IB Biology - 2.1 Molecules to Metabolism

Molecular biology

Molecular biology

explains living processes in terms of the chemical substances

organic compounds

Compounds that contain carbon

Exceptions to organic compounds

carbides, carbonates, oxides of carbon and cyanides (ARE NOT ORGANIC COMPOUNDS)

How many covalent bonds can carbon atoms form?

four

Main classes of carbon compounds

carbohydrates, lipids, nucleic acids, proteins

Carbohydrates

carbon, hydrogen, oxygen 1:2:1 ratio (CH2O)n Most abundant organic compound found in nature, a source of energy, a recognition molecule (glycoprotein), a structural component of DNA

Lipids

Non-polar, hydrophobic molecules, major component of cell membranes, may be utilized as a long-term energy storage molecule, function as a signaling molecule (steroids); (triglycerides, phospholipids and steroids are lipids)

Nucleic acids

genetic material of all cells, determines the inherited features, DNA functions as a master code for protein assembly, RNA is involved in the manufacturing of proteins

Proteins

major regulatory molecules involved in catalysis (enzymes are proteins), functions as structural molecules, plays a role in cellular signaling; part of polypeptide

Monomers

(subunits) building blocks of polymers

Lipid monomers

fatty acids, mono-glycerides

Carbohydrate monomers

monosaccharides

Protein monomers

amino acids

Pentose

A five-carbon monosaccharide (ribose)

Anabolism

synthesis of complex molecules from simpler molecules (formation of macromolecules from monomers) by a condensation reaction

Condensation reaction

a chemical reaction in which two or more molecules combine to produce water

Macromolecules

large molecules

Catabolism

breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules

carboxyl group

COOH

amine group

NH2

variable group of an amino acid

R

dipeptide

Two amino acids

folding of the polypeptide chain

depends on the order of amino acids in a sequence

single nucleotide

base (ATGC), pentose sugar, phosphate group

polynucleotide chain

bond between pentose sugar and phosphate group

DNA formation

two complementary chains paired by hydrogen bonding between nitrogenous bases to form double strands

Vitalism

organic molecules can only be synthesized by living things

Living things (vitalism)

possessed a "vital force" needed to make organic molecules

How was vitalism disproved?

In 1828, Friedrich Wöhler successfully synthesized urea from cyanic acid and ammonia

What did Wohler's experiment state

organic molecules are not fundamentally different to inorganic molecules

metabolism

web of all enzyme-catalyzed reactions that occur within a cell or organism

functions of metabolic reactions

provide a source of energy for cellular processes (growth, reproduction, etc.), enable the synthesis and assimilation of new materials for use within the cell

When do condensation reactions occur?

when monomers are covalently joined and water is produced as a by-product

types of linkages/bonds

glycosidic, ester, peptide, phosphodiester

Examples of anabolism

Protein synthesis, DNA synthesis, Photosynthesis

examples of catabolism

Digestion, cell respiration, glycolysis

Glucose

C6H12O6 (monosaccharide)

ribose

A five-carbon sugar present in RNA

saturated fatty acid

sugar

carbon-based compounds with hydrogen