1 biological molecules Flashcards

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1
Q

what is the reaction that causes two monomers to be joined together and what happens to a water molecule?

A

condensation reaction
water molecule is formed

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2
Q

what is the reaction that breaks down polymers and what happens to a water molecule?

A

hydrolysis
water molecule is added

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3
Q

what is the formula for glucose?

A

C6H12O6

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4
Q

what is the name for a monomer of a sugar?

A

monosaccharide

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5
Q

give 3 examples of a monosaccharide

A

glucose
galactose
fructose

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6
Q

what is the name for a polymer of a sugar?

A

polysaccharide

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7
Q

give 3 examples of a polysaccharide

A

starch
glycogen
cellulose

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8
Q

give 3 examples of a disaccharide

A

maltose
sucrose
lactose

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9
Q

how do you make maltose?

A

glucose + glucose

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10
Q

how do you make sucrose?

A

glucose + fructose

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11
Q

how do you make lactose?

A

glucose + galactose

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12
Q

how do you test for reducing sugar?

A

benedict’s test

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13
Q

how do you carry out the test for reducing sugars?

A
  1. add 2cm3 of benedict’s reagent to 2cm3 of sample
  2. heat in 95 degrees water bath for 5 mins
  3. positive result = blue to brick red precipitate
    negative result = no colour change
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14
Q

what is the bond called that is formed between two monosaccarides?

A

glycosidic

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15
Q

describe a test for a non-reducing sugar

A
  1. if benedict’s test for reducing sugar has a negative result,
  2. add equal amount of dilute HCl to sample and heat in 95 water bath for 5 min
  3. add sodium hydrogencarbonate to neutralise
  4. add equal amount of benedict’s solution and heat to 95 for 5 min
  5. positive = blue to brick red precipitate
    negative = no colour change
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16
Q

describe the structure of starch (amylose)

A

unbranched coiled chain of alpha glucose
1-4 glycosidic bonds

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17
Q

give the functions of amylose

A

insoluble so doesn’t affect water potential
insoluble so doesn’t diffuse out of cells
compact so a lot can be stored in small spaces

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18
Q

describe the structure of amylopectin

A

branched chain of alpha glucose
1-4, 1-6 glycosidic bonds

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19
Q

give a function of amylopectin

A

branches mean monosaccharides can be released rapidly

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20
Q

what is the test for starch?

A

iodine

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21
Q

describe the iodine test for starch

A
  1. place 2cm3 of sample in test tube
  2. add iodine solution and shake
  3. positive result = blue black colour
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22
Q

what is the structure of glycogen?

A

branched chain of alpha glucose
1-4 and 1-6 glycosidic bonds

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23
Q

what are functions for glycogen?

A

insoluble so doesn’t diffuse out of cells
compact so a lot can be stored in small spaces
highly branched so can be readily hydrolysed

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24
Q

what is the structure of cellulose?

A

straight unbranched chains of beta glucose (each molecule rotated 180)
1-4 glycosidic bonds
cellulose molecules run parallel to eachother and cross linked by H bonds to form microfibrils which form fibrils

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25
Q

where is cellulose found?

A

component of plant cell walls -prevents cell from bursting

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26
Q

where is glycogen found?

A

animal muscles

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27
Q

where is starch found?

A

plants

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28
Q

what is the bond for lipids called?

A

ester bond

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29
Q

what is a triglyceride?

A

three fatty acids and a glycerol

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30
Q

what is a phospholipid?

A

glycerol phosphate group and two fatty acids

31
Q

what does saturated mean in terms of double bonds in lipids?

A

no double bonds (c=c)

32
Q

what does unsaturated mean in terms of double bonds?

A

double bonds present

33
Q

are triglycerides polar on non polar?

A

non polar

34
Q

are phospholipids polar or non polar?

A

polar

35
Q

what happens due to triglycerides being non polar?

A

they don’t affect osmosis or water potential in cells

36
Q

what happens due to phospholipids being polar?

A

hydrophilic head and hydrophobic tails create a bilayer with the heads being close to the water and the tails being away from the water

37
Q

what is the test for lipids?

A

emulsion test

38
Q

describe the emulsion test for lipids

A
  1. add ethanol to sample
  2. shake
  3. add water
  4. shake
  5. cloudy white colour indicates presence of lipid
39
Q

what are the monomers and polymers for proteins called?

A

amino acids and polypeptides

40
Q

what are the bonds in proteins called?

A

peptide bonds

41
Q

what is the structure of an amino acid?

A

amino group-C attached to H and R group-carboxyl group

42
Q

what is the primary structure for a protein?

A

number and sequence of amino acids in a polypeptide chain

43
Q

what is the secondary structure of a protein?

A

folding of the polypeptide into alpha helix or beta pleated sheet (H bonds)

44
Q

what is the tertiary structure of a protein?

A

further folding of the secondary protein into a compact structure maintained by disulphide bridges, H bonds and ionic bonds

45
Q

what is the quaternary structure of a protein?

A

combination of 2 or more different polypeptide chains grouped into a large complex molecule

46
Q

give an example of a quaternary protein

A

haemoglobin, collagen, keratin

47
Q

what is the test for proteins?

A

buiret test

48
Q

describe the biuret test

A
  1. add equal volume of NaOH to sample at room temperature
  2. add dilute copper sulphate and mix
  3. lilac colour=positive result
    remains a blue colour=negative result
49
Q

what does a catalyst do?

A

alter the rate of a reaction without undergoing permanent damage themselves
create an alternative pathway that increases the rate of reaction

50
Q

what does bond breaking require?

A

activation energy

51
Q

how do enzymes increase the rate of reaction?

A

by lowering the activation energy by stressing or distorting the bonds in a substrate

52
Q

what does the substrate bind to on an enzyme?

A

active site

53
Q

what is it called when the substrate binds to the enzymes active site?

A

enzyme substrate complex

54
Q

why do only enzymes have active sites?

A

because of their specific tertiary structure

55
Q

why can a substrate bind to an active site?

A

because the active site is specifically complementary to the substrate

56
Q

what does the lock and key model state?

A

the active site is specifically complementary to its substrate

57
Q

give the 5 stages of the lock and key model

A
  1. active site is rigid and doesn’t change shape
  2. substrate binds to active site
  3. substrate fits exactly into active site as it is complementary
  4. products form and no longer fit so released
  5. enzyme free to take part in another reaction
58
Q

what does the induced fit model state?

A

that the active site is not fixed and the substrate induces a change in the tertiary structure making it complementary

59
Q

give the 5 stages of induced fit model

A
  1. substrate binds to enzymes active site
  2. binding induces a change in the shape of the active site
  3. shape change applies stress to the bonds
  4. substrate leaves and active site returns to natural shape
  5. enzyme free to take part in other reactions
60
Q

what factors affect enzyme action?

A

pH
temperature
substrate concentration
inhibitors

61
Q

how does the temperature affect an enzyme?

A

enzyme denature at high temperatures

62
Q

why do enzymes denature at high temperatures?

A

kinetic energy increases causing atoms to vibrate and bonds to break- changing the tertiary structure

63
Q

why is it bad that enzymes denature?

A

enzymes will no longer be complementary to substrates and can no longer form ESC to catalyse reactions

64
Q

what happens to enzymes when the pH changes?

A

the charge on the R groups are altered and bonds are broken changing the shape of the active site

65
Q

what happens to the rate of reaction when the enzyme concentration increases?

A

rate of reaction increases as long as there is an excess of substrate

66
Q

what will happen to rate of reaction when substrate concentration is increased?

A

rate of reaction increases in proportion to the concentration of substrates

67
Q

what are enzyme inhibitors?

A

substances that interfere with the functioning of enzymes

68
Q

what are the 2 different types of enzyme inhibitors?

A

competitive
non- competitive

69
Q

how does a competitive inhibitor work?

A
  1. has a similar shape to a substrate
  2. compete with substrate to bind to enzymes active site
70
Q

what happens if the substrate concentration increases within the presence of a competitive inhibitor?

A

the effect of the inhibitor is reduced

71
Q

do competitive inhibitors permanently bind to active sites?

A

no

72
Q

what happens when a competitive inhibitor leaves the active site of an enzyme?

A

other molecules are free to bind

73
Q

how does a non-competitive inhibitor work?

A
  1. binds to allosteric site
  2. which changes tertiary structure of enzyme causing shape of active site to change
  3. active site no longer specifically complementary to substrate
  4. no enzyme substrate complexes can form
74
Q

what is a monomer?

A

small repeating unit that can be condensed into larger molecules eg polysaccharides