Physiology of Cells

1. Physiology of Cells Cellular Processes

2. Membrane Transport • Passive Transport • Simple diffusion down concentration gradient • Facilitated Diffusion occurs through channel proteins • Active Transport • Requires energy

3. Permeability • Plasma membrane allows only certain substance to diffuse across. • Non-polar lipid based substances, steroids, diffuse quickly through membrane

4. Diffusion • Molecules always move from high to low concentrations • Occurs down a concentration gradient • Effective only across small distance.

6. Facilitated Diffusion • When a molecule either passes through or binds to an channel protein to cross a membrane.

7. Carrier Proteins • When substance being transported binds to protein

8. Osmosis • Diffusion of water • Occurs easily through bi-lipid layer • Aquaporins allow for quicker movement of water

9. Solute Concentrations • Isotonic- equal amount of solutes • Hypotonic- solution has lower solute concentration • Hypertonic- solution has higher concentration of solutes

10. Active Transport • Moves substances against concentration gradient • Sodium-Potassium pump

11. Bulk Transport • Endocytosis • Phagocytosis movement of large molecules into the cell • Pinocytosis is the ingestion of extracellular fluid • Exocytosis moves large molecules out of cell • Ex: proteins, waste

13. Cell Transport

16. Cellular Respiration • Metabolism happens in a series of separate reactions • Each step is catalzyed by a separate enzyme • Cellular respiration occurs inside the mitochondria(except glycolysis)

17. Steps of Cellular Respiration • Glycolysis • Pyruvate Oxidation • Kreb Cycle • Electron Transport Chain • Net gain of 36 ATP • Waste products CO2 & H2O http://biology.clc.uc.edu/courses/bio104/atp.htm

18. Relationships between Metabolic Pathways • Catabolic interconversions: • Polysaccharides are hydrolyzed into glucose, which passes on to glycolysis. • Lipids are converted to fatty acids, which become acetate (then acetyl CoA), and glycerol, which is converted to an intermediate in glycolysis. • Proteins are hydrolyzed into amino acids, which feed into glycolysis or the citric acid cycle.

19. Relationships between Metabolic Pathways • What happens if inadequate food molecules are available? • Glycogen stores in muscle and liver are used first. • Fats are used next. But the brain can only use glucose, so it must be synthesized by gluconeogenesis which uses mostly amino acids. • Therefore, proteins must be broken down. • After fats are depleted, proteins alone provide energy.

20. Diseases of Cell Membrane • Cystic Fibrosis • does not allow Cl- to pumped across the membrane • Mucus and secretions in lungs, pancreas thicken • Duchenne Muscular Dystrophy • “leaky” Ca++ channels • Type II Diabetes • Cells become less sensitive to insulin

21. Cell Division and Protein Synthesis DNA DNA RNA T T T T T T A A A A A A A A A A A A T T T T T T MET THR LEU ARG G G G G G G G G G C C C C C C C C C C C C C C C G G G G G G Nucleus Transcription Cell Growth and “Everyday Activity” ~ Protein Synthesis ~Transcription  Translation Interphase Translation RNA Nucleus Cytokinesis Cytoplasm is divided up into each cell. ReplicationDNA is doubled so each cell will have an exact copy of DNA. “Replicated DNA” is given to each cell. Replication Mitosis

22. Cell Division: Mitosis Mitosis:Dividing the DNA When cells divide, they must make a copy of the DNA so the two resulting cells each have the exact same copy of genetic code. Cytokinesis:Dividing of the cell

23. T T T T T T A A A A A A A A A A A A T T T T T T G G G G G G G G G C C C C C C C C C C C C C C C G G G G G G Cell DivisionThe newly formed cell receives the replicated copy of DNA. The free-floating nucleotides in the nucleus attach themselves to each side of the ladder. Once replicationhas occurred, the cell can divide into 2. -Creates 2 IDENTICAL DAUGHTER CELLS. -Process that all body (somatic) cells go through -Replace old cells, repair damage

24. Protein Synthesis: Using DNA to make proteins 1 Transcription DNA makes messenger RNA (mRNA), and then it is sent to the ribosome. 2 3 Translation Protein Synthesis mRNA serves as the code sotransfer RNA (tRNA) can placethe amino acids in sequence. The protein is made from the coded message. ARG LEU LEU ARG MET THR THR MET

25. DNA RNA RNA T T T T T T T T T T T T T T DNA Cytoplasm TranscriptionDNA writes its code to make mRNA. Nucleus Next is translation DNA mRNA message sent to Ribosome

26. VAL LEU tRNA anticodon mRNA Codon mRNA Codon mRNA Codon MET PRO tRNA tRNA tRNA anticodon anticodon anticodon mRNA Codon Phenylal-anine Glycine GlutamicAcid AsparticAcid Leucine U C G A A C G U U G G U A C C A A U C Serine G Alanine G U A C A C A C G U U G Tyrosine G U G U Valine A C Stop A C G U Typtophan G U A C G U Arginine A A C C A Leucine C U G Serine G U A C A C C A Lysine U G G U Proline U G C A Asparagine A C G U U G C A Histdine A G C U Threonine Glutamine Methionine Arginine Isoleucine This Is the “start” codon and begins the amino acid chain.

27. TranslationThe ribosome and tRNA helps assemble the protein chain of amino acids. The amino acids are bonded together to start the protein chain. THR LEU MET ARG