Key Words - Biological Molecules Flashcards
Activation energy
Energy required to bring about a reaction.
Active site
A group of amino acids that makes up the region of an enzyme into which the substrate fits to catalyse a reaction.
Alpha Glucose
An isomer of glucose that can bond together to form starch or glycogen.
Amine group
The -NH2 group of an amino acid
Amino Acid
A monomer which makes up proteins. Has a central carbon atom which is bonded to: a carboxylic acid group, an amino group and a R group.
Amino acid
A monomer which makes up proteins. Has a central carbon atom which is bonded to a: carboxylic acid group, an amino group, a hydrogen atom and a R group.
Benedict’s reagent
Blue solution, which is used to test for reducing or non reducing sugars.
Beta Glucose
An isomer of glucose that can bond together to form cellulose.
Biuret test
A simple biochemical reaction to detect the presence of protein, if the Biuret’s Solution turns purple bum protein is present.
Carboxyl group
The -COOH group of an amino acid.
Cellulose
A polysaccharide made up of beta-glucose found in plant cells. (beta 1,4-glycosidic bonds).
Competitive inhibitor
A form of inhibitor which binds to the active site of the enzyme preventing the binding of substrate.
Complimentary
Describes the relationship between the active site of an enzyme and the substrate molecule - the way in which the fit together.
Condensation Reaction
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.
Covalent Bond
Type of chemical bond in which two atoms share a pair of electrons.
Disaccharide
Made up of two sugar units that are formed by a condensation reaction. Monosaccharides are joined by a glycosidic bond.
Disulphide bridge
Bond formed between sulphur atoms in R groups of amino acids.
Emulsion test
Test for lipids. Mix your sample with ethanol and then add water. If a white cloudy emulsion forms, then a lipid is present.
Enzyme
A protein that acts as a catalyst and so lowers the activation energy needed for a reaction.
Enzyme-substrate (ES) complex
The intermediate formed when a substrate molecule interacts with the active site if an enzyme.
Glucose
C6H12O6 - a single sugar which is used in respiration.
Glycerol
A molecule which combines with three fatty acids to form triglycerides. It is a carbon chain with 3 hydroxyl groups.
Glycogen
A highly branched polysaccharide made up of alpha glucose found in animal cells (alpha-1,4 and alpha-1,6 glycosidic bond).
Glycosidic bond
Bond between sugar molecules in disaccharides and polysaccharides.
Hexose sugar
A sugar made up of 6 carbons.
Hydrogen bond
Chemical bond formed between the positive charge on a hydrogen atom and the negative charge on another atom of an adjacent molecule. Often between a negative oxygen and positive hydrogen atoms.
Hydrolysis
The breaking down of large molecules into smaller ones by the addition of water molecules.
Hydrophilic
Section of a molecule which is attracted to water.
Hydrophobic
Section of a molecule which is repulsed by water.
Induced fit model
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 to allow an enzyme-substrate complex to be formed.
Inhibitor
A substance which reduces the activity of an enzyme.
Ionic bond
A bond between the positive ion which has lost an electron(s) and a negative ion which has gained an electron(s).
Isomer
Two or more compounds with the same formula but a different arrangement of atoms in the molecule and therefore different properties.
Kinetic energy
The energy of motion, observable as the movement of an object, particle or set of particles.
Lipid
A class of organic compounds that are fatty acids in their deriatives and are insoluble in water but soluble in organic solvents. They include triglycerides, phospholipids, waxes and steroids.
Lock and key model
An analogy for how enzymes work - only the correctly sized key fits into the keyhole (active site) of the lock (enzymes).
Metabolism
All of the chemical processes that take place in living organisms.
Mono-unsaturated fatty acid
Fatty acid which possesses a carbon chain with a single double bond between carbon atoms.
Monomer
One of many small molecules that combine together to form a polymer.
Monosaccharide
A single sugar e.g. glucose. The monomers of long chain carbohydrate polymers.
Non reducing sugar
A sugar which cannot serve as a reducing agent. An example is sucrose.
Non reducing sugar test
Following a negative reducing sugars test. Heat the solution with HCl to hydrolyse the non-reducing sugar into its monosaccharides. Then perform the Benedix test again. If you get a positive result, after hydrolysis, then a non reducing sugar is present.
Non-competitive inhibitor
A form of inhibitor which does not bind at the active site of the enzyme which prevents the binding of substrate.
Non-reducing sugar
A sugar which cannot serve as a reducing agent. An example is sucrose.
Nucleotide
A compound consisting of an organic base and ribose sugar linked to a phosphate group. Nucleotides form monomers of nucleic acids such as DNA.
Organic Molecule
Molecules containing carbon that can be found in living things; four classes are carbohydrates, proteins, lipids and nucleic acids - such as DNA.
Peptide Bond
The type of bond that is formed between two amino acids.
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+].
Phospholipid
Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule. Phospholipids are important in the structure and function of plasma membranes.
Polysaccharide
Made of many sugar units which are formed by a condensation reaction. Monosaccharides are joined by a glycosidic bond.
Polyunsaturated fatty acid
Fatty acid which possesses a carbon chain with many double bonds between carbon atoms.
Primary protein structure.
The sequence of amino acids that makes up the polypeptides of a protein.
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.
Quaternary structure
A number of polypeptide chains linked together, and sometimes associated with non-protein groups to form a protein.
R-group
Each of the 20 amino acids has a different R group - determines the bonding that the body can carry out.
Rate of reaction
The speed of a chemical reaction - can be worked out by looking at the decrease in concentration of a reaction over time or increase in concentration of a product over time.
Reducing sugar
A sugar that serves as a reducing agent. All monosaccharides are reducing sugars along with some disaccharides.
Reducing sugar
A sugar that serves as a reducing agent. All monosaccharides are reducing sugars along with some disaccharides.
Reducing sugar test
Heat solution with Benedict’s reagent to test for reducing sugars. If it goes brick red, then the reducing sugar is present.
Saturated fatty acid
A fatty acid in which there are no double bonds between the carbon atoms.
Secondary protein structure
The way in which the chain of amino acids of the polypeptides determine if a protein is folded.
Specific
Describes how each enzyme only catalyses a certain chemical reaction.
Polypeptide
Many amino acids joined together by peptide bonds.
Starch
A polysaccharide found in plant cells made up of alpha glucose - comprised of amylose (alpha-1,4 glycosidic bonds) and amylopectin (alpha-1,4 and alpha-1,6 glycosidic bonds).
Substrate
A substance that is acted on or used by another substance or process. Fits into the active site of an enzyme.
Tertiary protein structure
The folding of a whole polypeptide chain in a precise way, as determined by the amino acids of which is composed.
Triglyceride
An individual lipid molecule made up of a glycerol molecule and three fatty acids. It contains ester bonds.
Anticodon
A sequence of three adjacent nucleotides on a molecule of transfer RNA that is complementary to a particular codon on a messenger RNA molecule.
ADP
A nucleotide which combines in a condensation reaction, catalysed by ATP synthase, with a phosphate molecule to form ATP.
ATP (adenosine triphosphate)
Nucleotide found in all living organisms, which is produced during respiration and is important in the transfer of energy.
Clone
A group of genetically identical organisms formed from a single parent as a result of asexual reproduction or by artificial means.
Codon
A sequence of three adjacent nucleotides in mRNA that codes for one amino acid.
Complimentary base pairing
Specific rules for how the bases pair together. Adenine pairs with thymine with two hydrogen bonds, guanine binds with cytosine with three hydrogen bonds.
Conjugation
The transfer of DNA from one cell to another by means of a thin tube between the two.
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 anti, parallel 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 and cytosine.
DNA Helicase
And 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.
DNA polymerase
Enzyme that joins DNA nucleotides together in a condensation reaction, (forming phosphodiester bonds) during DNA replication.
Double helix
Structure of DNA made up of two strands of nucleotides running in opposite directions.
Genotype
The genetic composition of an organism.
Gene
A section of DNA on a chromosome coding for one or more polypeptide.
Condensation
A chemical process, in which two molecules combine to form a more complex one with the elimination of a simple substance, usually water.
Complimentary DNA
DNA that was made from messenger RNA in a process that is the reverse of normal transcription.
Enzyme
A protein or a RNA that acts as a catalyst, and so alters the speed of a biochemical reaction.
Hydrogen bond
Chemical bond formed between the positive charge on a hydrogen atom and the negative charge on another atom of an adjacent molecule.
Hydrolysis
The breaking down of large molecules into smaller ones by the addition of water molecules
Mitosis
The type of nuclear division in which the daughter cells have the same number of chromosomes as the parent cell.
Mutagen.
Any agent that induces a mutation.
Mutation
A sudden change in the amount or arrangement of the genetic material on the cell.
Nucleotides
Complex chemical is made up of an organic base, a cigar, and a phosphate. They are the basic units of which the nucleic acids DNA and RNA are made.
Organic base
Part of a nucleotide - either adenine, thymine, cytosine, guanine or uracil.
Pentose
A sugar that possesses five carbon atoms
Peptide bond
The chemical bond formed between two amino acids during condensation
Phenotype
The characteristics of an organism, often visible, resulting from both its genotype, and the effects of the environment.
Phosphodiester bond
The bond formed by condensation reaction between phosphate group of one nucleotide and the pentose sugar of another nucleotide.
Polynucleotide
A polymer of monomers called nucleotides
Primary structure of a protein
The sequence of amino acids that makes up the polypeptide of a protein.
Quaternary structure of a protein
A number of polypeptide chains linked together, and sometimes associated with non-protein groups to form a protein.
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, rRNA.
Secondary structure of a protein
The way in which the chain of amino acids of the polypeptides of a protein are folded. Can be either: beta pleated or alpha helix
Semi-conservative replication
The means by which DNA makes exact copies of itself by unwinding the double helix so that each chain acts as a template for the next.
Tertiary structure of a protein
The folding of a whole polypeptide chain in a precise way, as determined by the amino acids of which it is composed.
Transcription
The formation of messenger RNA molecules from the DNA that makes up a particular gene.
