Photosynthesis. A process in which light energy is converted to chemical energy (glucose) Chloroplasts (organelle) Leaves (plant structure)

Transcription

1 Photosynthesis

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3 Photosynthesis A process in which light energy is converted to chemical energy (glucose) Chloroplasts (organelle) Leaves (plant structure)

4 Background Concepts Autotroph (producer) Organism that uses energy from the sun to produce organic compounds Glucose Plants Some bacteria Some protists Heterotroph (consumer) Organism that must get energy from the food they consume Animals Fungus Some bacteria Some protists

5 Photosynthesis 6 Carbon dioxide + 6 water + Light Glucose + 6 Oxygen 6CO2 + 6H20 + Light C6H1206 +CO2

6 Plant Pigments Biological molecules used to absorb light Chlorophyll a and b Absorbs: red, orange, blue, indigo, violet Reflects: green, yellow Carotenoids Absorbs: green, blue, indigo, violet Reflect: red, orange, yellow

7 Electromagnetic Spectrum Plants utilize the visible portion of the electromagnetic spectrum ROY G BIV

8 Absorption Spectrum Shows which wavelength of the visible spectrum are absorbed by chlorophyll a and b, and carotenoids

9 Mystery Solved!

10 Stages of Photosynthesis 1. Light Reactions 2. Calvin Cycle

11 Light Reactions Absorb light energy to make ATP and NADPH Needs water (soil) and light (sun) to run Produces oxygen gas, ATP, NADPH

12 Calvin Cycle Uses the ATP and NADPH made in the light reactions to make sugar (glucose) Needs ATP and NADPH Produces glucose

13 Products of Light Reactions ADP + P ATP (Reduced) NADP + + H NADPH (Reduced) Oxygen comes from the splitting of H 2 O, not CO 2 H 2 O 1/2 O 2 + 2H +

14 Cytoplasm ATP Synthesis (Like a Dam) Proton Pump Powered by Hydrogen (Protons) Powers ATP synthesis. Stroma Located in the thylakoid membranes. Uses ATP synthase (enzyme) to make ATP. Photophosphorylation: addition of phosphate to ADP to make ATP.

15 ATP Synthesis

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17 Calvin Cycle Carbon Fixation (light independent rxn). C 3 plants (80% of plants on earth). Occurs in the stroma. Uses ATP and NADPH from light rxn. Uses CO 2. To produce glucose: it takes 6 turns and uses 18 ATP and 12 NADPH.

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19 Calvin Cycle (C 3 fixation) (36C) (6C) 6C-C-C-C-C-C 6CO 2 (30C) (unstable) 6C-C-C 6ATP 6C-C-C 6ATP 12PGA (36C) 6C-C-C-C-C RuBP 6NADPH 6NADPH 6ATP 6C-C-C 6C-C-C (36C) 12G 3 P C 3 (30C) (6C) glucose C-C-C-C-C-C Glucose

20 Calvin Cycle Remember: C3 = Calvin Cycle C 3 Glucose

21 Photorespiration Occurs on hot, dry, bright days. Stomates close. Fixation of O 2 instead of CO 2. Produces 2-C molecules instead of 3-C sugar molecules. Produces no sugar molecules or no ATP.

22 Photorespiration Because of photorespiration: Plants have special adaptations to limit the effect of photorespiration. 1. C4 plants 2. CAM plants

23 C4 Plants Hot, moist environments. 15% of plants (grasses, corn, sugarcane). Divides photosynthesis spatially. Light rxn - mesophyll cells. Calvin cycle - bundle sheath cells.

24 CAM Plants Hot, dry environments. 5% of plants (cactus and ice plants). Stomates closed during day. Stomates open during the night. Light rxn - occurs during the day. Calvin Cycle - occurs when CO 2 is present.

25 Question: Why would CAM plants close their stomates during the day?

26 Purpose of Photosynthesis 1. Plants use the sugar made through photosynthesis for energy 2. Plants use the sugars to make starch, which can be stored for energy 3. Plants use the sugars to make cellulose, which is used for building cell walls

27 Purpose of Photosynthesis 1. Animals and fungus use the oxygen and sugars for cellular respiration To make ATP

28 Cellular Respiration and Fermentation

29 Cellular Respiration Cellular Respiration Transfer of energy in organic compounds to ATP Carbohydrates, fats, and proteins can all be used as fuels Process more efficient when oxygen is present Carried out in the mitochondria Aerobic processes Require oxygen If oxygen is available, 40% of energy in glucose can be used to make 38 ATP Anaerobic processes Do not require oxygen If oxygen is unavailable, 2% of the energy in glucose can be used to make 2 ATP

30 Structure of Mitochondrion

31 Cellular Respiration Cellular Respiration Glucose is main substance converted to ATP Equation: C₆H₁₂O₆ + 6O₂ 6CO₂ + 6H₂O + energy glucose oxygen carbon water ATP (heat + 38 ATP) gas dioxide

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33 Stages of Cellular Respiration 1. Glycolysis 2. Transition Reaction 3. Kreb s Cycle 4. Electron Transport Chain

34 Stages of Cellular Respiration Glycolysis: Occurs in the cytoplasm Anaerobic Does not require oxygen 2 ATP molecules used in glycolysis, 4 ATP molecules produced in glycolysis Net gain of 2 ATP molecules

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36 Stages of Cellular Respirations Transition Reactions Matrix of the Mitochondria 0 ATP produced 2 molecules of CO2

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38 Stages of Cellular Respiration Krebs Cycle/Citric Acid Cycle Matrix of Mitochondria Aerobic Oxygen must be present 4 molecules of CO2 2 ATP molecules produced

39 Krebs/Citric Acid Cycle

40 Stages of Cellular Respiration Electron Transport Chain Inner membrane of mitochondria 6 H2O molecules produced Aerobic Oxygen must be present 6 oxygen molecules are used Produces up to 34 ATP molecules

41 Cytoplasm

42 Fermentation Fermentation Breakdown of carbs by enzymes, bacteria, yeasts, or mold in the absence of oxygen Anaerobic No oxygen required 2 main types Lactic acid fermentation Alcoholic fermentation

43 Lactic Acid Fermentation Lactic Acid Fermentation Produces Lactic Acid Anaerobic process Only produces 2 ATP Bacteria, humans (in muscles) Importance/Effects to humans: Cheese and yogurt production (bacteria) Muscle soreness (reduced performance)

44 Lactic Acid Fermentation

45 Alcoholic Fermentation Alcoholic Fermentation Produces ethanol and CO2 Anaerobic process Only produces 2 ATP Yeast Importance to humans: Alcoholic fermentation by yeast produces: Biofuels (ethanol) Brewing industry Baking industry (rising bread)

46 Alcoholic Fermentation

47 Purpose of Cellular Respiration & Fermentation Both processes produce ATP that is needed to power metabolism

48 Mitosis

49 Background Concepts Genetic information is contained in the nucleus Chromosomes: structures in a nucleus made out of DNA, which contain genes 46 chromosomes in human cells Visible during cell division Light microscope

50 Background Concepts Chromatids: two copies of a chromosome held together at the centromere Chromosomes are copied to ensure each of the new cells receives a complete set of chromosomes

51 Cell Cycle The repeating sequence of growth and cell division during the life of an organism

52 Interphase Preparation for cell division G1: cell grows to ensure both daughter cells receive large amounts of cytoplasm S: cell copies its DNA so each daughter cell receives a complete set of chromosomes G2: cell grows more

53 Cell Division Mitosis: division of the nucleus Prophase Metaphase Anaphase Telophase Cytokinesis: division of the cytoplasm

54 Cell Division Prophase Nuclear envelope breaks down Chromosomes coil Spindle forms Moves chromosomes during cell division

55 Cell Division Metaphase Chromosomes are at the equator of the cell

56 Cell Division Anaphase Chromosomes are pulled apart and moved to the poles

57 Cell Division Telophase Nuclear envelope forms Chromosomes uncoil Spindle breaks down Cytokinesis: division of the cytoplasm

58 Result Mitosis and Cytokinesis Two Genetically Identical Daughter Cells

59 Cytokinesis in Plant Cells Cell Plate: splits cytoplasm in half

60 Importance of Cell Division 1. Allows organisms to reproduce yeast cells 2. Allows organisms to repair damaged tissue Wound healing 3. Allows organisms to replace cells that die Red blood cells skin

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62 Background Concepts Haploid Cell: cell (nucleus) that has only one set of unpaired chromosomes Gametes 23 chromosomes (in humans) Diploid Cell: cell that contains two sets of chromosomes Somatic cells 46 chromosomes (in humans)

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64 Somatic Cells vs Gametes Somatic Cells: body cells (other than eggs and sperm) Diploid 46 chromosomes Gametes: haploid reproductive cells that unite with another haploid cell to form a zygote Haploid 23 chromosomes

65 Homologous Chromosomes Pair of chromosomes Must be same length, have centromere location, and carry the same genes

66 Autosomes vs Sex Chromosomes Autosomes: any chromosome that is not a sex chromosome Contains genes for 1,000s of traits Somatic cells contain 44 autosomes Sex Chromosomes: one of the pair of chromosomes that determine the sex of an individual Contains genes to determine gender Somatic cells contain 2 (XX=female, XY=male)

67 Life Cycles The entire span in the life of an organism, from one generation to the next Meiosis: type of cell division that produces gametes Gametes: haploid sex cells (egg and sperm cells) Fertilization: joining of egg and sperm cells Zygote: single diploid cell, results from fertilization

68 Meiosis Interphase: G1: cell grows S: cell copies its DNA G2: cell grows more

69 Meiosis Meiosis 1: Prophase 1 (crossing over occurs) Metaphase 1 (independent assortment occurs) Anaphase 1 Telophase 1 Cytokinesis (results in 2 daughter cells)

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71 Meiosis Meiosis 2: Prophase 2 Metaphase 2 Anaphase 2 Telophase 2 Cytokinesis Results in 4 genetically different, haploid cells Daughter cells develop into eggs or sperm (gametes)

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73 Mechanisms of Genetic Variation Crossing Over: two chromosomes, in a homologous pair, exchange sections Prophase 1 Genetic variation in gametes

74 Mechanisms for Genetic Variation Independent Assortment: random distribution of homologous chromosomes at the equator of the cells Occurs during metaphase 1 Genetic variation in gametes

75 Mechanisms of Genetic Variation Random Fertilization: unpredictable nature of fertilization Occurs after meiosis is complete Results in genetic variation in a zygote

76 Karyotype Photograph of an individual s chromosomes Chromosomes organized from largest to smallest homologous pair Last pair always includes the sex chromosomes May indicate if an unborn child has a genetic disorder Trisomy 21 (Down Syndrome)

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79 Purpose of Meiosis Produces haploid gametes with genetic variation Haploid gametes can join, through fertilization, to produce a zygote with genetic variation If a species lacks genetic variation, many individuals would not survive in a changing environment