BS 161 1st EditionExam 3 Study Guide: Lectures: 18- 28Lecture 18- -Finishing up cell respiration:-fermentation: regenerate NAD+ so that glycolysis can continue even without oxygen, produces 2 ATP per glucose molecule-2 kinds: alcohol and lactic acid-human muscles use lactic acid fermentation when there is a lack of oxygen-Photosynthesis: -photosynthesis: the process that converts solar energy into chemical energy-autotrophs: producers of the biosphere-heterotrophs: consumers of the biosphere-chloroplasts: similar (and likely evolved from) bacteria; have their own circular DNA and bacteria like ribosomes; similar to the mitochondria in animal cells-leaves are the major location of photosynthesis, get their green color from chlorophyll-stomata: pores that allow oxygen to exit and carbon dioxide to enter-mesophyll: interior tissue of leaves, contain chloroplasts-thylakoids: connected sacs in chloroplast, contains chlorophyll, stacked in columns called grana-stroma: dense fluid in chloroplasts-oxygen comes from splitting the water molecules-photosynthesis is a redox process-water is oxidized-carbon dioxide is reduced-light reactions: energy capturing reactions-calvin cycle: carbon fixing reducing reactions-wavelength: difference between crests or troughs of waves, determines type of electromagnetic energy-photosynthesis is only concerned with visible light (400-700nm)-light consists of discrete particles called photons or quanta-pigments: molecules that absorb visible lightLecture 19-green light is reflected and transmitted by chloroplasts-all other wavelengths of light are absorbed-absorption spectrum: graph plotting a pigment’s absorption vs wavelength-action spectrum: profiles the relative effectiveness of different wavelengths of radiation in driving a process-when a pigment absorbs light, it goes from a ground state to an excited state-fluorescence: when electrons fall back to ground state, photons are given off-photosystem: consists of reaction center complex surrounded by light harvesting complexes-light harvesting complexes: funnel the energy of photons to the reaction center-primary electron acceptor: accepts an excited electron from chlorophyll a-occurs in the thylakoid membrane -z scheme (aka linear electron flow): transfer of electrons; primary pathway; produces ATP and NADH using light energy-goes from photosystem II to photosystem I-photosystem II: best at absorbing wavelength of 680 nm-photosystem I: best at absorbing wavelength of 700 nm-Chl: ground state chlorophyll-Chl*: excited chlorophyll-Chl+: electron deficient chlorophyll-H2O is split be enzyme, replenishes electrons for electron deficient chlorophyll-diffusion of protons (H+) drives ATP synthesis-cyclic electron flow: uses only photosystem I and produces ATP but not NADPHLecture 20-Calvin Cycle: regenerates its starting material after molecules enter and leave the cycle-builds sugar from smaller molecules-second phase of photosynthesis-carbon enters cell as CO2-leaves as sugar called glyceraldehyde 3 phosphate (G3P)-cycle has to take place 3 times (fixing 3 molecules of CO2) to make one G3P-calvin cycle has 3 phases:1. carbon fixation: catalyzed by rubisco2. reduction: requires a lot of energy, reduces acid to a sugar, opposite reaction of glycolosis3. regeneration of CO2 receptor ribulose bisphosphate (RuBP)-C3 plants: first compound with fixed C is 3C-C4 plants: perform photorespiration, doesn’t produce ATP or sugar; uses the enzyme PEP carboxylase; release CO2 in bundle sheath cells-some plants use crassulacean acid metabolism (CAM): open their stomata at nightLecture 21-main idea: through signaling, one cell can control what another cell is doing-example: epinephorine (fight or flight)-epinephorine is hydrophilic and impermeable to the cell-glycogen phosphorylate is not activated directly by epinephrine-a signal (ligand) is received by a receptor, transduced through the receptor then the cytoplasm, and a cell-type specific response is made-paracrine: one cell makes it, a different cell responds to it-autocrine: same cell makes and responds-gap junctions are very small pores, not a lot can pass between cells, proteins can’t pass between-hydrophilic ligands need a plasma membrane receptor-know what hydrophilic and hydrophobic molecules look likeLecture 22-hydrophobic ligands have a receptor within the cell-ex. steroids, gases, and lipids-two types of chemical ligands have different receptor sites-nonpolar is inside the cell-polar is outside the cell on the transmembrane receptor-four types of receptor proteins-g protein coupled receptor: binds to g protein-tyrosine kinase receptor: kinase function is activating after binding-ion channel receptor: bind the ligand then increase/decrease a specific ion entry to thecell-intracellular receptor: within the cytoplasm, become activated transcription factors able to directly affect transcriptionLecture 23-second messengers: small nonprotein molecules or ions; they amplify the signal-examples: cAMP, IP3, DAG, calcium (Ca2+)-cyclic AMP (cAMP): made from ATP by an enzyme called adenylyl cyclase; activates protein kinase A-know what a kinase cascade looks like and does (picture in book and on slide 38 from lecture)-a kinase cascade causes amplification-glucose 1-phosphate doesn’t exit the cell because the phosphate causes it to be charged and it doesn’t look enough like glucose to pass through the membrane-IP3 and DAG are made from membrane phospholipids by the enzyme phospholipase C-they act to open up calcium channels in the endoplasmic reticulum-scaffolding protein: complexes of proteins, look like three proteins linked together-different cells can respond differently to the same signal if they have different intracellular transduction pathways -cell cycle: the life of the cell until it divides-cell division: cell reproduction: cell proliferation-chromosome replication starts at one ori (origin of replication)-later a cell wall forms between separated nucleoidsLecture 24-interphase: when the cell grows, DNA is replicated-mitosis: division of the nucleus-cytokinesis: division of the cell-growth must be coordinated with DNA replication-check points ensure coordination-different cells divide at different rates-Gap 1 (G1): cell gets signals and decides whether they are the right signals, prepares for DNA synthesis-check point here called start, most important one-DNA synthesis (S): replicated DNA, takes 8-12 hours-Gap 2 (G2): doubles amount of DNA and