Biological Molecules Flashcards

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1
Q

what are carbohydrates made from?

A

carbon
hydrogen
oxygen

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2
Q

Types of simple carbohydrates?

A

monosaccharides
disaccharides

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3
Q

type of complex carbohydrates?

A

polysacharrides

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4
Q

examples of monosaccharides and their chemical formula?

A

glucose C6H12O6
fructose C6H12O6
galactose C6H12O6
ribose C5H10O5
triose C3H6O3

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5
Q

monosaccharides equation

A

Cn H2n On

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6
Q

disaccharides formula

A

C12 H22 O11

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7
Q

what are isomers?

A

molecules with the same formula but different structures

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8
Q

what is a Glycosidic bond?

A

a bond formed between two monosaccharides.

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9
Q

what are the importance of monosaccharides:

A

sources of energy (glucose)
able to be transported in solution in animals (as glucose in blood)

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10
Q

the equation fro the production of maltose

A

GLUCOSE + GLUCOSE -. MALTOSE (malt sugar) + WATER

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11
Q

the equation fro the production of sucrose

A

GLUCOSE + FRUCTOSE  SUCROSE (cane sugar) + WATER

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12
Q

the equation fro the production of lactose?

A

GLUCOSE + GALACTOSE  LACTOSE (milk sugar) + WATER

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13
Q

how are Disaccharides formed?

A

Monosaccharides join together in condensation reactions. A glycosidic bond between them forms and water is removed.

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14
Q

what happens to disaccharides in the presence of water?

A

they are hydrolysed into monosaccharide monomers. Within cells, these reactions are catalysed by specific enzymes.

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15
Q

what is a Condensation reaction?

A

joins two molecules together with the formation of a chemical bond and involves the elimination of a water molecule

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16
Q

what are Polysaccharides?

A

polymers formed by combining monosaccharides together, by glycosidic during condensation reactions. They’re large, insoluble molecules ,suitable as storage

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17
Q

Examples of polysaccharides

A
  • Starch
  • Cellulose
  • Glycogen
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18
Q

how is starch formed?

A

joining 200 – 100000 α glucose molecules by glycosidic bonds in a series of condensation reactions.

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19
Q

what are the 2 components of starch

A
  • amylose
  • amylopectin
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20
Q

amylose structure?

A

long , unbranched chain ,that is tightly coiled allowing lots of glucose to be sorted in small place (compact)

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21
Q

amylopectin structure?

A

branched polymer which increases surface area for enzymes to release sugars for respiration

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22
Q

what does amylase digest?

A

amylose
amylopectin

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23
Q

The main role of starch is energy storage, something its structure is especially suited for:

A
  • insoluble – doesn’t affect water potential
  • large & insoluble – doesn’t diffuse out of cells.
  • COMPACT – lots can be stored in a small space.
  • Branched form so glucose monomers are released rapidly
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24
Q

is starch found in animal cells?

A

NEVER found in animal cells. Another polysaccharide serves the same role, called glycogen.

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25
Q

glycogen structure

A

shorter chains and highly branched. this allows more sugar to be released quickly. its storage in animals, stored as small granules, in muscles & liver

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26
Q

how does the structure of glycogen lead to its function?

A

branched - increases surface area for rapid hydrolysis back to glucose
insoluble - wont affect water potential

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27
Q

why is cellulose different from starch and glycogen?

A

it is formed from β glucose molecules, rather than α glucose molecules.

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28
Q

what is the structure of cellulose?

A

straight, unbranched chains, inverted to another, are called micro fibrils. hydrogen bonds form cross-links between chains giving strength and rigidity

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29
Q

cellulose use in plants?

A

cellulose cell wall prevents the cell from bursting as water enters by osmosis. It exerts inward pressure that stops water. stems & leaves turgid to increase surface area for photosynthesis.

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30
Q

what is a Hydrolysis reaction?

A

breaks a chemical bond between 2 molecules & involves the use of a water molecule.

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31
Q

what are starch and glycogen cellulose polymers of

A

Starch & glycogen are polymers of α-glucose & cellulose is a polymer of β-glucose.

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32
Q

what is hydrogen bonding

A

electrons within a molecule aren’t evenly distributed, but tend to spend more time at one position. This region is more negatively charged than the rest of the molecule

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33
Q

testing for carbohydrates?

A
  1. crush / grind the solid and mix strongly with water
  2. add benedicts reagent
  3. heat / boil (<80)
    • result is a colour change from blue to brick red
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34
Q

quantitative benedicts test result?

A

green - low conc
yellow - medium conc
brick red - high conc

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35
Q

what test is for non reducing sugars (e.g. sucrose)

A
  1. use a fresh sample
  2. add HCL (still crush and mix)
  3. boil , this will hydrolyze sucrose into glucose & fructose
  4. add sodium hydrogen carbonate to neutralize (cant do Benedicts Test in an acidic solution)
  5. repeat benedicts test,+ results indicates sucrose in og solution
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36
Q

starch
monomers?
bonds between them?

A

alpha glucose

1-4 glycosidic bonds in amylose
1-4 & 1-6 in amylopectin

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37
Q

starch structure?

A

made of 2 polymers

amylose - unbranched helix
amylopectin - branched molecule

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38
Q

starch function?
location?

A

store of glucose
plant cells (e.g. chloroplast)

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39
Q

cellulose
monomers?
bond between them?

A

beta glucose
1-4 glycosidic bonds

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40
Q

Making dilutions equation

A

C1 V1 = C2 V2

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41
Q

What test tests for lipids?

A

The emulsion test

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42
Q

How do you carry out the emulsion test?

A

1) dissolve the sample in ethanol (its another non-polar substance)
2) mix well/strongly
3)add water, mix again
4) the presences of a milky emulsion shows that lipids are present

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43
Q

What is a triglyceride?

A

Type of lipid that consists of 3 fatty acid tails connected to glycerol.
It has an ester bond by a condensation reaction that occurs 3 times to make it

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44
Q

What is the difference between saturated and unsaturated

A

Unsaturated is a carbon- carbon double bond

45
Q

What is a phospholipid?

A

Are found in plasma membranes. They form a bilayer, as long as there is an aqueous solution on either side
Contains phosphate, glycerol and 2x fatty acid tails

46
Q

What is a nucleus acid?

A

Are information carrying molecules. They are all polymers of nucleotides

47
Q

What is a DNA’s Pentose sugar and what are there bases?

A

It’s pentose sugar is deoxyribose
The bases are: adenine, cytosine, thymine and guanine

48
Q

What is a RNA’s Pentose sugar and what are there bases?

A

The sugar is ribose
The bases are adenine, uracil , cytosine and guanine

49
Q

Other differences in DNA vs RNA are:

A
  • dna is a double helix, stable and a long molecule
  • RNA is a single stranded, unstable, shorter molecule
50
Q

What forms can RNA be found as:

A
  • mRNA - used in protein synthesis
  • tRNA - involved in protein synthesis
  • rRNA - part of ribosomes
51
Q

What bonds are in polymerisation?

A
  • phosphodiester bonds , formed by condensation reaction
  • hydrogen bonds, between complementary base pairs A-T C-G
52
Q

what enables accurate replication of the DNA molecule?

A

double helix structure of Dna and the complementary base pairing

53
Q

what is semi-conservative replication

A

in each of the 2 new DNA molecules, one of the polynucleotides strands is from the original molecule, and the other is a new one

54
Q

what are the stages of semi-conservative replication

A
  1. DNA helicase breaks the hydrogen bonds between polynucleotide strands, unwinding the double helix
  2. this exposes the bases on nucleotides to bind to their complementary bases
  3. DNA polymerase joins these new nucleotides together with phosphodiester bonds, from in the new nucleotide strand from each og template
55
Q

meselson and stahl experimetn

A
  1. agar in a Petri dish with 14. had another with N15
  2. grew bacteria for a couple of generations on these dishes
  3. took a sample of bacteria from each & spun it in a centrifuge tube
  4. N14- high band indicating it was light DNA. N15- had a low band, heavier DNA
  5. took some bacteria from N15 and grew it on a new petri dish with N14
  6. grew for 1 generation, made one bit of DNa
  7. ended up with heavy DNa. found that when it replicated the DNa had 1 og strand and 1 heavy strand
  8. they found this out by spinning the sample in the centrifuge- band was in the middle
56
Q

test fro proteins

A

biuret reagent being added to the sample
a color change from blue to purple is positive

57
Q

what is the monomer of a polypeptide

A

amino acid

58
Q

how many levels are there to a proteins structure

A

4

59
Q

what is the primary structure of a protein

A

the sequence of amino acids

60
Q

what is the secondary structure of a protein

A

where it forms localized hydrogen bonds between amino acids. this forms two characteristic shapes
- alpha helix
- beta pleated sheet

61
Q

what is the tertiary structure of a protein

A

the 3 dimensional folding involving hydrogen and ionic bonds, and disulphide bridges (interactions across the whole polypeptide). this gives the polypeptides its specific shape

62
Q

what is the quaternary structure of a protein

A

this is where a protein consists of two or more polypeptide chains

63
Q

do all proteins denature

A

yes

64
Q

when does denaturation occur

A

when hydrogen bonds and ionic bonds are broken, changing the tertiary structure of the protein. it is permanent

65
Q

what are enzymes made of

A

proteins

66
Q

what are enzymes

A

globular proteins that act as biological catalysts. this means that they speed up the rate of chemical reactions, by reducing the activation energy, but aren’t used up in the reaction

67
Q

what is the induced fit theory

A

the enzyme and substrate are almost complementary but when the substrate enters the active site, interactions between the substrate and amino acids cause the shape of the active site to change a little to become complementary to the substrate

68
Q

what are enzyme reactions affected by?

A
  • temperature
  • pH
  • concentration
69
Q

effect of temperature on enzyme reactions?
1st stage

A

as the temp increases so does the kinetic energy, so there are more successful collisions between the enzyme & substrate

70
Q

effect of temperature on enzyme reactions?
2nd stage

A

optimum temperature

71
Q

effect of temperature on enzyme reactions?
3rd stage

A

the enzyme denatures so the hydrogen and ionic bonds arte broken which changes the tertiary structure of the active site, and the substrate is no longer complimentary

72
Q

effect of pH on enzyme reactions?

A

either side of the optimum ph., the enzyme denatures, because the hydrogen and ionic bonds break, changing the tertiary structure of the active site, and the substrate so its no longer complimentary

73
Q

effect of concentration on enzyme reactions?
1st stage

A

as you increase the substrate concentration you increase the rate of reaction as there are more successful collisions so the substrate concentration is limiting

74
Q

effect of conc. on enzyme reactions?
2nd stage

A

the substrate concentration is no longer limiting as increasing it does not increase the rate of reaction. enzyme concentration may be limiting as all active sites may be in use

75
Q

what are the two types of enzyme inhibitors?

A
  • competitive inhibitors
  • non competitive inhibitors
76
Q

what are competitive inhibitors

A

similar shape to the substrate, so they can fit into the enzymes active site temporarily. this means they block access for the substrate

77
Q

do competitive inhibitors form an enzyme substrate complex?

A

no, as they are only temporary

78
Q

what are non competitive inhibitors

A

an inhibitor that are complementary to an allosteric site on the enzyme

79
Q

how do non competitive inhibitors work?

A

when the non competitive inhibitor binds it changes the tertiary structure of the active site so it is no longer complementary to the substrate. this effect is temporary as the inhibitor is only attached temporarily (however there are some exceptions)

80
Q

does the enzyme become denatured when the non competitive inhibitor binds to it

A

the enzyme does not become denatured, as denaturation is permanent and this is only temporary

81
Q

what is chromatography?

A

separates molecules e.g. amino acids, according to their solubility in a solvent

82
Q

if a chemical is very soluble where will it travel?

A

it will travel further up the paper

83
Q

how to work out the RF value

A

a / b

84
Q

how do you make a concentrated sample for chromatography?

A

add a drop of solution to the origin line allow it to dry and repeat to concentrate the sample

85
Q

what are exopeptidases

A

exopeptidases hydrolyze peptide bonds at the ends of polypeptides releasing either: amino acids or a dipeptide

86
Q

what are endopeptidases?

A

endopeptidases hydrolyze peptide bonds within a polypeptide, giving a larger surface area fro exopeptidase to function

87
Q

What is ATP and what does it contain?

A

ATP is a nucleotide derivative, used as a short term energy store
It contains: adenine, ribose, 3x phosphate groups

88
Q

What hydrolyses ATP

A

The enzyme ATP hydrolase will hydrolyse the bend between phosphates 2 and 3 leaving adenosine diphosphate (ADP) and Pi (phosphate)

89
Q

What happens during the hydrolysis of ATP

A

The reaction releases lots of energy that can be used n other reactions within cells. The Pi can be used to phosphorylase other compounds as well.

90
Q

What happens during respiration and photosynthesis?

A

ATP synthase can remake ATP by the condensation of ADP + Pi

91
Q

What are inorganic ions

A

Can occur in a solution throughout the body of organisms. They are charged atoms or group of atoms

92
Q

structure of a water molecule

A

the oxygen is slightly negative and the hydrogen is slightly positive. This makes it polar
for this reason you get weak hydrogen bonds forming between water molecules

93
Q

properties of a water molecule

A
  • its a metabolite
  • good solvent
  • relatively high heat capacity
  • relatively high latent heat of vaporization
  • cohesive
94
Q

why is water a metabolite

A

used in hydrolysis and made in condensations reactions

95
Q

why is water a good solvent

A

polar substances dissolve easily in water. it allows gases, enzymes, waste products e.g. ammonia & urea, to diffuse

96
Q

why does water have relatively high heat capacity

A

it takes a lot of energy to raise the temperature of water. it can act as a buffer
- help’s with homeostasis - keeps constant body temperature
- supports aquatic organisms

97
Q

why does water have a relatively large latent heat of vaporization

A

it takes a lot of energy to turn liquid water into water vapour. due to lots of weak hydrogen bonds
- its important for sweating and as a mechanism for temperature regulation

98
Q

why is water cohesive

A

the hydrogen bonds that form between water molecules allows transpiration in plants, it also provides surface tension (which is important for organisms that live under water). it supports columns of water

99
Q

The importance of H+ ion

A

The higher the conc of H+ the lower the ph, enzyme reactions wryly on the maintenance of ph levels

100
Q

The importance of iron ion

A

Found in haemoglobin, the iron binds to the oxygen to allow transportation around the body

101
Q

The importance of sodium ion

A

Used in co-transport of both glucose and amino acids

102
Q

The importance of phosphate ion

A

Found in nucleotides and ATP

103
Q

Have a same number and type of amino acids, but different tertiary structures. Explain why

A
  • hydrogen an ionic bonds form in different places
  • Different sequence of amino acids
104
Q

What is the monomer?

A

Repeating units which larger molecules are made from

105
Q

triglyceride structure related to their properties

A
  • lots of energy storing carbon-hydrogen bonds so they are an energy store
  • low mass to energy ratio, lots of energy being stored in small volume. animals have less mass to move around
    -large, non-polar lipids are insoluble so storage doesn’t affect water potential
  • release water when oxidised so are a water source for organism
106
Q

what happens when phospholipids come into contact with water

A

form micelles

107
Q

phospholipids structure related to their properties

A
  • aq environment means a bilayer is formed
  • form glycolipids with carbs on the cell surface membrane for cell recognition
108
Q

what is a buffer solution?

A

maintains an approximately constant pH, despite dilution or addition of small amounts of acid or base.