F212 1.1 - Biological Molecules Flashcards
1
Q
Acidic
A
A molecule which tends to ionize in water to release protons and lower pH
2
Q
Adhesion
A
The intermolecular attraction between unlike-molecules
3
Q
Amphipathic
A
A molecule with dual properties such as a hydrophobic section at one end and a hydrophilic section at the other
4
Q
Amphoteric
A
A chemical which can act as both an acid and a base e.g. an amino acid.
5
Q
Anion
A
A negatively charged ion with more electrons than protons
6
Q
Atom
A
The smallest division of an element exhibiting all the properties of the element
7
Q
Atomic number
A
The number of protons in the nucleus of an atom of an element. The atomic number determines the position of the element in the periodic table
8
Q
Basic
A
A molecule which tends to become charged in water by accepting protons and thus raise pH
9
Q
Buffer
A
Any substance that by virtue of its own acid/base properties is able to resist an applied pH change by taking up hydrogen ions if some are added or releasing them in response to the addition of a base
10
Q
Cation
A
A positively charged ion with more protons than electrons
11
Q
Chromatography
A
A technique for separating molecules according to their solubility
12
Q
Cohesion
A
The intermolecular attraction between like-molecules
13
Q
Compound
A
A molecule containing two or more different elements, chemically combined
14
Q
Covalent bond
A
A bond in which a pair of electrons is shared between 2 atoms in a molecule
15
Q
Denaturation
A
A process whereby some agency such as temperature or pH disrupts the normal balance of forces maintaining the higher order structure of a macromolecule to the extent that the weak forces are overcome and the structure collapses and loses function. It is sometimes irreversible. Often used when talking about enzymes
16
Q
Double bond
A
Two bonds consisting of 2 pairs of electrons shared between the same 2 atoms
17
Q
Electron
A
A negatively charged particle with defined charge, mass and spin forming part of an atom
18
Q
Electron shells
A
The way electrons are arranged around an atom. Each shell can hold a specific number of electrons
19
Q
Electrophoresis
A
A technique for separating molecules according to their size and electrical charge
20
Q
Element
A
One of over 100 fundamental substances that cannot be chemically broken down into any others
21
Q
Empirical formula
A
The simplest way in which the elemental composition of a molecule can be represented
22
Q
Endergonic
A
A reaction which uses energy
23
Q
Endothermic
A
A reaction which uses heat energy
24
Q
Exergonic
A
A reaction which releases energy
25
Exothermic
A reaction which releases energy as heat
26
Hydrogen bond
A weak attractive force between a slightly positively-charged hydrogen atom (∂+) covalently bonded to a more electronegative atom and another nearby negatively or partially-negatively charged atom (∂-)
27
Hydrophilic
“Water-loving”. A property of polar molecules able to interact with/participate in the hydrogen bonding network of water molecules leading to solubility in water
28
Hydrophobic effect
“Water-fearing”. An effect created by the tendency of water molecules to form extensive hydrogen bonding networks so that non-polar groups are excluded and therefore cluster together away from water
29
Ion
A charged particle
30
Ionic bond
A force of electrostatic attraction between ions of opposite charge
31
Isotope
One of two or more forms of an element differing in the number of neutrons in the nucleus
32
Mass number
The number of protons and neutrons in the nucleus of an atom of an element
33
Mixture
Two or more chemical elements mixed together but not chemically combined
34
Neutron
An uncharged particle forming part of an atomic nucleus
35
Non-polar
A molecule or group which is not electrically charged and is hydrophobic
36
Oxidation
The loss of electrons
37
pH
A measure of the relative acidity/alkalinity of a solution numerically equal to the negative logarithm to the base ten of the hydrogen ion concentration with pH 7 being the neutral point. A pH above 7 is alkaline, below 7 is acidic
38
Polar
A molecule or group which is electrically charged and is hydrophilic
39
Proton
A positively charged particle forming part of an atomic nucleus
40
Radioisotope
An isotope in which the nucleus is unstable and will undergo radioactive decay
41
Reduction
The gain of electrons
42
Single bond
A bond consisting of 1 pair of electrons shared between the same 2 atoms
43
Solute
A chemical which dissolves in a solvent to form a solution
44
Solvent
A chemical in which other molecules dissolve to form a solution
45
Triple bond
Three bonds consisting of 3 pairs of electrons shared between the same 2 atoms
46
Valency
The combining capacity of an element, the number of bonds an atom can make with other atoms. The electron configuration determines valency
47
Van der Waals' force
A weak force between neutral atoms and molecules resulting from electron movements creating short-lived dipoles which can then induce/interact with others
48
X-ray crystallography/diffraction
A technique for working out the 3D structure and arrangement of atoms in a molecule using an X-ray beam passing through a crystal of the compound. Used to find out the higher order structure of protein and nucleic acids
49
Amine group
-NH2
50
Anabolism
The build-up chemical reactions in an organism (adjective = anabolic)
51
ATP
Adenosine triphosphate, often described as the energy currency of the cell
52
Biochemistry
The study of chemical processes within, and relating to, living organisms.
53
Carboxyl group
-COOH
54
Catabolism
The break-down chemical reactions in an organism (adjective = catabolic)
55
Complementary
A term used to describe two molecules whose shape and charges enable them to fit together e.g. an enzyme and its substrate, an antibody and an antigen
56
Condensation
A type of reaction in which monomers are joined together with the loss of a water molecule forming a new covalent bond linking the monomers (or joining monomers to a growing polymer)
57
Dimer
Two monomers joined together
58
Dipole
A molecule with a positively and negatively charged regions
59
Hydrocarbon
A molecule or group containing only carbon and hydrogen
60
Hydrolysis
A type of reaction in which polymers etc. are separated into monomers by breaking a covalent bond with the addition of a water molecule each time a monomer is removed or a larger polymer is split into 2 smaller ones
61
Hydroxyl group
-OH
62
Kinetic energy
Energy due to motion
63
Macromolecule
A large molecule usually composed of multiple monomers condensed together to produce a product with very different properties
64
Metabolism
The chemical reactions in an organism
65
Methyl group
-CH3
66
Monomer
A single unit from which dimers, trimers and polymers can be built
67
Oligomer
Several monomers joined together
68
Organic compound
A compound based on a carbon skeleton, usually chains or rings
69
Polymer
Lots of monomers joined together
70
Thiol/sulphydryl group
-SH
71
Variable group
-R
72
Capillarity (Water)
The ability of a liquid such as water to flow in narrow spaces e.g. water moving up a narrow tube.
73
Heat capacity (Water)
The amount of heat needed to raise 1kg of a substance by 1oC. Water has a high heat capacity which means a large increase in heat energy is needed to raise the temperature of water
74
Heat of fusion (Water)
The heat energy needed to melt a solid. Water needs a large amount of heat energy to melt but equally it needs to lose a lot of heat energy to freeze. This means, when it gets cold, cells and their environment are less likely to freeze
75
Heat of vaporization (Water)
The heat energy needed to vaporize a liquid, for it to evaporate. Water takes a lot of heat energy to evaporate which is why it’s a good coolant
76
Solvent (Water)
A chemical in which other molecules dissolve to form a solution. Water is the main solvent in living organisms
77
Surface tension (Water)
The cohesive forces at the surface of a liquid. Water has a higher surface tension than any other liquid
78
α-helix (Proteins)
One of the two common secondary structures found in proteins whereby the primary sequence adopts a coiled shape with hydrogen bonds parallel to the helix axis to give an almost solid rod
79
Amino acid (Proteins)
An organic chemical consisting of a central carbon covalently bonded to a hydrogen atom, an amine group, a carboxylic acid group and a side-chain or R group of variable composition which forms a monomer for polypeptide and protein construction
80
β-pleated sheet (Proteins)
One of the two common secondary structures found in proteins whereby the primary sequence adopts a series of parallel or anti-parallel alignments with hydrogen bonds between the strands to give a corrugated sheet form.
81
Biuret test (Proteins)
A standard chemical test for the detection of a protein in aqueous alkaline solution whereby a purple colour is developed in the presence of a copper salt
82
C terminal (Proteins)
The end of a polypeptide chain with a carboxyl group
83
Collagen (Proteins)
The trimeric fibrous protein found in tendons, blood vessel walls, basement membranes etc. responsible for providing mechanical strength to tissues
84
Conjugated protein (Proteins)
A protein bonded to a non-protein group (prosthetic group) e.g. a glycoprotein or a lipoprotein
85
Dipeptide (Proteins)
Two amino acids linked together by a peptide bond formed by a condensation reaction
86
Disulphide bond (Proteins)
A special type of covalent bond formed at tertiary and quaternary levels of protein structure to provide additional stability in extracellular proteins. It forms by the oxidation of two thiol or sulphydryl (-SH) groups on the side chain of cysteine amino acids
87
Essential amino acid (Proteins)
An amino acid which must be present in the diet and cannot be made in the body
88
Fibrous protein (Proteins)
A protein whose higher order structure results in a product with a high axial ratio (long helices or flat sheets) often with a high content of hydrophobic amino acids causing insolubility so they have mainly structural roles
89
First class protein (Proteins)
A protein containing all of the 9 essential amino acids
90
Globular protein (Proteins)
A protein whose higher order structure results in a product with a low axial ratio (roughly spherical). e.g. haemoglobin
91
Glycoprotein (Proteins)
A protein with carbohydrate molecule(s) attached
92
Glucagon (Proteins)
The polypeptide hormone secreted by the α cells of the Islets of Langerhans in the pancreas responsible for maintaining the blood glucose concentration between meals
93
Haem (Proteins)
The iron-containing prosthetic group in haemoglobin
94
Haemoglobin (Proteins)
The tetrameric globular protein found in red blood cells responsible for carrying oxygen molecules reversibly bound to its 4 haem groups from respiratory surfaces to respiring tissues
95
Insulin (Proteins)
The protein hormone secreted by the β cells of the Islets of Langerhans in the pancreas responsible for reducing circulating blood glucose concentrations after a meal
96
Keratin (Proteins)
A fibrous protein found in skin, hair and nails
97
N terminal (Proteins)
The end of a polypeptide chain with an amine group
98
Non-essential amino acid (Proteins)
An amino acid which doesn’t have to be in the diet as it can be made from other amino acids (11 of the 20 commonly occurring amino acids are non- essential)
99
Peptide bond (Proteins)
The type of bond formed by the loss of a water molecule when 2 amino acids are joined together by condensing the carboxylic acid group of one with the amino group of the other. Found in proteins
100
Polypeptide (Proteins)
Many amino acids linked together by peptide bonds formed by successive condensation reactions. Longer polypeptides are usually called proteins
101
Primary structure (Proteins)
The number and sequence in which amino acids are condensed together to form a polypeptide or protein
102
Prosthetic group (Proteins)
An organic non-protein molecule that is bonded to a protein to give a functional molecule
103
Quaternary structure (Proteins)
This occurs when separate polypeptide chains associate to form more complex structures as a result of further interactions between the chains using the same forces as those seen at the tertiary level
104
Second class protein (Proteins)
A protein containing only some of the 9 essential amino acids
105
Secondary structure (Proteins)
A regular, repetitive folding pattern adopted by the primary structure of a protein or nucleic acid and stabilized by co-operative hydrogen bonding between elements of the polypeptide chain peptide bonds or specific pairs of organic nitrogenous bases. Usually takes the form of an alpha-helix or beta-pleated sheet in proteins or helices in nucleic acids
106
Tertiary structure (Proteins)
The overall 3-dimensional folding pattern of a polypeptide chain incorporating secondary structures (where present) and stabilized by a variety of weak forces such as hydrogen and ionic bonds, Van der Waals forces and hydrophobic effects
107
Zwitterion (Proteins)
The state of an amino acid when the amine group is positively charged, NH3+ and the carboxyl group is negatively charged –COO-
108
Benedict's test (Carbohydrates)
A standard chemical test for the detection of a reducing sugar in a boiling solution whereby copper ions are reduced from soluble blue form to insoluble reddish-brown
109
Carbohydrate (Carbohydrates)
Any of a class of compound containing C,H and O in the ratio Cx(H2O)y
110
Cellulose (Carbohydrates)
The insoluble structural polysaccharide of glucose found in plants consisting of bundles of linear molecules which provide the chief component of most plant cell walls
111
Deoxyribose (Carbohydrates)
The pentose found in DNA
112
Disaccharide (Carbohydrates)
A molecule formed by the condensation of two monosaccharides
113
Fructose (Carbohydrates)
A common hexose found in the disaccharide sucrose
114
Galactose (Carbohydrates)
A hexose found in the disaccharide lactose
115
Glucose (Carbohydrates)
The most common hexose
116
Glycogen (Carbohydrates)
The insoluble storage polysaccharide of glucose found in animals and fungi
117
Glycosidic bond (Carbohydrates)
The type of bond formed by the loss of a water molecule when 2 monosaccharides are joined together by condensation between 2 –OH groups. Found in carbohydrates
118
Hexose (Carbohydrates)
A monosaccharide with six carbon atoms
119
Iodine solution test (Carbohydrates)
A test for starch. Turns from red-brown to blue-black in the presence of starch
120
Lactose (Carbohydrates)
The disaccharide found in milk. It contains glucose and galactose and is reducing
121
Maltose (Carbohydrates)
A dissacharide found in grains such as barley. Contains two α glucose residues and is reducing
122
Monosaccharide (Carbohydrates)
These are monomers or simple sugars with only one copy of the basic carbohydrate structural unit. They are all reducing sugars
123
Non-reducing sugar (Carbohydrates)
A sugar which cannot act as an electron donor
124
Pentose (Carbohydrates)
A monosaccharide with five carbon atoms
125
Polysaccharide (Carbohydrates)
A molecule formed by the condensation of many monosaccharides. In most biological polymers of this type the monomers are all glucose
126
Reducing sugar (Carbohydrates)
Simple sugars are reducing if they can act as electron donors in redox reactions. The usual distinguishing test is with Benedict’s reagent in which copper ions can be reduced from Cu2+ (blue) to Cu+ (red) on boiling with a reducing sugar
127
Ribose (Carbohydrates)
The pentose found in RNA
128
Ribulose (Carbohydrates)
The pentose associated with the Calvin cycle in photosynthesis
129
Sucrose (Carbohydrates)
The commonest disaccharide often referred to simply as sugar. It contains glucose and fructose and is non-reducing
130
Starch (Carbohydrates)
The insoluble storage polysaccharide of glucose found in plants consisting of linear amylose and branched amylopectin
131
Triose (Carbohydrates)
A monosaccharide with three carbon atoms
132
Cholesterol (Lipids)
A fat-soluble steroid alcohol widely distributed in animal tissues forming an important component of animal membranes and acting as the starting point for the synthesis of a range of compounds such as steroid hormones e.g. testosterone, oestrogen and progesterone
133
Emulsion test (Lipids)
A standard chemical test for the detection of a lipid in an organic solvent whereby the addition of water causes the formation of a white emulsion as the lipid is driven out of solution
134
Ester bond (Lipids)
The type of bond formed by the loss of a water molecule when an alcohol is joined to a carboxylic acid by a condensation reaction. Found in lipids and phospholipids
135
Fat (Lipids)
A lipid which is solid at room temperature
136
Fatty acid (Lipids)
A molecule consisting of a fatty hydrocarbon( i.e. containing only C and H atoms) chain terminating in a carboxylic acid group (-COOH)
137
Glycolipid (Lipids)
A lipid with carbohydrate molecule(s) attached
138
Glycerol (Lipids)
An alcohol forming a key component of triglycerides and phospholipids
139
Lipid (Lipids)
Any of a wide variety of compounds (such as triglycerides or steroids) extractable from living organisms and which are more soluble in non-polar solvents than water
140
Oil (Lipids)
A lipid which is liquid at room temperature
141
Phospholipid (Lipids)
A molecule consisting of two fatty acids, a glycerol and a phosphate all covalently bonded together by ester bonds most commonly found in membranes
142
Saturated fatty acid (Lipids)
A fatty acid with no carbon-carbon double bonds
143
Steroid (Lipids)
A lipid with 4 connected rings e.g. cholesterol
144
Triglyceride (Lipids)
A molecule consisting of three fatty acids and a glycerol held together by covalent (ester) bonds.
145
Unsaturated fatty acid (Lipids)
A fatty acid with one or more carbon-carbon double bonds
