Cells Unit Cont’d

1. Cells Unit Cont’d Proks,Euks, Cell Membrane S&F, Cell Transport, Cell Cycle

2. Prokaryotic vs. Eukaryotic Cells Characteristics • Prokaryotes Eukaryote • Size of cell • 0.2-2.0 m m in diameter 10-100 m m in diameter • Nucleus • None True nucleus • Membrane-enclosed organelles • Absent Present; examples include • lysosomes, Golgi complex, • endoplasmic reticulum, • mitochondria & chloroplasts • Flagella • Consist of two protein building Complex; consist of multiple blocks microtubules • Cell wall • Often present; chemically complex When present, chemically simple • Plasma membrane • No carbohydrates and Sterols and carbohydrates that generally lacks sterols serve as receptors present

3. Proks. Vs. Euks. Cont’d • Cytoplasm • No cytosketeton or Cytoskeleton; cytoplasmic cytoplasmic streaming streaming • Ribosomes • Smaller size (70S) Larger size (80S); smaller size (70S) in organelles • Chromosome (DNA) arrangement • Single circular chromosome; Multiple linear lacks histones chromosomes with histones • Cell division • Binary fission Mitosis • Sexual reproduction • No meiosis; transfer of DNA Involves meiosis fragments only (conjugation)

4. Comparing Plant vs. Animal Cells

5. Cell Membrane Structure

6. Membranes cont’d • The role and significance of the amphipathic phospholipids

7. Membrane Proteins • Types of MPs • IMPs and PPs • Functions: • Enzymes • Hormone binding sites • Channels for passive transport • Pumps for active transport • Electron Carriers

8. Types of Cell Transport – Passive Transport Diffusion – the passive movement of particles from a region of higher concentrations to a region of lower concentration, as a result of random molecular motion Role of membrane permeability

9. Simple vs. Facilitated Diffusion • Exs. Of FD (Na+, K+ and Cl- during nerve cell activity)

10. Osmosis Different from diffusion across cell membranes because water is a solvent. • The direction in which water moves is due to the concentration of solutes rather than the conc. of water molecules • Defined as - the passive movement of water molecules from a region of lower solute concentration to a region of higher solute conc across a selectively permeable membrane.

11. Active Transport • The movement of substances across membranes and against their conc. gradient, using energy from ATP • Ex. Na+ - K+ pump; proton (H+) pumps;

13. General Types of Transport Proteins

14. Vesicle Transport • Exocytosis – • Endocytosis – • R.M. Endocytosis –