CELL PROCESSES

• Cell


  Basic unit of life, building blocks of all living organisms
• Cellular Respiration


  Metabolic pathway that breaks down glucose and produces ATP
• Why Cells Require Energy

  • To drive metabolic reactions that would not occur automatically
  • To transport needed substances across membranes
  • To do mechanical work (moving muscles)
• Aerobic Respiration


  Producing energy involving oxygen
• Anaerobic Respiration


  Producing energy without oxygen, occurs in muscle cells and prokaryotic organisms
• Cellular Respiration Formula


  Reactants initiate the process, Products are molecules produced during and after the process
• Glycolysis


  1. Breaking down of glucose molecules to generate energy and electron barriers

  2. Ends with formation of pyruvate

  3. Can take place without oxygen in a process called fermentation

  4. Takes place in cytosol
• Energy-Investment Phase


  Involves the use of ATP
• Energy-harvesting Phase


  Involves the production of ATP and NADH
• Net Products of Glycolysis
• Pyruvate Oxidation


  1. Links glycolysis to the rest of the cellular respiration

  2. Takes place in mitochondrial matrix (eukaryotes)

  3. Converts pyruvate into acetyl CoA
• Hans Adolf Krebs


  German-British scientist who discovered Krebs cycle in 1930s
• Krebs Cycle


  Oxidizing and further breaking down two pyruvate molecules to produce energy, also called citric acid cycle
• RedOx Reactions Products
• CO2


  Released into the environment
• NADH and FADH2


  Used to produce more ATP in electron transport chain, NADH = 3 ATP, FADH2 = 2 ATP
• GTP


  Used to drive chemical reactions similar to how cells use ATP
• Electron Transport Chain


  Series of multiprotein complexes embedded in the inner membrane of mitochondria
• Proton Gradient


  Produced by pumping hydrogen ions from the matrix to the intermembrane space
• Chemiosmosis


  Downhill transport of hydrogen ions from the intermembrane space to the matrix, provides energy to ATP synthase to phosphorylate ADP into ATP, produces 34 ATP along with electron transport chain
• DNA Replication


  Duplication of the cell's genetic material before cell division
• Helicase


  Splits open the DNA into two DNA template strands
• Single Stranded Binding Proteins

  Holds the DNA template strands
• RNA Primase


  Makes an RNA primer complementary to the template for the DNA polymerase to hook onto
• DNA Polymerase


  Makes a new DNA strand by adding nucleotides onto the chain, can only make DNA in the 5' to 3' direction
• Leading Strand


  New strand that runs from 5' to 3', made continuously
• Lagging Strand


  New strand that runs from 3' to 5', made in fragments
• Okazaki Fragments


  Fragments made in the lagging strand
• DNA Ligase


  Enzyme that joins the Okazaki fragments together
• Cell Division


  Reproduction of cells
• Phases of Interphase


  • G0 Phase (Resting Phase)
  • G1 Phase (Gap 1)
  • S Phase (Synthesis)
  • G2 Phase (Gap 2)
• G0 Phase (Resting Phase)


  Cell neither divides nor prepares itself for the division
• G1 Phase (Gap 1)


  Cell is metabolically active and grows continuously during this phase
• S phase (Synthesis)


  DNA replication occur
• G2 Phase (Gap 2)


  Protein synthesis
• Mitosis


  Vegetative division, exact replicas of cells, almost all of body's cells
• Phases of Mitosis


  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• Prophase (Mitosis)


  Break down some structures and build others up, chromosomes start to condense, mitotic spindle starts to form
• Prometaphase (Mitosis)


  Late prophase, mitotic spindle captures and organizes the chromosomes
• Metaphase (Mitosis)


  Chromosomes are lined up, cell is ready to divide