TOPIC 2 - MOLECULAR BIOLOGY Flashcards
What is molecular biology?
Molecular biology explains these biological processes in terms of the chemical substances (molecules) involved
What is metabolism? (2)
Metabolism describes the totality of chemical processes that occur within a living organism in order to maintain life • It is the web of all enzyme–catalysed reactions that occur within a particular cell or organism
What are organic compounds? (2)
Organic compounds are molecules that contain carbon and are found in living things
• Exceptions include carbonates and oxides of carbon
What are carbon atoms? (2)
Carbon atoms form the basis of organic life due to their capacity to form four covalent bonds
• This allows a diversity of stable compounds to exist
What are the 4 main groups of organic compounds in cells:
- Carbohydrates
- Lipids
- Nucleic Acids
- Proteins
Definition of Anabolism: (3)
- The synthesis of complex molecules from simpler ones
- Involves condensation reactions (water is produced)
- An example of an anabolic reaction is photosynthesis
Definition of catabolism: (3)
- The break down of complex molecules into simpler ones
- Involves hydrolysis reactions (water is consumed)
- An example of a catabolic reaction is cellular respiratio
What is the, monomer and polymer of carbohydrates?
Monomer: monosaccharide
Polymer: polysaccharide
What is the, monomer and polymer of proteins?
Monomer: Amino Acid
Polymer: Polypeptide
What is the, monomer and polymer of lipids?
Lipids are not composed of repeating monomers, but may contain smaller subunits (e.g. triglycerides).
What is the, monomer and polymer of nucleic acids?
Monomer: Nucleotide
Polymer: DNA/RNA
What is the theory of vitalism? (2)
Vitalism was a doctrine that dictated that organic molecules could only be synthesized by living systems
• Living organisms were thought to possess a “vital force” that was required to manufacture organic compounds.
Falsification of vitalism? (2)
In 1828, Frederick Woehler disproved the theory of vitalism by artificially synthesizing an organic molecule
• He heated an inorganic salt (ammonium cyanate) under laboratory conditions to produce urea (organic)
Structure of water: (2)
Water is made up of two hydrogen atoms covalently bonded to an oxygen atom (molecular formula: H2O)
Oxygen has a higher electronegativity and attracts the shared electrons more strongly, resulting in polarity
Why does hydrogen bonding occur in water? (2)
The dipolarity of the water molecule enables it to form polar associations with other charged molecules (polar or ionic)
Water molecules can also form hydrogen bonds with other water molecules (between an δ+ hydrogen and an δ– oxygen)
What are the 3 main properties of water?
Thermal properties
Cohesive properties
Solvent properties
Cohesive properties in water: (3)
Water can form intermolecular associations with other molecules that share common properties (e.g. polarity)
• Water can form hydrogen bonds with other water molecules (cohesion: like molecules stick together)
• Water can form polar associations with charged molecules (adhesion: unlike molecules stick together)
What does cohesive properties in water result to?
The cohesive properties of water results in a relatively high surface tension (can resist low level external forces)
What does adhesive properties in water result to?
The cohesive properties of water results in a relatively high surface tension (can resist low level external forces)
Solvent properties in water: (2)
Water is commonly referred to as the universal solvent due to its capacity to dissolve a large number of substances (ionic / polar)
• Largequantitiesofwatermoleculescansufficientlyweaken
forces (e.g. ionic bonds) and form dispersive hydration shells
What does solvent properties in water result to?
These solvent properties make water an important medium for metabolic reactions, as well as a necessary transport medium
Thermal properties in water: (6)
Water has the capacity to absorb large amounts of heat energy before undergoing a resultant change in state
• Extensivehydrogenbondingmustfirstbebroken
Water therefore has a very high specific heat capacity
• Energy required to raise temperature of 1g by 1oC
These properties make water a very effective coolant
• Evaporation of sweat requires absorption of heat
Water vs Methane: (2)
- Water and methane differ in thermal properties despite having similar structures (comparable weight, size, valence structure)
- The differences are due to the polarity of water and its capacity to form intermolecular hydrogen bonds
Is methane polar or non polar?
Non polar
