latent heat of vaporisation

A
  • lots of energy required to vaporise
  • water in sweat absorbs heat energy as it evaporates = efficient cooling mechanism
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13
Q

how does water have high cohesion

A
  • cohesion between water molecules, in lattice
  • water molecules on surface pulled down = surface tension
  • provides support and buoyancy
    e.g. water pulled up xylem, pond skaters walk on water
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14
Q

water and its density

A
  • liquid water is more dense than ice
  • ice floats providing insulation beneath and water beneath doesn’t freeze
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15
Q

benefit of water being transparent

A
  • allows photosynthesises
  • light penetrates through
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16
Q

how is water a metabolite

A
  • a reactant necessary to start a metabolic reaction (essential for life), and a by product
  • reactant in photosynthesis and hydrolysis
  • product of aerobic respiration and condensation
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17
Q

what is a carbohydrate

A

-organic molecule consisting of carbon, hydrogen, oxygen

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18
Q

what is a monosaccharide

A
  • building blocks of complex carbs
  • most basic monomers
  • general formula: (CH2O)n
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19
Q

monosaccharide examples

A
  • triose (3C) e.g. glyceraldehyde
  • pentose (5C) e.g. ribose, deoxyribose
  • hexose (6C) e.g. glucose, fructose, galactose
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20
Q

function of monosaccharides

A
  • energy in respiration, bonds break releasing energy to make ATP
  • building blocks
  • intermediates in reactions e.g. triose in respiration
  • nucleotides (DNA deoxyribose)
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21
Q

glycerol chemical formula

A

C3H8O3

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22
Q

what is a disaccharide

A

2 monosaccharides bonded by a glycosidic bond with the elimination of water in a condensation reaction

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23
Q

disaccharide general formula

A

C12H22O11

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24
Q

disaccharide examples

A
  • maltose (glucose+glucose)
  • sucrose (glucose+fructose)
  • lactose (glucose+galactose)
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25
Q

maltose function

A

seed germination

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26
Q

sucrose function

A

phloem transport

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27
Q

lactose function

A

mammalian milk

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28
Q

what is a polysaccharide

A

large complex polymer
consist of monosaccharide units (the monomers) joined by glycosidic bonds
insoluble

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29
Q

polysaccharide examples

A

starch
glycogen
cellulose
chitin

30
Q

why is glycogen more suitable than glucose in animals?

A
  • it is insoluble = has no osmotic effect
  • it can’t diffuse out cells
  • it is compact = fit in small spaces
  • carries lots of energy in its bonds
31
Q

what is an isomer?

A

molecules with the same molecular formula but different arrangement of atoms

32
Q

alpha vs beta glucose

A

alpha = OH group on bottom
beta = OH group on top

33
Q

what is starch

A

the key energy store in plant
alpha glucose
amylopectin or amylase

34
Q

amylase

A
  • linear, unbranched
  • alpha 1-4 glycosidic bonds
  • coiled and compact = store lots of energy
  • chain of a-glucose coiled into a helix
  • glucose storage
35
Q

amylopectin

A
  • branched
  • chains of glucose monomers with 1,4 glycosidic bonds. cross linked with a-1,6 glycosidic bonds between parallel chains.
  • 1,6 bonds = side branches
  • branches = rapidly digested by enzymes = quick energy release (quickly hydrolysed)
  • water insoluble
36
Q

glycogen

A
  • energy storage molecule in animals
  • insoluble
  • molecules of a-glucose joined by 1,4 and 1,6 glycosidic bonds
  • side branches = quick energy release
  • large but compact, maximising energy store
37
Q

cellulose

A
  • in plant cell walls, structural role
  • long chain of b-glucose units joined by b-1,4 glycosidic bonds
  • straight, unbranched
  • H (H+OH) bonds provide stability between parallel molecules
  • tightly crosslinked by h bonds form microfibril held in bundles (fibres)
  • permeable, allows water through cell membrane
  • adjacent monomers twisted 180 to each other
38
Q

chitin

A
  • in exoskeleton of insects, fungal cell walls
  • chains of b-glucose monomers with amino acid side chains
  • b-glucose 1,4 glycosidic bonds
  • strong, waterproof, lightweight
  • each have an acetlyamine group
  • polysaccharide
39
Q

what are lipids?

A
  • formed of C, H, O2 (little)
  • non-polar compounds
  • water insoluble
  • soluble in organic compounds (alcohol)
40
Q

what is a triglyceride composed of ?

A
  • 1 glycerol molecule
  • 3 fatty acid chains (carboxylic group and hydrogen chain)
  • energy reserves in plant/animal cells
41
Q

how are triglycerides formed?

A

in a condensation reaction
ester bonds is formed
3 water molecules removed

42
Q

what are saturated fatty acids

A

contain no double bonds between 2 carbon atoms
- animal fats
- solid at room temp

43
Q

what are unsaturated fatty acids

A

contain at least 1 double carbon-carbon bond
- poly = more than 1
- mono = 1
- plant fats
- liquid at room temp

44
Q

why do unsaturated fatty acids have a lower melting point?

A
  • more unsaturated bonds the weaker the intermolecular bonds
    = lower m.p
    (can’t align uniformly = doesn’t solidify readily)
45
Q

triglyceride functions

A
  • energy reserve: more C-H bonds than carbohydrates
  • thermal insulation: stored under skin, insulates
  • protection: fat stored round delicate organs, protect from physical damage
  • producing metabolic water: water released from body’s chemical reactions
46
Q

what are phospholipids comprised of

A
  • 1 glycerol molecule
  • 2 fatty acid tails
  • 1 phosphate group
47
Q

properties of a phospholipid

A
  • phosphate head = hydrophilic = water soluble = attracts water = polar
  • fatty acids = hydrophobic = repel water
48
Q

phospholipid functions

A
  • structural in biological membranes
  • electrical insulation in myelin sheath
  • waxes: waterproofing in exoskeletons and leaf cuticles
49
Q

effects of saturated fats on health

A
  • raises low density lipoprotein (LDL) cholesterol levels
  • increases incidence of atheroma in coronary arteries
  • LDL deposits in arteries = atherosclerosis (plaque build up)
  • reduces blood supply to heart muscle
50
Q

effects of unsaturated fats on health

A
  • increase HDL
  • carries fats to liver for disposal
51
Q

amino acids

A
  • form a polypeptide in a single chain
  • 20 types (vary in R group)
  • 2 = dipeptide
  • join via a condensation reaction, forms peptide bond (+ water)
52
Q

amino acid structure

A
  • amine group - NH2
  • carboxylic acid group - COOH
  • variable group - R
53
Q

what are proteins

A

polymers of amino acids
2+ polypeptide chains

54
Q

protein primary structure

A

polypeptide chain / amino acid sequence
determined by gene coding for polypeptide

55
Q

protein secondary strucutre

A

hydrogen bonding between amino acids
chain coils into a a-helix or b-pleated sheet

56
Q

protein tertiary structure

A

globular or fibrous
further folding of secondary/chain = 3D
hydrogen bonds
interactions between amino acids - disulphide bridges, ionic bonds, hydrophobic interactions

57
Q

protein quaternary strucutre

A

association of several polypeptide chain
some have prosthetic groups

58
Q

what is protein function determined by

A

bonding within the protein affects the 3D structure

59
Q

what are fibrous proteins

A

long strands
insoluble
structural role
e.g. keratin, collagen

60
Q

collagen protein structure

A

in skin, teeth, bones, tendons
3 identical polypeptide chains wound into triple helix

61
Q

what are globular proteins

A

sphere shaped
water soluble (hydrophobic and hydrophilic ends)
metabolic role
e.g. enzymes, haemoglobin

62
Q

haemoglobin protein structure

A

4 polypeptides (2a, 2b)
4 haem groups
water soluble

63
Q

iodine test for starch

A
  • add 2 drops of iodine to test solution
  • present = orange to blue-black colour change
    (iodine in potassium-iodine solution)
64
Q

biuret test for protein

A
  • mix equal volumes of sample and Biurets reagent
  • cover boiling tube and invert once
  • present = blue to purple colour change
65
Q

emulsion test for lipids

A
  • mix sample with alcohol
  • shake boiling tube
  • pour mix into cold water
  • present = cloudy white emulsion/precipitate
66
Q

benedicts test for reducing sugars

A
  • mix equal volumes of sample and benedicts reagent
  • heat in water bath at 80c for 5 mins
  • present = blue to brick red colour change
67
Q

benedicts test for non-reducing sugars

A
  • complete test for reducing and get negative result
  • add hydrochloric acid to sample
  • heat in water baths at 80c for 2 mins
  • add sodium hydroxide
  • add benedicts reagent
  • heat in water bath at 80c for 5 mins
  • present = blue to brick red colour change
68
Q

examples of reducing sugars

A
  • most monosaccharides and disaccharides
  • glucose, fructose, lactose, maltose
69
Q

example of non-reducing suagr

A

sucrose

70
Q

how does water allow plants to grow under water?

A

water is transparent
allows light to penetrate for photosynthesis
CO2 can be absorbed for photosynthesis

71
Q

why is sulphate needed?

A

for amino acid synthesis