Ch 10 Photoautotrophs-organisms that exist w/light as their energy source

1. Ch 10 • Photoautotrophs-organisms that exist w/light as their energy source • Chemoautotrophs-organisms that exist w/inorganic compounds as their energy source

2. Leaves are photosynthetic organism of plants • Cells in the mesophyll tissues in the leaves contain many chloroplasts • Stomata are little pores by which CO2 enters & Oxygen & H2O leave

3. Chloroplasts have an outer & inner membrane • The inner fluid is the stroma • In the stroma are stacks of thylakoids (grana) • In the thylakoid membranes is chlorophyll • Chlorophyll is the light-absorbing pigment that drives photosynthesis

4. The equation for photosynthesis is: • 6CO2 + 12H2O + light →C6H12O6 + 6H2O • Photosynthesis has 2 parts: • Light rxns • Calvin Cycle

5. Light rxns: • Light goes in • light is absorbed by chlorophyll & excites the e-’s moving them to a higher energy level; they fall down the ETC & that energy is used to pump H+ ions that are later used to power ATPsynthase to make ATP • Water is split in 2 e-’s, 2 H+ & O; O combines w/another & is released • What comes out--ATP, NADPH, O2

6. IN the thylokoid membrane are 2 photosystems: • Each that have a rxn center • PS II (absorbs light in p680 λ) • Water is split into 2 H+ ions, 2e-’s & an O atom • Excited e-s go from e- acceptor of PSII to PSI via an ETC

7. The fall of e-’s powers the phosphorylation of ADP to ATP • E-’s then goto P700 in PSI & then the e-’s fall down another ETC then eventually to NADP+ reducing it to NADPH

8. This is noncyclic electron flow & makes an even amount of ATP & NADPH • Calvin cycle uses more ATP than NADPH • In cyclic electron flow only PSI is used to make ATP but no O2 or NADPH is made

9. Calvin cycle • Happens in stroma • CO2 is made into organic molecules via carbon fixation • Fixed carbon is used to make carbs • NADPH is used to power this process • ATP is also used

10. Carbon fixation takes place by CO2 added to RuBP • the rxn is catalyzed by rubisco • 9 ATP used • 6 NADPH used • 1 of the 6 G3P that was made is later made into glucose

11. 1 turn uses 1 CO2 molecule so it takes 6 turns to produce 1 glucose molecule • e-’s travel from: water→ETC→NADPH→Calvin cycle

12. C4 fixation-plants in hot dry climates • Bundle sheath cells & mesophyll cells are both photosynthetic cells

13. CAM photosynthesis-hot, dry climates • Stomata closed in daytime to prevent water loss; open at nite to allow CO2 in • The CO2 is changed into organic compounds & stored in vacuoles to use later • In both CAM & C4 CO2 is changed into an organic intermediate b4 the Calvin Cycle

14. CH11 Cell communication • Yeast cells • Identify their mates by cell signaling (a likes to mate w/ α) • Cells communicate via direct contact or by secreting local regulators such as growth factors or neurotransmitters

15. Paracrine signaling involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid When a cell releases a signal molecule into the environment and a number of cells in the immediate vicinity respond, this type of signaling is

16. 3 stages of cell signaling: Reception, transduction, & response • The signal molecule (ligand) & a receptor is highly specific • A conformational change in a receptor is usually the 1st transduction of the signal

17. Intracellular receptors are proteins in the cytoplasm or nucleus • Steroids like testosterone are intracellular signal molecules that bind w/ a receptor protein that enters the nucleus & activates specific genes • Can act as txn factors to activate or turn off genes

18. Receptors in the membrane are: • g-protein linked receptors • Receptor tyrosine kinases • Ligand-gated ion channels

19. A G-protein-linked receptor is a pm receptor that works w/ the help of a G protein • Used by yeast mating factors, epinephrine, & neurotransmitters • >60% of our medicines work on these receptors

20. Receptor tyrosine kinases- membrane receptors that attach P’s to tyrosines • Growth factors use these receptors

21. Phosphorylation good b/c: • amplifies the signal & • used for greater specifity

22. An ion channel receptor acts as a gate when the receptor changes shape • When a signal molecule binds as a ligand to the receptor, the gate allows specific ions, such as Na+ or Ca2+, through a channel in the receptor • Important for nervous system • Causes changes in Na+ & Ca+ concentrations in the cell • Open & close in response to chemical signals

23. Ch 12 Cell division • B4 the cell divides it need to replicate its DNA • All euk somatic cells have a specific # of chromosomes in their nucleus • Sex cells (gametes) are haploid meaning they have only have the # of chromosomes • Sperm & egg

24. Just before mitosis each duplicated chromosomes has 2 sister chromatids attached by a CENTROMERE • Mitosis-division of the nucleus • Cytokinesis-division of the cytoplasm • Interphase-growth, DNA replication, & making of organelles & proteins

25. The cell cycle consists of • G1 phase-restriction point occurs here • S phase-DNA replication takes place here • G2 phase-growth phase • M phase-cell division • *during all of interphase (G1, S, G2) cell growth, making organelles, & proteins is occurring • G0- non-dividing cells (nerve, muscle)

26. A cell with 102 chromosome during metaphase would make 2 daughter cells w/how many chromosomes?

27. Mitosis • Prophase: • Spindle is organized • Centrioles move to opp poles • Nucleolus can’t be seen anymore • Nuclear envelope disappears • Chromatin becomes tightly coiled

28. Prometaphase: • Nuclear envelope completely disappears • Microtubles attach to chromosomes • Chromo condensed further • Chromatids form pairs & have kinetochore at centromere region

29. Metaphase: • Centrioles migrated to poles • Chromosome line up at metaphase plate in middle of the cell • Kinetochores have attached microtubules • **longest phase

30. Anaphase: • Microtubules retract • Chromatids separate • Cell elongates • By the end each side of the cell has a complete set of chromo

31. Telophase: • Nuclear envelope reforms around chromo’s • Chromatin of chromo’s becomes less condensed • Cytokinesis starts

32. Cytokinesis: • Animal cells-form cleavage furrow • Plant cells-cell plate

33. Cyclins & cdk’s (MPF) regulate the cell cycle • MPF triggers the cell to pass the • G2 √point • G1 phase √point **most imp • G2 phase √point • & M phase √point

34. Essay questions • Explain the 3 stages of cell signaling in detail!

35. Communication occurs among the cells in a multicellular organism. Choose 2 of the following examples of cell-to-cell communication, & for each example DESCRIBE the communication that occurs & the types of responses that result from this communication. • -communication b/w 2 plant cells • -communication b/w 2 immune system cells • -communication either b/w a neuron & another neuron, or b/w a neuron & a muscle cell • -communication b/w a specific endocrine-gland cell & its target cell

36. Cell division functions in growth, repair, & reproduction • a. List the phases of the cell cycle and briefly describe what is occurring at each step (include a description for each separate part!) • b. What is the difference between cytokinesis in plants & animals? • c. What happens when there is no control of the cell cycle? • d. What are the stages of cell division?

37. Be able to interpret data from an experiment on photosynthesis that used DPIP as an electron acceptor and draw a graph of it • Look it up on the college board website