Biological Classification and Protein Structure Fundamentals

Invertebrate Classification

• Porifera: Sponges living on the seabed; reproduce sexually and asexually.
• Cnidarians: Jellyfish and corals with radial symmetry; bag-shaped bodies; reproduce sexually and asexually.
• Annelids: Earthworms requiring moisture; reproduce sexually.
• Echinoderms: Starfish with radial symmetry and bodies covered in calcareous plates.
• Mollusks: Soft-bodied organisms, often with a CaCO3 shell; reproduce sexually.
• Myriapods: Centipedes with an external chitin skeleton; breathe via gills or tracheae; reproduce sexually.

Protein Biochemistry

Proteins are organic macromolecules formed by C, O, H, N, and S. They are composed of 20 different amino acids, where the R-group determines the variation. Amino acids are linked by peptide bonds.

Functions of Peptides

• Hormones: Substances responsible for regulating bodily functions (e.g., insulin).
• Antibiotics: Substances produced by organisms to prevent bacterial reproduction (e.g., penicillin).

Levels of Protein Structure

• Primary: Amino acids form a peptide chain starting with an amino group and ending with a carboxyl group.
• Secondary: Conformations produced by hydrogen bond interactions, such as the Alpha Helix or Beta Sheet (folded zig-zag).
• Tertiary: Complex folding essential for protein function, determined by the affinity of variable groups toward water.
• Quaternary: Found in large, complex proteins consisting of multiple similar or different polypeptide chains.

Properties and Classification

Proteins can interact accurately with other molecules and may become ionized depending on the pH. Fibrous proteins are insoluble and structural, while globular proteins are generally more soluble.

• Structural: Collagen and elastin.
• Storage: Casein and gliadin.
• Contractile: Actin and myosin.
• Defensive: Antibodies.

Nucleic Acids and Genetics

Nucleic acids are polymers of nucleotides, consisting of a pentose sugar, phosphoric acid, and a nucleobase.

• DNA: Deoxyribonucleic acid (carrier of genetic information).
• RNA: Ribonucleic acid (transmitter of genetic information).

Cellular Context:

• Eukaryotic: Contain a nucleus, mitochondria, and chloroplasts.
• Prokaryotic: Genetic material located in the cytoplasm.
• Viruses: Composed of fragments of DNA or RNA.

Key Processes:

• Replication: The process of copying DNA.
• Transcription: The step of converting DNA to RNA.