Cells (Form and function)
- Membranes and transport
- Lipid bilayer
- Amphipathic phospholipids
- Hydrophobic core is a barrier
- O₂, CO₂ by simple diffusion
- Osmosis
- Water to higher solute concentration
- Aquaporins speed it up
- Transport proteins
- Channels: facilitated diffusion
- Pumps: ATP, against gradient
- Selective permeability
- Fluid mosaic model
- Integral and peripheral proteins
- Glycoproteins and glycolipids outside
- Recognition and adhesion
- Membrane fluidity HL only
- Unsaturated: lower melting point
- Cholesterol modulates fluidity
- Endocytosis and exocytosis
- Gated channels and transporters HL only
- Acetylcholine and voltage gates
- Na⁺/K⁺ pump: 3 out, 2 in
- Na⁺–glucose cotransport
- Cell adhesion HL only
- CAMs bind cells
- Different CAMs, different junctions
- Lipid bilayer
- Organelles
- Organelles
- Discrete subunits, specific functions
- Not wall, cytoskeleton, cytoplasm
- Cell fractionation
- Ultracentrifuge
- Nuclei pellet first
- Compartmentalization
- Nucleus: modify mRNA first
- Concentrate enzymes and substrates
- Lysosomes, phagocytic vacuoles
- Mitochondrion and chloroplast HL only
- Cristae, small intermembrane space
- Thylakoids with photosystems
- Matrix: Krebs; stroma: Calvin
- Nucleus and ribosomes HL only
- Double membrane with pores
- Breaks into vesicles in division
- Free versus rER ribosomes
- Golgi and vesicles HL only
- Processing and secretion
- Clathrin forms vesicles
- Organelles
- Cell specialization
- Differentiation
- Zygote → unspecialized cells
- Gradients control gene expression
- Stem cells
- Divide endlessly, differentiate
- Niches: bone marrow, hair follicles
- Toti-, pluri-, multipotent
- Cell size and SA:V
- Gametes, blood cells, neurons, muscle
- Cube SA:V = 6 ÷ L
- Exchange: area; need: volume
- Increasing SA:V HL only
- Flattened erythrocytes
- PCT microvilli and invagination
- Pneumocytes HL only
- Type I: extremely thin
- Type II: lamellar bodies, surfactant
- Muscle and gametes HL only
- Cardiac: branched, one nucleus
- Striated: long, multinucleate
- Sperm and egg adaptations
- Differentiation