2.1 Syllabus
U1. Molecular biology explains living processes in terms of the chemical substances involved
-Many molecules r important in living organisms including water simply, but most varied and complex molecules are nucleic acids and proteins.
→ Nucleic acids comprise DNA and RNA (are chemicals used to make genes)
→ Proteins astonishingly varied in structure and carry out huge range of tasks within the cell including controlling chemical reactions of cell by acting as enzymes.
-Molecular biology is a field of study that focuses on investigating biological activity at a molecular level
-Biological processes are tightly regulated by enzymes, whose expression is controlled by gene activation (DNA)
→ Nucleic acids comprise DNA and RNA (are chemicals used to make genes)
→ Proteins astonishingly varied in structure and carry out huge range of tasks within the cell including controlling chemical reactions of cell by acting as enzymes.
-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
-Biological processes are tightly regulated by enzymes, whose expression is controlled by gene activation (DNA)
- Changes in activity are typically determined by signaling molecules (either endogenous or exogenous in origin)
U2. Carbon atoms can form four covalent bonds allowing a diversity of stable compounds to exist
Organic Compounds
An organic compound is a compound that contains carbon and is found in living things
Carbon – 15th most abundant element on Earth (can be used to make huge range
-Carbon forms the basis of organic life due to its ability to form large and complex molecules via covalent bonding
-Carbon atoms can form four covalent bonds (strongest types of bond between atoms so table molecules based on carbon can be produced), with bonds between carbon atoms being particularly stable (catenation). It’s formed when 2 adjacent atoms share pair of electrons with one electron contributed by each atom.
An organic compound is a compound that contains carbon and is found in living things
- Exceptions include carbides (e.g. CaC2), carbonates (CO32–), oxides of carbon (CO, CO2) and cyanides (CN–)
Carbon – 15th most abundant element on Earth (can be used to make huge range
-Carbon forms the basis of organic life due to its ability to form large and complex molecules via covalent bonding
-Carbon atoms can form four covalent bonds (strongest types of bond between atoms so table molecules based on carbon can be produced), with bonds between carbon atoms being particularly stable (catenation). It’s formed when 2 adjacent atoms share pair of electrons with one electron contributed by each atom.
- These properties allow carbon to form a wide variety of organic compounds that are chemically stable
U3. Life is based on carbon compounds including carbohydrates, lipids proteins and nucleic acids
Main Classes of Carbon Compounds
There are four principle groups of organic compounds that contribute to much of the structure and function of a cell
1. Carbohydrates
There are four principle groups of organic compounds that contribute to much of the structure and function of a cell
1. Carbohydrates
- Most abundant organic compound found in nature, composed primarily of C,H and O atoms in a common ratio – (CH2O)n
- Principally function as a source of energy (and as a short-term energy storage option)
- Non-polar, hydrophobic molecules which may come in a variety of forms (simple, complex or derived)
- Lipids serve as a major component of cell membranes (phospholipids and cholesterol)
- Genetic material of all cells and determines the inherited features of an organism
- DNA functions as a master code for protein assembly, while RNA plays an active role in the manufacturing of proteins
- Make over 50% of the dry weight of cells; are composed of C, H, O and N atoms (some may include S)
- Major regulatory molecules involved in catalysis (all enzymes are proteins)
U4. Metabolism is the web of all the enzyme-catalyzed reactions in a cell or organism
-All living organisms carry out large numbers of different chemical reactions and these reactions are catalyzed
→Happen in cytoplasm of cells but some are extracellular such as reactions used to digest food in small intestine.
= Metabolism: sum of all reactions that occur in an organism
-Metabolism describes the totality of chemical processes that occur within a living organism in order to maintain life and consists of pathways by which 1 type of molecule is transformed into another, in a series of small steps.
Metabolic reactions serve two key functions:
→Happen in cytoplasm of cells but some are extracellular such as reactions used to digest food in small intestine.
= Metabolism: sum of all reactions that occur in an organism
-Metabolism describes the totality of chemical processes that occur within a living organism in order to maintain life and consists of pathways by which 1 type of molecule is transformed into another, in a series of small steps.
- It is the web of all enzyme-catalyzed reactions that occur within a cell or organism
Metabolic reactions serve two key functions:
- 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
U5. Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions
-Anabolic reactions describe the set of metabolic reactions that build up complex molecules from simpler ones. Anabolic steroids are hormones that promote body building.
→Requires energy, usually supplied in form of ATP
-The synthesis of organic molecules via anabolism typically occurs via condensation reactions
Condensation reactions occur when monomers are covalently joined and water is produced as a by-product
Example:
→Requires energy, usually supplied in form of ATP
-The synthesis of organic molecules via anabolism typically occurs via condensation reactions
Condensation reactions occur when monomers are covalently joined and water is produced as a by-product
Example:
- DNA synthesis during replication
- Photosynthesis, including production of glucose from CO2 and H2O
- Synthesis of complex carbohydrates including starch, cellulose and glycogen
U6. Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers
-Catabolic reactions describe the set of metabolic reactions that break complex molecules down into simpler molecules. It releases energy and in some cases this energy is captured in the form of ATP, which can then be used in the cell.
-The breakdown of organic molecules via catabolism typically occurs via hydrolysis reactions
-Hydrolysis reactions require the consumption of water molecules to break the bonds within the polymer
Example:
-The breakdown of organic molecules via catabolism typically occurs via hydrolysis reactions
-Hydrolysis reactions require the consumption of water molecules to break the bonds within the polymer
Example:
- Digestion of food in the mouth, stomach and small intestine
- Cell respiration in which glucose or lipids are oxidized to CO2 and water
A1. Urea as an example of a compound that is produced by living organisms but can also be artificially synthesized
-Urea= nitrogen containing compound with a relatively simple molecule structure. It’s a component of urine. Produced when there is an excess of amino acids in the body as means of excreting N from the amino acids.
→ Cycle of reactions, catalyzed by enzyme, used to produce it and happens in the liver. Urea then transported by blood stream to kidneys where it’s filtered out and passes out of body in urine
-Vitalism was a theory that dictated that organic molecules could only be synthesized by living systems
→ Cycle of reactions, catalyzed by enzyme, used to produce it and happens in the liver. Urea then transported by blood stream to kidneys where it’s filtered out and passes out of body in urine
-Vitalism was a theory that dictated that organic molecules could only be synthesized by living systems
- It was believed that living things possessed a certain “vital force” needed to make organic molecules
- Hence organic compounds were thought to possess a non-physical element lacking from inorganic molecules
S1. Drawing molecular diagrams of glucose, ribose, a saturated fatty acid and a generalized amino acid
1. Carbohydrates: are composed of monomers called monosaccharides ('single sugar unit')
2. Lipids: Fatty acids are long chains of hydrocarbons that may or may not contain double bonds (unsaturated vs saturated)
3. Proteins:
- Each amino acid consists of a central carbon connected to an amine group (NH2) and an opposing carboxyl group (COOH
- A variable group (denoted ‘R’) gives different amino acids different properties (e.g. may be polar or non-polar, etc.)
4. Nucleic Acids
- Nucleic acids are composed of monomers called nucleotides, which join together to form polynucleotide chains
- Each nucleotide consists of 3 components – a pentose sugar, a phosphate group and a nitrogenous base
- The type of sugar and composition of bases differs between DNA and RNA
