Biology Chapter 8: The Process of Photosynthesis. Ms. Nguyen

Transcription

1 Biology Chapter 8: The Process of Photosynthesis Ms. Nguyen

2 Add to a new section of IAN Left side. Chapter 8 Big Idea: Cellular Basis of Life Essential Question: How do plants and other organisms capture energy from the sun? 8.1 Main Question: How do Organisms story energy? 8.2 Main Question: What Cellular structures and molecules are involved in photosynthesis? 8.3 Main Question: How do photosynthetic organisms convert the sun s energy into chemical energy?

3 Bell Ringer Chapter 7: Flashback A. Passive Transport 1) Diffusion 2) Facilitated Diffusion 3) Osmosis (water) B. Active Transport 1) Endocytosis 2) Exocytosis

4 Lesson Overview 8.1 Energy and Life

5 Bell Ringer Homeostasis is hard work. Organisms and the cells within them have to grow and develop, move materials around, build new molecules, and respond to environmental changes. 1) What powers so much activity, and where does that power come from?

6 I. Chemical Energy and ATP A. What is ATP? 1. ATP = release and store energy by breaking and re-forming the bonds between its phosphate groups. 2. ATP = basic energy source for all cells.

7 B. Why is ATP useful to cells 1. Energy = ability to do work 2. Energy = build new molecules, contract muscles, and carry out active transport. 3. No energy = no life

8 C. How is ATP formed? 1. Adenosine triphosphate (ATP) 2. ATP = Adenine, ribose, and three phosphate groups 3. Adenine and Ribose = a 5-carbon sugar

9 II. ADP versus ATP A. Adenosine diphosphate (ADP) 1. ADP = two phosphate groups > not as much as ATP. 2. When a cell has energy available, it can store small amounts of it by adding phosphate groups to ADP, producing ATP. ADP is like a rechargeable battery that powers the machinery of the cell.

10 III. Releasing Energy A. Purpose of ATP and ADP 1. Cells can release the energy stored in ATP by breaking the bonds between the second and third phosphate groups. 2. Because a cell can add or subtract these phosphate groups, it has an efficient way of storing and releasing energy as needed 3. ATP > carry out active transport

11 IV. Using Biochemical Energy A. ATP = energy for movement 1. ATP = powers movement > energy for motor proteins that contract muscle and power the movement of cilia and flagella

12 B. ATP = protein synthesis 1. ATP = powers the synthesis of proteins and responses to chemical signals at the cell surface.

13 C. ATP does not store large amounts of energy 1. Cells can regenerate ATP from ADP as needed by using the energy in foods like glucose.

14 V. Heterotrophs and Autotrophs A. Heterotrophs 1. Organisms that obtain food by consuming other living things 2. Some eat plants. 3. Some indirectly eat plants by feeding on plant-eating animals. 4. Some (mushrooms) decompose other organisms.

15 B. Autotrophs 1. Organisms that make their own food 2. Example: Plants, algae, and some bacteria. 3. Photosynthesis- use the energy of sunlight to produce high-energy carbohydrates that can be used for food.

16 Lesson Overview 8.2 Photosynthesis: An Overview

17 Bell Ringer. 1) Compare and contrast heterotrophs and autotrophs.

18 VI. Chlorophyll and Chloroplasts A. What role do pigments play in the process of photosynthesis? 1. Photosynthetic organisms capture energy from sunlight with pigments B. Light. 1. Energy from the sun travels to Earth in the form of light. 2. Sunlight = mixture of different wavelengths, many of which are visible to our eyes and make up the visible spectrum.

19 C. Pigments 1. Plants gather the sun s energy with light-absorbing molecules 2. The plants principal pigment is chlorophyll -chlorophyll a and chlorophyll b >blue-violet and red regions - Carotene > red and orange

20 D. Chloroplasts 1. Photosynthesis takes place inside organelles called chloroplasts. 2. Chloroplasts = saclike photosynthetic membranes called thylakoids, which are interconnected and arranged in stacks known as grana.

21 VII. Energy Collection A. Light into Energy 1. Light = energy 2. Chlorophyll absorbs visible light Chlorophyll = light electron = photosynthesis = energy

22 VIII. An Overview of Photosynthesis A. What are the reactants and products of photosynthesis? 1.Photosynthesis uses the energy of sunlight to convert water and carbon dioxide (reactants) into high-energy sugars and oxygen (products).

23 B. Sugar becomes Plants use the sugars generated by photosynthesis to produce complex carbohydrates such as starches, and to provide energy for the synthesis of other compounds, including proteins and lipids.

24 IX. Light versus Light Independent A. Photosynthesis involves two sets of reactions. 1. Light-dependent reactions because they require the direct involvement of light and light-absorbing pigments. 2. Light-independent reactions, ATP and NADPH molecules produced in the light-dependent reactions are used to produce high-energy sugars from carbon

25 1. Light independent: No light is required to power the lightindependent reactions. 2. Reactions take place outside the thylakoids, in the stroma. 1 Light-dependent: use energy from sunlight to produce ATP and NADPH. 2.These reactions take place inside the thylakoid membranes of the chloroplast. 3.Water is required as a source of electrons and hydrogen ions. Oxygen is released as a byproduct

26 Lesson Overview 8.3 The Process of Photosynthesis

27 Bell Ringer What happens during the light-dependent reactions compared to light-independent reactions?

28 X. Summary of the Calvin Cycle A. The Calvin cycle uses 6 molecules of carbon dioxide to produce a single 6-carbon sugar molecule.

29 Summary of the Calvin Cycle B. The energy for the reactions is supplied by compounds produced in the light-dependent reactions.

30 Summary of the Calvin Cycle C. The plant uses the sugars produced by the Calvin cycle to meet its energy needs and to build macromolecules needed for growth and development. D. When other organisms eat plants, they can use the energy and raw materials stored in these compounds.

31 The End Results E. The two sets of photosynthetic reactions work together the light-dependent reactions trap the energy of sunlight in chemical form, and the lightindependent reactions use that chemical energy to produce stable, high-energy sugars from carbon dioxide and water. In the process, animals, including humans, get food and an atmosphere filled with oxygen.

32 XI. Temperature, Light, and Water A. The reactions of photosynthesis are made possible by enzymes that function best between 0 C and 35 C. B. Temperatures above or below this range may affect those enzymes, slowing down the rate of photosynthesis or stopping it entirely.

33 Temperature, Light, and Water C. High light intensity increases the rate of photosynthesis. D. After the light intensity reaches a certain level, however, the plant reaches its maximum rate of photosynthesis, as is seen in the graph.

34 Temperature, Light, and Water E. Because water is one of the raw materials in photosynthesis, a shortage of water can slow or even stop photosynthesis. F. Water loss can also damage plant tissues. G. Plants that live in dry conditions often have waxy coatings on their leaves to reduce water loss. They may also have biochemical adaptations that make photosynthesis more efficient under dry conditions.

35 XII. CAM Plants A. Members of the Crassulacae family, such as cacti and succulents, incorporate carbon dioxide into organic acids during photosynthesis in a process called Crassulacean Acid Metabolism (CAM).

36 CAM Plants B. CAM plants admit air into their leaves only at night, where carbon dioxide is combined with existing molecules to produce organic acids, trapping the carbon within the leaves. C. During the daytime, when leaves are tightly sealed to prevent water loss, these compounds release carbon dioxide, enabling carbohydrate production. D. CAM plants include pineapple trees, many desert cacti, and ice plants.