General Biology: Core Concepts, Biomolecules, and Biological Organization

Information: Genetic Expression and Transmission

Genetic Information Flow

Life's processes depend on the storage, expression, and transmission of genetic information encoded in DNA and RNA.

• Central Dogma: Describes the flow of genetic information: DNA → RNA → Protein.

• Transcription: DNA sequence is copied into mRNA.

• Translation: mRNA is read by ribosomes to assemble proteins.

Equation:

$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$

Example: The gene for insulin is transcribed and translated to produce the insulin protein.

Evolution as a Unifying Principle

Structure and Function of Biomolecules

Major Classes of Biomolecules

Biomolecules are essential for life and include carbohydrates, lipids, proteins, and nucleic acids. Each class has unique structures and functions.

• Carbohydrates (CHO): Provide energy and structural support.

• Lipids (CHO): Store energy, form membranes, and act as signaling molecules.

• Proteins (CHON): Catalyze reactions, provide structure, and regulate processes.

• Nucleic Acids (CHONP): Store and transmit genetic information.

Functional Groups in Biomolecules

Functional groups are specific groups of atoms within molecules that determine their chemical properties and reactions.

• Amino (-NH2): Basic, found in proteins and nucleic acids.

• Hydroxyl (-OH): Hydrophilic, increases solubility.

• Phosphate (-PO4): Found in ATP, nucleic acids, and phospholipids.

• Methyl (-CH3): Nonpolar, biological tag.

• Carboxyl (-COOH): Acidic, found in proteins and lipids.

• Sulfhydryl (-SH): Forms disulfide bridges in proteins.

Isomers in Organic Molecules

Isomers are compounds with the same molecular formula but different structures.

• Structural Isomers: Differ in the covalent arrangement of atoms.

• Cis-trans Isomers: Differ in arrangement around a double bond.

• Enantiomers: Mirror images, differ in spatial arrangement around a central carbon.

Polymer Formation and Breakdown

Biomolecules are often polymers formed by joining monomers through dehydration synthesis and broken down by hydrolysis.

• Dehydration Synthesis: Removes water to join monomers.

• Hydrolysis: Adds water to break polymers into monomers.

Summary Table: Major Biomolecules

Biomolecule	Elements	Monomer	Function	Examples
Carbohydrates	C, H, O	Monosaccharide	Energy, structure	Glucose, starch, cellulose
Lipids	C, H, O	Fatty acid, glycerol	Energy storage, membranes	Fats, oils, phospholipids
Proteins	C, H, O, N	Amino acid	Catalysis, structure, regulation	Enzymes, hemoglobin
Nucleic Acids	C, H, O, N, P	Nucleotide	Genetic information	DNA, RNA

Protein Structure and Function

Levels of Protein Structure

Proteins have four levels of structure that determine their function.

• Primary: Sequence of amino acids.

• Secondary: Folding into α-helices and β-sheets.

• Tertiary: 3D shape due to interactions among R groups.

• Quaternary: Multiple polypeptides joined together.

Denaturation: Loss of protein structure due to environmental changes.

Genomics

Study of All Genes in an Organism

Genomics involves analyzing the complete set of genes in an organism, providing insights into evolution, conservation, and species diversity.

• Allows comparison of gene sets across species.

• Helps understand adaptation and evolutionary relationships.

Additional info: Some explanations and examples were expanded for clarity and completeness based on standard biology curriculum.