3.1: Biological Molecules Keywords Flashcards
(92 cards)
1
Q
Covalent Bond
A
Type of chemical bond in which two atoms share a pair of electrons
2
Q
Ionic Bond
A
A bond between a positive ion which has lost an electron(s) and a negative ion which has gained an electron(s)
3
Q
Hydrogen Bond
A
Chemical bond formed between the positive charge on a hydrogen atom
4
Q
Polar molecule
A
A molecule which has a partially positive charge in one part of the molecule and completely negative charge in another part (a dipole)
5
Q
Monomer
A
One of many small molecules that combine together to form a polymer
6
Q
Polymer
A
Large molecules made up of many repeating smaller molecules (monomers)
7
Q
Polymerisation
A
The process of making a polymer
8
Q
Condensation
A
- Chemical process in which two molecules combine to form a more complex one with the elimination of a simple substance, usually water
- Many biological polymers (e.g. polysaccharides, polypeptides) are formed by condensation
9
Q
Hydrolysis
A
The breaking down of large molecules into smaller ones by the addition of water molecules
10
Q
Metabolism
A
All the chemical processes that take place in living organisms
11
Q
Mole
A
The mass of a substance containing the same number of fundamental units as there are atoms in exactly 12g of 12C
12
Q
Molar (M) Solution
A
An aqueous solution that contains 1 mole of solute in 1 litre of solution
13
Q
Carbohydrate
A
- Compounds made from carbon, hydrogen and oxygen
- Either monosaccharides, disaccharides and polysaccharides
14
Q
Monosaccharide
A
A single sugar e.g. glucose
15
Q
Organic Molecule
A
- Molecules containing carbon that can be found in living things
- Four classes are carbohydrates, proteins (chain of amino acids), lipids and nucleic acids
16
Q
Disaccharide
A
- Made up of two sugar units that are formed by a condensation reaction
- Monosaccharides are joined by a glycosidic bond
17
Q
Polysaccharide
A
- Made of many sugar units that are formed by a condensation reaction
- Monosaccharides are joined by a glycosidic bond
18
Q
Hexose sugar
A
A sugar made up of 6 carbons
19
Q
Glucose
A
- C6H12O6
- A single sugar which is used in respiration
20
Q
Reducing sugar
A
- A sugar that serves as a reducing agent
- All monosaccharides are reducing sugars along with some disaccharides
21
Q
Reducing sugar’s test
A
- Heat solution with Benedict’s reagent
- Brick red = present
22
Q
Benedict’s reagent
A
Blue solution which is used to test for reducing and non-reducing sugars
23
Q
Glycosidic bond
A
Bond between sugar molecules in disaccharides and polysaccharides
24
Q
Non-reducing sugar
A
- A sugar which cannot serve as a reducing agent
- An example is sucrose
25
Non-reducing sugar's test
- Following a negative reducing sugars test, heat solution with HCl to hydrolyse the non-reducing sugars into its monosaccharides
- Perform the Benedict's test again and if positive result then present
26
Starch
A polysaccharide found in plant cells made up of alpha-glucose - comprised of amylose (alpha-1,4 glycosidic bonds) and amylopectic (alpha-1,4 and alpha-1,6 glycosidic bonds)
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Glycogen
A highly branched polysaccharide made up of alpha-glucose found in animal cells (alpha-1,4 and alpha-1,6 glycosidic bonds)
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Cellulose
A polysaccharide made up of beta-glucose found in plant cells (beta-1,4 glycosidic bonds)
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Alpha glucose
An isomer of glucose that can bond together to form starch or glycogen
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Beta glucose
An isomer of glucose that can bond together to form cellulose
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Lipid
- A class of organic compounds with fatty acids as their derivatives and are insoluble in water but soluble in organic solvents
- Include triglycerides, phospholipids, waxes and steroids
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Triglyceride
- An individual lipid molecule made up of a glycerol molecule and three fatty acids
- Contains ester bonds
33
Fatty acid
A carboxylic acid with a hydrocarbon tail
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Glycerol
- A molecule which combines with three fatty acids to form triglycerides
- It's a 3 carbon chain with 3 hydroxyl groups
35
Saturated fatty acid
A fatty acid in which there are no double bonds between carbon atoms
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Mono-unsaturated fatty acid
A fatty acid which possesses a carbon chain with a single double bond between carbon atoms
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Poly-unsaturated fatty acid
A fatty acid which possesses a carbon chain with many double bonds between carbon atoms
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Phospholipid
- Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule
- Important in structure and functioning of plasma membranes
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Hydrophilic
Section of a molecule which is attracted to water
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Hydrophobic
Section of a molecule which is repulsed by water
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Emulsion test
- Test for lipids
- Mix sample with ethanol and add water
- If a white cloudy emulsion forms, then a lipid is present
42
Protein
- A polymer which is made up of amino acids linked by peptide bonds
- May also contain prosthetic groups as part of its quaternary structure
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Amino acid
- A monomer which makes up proteins
| - Has a central carbon atom which is bonded to a carboxylic group, an amine group, a hydrogen atom and a R group
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Amino group
The -NH2 group of an amino acid
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Carboxyl group
The -COOH group of an amino acid
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R-group
Each of the 20 amino acids have a different R group - determines the bonding that the amino acid can carry out
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Peptide bond
The type of bond that is formed between two amino acids
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Polypeptide
Many amino acids joined together by peptide bonds
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Primary protein structure
The sequence of amino acids that makes up the polypeptides of a protein
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Secondary protein structure
The way in which the chain of amino acids of polypeptides of a protein are folded
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Tertiary protein structure
The folding of a whole polypeptide chain in a precise way, as determined by the amino acids of which it's composed
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Disulfide bridge
Bond formed between Sulphur atoms in R groups of amino acids
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Quaternary protein structure
A number of polypeptide chains linked together, and sometimes associated with non-protein groups to form a protein
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Biuret test
A simple biochemical reaction to detect presence of protein, if Biuret's solution turns purple then protein is present
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Enzyme
A protein that acts as a catalyst and so lowers the activation energy needed for a reaction
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Activation energy
Energy required to bring about a reaction
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Active site
A group of amino acids that makes up the region of an enzyme into which the substrate fits in order to catalyse a reaction
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Substrate
- A substance that is acted on or used by another substance or process
- Fits into the active site of an enzyme
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Enzyme-substrate complex
The intermediate formed when a substrate molecule interacts with the active site of an enzyme
60
Complimentary
Describes the relationship between the active site of an enzyme and the substrate molecule - the way in which they fit together
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Specific
Describes how enzymes catalyse a certain chemical reaction
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Induced Fit
- A mechanism of interaction between an enzyme and a substrate
- As the substrate fits into the active site, the active site of the enzyme changes shape in order to allow an enzyme-substrate complex to be formed
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Lock and Key
An analogy for how enzymes work - only the correctly sized key (substrate) fits into the keyhole (active site) of the lock (enzyme)
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Rate of reaction
The speed of a chemical reaction - can be worked out by looking at the decrease in concentration of a reactant over time or increase in concentration of a product over time
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Kinetic energy
The energy of motion, observable as the movement of an object, particle or set of particles
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pH
- A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acidic and higher values are more alkaline.
- Equivalent to -log10[H+].
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Inhibitor
A substance which reduces the activity of an enzyme
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Competitive Inhibitor
A form of inhibitor which binds to the active site of the enzyme, preventing the binding of substrate
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Non-competitive inhibitor
A form of inhibitor which does not bind at the active site of the enzyme and prevents the binding of substrate
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DNA
- Deoxyribonucleic acid which is present in nearly all living organisms as the carrier of genetic information
- A double helix made up of two polynucleotide chains, running antiparallel to each other, with the sugar-phosphate backbone on the outside and organic bases bonded together by Hydrogen bonds in the centre of the helix
- The nucleotides have a deoxyribose sugar and the bases adenine, thymine, guanine or cytosine
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Nucleotide
- Complex chemicals made up of an organic base, a sugar and a phosphate
- They are the basic units of which the nucleic acids DNA and RNA are made
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Polynucleotide
A polymer of monomers called nucleotides
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Phosphodiester bond
The bond formed by a condensation reaction between the phosphate group of one nucleotide and the pentose sugar of another nucleotide
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Organic base
Part of a nucleotide - either adenine, thymine, cytosine, guanine or uracil
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RNA
- A polynucleotide which contains nucleotides that have the pentose sugar ribose rather than deoxyribose and contains the bases adenine, uracil, guanine or cytosine
- Can be either mRNA, tRNA or rRNA.
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Complimentary base pairing
- Specific rules for how the bases pair together
- Adenine pairs with thymine with 2 hydrogen bonds
- Guanine binds with cytosine with 3 hydrogen bonds.
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Double helix
Structure of DNA made up of 2 strands of nucleotides running in opposite directions
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Semi-conservative replication
The process in which the double helix of a DNA molecule unwinds and each strand acts as a template on which a new strand is constructed
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DNA helicase
Enzyme that acts on a specific region of the DNA molecule to break the hydrogen bonds between the bases causing the two strands to separate and expose the nucleotide bases in that region
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DNA polymerase
Enzyme that joins DNA nucleotides together in a condensation reaction (forming phosphodiester bonds) during DNA replication
81
ATP (Adenosine triphosphate)
- An activated nucleotide found in all living organisms, which is produced during respiration and acts as an energy carrier
- The hydrolysis of ATP (catalyzed by ATP hydrolase) leads to the formation of adenosine diphosphate (ADP) and inorganic phosphate, with the release of energy
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ADP
A nucleotide which combines in a condensation reaction, catalysed by ATP synthase, with a phosphate molecule to form ATP
83
ATP Synthase
An enzyme which catalyses the formation of ATP.
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ATP Hydrolase
An enzyme which catalyses the hydrolysis of ATP
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Polymerases
Group of enzymes that catalyse the formation of polymers from monomers
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Specific heat capacity
The amount of energy needed to change the temperature of 1kg of the substance by 1℃
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Latent heat of Vaporisation
The heat energy needed to change the substance from a liquid at its boiling point into gas at the same temperature
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Cohesion
- Attraction between molecules of the same type
| - It is important in the movement of water up a plant
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Surface tension
The tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid
90
Solvent
The liquid in which a solute is dissolved to form a solution
91
Inorganic ions
Formed when an element or compound, that does not contain carbon, gains or looses electrons to become negatively or positively charged, for example: hydrogen ions, phosphate ions, iron ions and sodium ions
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Transparent
A material that allows light to pass through so that objects behind can be distinctly seen
