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Biology > Topic 1 - Biological molecules > Flashcards

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
Lactose
Galactose + glucose
26
Maltose
Glucose + glucose
27
Cellulose
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
28
Starch (amylose)
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
29
Starch (amylopectin)
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
30
Release of glucose in amylose vs amylopectin
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
31
Glycogen
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
32
Lipid
Fatty acid
33
Fatty acid chain
Long hydrocarbon chain Carboxyl terminal group (COOH)
34
Unsaturated acid chain
long hydrocarbon chain carboxyl terminal group (COOH)
35
Unsaturated fatty acid characteristics
Liquid at room temperature Oils One or more double C-C bond present, causing kinks in the fatty acid chain
36
Why are unsaturated fatty acids liquid at room temp
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
Saturated fatty acid characteristics
Solid at room temp Fats No double C-C bonds present
38
What is a triglyceride/lipid made from
Fatty acids x3 + glycerol
39
Triglyceride
Lipid made up of three fatty acids and a glycerol
40
Ester bond
Bond formed when oxygen from a fatty acid joins onto carbon from glycerol in a condensation reaction (O-C=O)
41
Esterification
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
Phospholipid
A chemical in which glycerol bonds with two fatty acids and an inorganic phosphate group
43
Function of lipids: Energy storage
High energy density (produce 34kj/g) Insoluble in water/osmostically inactive
44
Function of lipids: Waterproofing
Hydrophobic - will not dissolve in water (insoluble) e.g. bird feathers - preen gland fur of mammals - sebaceous gland surface of ginkgo leaves
45
Function of lipids: Insulation
Lipids are large, covalent molecules with no free electrons = poor conductors, good insulators Prevent too much heat loss
46
Thermal insulation
Subcutaneous layers of skin e.g. blubber of whales
47
Mechanical insulation
Around major organs, shock absorbing e.g. protect the kidneys
48
Electrical insulation
Makes impulses travel faster e.g. myelin sheath around axons of neurones
49
Function of lipids: buoyancy
Lipids are low density Body fat of water mammals allows them to float easily
50
Micelle
A spherical aggregate of molecules in water with hydrophobic middle areas and hydrophilic outer areas
51
Bilayer
Double layer of closely pack atoms or molecules
52
Unit membrane
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
Fluid mosaic structure
A mixture of molecules e.g. proteins, phospholipids and cholesterol which are able to change positions within the membrane
54
Phosphate group
The 'head' of the molecule Hydrophilic, dissolves in water
55
Amino acids
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
Behaviour of fatty acids in phospholipid
The 'tail' of the molecule Hydrophobic, does not dissolve in water
57
Protein
A three dimensional polypeptide chain made of monomers of amino acids
58
Peptide bond
Formed when two amino acids join together through a condensation reaction. H20 is removed
59
Dipeptide
Two amino acids which have been joined together by a peptide bond
60
Polypeptide
When many amino acids are joined together by peptide bonds. They form an unbranched chain; a polypeptide
61
Primary structure
The sequence of amino acids in a polypeptide chain
62
Secondary structure
The way a polypeptide chain is twisted and folded. Can be an alpha helix or a beta pleated sheet
63
Tertiary structure
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
Bonds that help maintain tertiary structure of a protein
Hydrogen bonds between R groups Ionic bonds between R groups Disulphide bridges between R groups
65
Globular proteins
More spherical in shape. Soluble. Metabolic function e.g. enzymes, haemoglobin, insulin, antibodies
66
Fibrous proteins
Long and thin. Insoluble. Structural function e.g. collagen, keratin
67
Test for proteins
Biuret test Add sodium hydroxide to the test sample. Add a few drops of dilute copper sulphate solution. Positive result - solution = violet/purple
68
Test for lipids
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
Behaviour of phosphate in triglyceride
The 'head' of the molecule. Hydrophilic, attracted to water
70
Catalyst
A substance that speeds up a reaction without changing the substance produced or changing itself
71
Enzymes
Biological catalysts
72
Specificity
Each enzyme will only catalyse a one particular reaction or group of reactions
73
Anabolic reaction
Build up new molecules
74
Catabolic reaction
Breaks down substances
75
Metabolism
Sum of all anabolic and catabolic reactions
76
Intracellular
Within the cell
77
Extracellular
Outside the cell
78
Activation energy
Energy needed for a reaction to start
79
Substrate
Molecule or molecules on which an enzyme acts
80
Lock and key
The theory of when enzymes and substrates slot together to form a complex
81
Active site
The area of the enzyme that has a specific shape into which the substrate fits
82
Induced fit
Once the substrate enter the active site the share of site changes to form the ESC
83
Enzyme inhibitor
Substances that slow down enzymes for stop them from working
84
Reversible inhibition
Inhibitor does not permanently affect functioning of the enzyme. Often used to control reaction rates within a cell
85
Irreversible inhibition
Inhibition that is permanent. Never used to control reaction rates
86
Competitive inhibition
Inhibitor molecule is similar shape to substrate and competes with it for the active site. Affected by inhibitor and substate concentration
87
Non-competitive inhibition
Inhibitor binds to site away from active site. Only affected by inhibitor concentration
88
End product inhibition
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.

Biology (20 decks)

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