Topic 1 - Biological molecules Flashcards

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1
Q

Hydroxyl group OH

A

This is a simple chemical group consisting of oxygen creating a covalent bond with hydrogen. ‘R’ can be anything and varies

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2
Q

Carboxyl group COOH

A

Made of one carbon atom boded with hydroxide and oxygen and ‘R’ where there are two bonds with oxygen .

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3
Q

Amine group NH2

A

Here, the nitrogen is bonded with 2 hydrogen atoms and “R” which can vary

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4
Q

Alpha glucose

A

complex molecule that has 6 carbon atoms, type of hexose sugar. It can form the polymer carbohydrate - e.g. starch, cellulose

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5
Q

Beta glucose

A

Complex molecule, the same as alpha glucose but the OH and H swap in the first carbon atom in the sequence

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6
Q

Fatty acid

A

Complex molecule, contains a carboxyl group on its end. It can be unsaturated (has double bonds) or saturated (no double bonds). It creates lipids

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7
Q

Amino acid

A

Complex molecule, contains amine group and carboxyl group with a carbon in the middle, bonded with the amine group, carboxyl group, hydrogen and ‘R’. It forms proteins

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8
Q

Ribose

A

Complex molecule, type of pentose sugar.
Creates RNA and DNA

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9
Q

Hydrogen bond

A

A hydrogen bond between water occurs when a slightly negatively charged water molecule is attracted to a slightly positively charged hydrogen atom in a water molecule

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10
Q

Monosaccharide

A

Single sub unit of sugar, for instance glucose, which can join together through condensation reaction to form a disaccharide or a polysaccharide

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11
Q

Disaccharide

A

A disaccaride is 2 monosaccharides joined together through a condensation reaction. A disaccharide can split back into 2 monosaccharides through a hydrolysis reaction

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12
Q

Polysaccharide

A

Many monosaccharides joined together through a condensation reaction. A polysaccharide can be broken down into a disaccharide and then broken again into monosaccharides through a hydrolysis reaction

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13
Q

Condensation reaction

A

Involves the removal of water in order for two monosaccharides to join together

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14
Q

Hydrolysis reaction

A

Involves the addition of water to a disaccharide or polysaccharide in order to turn back into a monosaccharide

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15
Q

Reducing sugar

A

Easily oxidised - a sugar that donates electrons to other chemicals e.g. monosaccharides, maltose and lactose

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16
Q

Non reducing sugar

A

Cannot be easily oxidised - a sugar that accepts electrons from other chemicals. E.g. sucrose

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17
Q

Glycosidic bond

A

The covalent bond formed between two monosaccharides during a condensation reaction

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18
Q

Test for reducing sugars (Benedicts reagent)

A

1) Add Benedicts reagent to substance
2) Orange/red = reducing sugar present

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19
Q

Test for non reducing sugars

A

1) add HCL to substance and warm
2) Add sodium hydroxide (neutralise HCL)
3) Test final substance with Benedicts reagent

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20
Q

Test for starch (Iodine)

A

1) Put iodine into substance
2) Iodine turns blue/black (starch present)

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21
Q

Sweet flavour

A

Monosaccharides:
Glucose, galactose, fructose

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22
Q

Storage polysaccharides

A

Glycogen, starch
(insoluble, compact, osmotically inactive)

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23
Q

Structural polysaccharides

A

Cellulose
(insoluble, strong, freely permeable to solutes/solvents)

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24
Q

Sucrose

A

Glucose + Fructose

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25
Q

Lactose

A

Galactose + glucose

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26
Q

Maltose

A

Glucose + glucose

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27
Q

Cellulose

A

Source: plants (cell wall)
Subunit: b-glucose
Bonds: 1,4 alternating glycosidic bonds
Branches: no
Shape: straight chains
Function: support cell
Info: alternative bonding causes chains of cellulose to line up parallel to each other. They’re linked by weak hydrogen bonds which forms intermolecular forces which are collectively very strong. Intermolecular forces bundle up to make microfibrils. Cellulose is insoluble

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28
Q

Starch (amylose)

A

Source: plants
Subunit: a-glucose
Bonds: 1,4 glycosidic bonds
Branches: No
Shape: helical
Function: storage
Info: No alternative bonding so molecules bend, creating spiral shape which is held by hydrogen bonds. Amylose is insoluble

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29
Q

Starch (amylopectin)

A

Source: plants
Subunit: a-glucose
Bonds: 1,4 and 1,6 glycosidic bonds
Branches: yes
Shape: compact, branched
Function: storage
Info: many branches, so amylopectin folds compactly which makes it easier to store molecules. Its insoluble

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30
Q

Release of glucose in amylose vs amylopectin

A

Amylose = slow due to few terminal molecules, slower hydrolysis and production of glucose
Amylopectin = fast due to many terminal molecules on branches, faster hydrolysis and production of glucose

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31
Q

Glycogen

A

Source: animals
Subunit: a-glucose
Bonds: 1,4 and 1,6 glycosidic bonds
Branches: yes
Shape: compact, branched
Function: storage of glucose in body
Info: glycogen found in liver and muscles, where rate of respiration is regularly raised very rapidly

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32
Q

Lipid

A

Fatty acid

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33
Q

Fatty acid chain

A

Long hydrocarbon chain
Carboxyl terminal group (COOH)

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34
Q

Unsaturated acid chain

A

long hydrocarbon chain
carboxyl terminal group (COOH)

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35
Q

Unsaturated fatty acid characteristics

A

Liquid at room temperature
Oils
One or more double C-C bond present, causing kinks in the fatty acid chain

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36
Q

Why are unsaturated fatty acids liquid at room temp

A

The double C-C bonds cause kinks in the fatty acid chain.
When lots of triglycerides lie together, there is more space between the unsaturated fatty acids.
This results in weaker intermolecular forces that require less energy to break, resulting in a lower melting point

37
Q

Saturated fatty acid characteristics

A

Solid at room temp
Fats
No double C-C bonds present

38
Q

What is a triglyceride/lipid made from

A

Fatty acids x3 + glycerol

39
Q

Triglyceride

A

Lipid made up of three fatty acids and a glycerol

40
Q

Ester bond

A

Bond formed when oxygen from a fatty acid joins onto carbon from glycerol in a condensation reaction (O-C=O)

41
Q

Esterification

A

When glycerol combines with 3 fatty acids in a condensation reaction between the COOH group of the fatty acid and the OH group of glycerol

42
Q

Phospholipid

A

A chemical in which glycerol bonds with two fatty acids and an inorganic phosphate group

43
Q

Function of lipids: Energy storage

A

High energy density (produce 34kj/g)
Insoluble in water/osmostically inactive

44
Q

Function of lipids: Waterproofing

A

Hydrophobic - will not dissolve in water (insoluble)
e.g. bird feathers - preen gland
fur of mammals - sebaceous gland
surface of ginkgo leaves

45
Q

Function of lipids: Insulation

A

Lipids are large, covalent molecules with no free electrons = poor conductors, good insulators
Prevent too much heat loss

46
Q

Thermal insulation

A

Subcutaneous layers of skin e.g. blubber of whales

47
Q

Mechanical insulation

A

Around major organs, shock absorbing
e.g. protect the kidneys

48
Q

Electrical insulation

A

Makes impulses travel faster
e.g. myelin sheath around axons of neurones

49
Q

Function of lipids: buoyancy

A

Lipids are low density
Body fat of water mammals allows them to float easily

50
Q

Micelle

A

A spherical aggregate of molecules in water with hydrophobic middle areas and hydrophilic outer areas

51
Q

Bilayer

A

Double layer of closely pack atoms or molecules

52
Q

Unit membrane

A

A bilayer structure formed by phospholipids in an aqueous environment, with the hydrophobic, non polar tails in the middle and the hydrophilic, polar heads on the outside

53
Q

Fluid mosaic structure

A

A mixture of molecules
e.g. proteins, phospholipids and cholesterol
which are able to change positions within the membrane

54
Q

Phosphate group

A

The ‘head’ of the molecule
Hydrophilic, dissolves in water

55
Q

Amino acids

A

Building blocks of proteins, with an amino group (NH2) and a carboxyl group (COOH) attached to a central carbon atom and a variable R-group

56
Q

Behaviour of fatty acids in phospholipid

A

The ‘tail’ of the molecule
Hydrophobic, does not dissolve in water

57
Q

Protein

A

A three dimensional polypeptide chain made of monomers of amino acids

58
Q

Peptide bond

A

Formed when two amino acids join together through a condensation reaction. H20 is removed

59
Q

Dipeptide

A

Two amino acids which have been joined together by a peptide bond

60
Q

Polypeptide

A

When many amino acids are joined together by peptide bonds. They form an unbranched chain; a polypeptide

61
Q

Primary structure

A

The sequence of amino acids in a polypeptide chain

62
Q

Secondary structure

A

The way a polypeptide chain is twisted and folded. Can be an alpha helix or a beta pleated sheet

63
Q

Tertiary structure

A

Twisted and folded polypeptide chain folds up further to give the whole polypeptide molecule a globular shape. Bonds include hydrogen bonds, disulphide bridges and ionic bonds

64
Q

Bonds that help maintain tertiary structure of a protein

A

Hydrogen bonds between R groups
Ionic bonds between R groups
Disulphide bridges between R groups

65
Q

Globular proteins

A

More spherical in shape. Soluble. Metabolic function e.g. enzymes, haemoglobin, insulin, antibodies

66
Q

Fibrous proteins

A

Long and thin. Insoluble. Structural function e.g. collagen, keratin

67
Q

Test for proteins

A

Biuret test
Add sodium hydroxide to the test sample.
Add a few drops of dilute copper sulphate solution.
Positive result - solution = violet/purple

68
Q

Test for lipids

A

Emulsion test
Add 2cm3 of the unknown solution to a test tube
Add 2cm3 of ethanol to the same tube and shake well to mix
Fill another test tube to just over half way with ice cold distilled water
Very slowly and carefully, pour the ethanol-solution mixture down the inside of the 2nd tube, onto the water.
Positive result - a band/ring

69
Q

Behaviour of phosphate in triglyceride

A

The ‘head’ of the molecule.
Hydrophilic, attracted to water

70
Q

Catalyst

A

A substance that speeds up a reaction without changing the substance produced or changing itself

71
Q

Enzymes

A

Biological catalysts

72
Q

Specificity

A

Each enzyme will only catalyse a one particular reaction or group of reactions

73
Q

Anabolic reaction

A

Build up new molecules

74
Q

Catabolic reaction

A

Breaks down substances

75
Q

Metabolism

A

Sum of all anabolic and catabolic reactions

76
Q

Intracellular

A

Within the cell

77
Q

Extracellular

A

Outside the cell

78
Q

Activation energy

A

Energy needed for a reaction to start

79
Q

Substrate

A

Molecule or molecules on which an enzyme acts

80
Q

Lock and key

A

The theory of when enzymes and substrates slot together to form a complex

81
Q

Active site

A

The area of the enzyme that has a specific shape into which the substrate fits

82
Q

Induced fit

A

Once the substrate enter the active site the share of site changes to form the ESC

83
Q

Enzyme inhibitor

A

Substances that slow down enzymes for stop them from working

84
Q

Reversible inhibition

A

Inhibitor does not permanently affect functioning of the enzyme. Often used to control reaction rates within a cell

85
Q

Irreversible inhibition

A

Inhibition that is permanent. Never used to control reaction rates

86
Q

Competitive inhibition

A

Inhibitor molecule is similar shape to substrate and competes with it for the active site. Affected by inhibitor and substate concentration

87
Q

Non-competitive inhibition

A

Inhibitor binds to site away from active site. Only affected by inhibitor concentration

88
Q

End product inhibition

A

A control system in many metabolic pathways in which an enzyme at the beginning of the pathway is inhibited by one of the end products of the pathway.