2.1 Molecular Biology Flashcards
What is the main role of molecular biology as a field?
Molecular biology is a field of study that focuses on investigating biological activity at a molecular level
This includes elucidating the structure and function of chemical substances and determining their interactions as parts of living processes
What are biological processes regulated by?
Biological processes are tightly regulated by enzymes, whose expression is controlled by gene activation (DNA)
What are changes in activity usually determined by?
Changes in activity are typically determined by signalling molecules (either endogenous or exogenous in origin)
What does an organic compound contain?
An organic compound is a compound that contains carbon
Where are organic compounds found? (general)
found in living things
What are 4 exceptions of compounds that contain carbon but are not organic?
Exceptions include carbides (e.g. CaC2), carbonates (CO32–), oxides of carbon (CO, CO2) and cyanides (CN–)
Why is carbon the basis of organic life?
Carbon forms the basis of organic life due to its ability to form large and complex molecules via covalent bonding
How does electronic configuration affect carbons ability to form bonds?
Carbon atoms can form four covalent bonds, with bonds between carbon atoms being particularly stable (catenation)
These properties allows carbon to form a wide variety of organic compounds that are chemically stable
What are the 4 main categories of organic compounds?
- carbohydrates
- lipids
- nucleic acids
- proteins
What are carbohydrates composed of?
composed primarily of C,H and O atoms
What general formula do carbohydrates have?
(CH2O)n
What is the principal function of carbohydrates?
Principally function as a source of energy (and as a short-term energy storage option)
What are 2 other functions of carbohydrates?
Also important as a recognition molecule (e.g. glycoproteins) and as a structural component (part of DNA / RNA)
What are lipids?
Non-polar, hydrophobic molecules which may come in a variety of forms (simple, complex or derived)
What are lipids a major component of?
Lipids serve as a major component of cell membranes (phospholipids and cholesterol)
What 2 other functions can lipids have?
They may be utilised as a long-term energy storage molecule (fats and oils)
Also may function as a signalling molecule (steroids)
What are nucleic acids?
Genetic material of all cells and determines the inherited features of an organism
What is the role of DNA?
DNA functions as a master code for protein assembly
What is the role of RNA?
RNA plays an active role in the manufacturing of proteins
What are proteins composed of?
composed of C, H, O and N atoms (some may include S)
What 2 main functions may proteins have?
Major regulatory molecules involved in catalysis (all enzymes are proteins)
May also function as structural molecules or play a role in cellular signalling (transduction pathways)
What may complex macromolecules be made up of?
Complex macromolecules may commonly be comprised of smaller, recurring subunits called monomers
WHich organic compound is not made up of repeating monomers?
Lipids do not contain recurring monomers, however certain types may be composed of distinct subunits (e.g. triglycerides)
What are carbohydrates composed of?
Carbohydrates are composed of monomers called monosaccharides (‘single sugar unit’)
What can monosaccharides join to form?
Monosaccharides are the building blocks of disaccharides (two sugar units) and polysaccharides (many sugar units)
What structures can most monosaccharides take?
Most monosaccharides form ring structures and can exist in different 3D configurations (stereoisomers)
What type of repeating monomer may lipids contain?
However several types of lipids (triglycerides, phospholipids, waxes) contain fatty acid chains as part of their overall structure
What do fatty acids look like?
Fatty acids are long chains of hydrocarbons that may or may not contain double bonds (unsaturated vs saturated)
What are proteins composed of?
Proteins are composed of monomers called amino acids, which join together to form polypeptide chains
WHat is the structure of a protein? (what does the c connect to?)
Each amino acid consists of a central carbon connected to an amine group (NH2) and an opposing carboxyl group (COOH)
What is different about each amino acid?
A variable group (denoted ‘R’) gives different amino acids different properties (e.g. may be polar or non-polar, etc.)
What are nucleic acids composed of?
Nucleic acids are composed of monomers called nucleotides, which join together to form polynucleotide chains
What does each nucleotide contain?
Each nucleotide consists of 3 components – a pentose sugar, a phosphate group and a nitrogenous base
What is metabolism?
Metabolism describes the totality of chemical processes that occur within a living organism in order to maintain life
What are the 2 key purposes of metabolic reactions?
They provide a source of energy for cellular processes (growth, reproduction, etc.)
They enable the synthesis and assimilation of new materials for use within the cell
What are anabolic reactions?
Anabolic reactions describe the set of metabolic reactions that build up complex molecules from simpler ones
What reaction is usually involved in anabolism?
The synthesis of organic molecules via anabolism typically occurs via condensation reactions
How do condensation reactions occur?
Condensation reactions occur when monomers are covalently joined and water is produced as a by-product
What linkage joins monosaccharides?
Monosaccharides are joined via glycosidic linkages to form disaccharides and polysaccharides
What linkage joins amino acids?
Amino acids are joined via peptide bonds to make polypeptide chains
What linkage joins glycerol and fatty acids?
Glycerol and fatty acids are joined via an ester linkage to create triglycerides
What are nucleotides joined together by?
Nucleotides are joined by phosphodiester bonds to form polynucleotide chains
What is the purpose of anabolism?
synthesising new molecules from simpler ones
What are the energetics of anabolism?
uses energy to construct new bonds
What mechanism does anabolism use?
typically involves reduction reactions
What are catabolic reactions?
Catabolic reactions describe the set of metabolic reactions that break complex molecules down into simpler molecules
What reaction does catabolism contain?
The breakdown of organic molecules via catabolism typically occurs via hydrolysis reactions
What does hydrolysis require?
Hydrolysis reactions require the consumption of water molecules to break the bonds within the polymer
What is the purpose of catabolism?
breaking down complex molecules into simpler ones
What are the energetics of catabolism?
releasing energy when bonds are broken
What mechanism does catabolism involve?
typically involves oxidation reactions
What is vitalism?
Vitalism was a doctrine that dictated that organic molecules could only be synthesised by living systems
What was the justification for vitalism?
It was believed that living things possessed a certain “vital force” needed to make organic molecules
According to vitalism how are non and organic compounds different?
organic compounds were thought to possess a non-physical element lacking from inorganic molecules
How was vitalism disproved?
Vitalism as a theory has since been disproven with the discovery that organic molecules can be artificially synthesised
Who disproved vitalism and how?
In 1828, Frederick Woehler heated an inorganic salt (ammonium cyanate) and produced urea
What is urea?
Urea is a waste product of nitrogen metabolism and is eliminated by the kidneys in mammals
How did the synthesis of urea disprove vitalism?
The artificial synthesis of urea demonstrates that organic molecules are not fundamentally different to inorganic molecules
