The document summarizes key concepts about cells: - The cell is the basic structural and functional unit of living organisms according to cell theory established by Schleiden and Schwann. - Cells contain organelles that carry out specific functions and transport systems that allow movement of materials into and out of the cell. - DNA in the nucleus serves as the genetic blueprint, which is used to synthesize proteins through transcription and translation.

1. Chapter 3 Cells: The Living Units The cell is the basic structural and functional unit of living organisms.

3. Generic Cell

5. Membrane

6. Cell Junctions Tight Junction impermeable junction that encircles the cell

7. Cell Junctions Desmosome anchoring junction scattered along the sides of cells

8. Cell Junctions Gap Junction allows chemical substances to pass between cells

10. Simple Diffusion

11. Simple Diffusion

12. Facilitated Diffusion

16. Generating and Maintaining a Resting Membrane Potential 2 important ions – Na + and K +

18. Types of Active Transport Figure 3.11

21. Cytoplasm Extracellular fluid K + is released and Na + sites are ready to bind Na + again; the cycle repeats. Cell ADP Phosphorylation causes the protein to change its shape. Concentration gradients of K + and Na + The shape change expels Na + to the outside, and extracellular K + binds. Loss of phosphate restores the original conformation of the pump protein. K + binding triggers release of the phosphate group. Binding of cytoplasmic Na + to the pump protein stimulates phosphorylation by ATP. Na + Na + Na + Na + Na + K + K + K + K + Na + Na + Na + ATP P P Na + Na + Na + K + K + P P i K + K +

31. DNA Replication Figure 3.31

34. Telophase and Cytokinesis Figure 3.32.6

36. From DNA to Protein Figure 3.33 Nuclear envelope DNA Pre-mRNA mRNA Ribosome Polypeptide Translation RNA Processing Transcription

39. Figure 3.36 After mRNA processing, mRNA leaves nucleus and attaches to ribosome, and translation begins. Amino acids tRNA Aminoacyl-tRNA synthetase tRNA “head” bearing anticodon Large ribosomal subunit Small ribosomal subunit Released mRNA mRNA Template strand of DNA RNA polymerase Nuclear pore Nuclear membrane Portion of mRNA already translated Direction of ribosome advance Nucleus Once its amino acid is released, tRNA is ratcheted to the E site and then released to reenter the cytoplasmic pool, ready to be recharged with a new amino acid. Incoming aminoacyl- tRNA hydrogen bonds via its anticodon to complementary mRNA sequence (codon) at the A site on the ribosome. As the ribosome moves along the mRNA, a new amino acid is added to the growing protein chain and the tRNA in the A site is translocated to the P site. Codon 16 Codon 15 Codon 17 Energized by ATP, the correct amino acid is attached to each species of tRNA by aminoacyl-tRNA synthetase enzyme. 1 2 3 4

42. Information Transfer from DNA to RNA Figure 3.38