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biology (2) : foundations in bio > BIOLOGICAL MOLECULES (2.1.2) > Flashcards

BIOLOGICAL MOLECULES (2.1.2) Flashcards

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1
Q

what is latent heat

A

heat energy needed to change a substance from one state to another , e.g from a liquid to a gas

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2
Q

define the term “polar molecule”

A

a molecule that has a slightly positive charge on one side and a slightly negative charge on the other

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3
Q

what do water molecules form with other water molecules due to its polarity?

A

hydrogen bonds

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4
Q

why does water have a high specific heat capacity?

A
  • hydrogen bonds between H2O molecules can absorb a lot of energy
  • results in a lot of energy needed to heat it up
  • means that water doesn’t experience rapid temperature changes
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5
Q

what effect does waters high specific heat capacity have on its function?

A
  • makes water a good habitat
  • water doesn’t experience rapid temperature changes
  • means temperature underwater is more stable than on land
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6
Q

why is water cohesive?

A
  • due to waters polarity, molecules are attracted to one another and “stick” to each other
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7
Q

what’s effect does water’s cohesive nature have on its function?

A
  • allows water to flow
  • makes water a good transport medium
  • helps water be transported up plant stems in transpiration stream
  • produces surface tension for small organisms to walk on
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8
Q

why is water a good solvent?

A
  • due to waters polarity, it can dissolve ionic substances
  • waters δ+ side is attracted to the negative ion
  • waters δ- side is attracted to the positive ion
  • ions get surrounded by H2O molecules and dissolve
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9
Q

what affect does waters ability to be a good solvent have on its function?

A
  • makes it a good reaction medium, since many substances in biological reactions are ionic
  • makes it a good transport medium, as it can transport useful substances
  • makes it a good habitat, as it contains useful ions
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10
Q

why does water have a high latent heat of evaporation?

A
  • takes a high amount of energy to break hydrogen bonds between H2O molecules
  • this means a lot of energy is needed to change water from a liquid to a gas
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11
Q

what affect does water having a high latent heat of evaporation have on its function?

A
  • makes water a useful coolant
  • used as a thermoregulatory system by organisms
  • sweating/transpiring allows heat to be carried away by vapourised h2o molecules
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12
Q

why does water have a lower density when solid?

A
  • h2o molecules are held further apart in ice than in liquid
  • each molecule forms 4 hydrogen bonds with other h2o molecules to form a lattice shape
  • allows ice to float on top of water
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13
Q

what affect does water having a lower density when solid have on its function?

A
  • makes it a good habitat
  • ice floats on top of water, forming an insulating layer on top of water
  • liquid below and organisms within (e.g. fish) don’t freeze
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14
Q

what elements do carbohydrates contain?

A
  • Carbon
  • Hydrogen
  • Oxygen
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15
Q

define and state 3 examples of a monosaccharide

A

a monomer
- alpha glucose
- beta glucose
- ribose

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16
Q

where is the hydroxyl (OH) group on α-glucose ?

A
  • bonded to the bottom right of Carbon 1
    H
    /
    C1
    \
    OH
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17
Q

where is the hydroxyl (OH) group on β-glucose?

A
  • bonded to the top right of Carbon 1
    OH
    /
    C1
    \
    H
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18
Q

state the formula of glucose

A

C6 H12 O6

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19
Q

what type of monosaccharide is glucose?

A
  • a hexose monosaccharide
  • has 6 carbons
  • is a sugar
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20
Q

how is glucose’s structure related to = its function?

A
  • it is soluble, so can be easily transported
  • it’s chemical bonds contain energy, making it a good energy source
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21
Q

what is the chemical formula for Ribose?

A
  • C5 H10 O5
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22
Q

structural formula of ribose

A

CH2OH O OH
| / \ /
C4 H H C1
/ \ / \ / \
H C3___C2 H
/ \
HO OH

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23
Q

what type of monosaccharide is ribose?

A
  • a pentose monosaccharide
  • has 5 carbons
  • is a sugar
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24
Q

what is ribose’s function?

A
  • is a the sugar component of RNA molecules
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25
Q

how are polysaccharides formed?

A
  • by glycosidic bonds formed during condensation polymerisation
  • H atom on one monosaccharide bonds to a OH group on another
  • releases H2O, water molecule
    H H H H
    / \ / \
    C + C ➡️ C C + H2O
    \ / \ /
    OH HO O
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26
Q

what is excess glucose stored as in plants?

A
  • starch
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27
Q

what is starch a mixture of?

A
  • 2 polysaccharides of alpha-glucose
  • 70% amylose
  • 30% amylopectin
28
Q

describe the structure of amylose

A
  • long unbranded chain of alpha-glucose
  • has C1 to C4 glycosidic bonds ONLY
  • coiled structure, due to angles of bonds
29
Q

what effects does the structure of amylose have on its function?

A
  • good for storage, due to compact structure
  • insoluble, so no osmotic effect on cells
  • energy not released quickly, since plants have a low metabolic rate
30
Q

why do plants have a low metabolic rate?

A
  • they don’t move
  • they don’t regulate their temperature
31
Q

describe the structure of amylopectin

A
  • long branched chain of alpha-glucose
  • C1 to C4 glycosidic bonds, SOME C1 to C6 bonds
32
Q

what effects does the structure of amylopectin have on its function?

A
  • side branches (1-6 bonds) allow enzymes to reach glycosodic bonds easier, and therefore release glucose (energy) easier
  • insoluble, no osmotic effects
  • good for storage, due to coiled/compact structure
33
Q

why is lots of branching not required in plant storage of glucose?

A

plants have a low metabolic rate, so do not require much energy

34
Q

what is the animal storage of glucose?

A

glycogen

35
Q

describe the structure of glycogen

A
  • polysaccharide of alpha-glucose
  • C1 to C4 bonds
  • many C1 - C6 bonds (lots of branching)
36
Q

why does glycogen have lots of branching?

A
  • to allow enzymes that break down molecules to reach glycosidic bonds easier and release glucose (energy)
  • more readily available energy
  • animals have a higher metabolic rate
37
Q

why do animals require a store that provides more readily available energy (glucose)?

A
  • animals have a higher metabolic rate, due to movement and temperature control
38
Q

what is cellulose’s function?

A
  • present in cell walls of plants
  • provides structural support/maintains shape of plant cells
39
Q

describe the structure of cellulose

A
  • polysaccharide of beta-glucose
  • every other beta-glucose is rotated 180degrees to form a linear chain
  • cellulose chains link together by hydrogen bonds to form microfibrils
40
Q

how are cellulose chains linked together?

A
  • by hydrogen bonds
  • forms microfibrils (strong fibres) that provide structural support for the cell
41
Q

how are disaccharides formed?

A

when 2 monosaccharides join together through condensation polymerisation

42
Q

how is maltose formed [disaccharide]?

A

when 2 alpha-glucose monosaccharides join together

43
Q

how is sucrose [disaccharide] formed?

A

when an alpha-glucose and fructose monosaccharide join together

44
Q

how is lactose [disaccharide] formed?

A

when a galactose and EITHER alpha or beta-glucose join together

45
Q

give 3 examples of disaccharides

A
  • maltose
  • sucrose
  • lactose
46
Q

which elements do lipids contain?

A
  • Carbon
  • Hydrogen
  • Oxygen
47
Q

what do lipids dissolve in?

A
  • inorganic solvents (e.g. chloroform)
  • NOT water
48
Q

why do lipids not dissolve in water?

A
  • they are non-polar (electrons distributed evenly)
  • have no charged groups
  • water has nothing to interact with
49
Q

describe the structure of a triglyceride

A
  • a glycerol molecule
  • 3 fatty acid chains
  • held together by 3 ester bonds
50
Q

how are triglycerides formed?

A
  • condensation reaction, known as esterification
  • each fatty acids hydroxyl group (OH) reacts with one of the 3 OH groups on the glycerol
  • forms 3 ester bonds and 3 H2O molecules
    H O
    | ||
    H—C-—O—-C—(CH2)nCH3
    X3
51
Q

describe the structure of a fatty acid molecule and the effect it has on lipids

A
  • have hydrocarbon tails, which can vary in structure
  • these HC tails are hydrophobic, so do not interact with water
  • these make lipids insoluble in water
52
Q

describe the structure of saturated fatty acids

A
  • have SINGLE carbon - carbon bonds ONLY
  • every carbon atom is saturated with hydrogen
53
Q

what is the general formula for saturated fatty acids?

A

CnH2n+1 COOH

54
Q

describe the structure of unsaturated fatty acids

A
  • HAVE carbon-carbon double bonds
  • C=C causes the chain to kink
  • kink means that they tend to be liquids (e.g. oil)
55
Q

state a property of fatty acids

A
  • carbon to carbon bonds release a lot of energy when broken
56
Q

what are the functions of triglycerides?

A
  • energy storage for animals and plants
  • energy and carbon storage for bacteria
57
Q

why are triglycerides a good energy storage?

A
  • fatty acid HC tail contains lots of energy
  • contain twice as much energy as carbohydrates
  • insoluble, so can be stored inside cells w/out an osmotic effect
  • triglycerides bundle as insoluble droplets, because hydrophobic tails face inwards shielded by glycerol heads
58
Q

state the functions of triglycerides

A
  • store of chemical energy
  • protection
  • waterproofing
  • buoyancy (fat layer beneath skin)
59
Q

describe the structure of a phospholipid

A
  • phosphate head
  • glycerol molecule
  • 2 fatty acid tails
60
Q

why do phospholipids form a bilayer membrane?

A
  • fatty acids and hydrophobic, so face inwards
  • phosphate head is hydrophilic, so point outwards on either side of the membrane
61
Q

state the functions of phospholipids

A
  • make up the bilayer within the cell membrane of eukaryotes and prokaryotes
  • protection from friction (act as a lubricant)
  • electrical insulation
62
Q

how does the membrane act as a barrier?

A
  • centre of bilayer is hydrophobic, due to hydrophobic fatty acid tails
  • water soluble substances (e.g ions, polar molecules) cannot easily pass through i
63
Q

describe the structure of cholesterol

A
  • hydroxyl (OH) group (polar, hydrophilic)
  • hydrocarbon rings (hydrophobic)
  • hydrocarbon tail (hydrophobic)
64
Q

describe the function of cholesterol

A
  • strengthen cell membrane
  • fit between phospholipids bilayer (due to small, flat shape)
  • needed to form vitamin D
  • needed for production of steroid hormones
65
Q

how does cholesterol interact with the cell membranes bilayer?

A
  • bonds to hydrophobic tails of phospholipids
  • causes phospholipids to pack closer together
  • make membranes less fluid, increasing rigidity

biology (2) : foundations in bio (5 decks)

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