BIO 1201 1st EditionExam # 2 Study Guide Lectures: 9-11Plant Cells & Photosynthesis (Chapters 4,6)Lecture 9 (March 3)1. Plant cell organellesa. Cell wall: composed largely of polysaccharides; wraps around plasma membrane and protects and physically supports cellb. Central Vacuole: storage space for the cellc. Chloroplasts: surrounded by a double membranei. Inner membrane (thylakoid) is extensively folded into stacks called granumii. Solution inside inner membrane is called stromaiii. Imbedded in thylakoid are proteins and molecules involved in photosynthesis, including pigments2. Light Reactions / Light-dependent reactions (Photosystems I & II)a. Two photosystems use light to produce ATP and NADPH, and also O2 as a byproductb. Photosystem II: chlorophyll absorbs light until two electrons get excited and are released. These electrons go through the electron transport chain and the energy released in this process is used to build ATP. To replace the lost energy from the depletedelectrons, H2O is broken apart, the electrons are added to H, and O2 is released as a byproductc. Photosystem I: two electrons are released and are stored in NADPH. These electrons are replaced by the spent electrons from Photosystem II3. Carbon Reactions / Light-independent reactions (Calvin-Benson)a. Series of chemical reactions that use ATP and electrons stored in NADPH to assemble glucose from the carbons and oxygens in CO2+H in water.Energy (Chapters 5,7)Lecture 10 (March 5)1. The first and second laws of thermodynamicsa. 1st: The total amount of energy in the universe remains constantb. 2nd: Any organized system tends to become more disorganized over timei. organisms can attain order with energy2. Metabolic pathways (anabolic vs catabolic)a. Anabolic: use energy and building blocks to synthesize molecules required by the cellb. Catabolic: break down molecules to generate energy and building blocks3. ATP and phosphorylationa. ATP (adenosine triphosphate) is energy currency for a cell and powers cellular work by phosphorylation4. Oxidation-reduction reactionsa. Oxidized: lost one or more electronsb. Reduced: gained one or more electrons5. Electron transporta. Electrons get passed from protein to protein to form ATP in the mitochondria from energy that is released6. Enzymes and their activitya. Enzymes: protein molecules that speed chemical reactions7. Obligate anaerobes / facultative anaerobes a. Obligate: organism that cannot live in presence of oxygenb. Facultative: organism that lives with or without oxygen8. Aerobic vs anaerobic energy-releasing pathwaysa. Aerobic: uses oxygen; efficientb. Anaerobic: without enough oxygen, only glycolysis can happen9. Glycolysis / Krebs Citric Acid Cyclea. Glycolysis: breaks glucose in half (pyruvate) and stores released electrons in NADH; takesplace in cytoplasmb. Krebs Cycle: breaks down pyruvate in mitochondria10. Electron transfer phosphorylationa. Without electron transport chain, electrons are not disposed of normally, but need to be, so cells can use anaerobic pathways11. Lactate vs ethanol fermentationa. Lactate: take pyruvate and add electrons stored in NADH to produce lactic acidb. Fermentation: take pyruvate, break it into a two carbon molecule and CO2, and add electrons to 2C molecule to make ethanolDNA Replication, Mitosis and the Cell Cycle (Chapter 8)Lecture 11 (March 17)1. DNA replicationa. Considered semiconservative because both parental strands of DNA are used as templates for newly synthesized DNA strands; each daughter molecule of DNA is made of one old and one new strand of DNA2. Random mutationsa. Radom errors in which incorrect nucleotides are paired together in DNA3. The cell cyclea. The series of steps as one cell divides to become two daughter cellsb. Interphase: cell decides if it should divide and prepares to divide; made of G1, S, and G2 phases4. Checkpointsa. Can delay cell cycle until certain conditions are metb. G1 checkpoint: delays division if cell does not contain certain growth factors or if DNA is damagedi. Apoptosis: programmed cell deathc. G2 checkpoint: makes sure DNA is replicatedd. Mitotic checkpoint: makes sure chromosomes are properly attached to the spindle and will be distributed evenly to daughter cells5. Mitosisa. Duplicated DNA and is distributed equally to daughter cellsb. Prophase: chromosomes condense, nucleolus disappears, and spindle fibers attach to chromosomesc. Metaphase: chromosomes are aligned at spindle equatord. Anaphase: sister chromatids separate and become daughter chromosomese. Telophase: spindle disappears and new nuclear envelopes form around daughter chromosomes6. Cell cycle exitsa. Quiescence: dormancyb. Apoptosis: programmed cell deathc. Differentiation: cells are specialized7. Stem cells and differentiationa. Stem cells have not differentiated, and so can become any kind of