Molecular Biology Flashcards
Define molecular biology.
The study of living processes in terms of chemical substances.
Define anabolism.
The synthesis of complex molecules from simpler molecules, including the formation of macromolecules from monomers by condensation reactions.
Define catabolism.
The breakdown of complex molecules into simpler molecules, including the hydrolysis of macromolecules into monomers.
State the theory of vitalism.
The theory that organic compounds can only be produced in living organisms because a vital force was needed for their synthesis. Falsified by the artificial synthesis of urea.
Define solvent properties.
The ability to dissolve substances.
Define cohesion.
The force by which individual molecules stick together.
Define adhesion.
The force by which individual molecules stick to surrounding material and surfaces.
Define specific heat capacity.
The amount of energy required to increase the temperature of 1kg of a particular substance by 1°C.
Define latent heat of vapourisation.
The amount of energy required to turn a substance from a liquid to a gas.
What are thermal properties ?
Refers to a substance’s responses to change in heat energy.
Why is water known as the medium of life ?
Because most of the metabolic reactions in cells occur in water and it is used as a transport medium and a coolant.
Define monomers.
Molecules that consist of a single sub-unit.
Define monosaccharides.
Simplest carbohydrates.
Define disaccharides.
2 simple sugars joined together.
Define polysaccharides.
Many monosaccharides joined together (polymers).
Équation to form maltose.
Glucose + glucose —> maltose + water
Equation to form lactose.
Glucose + galactose —> lactose + water
Equation to form sucrose.
Glucose + fructose —> sucrose + water
Define condensation reaction.
A reaction where 2 molecules join to form a larger one and water is formed.
Define hydrolysis.
A reaction where large molecules are split into smaller molecules with the addition of water.
Define appetite.
The feeling of hunger leading to the desire to eat.
Define proteins.
Macromolecules composed of C, H, O, N and sometimes S. Used for growth and repair
Define proteome.
The entire set of proteins expressed by a cell or organism.
What is the primary structure of a protein?
The sequence and number of amino acids in a polypeptide.
What is the secondary structure of a protein ?
Regular folding or spiralling of the polypeptide.
What is the tertiary structure of a polypeptide ?
Further folding resulting in its 3D conformation, it results in the precise, compact structure that is unique to proteins.
What is the quaternary structure of a protein?
Linking together of polypeptides to form a single protein.
Define enzyme.
Globular proteins that act as catalysts, hence speeding up a reaction without being used up in the process.
Define metabolic pathways.
A series of reactions which consist of chains and cycles of enzyme-catalysed reactions.
Define substrate.
The substance that enzymes convert into product.
Define denaturation.
A structural change in the 3D conformation of a protein that results in the loss of its biological properties.
What is enzyme substrate specificity ?
The enzyme’s active site and substrate have a specific 3D shape and chemical properties which must match.
How does pH affect enzyme activity ?
Gain or loss of hydrogen ion distorts tertiary structure of enzyme by disrupting hydrogen bonds.
How does temperature affect enzyme activity?
As temp increases, K.E of particles increases, there are more chances of a substrate colliding with an enzyme with enough force to bind to it.
Define immobilised enzyme.
An enzyme that is trapped in place and unable to move by attaching it to an insoluble surface.
Define coding region.
Region of eukaryotic DNA that codes for synthesis of DNA.
Define exons.
Protein-coding genes.
Define non-coding regions.
Regions that do not code for proteins.
Define enhancers & silencers.
DNA sequences that promote expression of a gene.
DNA sequences that inhibit expression of a gene.
Define introns.
DNA sequences that are interspersed with exons and process mRNA.
Define highly repetitive sequences.
Form telomeres at the end of chromosomes which prevent loss of genes.
Define variable number tandem repeats.
Specific unique regions that show significant variation (in terms of the number of times a sequence is repeated) between individuals. Used in DNA profiling.
Define structural DNA.
Occurs around the centromere and near the ends of chromosomes to provide structural support.
What is NADP ?
An electron carrier.
What is photophosphorylation ?
Production of ATP using light energy.
Define polysomes.
Groups of 2 or more ribosomes translating the same mRNA transcript.
Define transcription factors.
Proteins that bind to specific base sequences in DNA and regulate transcription
Define cell respiration
The controlled release of energy from organic compounds to form ATP
