Lecture Notes on Biological Concepts

Macromolecules and Functional Groups

• Functional Groups: Hydroxyl, carboxyl, amino, phosphate, etc.
  • Affect structure and function of biomolecule regions
• Dehydration Synthesis: Monomer - H2O + Monomer = Polymer
• Hydrolysis: Polymer + H2O = Monomer + Monomer

Carbohydrates

• Use hydroxyl functional groups (OH-)
• Monosaccharide + Monosaccharide = Disaccharide
• Starch: Linear chain of α glucose (hydroxyl all on one side)
• Cellulose: Linear chain of β glucose (hydroxyl on alternating sides)
• Glycogen: Stored in muscles

Lipids

• Non-polar (do not dissolve in H2O)
• Composed of 1 glycerol + 3 fatty acids
  • Saturated: No double bond
  • Unsaturated: 1+ double bonds, causes bending (doesn’t solidify)
• Phospholipids: 2 fatty acids + phosphate group (polar head, non-polar tail)
• Steroids: Cholesterol

Proteins

• Composed of amino acids linked by peptide bonds
  • Amino acids on left, carboxyl on right
  • Differ in properties due to differing R groups

Protein Structure

1. Primary (1st): Order of amino acids; overall shape
2. Secondary (2nd): Hydrogen bonds cause folding/coiling (helix & pleated sheet)
3. Tertiary (3rd): Reactions of amino acids & R groups; specific 3D shape

Cells

Types of Cells

• Prokaryote: Chromosomes in rings, no nucleus, bacteria
• Eukaryote: Linear chromosomes, have nucleus, organelles like lysosomes, mitochondria

Cell Membrane and Surface Area

• High surface area/volume ratio = efficient diffusion
• Folded membranes increase surface area
• Embedded proteins: hydrophilic or hydrophobic regions

Membrane and Transport

Osmosis

• Passive transport of water affecting solute concentration gradients
• Isotonic: Equal solutes inside and outside cell
• Hypertonic: Higher solute concentration outside
• Hypotonic: Higher solute concentration inside

Cell Wall

• Provides structure and permeability
• Special adaptations in organisms without cell walls for water balance

Membrane Proteins

1. Transport: Channel proteins, selective for solutes
2. Enzymes: Electron transport chain (ETC)
3. Receptor: Signal binding site
4. Glycoprotein: Cell identification

Diffusion

• Facilitated Diffusion: Uses proteins for large polar molecules
• Active Transport: Requires ATP, moves against gradient
• Co-Transport: Combines movement of ions down gradient with transport of other substances

Enzymes

• Lower activation energy
• Protein catalysts
• Substrate binds at active site
• Induced Fit: Flexibility in enzyme-substrate interaction

Photosynthesis and Cellular Respiration

Glycolysis

• Breakdown of glucose to release energy
• Occurs in cytoplasm
• Produces pyruvate, ATP, NADH

Krebs Cycle

• Extracts electrons for ETC
• Occurs in mitochondrial matrix
• Produces CO2, ATP, NADH

ETC

• Drives ATP synthesis
• Uses NADH, FADH2

Calvin Cycle

• Makes ATP using rubisco

Chloroplast Structure

• Double outer membrane, thylakoids contain pigments

Genetics

Chromosomal Inheritance

• Homologous chromosomes, diploid and haploid cells
• Mechanisms for genetic variation: Independent Assortment, Crossing Over, Segregation

Meiosis

• Meiosis I: Reduces chromosomes to haploid
• Meiosis II: Produces gametes

Genetic Disorders

• Nondisjunction leads to extra or missing chromosomes

Ratios in Genetics

• Different ratios indicate linkage or independent assortment

DNA Replication

• DNA is hereditary material
• Structure: Double helix, antiparallel
• Replication is semi-conservative

Protein Synthesis

• Transcription and translation processes
• Role of mRNA, tRNA, rRNA

Mutations

• Point mutations affect protein structure

Viruses

Retrovirus

• Use RNA, high mutation rate

Lysogenic Cycle

• Provirus dormant in host DNA

Gene Control

Prokaryotic and Eukaryotic Gene Control

• Operons, regulatory proteins

Mechanisms of Gene Regulation

• Chromatin packing, transcription factors, mRNA degradation

Developmental Patterns

• Influenced by cytoplasmic determinants and HOX genes

Genetic Changes in Cell Cycle

• Epigenetic changes, mutations affect growth
• Role of p53 gene as tumor suppressor