Anatomy and Physiology 1

1. Anatomy and Physiology 1 Organization of Cells and Beyond

2. The Bigger PictureWhere do the atoms and molecules that we have talked about fit into the bigger picture?

3. The Basic Unit of Life is the Cell Nucleus Chromosomes Lysosome Ribosome Mitochondria Energy production Synthesis of proteins Maintain intracellular environment Transport across the membrane Mitosis (DNA replication) Recycling old cellular components Endoplasmic reticulum Golgi Plasma membrane Membrane proteins

4. Organelles are made from macromolecules Lipids make plasma and organelle membranes Carbohydrates are used for energy and for macromolecules Structural components • Proteins • Glycolipids Information/communication • DNA • Proteins Energy sources • Carbohydrates • Lipids • ATP Amino acids make proteins

5. Plasma Membrane: separates the intracellular environment from the extracellular (interstitial) fluid

6. Phospholipid Phospholipid layer Phospholipid bilayer Plasma Membrane: phospholipid bilayer

7. Extracellular fluid (ECF): includes plasma and interstitial fluid Extracellular matrix: jellylike nonliving mesh containing proteins and carbohydrates secreted by cells. Self organizes into a mesh (varies from soft to rock hard) that glues the body together. Intracellular environment: also water based environment with salts, sugars, amino acids, proteins, membrane bound organelles

8. Proteins • 3D structure of protein determines its function. Disturb shape and loose function • All proteins are made from a mixture of the 20 amino acids. DNA sequence of genes codes for amino acid sequence • Each amino acid has chemical personality which influences the way the protein folds • Some amino acids are polar while others are hydrophobic. The hydrophobic amino acid are found in transmembrane sections of proteins

9. Transport Enzymatic activity Receptors Intercellular joining Cell-cell recognition Attachment

10. Crossing the membrane: what does semi-permeable mean? Simple diffusion Channel mediated Osmosis Carrier mediated May be active or passive May be active or passive The chemical properties of a molecule determine how that molecules moves across the plasma membrane.

11. Polar molecules cross via facilitated diffusion or active transport Carbohydrates • Monosaccharides are building blocks. Only form that crosses the membrane • 6 carbon (hexoses) such as glucose • 5 carbon (pentoses) such as ribose • Disaccharides are food made of two monosaccharides • sucrose, lactose and maltoses • Polysaccharides large carbohydrate storage molecules • Glycogen, cellulose

12. + Na+ (11p) Cl- (17P) Ions cross via ion channel proteins -

13. Concentrations do NOT have to be equal on both sides of the membrane. In many cases life depends on concentrations be different across membranes!

14. Concentrations inside the cells are NOT always equal to concentrations outside for many solutes. • Think about the generation of electricity by hydroelectric power • Membranes can act as dams preventing molecules from crossing. • When the concentration is higher on one side of the membrane there is drive toward equilibrium (same concentration on each side) • When molecules move from higher concentration to lower concentration energy can be captured • Pushing molecules up there concentration gradient requires energy input • Water in biological systems freely moves through membranes and never accumulates in a concentration gradient • Water is at the mercy of other concentration gradients and will move to achieve equilibrium

15. Outside cell Higher concentration Na+ Higher concentration Na+ Energy is needed to move across membrane No energy needed to move across membrane Lower concentration Na+ Lower concentration Na+ Inside cell

16. Outside cell Lower concentration K+ Lower concentration K+ No energy needed to move across membrane Energy is needed to move across membrane Higher concentration K+ Higher concentration K+ Inside cell

17. Water • Water freely diffuses across membranes (through aquaporins) • The direction of water movement is determined by the relative solute concentration inside and outside the cell • Water always moves down its concentration gradient

18. Higher concentration of solutes (hypertonic) Lower concentration of solutes (Hypotonic) Cell will dehydrate Cell will swell Lower concentration solutes Higher concentration solutes Outside cell Inside cell

19. Selective permeability of membranes is necessary for life • Selective permeability is a characteristic of healthy, intact cells. When a cell (or its plasma membrane) is severely damaged, the membrane becomes permeable to virtually everything, and substances flow into and out of the cell freely. This phenomenon is evident when someone has been severely burned. Precious fluids, proteins, and ions "weep" from the dead and damaged cells • Selective permeability maintains concentrations of molecules on both sides of the membrane • The cells in our body have both a plasma membrane surrounding the cell and a series of membrane bound internal structures called organelles that house the everyday functions of the cell. Internal membranes create microenvironments needed for reactions inside the cell.

20. So what do cells do all day? • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

21. Mitochondria • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

22. Hormone Receptors/Second Messengers Receptors • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

23. Ribosomes/Endoplasmic Reticulum/Golgi • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

24. Macromolecules are polymers of smaller molecules ~ 30 small precursors are combined into a diversity of macromolecules Biosynthesis is highly regulated Proteins are the doers in the cell. All information in DNA is about making proteins Proteins are not made directly from DNA, but rather from RNA (transcription is making RNA from DNA; translation is making proteins from RNA) After translation, proteins may be cut, glycosylated (sugars added), and packaged Making of macromolecules

25. Leu Met Met Leu GAC tRNAs bring in amino acids Ribosome tRNA UAC mRNA AUG CUG GGG GUA CUC GCG CUA CCC GGG UAA Ribosome tRNA GAC UAC mRNA AUG CUG GGG GUA CUC GCG CUA CCC GGG UAA

26. Leu Pro Met Leu Gly Val Leu Ala CGC Aminoacyl-tRNA transferase attaches amino acid to its tRNA tRNAs bring in amino acids Empty tRNA tRNA with amino acid Growing peptide chain (peptidyl transferase makes peptide bonds) GGG Ribosome GAU mRNA AUG CUG GGG GUA CUC GCG CUA CCC GGG UAA Stop signal

27. Lysosomes Glycogen and certain lipids in the brain are degraded by lysosomes at a relatively constant rate. In Tay-Sachs disease, an inherited condition seen mostly in Jews from Central Europe, the lysosomes lack an enzyme needed to break down a glycolipid abundant in nerve cell membranes. As a result, the nerve cell lysosomes swell with the undigested lipids, which interfere with nervous system functioning. Affected infants typically have doll-like features and pink translucent skin. At 3 to 6 months of age, the first signs of disease appear (listlessness, motor weakness). These progress to mental retardation, seizures, blindness, and ultimately death within 18 months. • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

28. Cytoskeleton • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

29. Microtubules/Centrioles • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

30. Tissues • Maintain concentration gradients • Metabolism to generate energy • Respond to chemical messages in the blood • Make useful proteins • Digest debris in the cytoplasm • Transport stuff around within the cell • Divide into 2 daughters cells • Organize into structural units called tissues

31. Essential Concepts: The Hierarchy of Structural Organization Cells – the basic structural and functional units of the organism Cells specialize in particular jobs, e.g., muscle cells are specialized for contracting Tissue level Groups of different cell types cooperate to perform specific functions

32. What does a highly organized body do?