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Chapter 4 Cell Processes and Energy. 4.1 Photosynthesis.

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Presentation on theme: "Chapter 4 Cell Processes and Energy. 4.1 Photosynthesis."— Presentation transcript:

1 Chapter 4 Cell Processes and Energy

2 4.1 Photosynthesis

3 photosynthesis The process by which a cell captures energy in sunlight and uses it to make food.

4 autotroph An organism that makes its own food.

5 heterotroph An organism that cannot make its own food. – Many heterotrophs obtain food by eating other organisms. (lion, zebra, human) – Some absorb their food from other organisms. (fungi)

6 pigment A color chemical compound that absorbs light and can be used to color other materials.

7 chlorophyll The main photosynthetic pigment found in the chloroplasts of plants, algae, and some bacteria.

8 stomata Small openings on a leaf through which oxygen and carbon dioxide can move.

9 Series (SIHR eez) Noun A number of things or events of the same class coming one after another in a spatial or temporal succession. Ingesting food is the first step in a long series of mechanical and chemical steps.

10 Photosynthesis Like baking cupcakes: – Mix ingredients together – Bake in oven – Yields 12 cupcakes “Recipe” for photosynthesis: – Combine carbon dioxide and water – Use energy from sunlight – Yields a sugar molecule and 6 oxygen molecules

11 Photosynthesis and Food Chains How do autotrophs get their food? – They make their own food using sunlight and photosynthesis. How does the sun supply heterotrophs with energy? – Heterotrophs get energy by eating plants or other animals that eat plants. The plants get their energy from sunlight, so heterotrophs get their energy from sunlight indirectly.

12 What Happens During Photosynthesis? What are the two stages of photosynthesis? – Capturing the sun’s energy and producing sugars What is the energy captured in the first stage used for? – To produce sugars in the second stage

13 What Happens During Photosynthesis? What pigment in chloroplasts absorbs light? – Chlorophyll How is chlorophyll like a solar cell? – Both chlorophyll and solar cells absorb light energy and use it to power a process.

14 What Happens During Photosynthesis? What happens in the second stage? – Water and carbon dioxide combine chemically to form sugars, and oxygen is released. How are roots and stomata important for photosynthesis? – Roots take up water, and stomata take in carbon dioxide, both of which are needed for photosynthesis.


16 The Photosynthesis Equation 6 Carbon Dioxide molecules combine with 6 water molecules due to a chemical reaction from light energy and produce one sugar molecule and 6 oxygen molecules! 6 CO H 2 O C 6 H 12 O 6 and 6 O 2

17 Section 2 Respiration

18 respiration The process by which cells obtain energy from glucose. During respiration, cells break down simple food molecules such as sugar and release the energy they contain.

19 fermentation The process by which cells break down molecule to release energy without using oxygen.

20 Constant (KAHN stunt) Noun Something invariable or unchanging. When birth and death rates are equal, a closed population will remain at a constant.

21 Background Knowledge What does a fire need to burn? – Fuel and oxygen What is released when fuel is burned? – Energy in the form of heat and light

22 Respiration A similar chemical process, called respiration, “burns” food molecules in cells. Like combustion, respiration uses fuel and oxygen to produce energy. The fuel comes from food, and the energy is used for cellular functions.

23 What is Respiration? The process by which cells obtain energy from glucose. During respiration, cells break down simple food molecules such as sugar and release the energy they contain. All cells respire.

24 Storing and Releasing Energy Like money in a bank – Store it until you want to use it Store energy – Plants: photosynthesis captures light energy and then stores it as sugar and carbohydrates. – Animals: eat a meal – add to your energy savings account. Withdraw energy when needed

25 Breathing and Respiration Respiration has two meanings. – 1. breathing – moving air into and out of lungs – 2. the process that takes place inside cells – sometimes called cellular respiration Connection – Breathing brings oxygen, which is usually necessary for cellular respiration, into your lungs.

26 The Two Stages of Respiration Stage 1 – Takes place in the cytoplasm – Glucose molecules broken into smaller molecules – Small amount of energy released Stage 2 – Takes place in the mitochondria – The small molecules are broken down even smaller – Large amount of energy released

27 The Two Stages of Respiration Two products of respiration – Carbon Dioxide – Water

28 The Respiration Equation C 6 H 12 O O 2 6 CO H 2 O + energy Raw materials for Respiration: – Sugar – Oxygen

29 Comparing Photosynthesis and Respiration Equations are opposite. Opposite processes These two processes form a cycle that keeps the levels of oxygen and carbon dioxide fairly constant in Earth’s atmosphere.

30 Two methods of producing and using energy. These methods work together to keep the atmosphere constant.

31 Events During Respiration Reminder: – The food you eat must be broken down to release energy it contains. What is the process called that releases energy from food? – Respiration Why is respiration important to cells? – It provides cells with the energy they need to carry out their functions.

32 Events During Respiration What happens in the first stage of respiration? – Glucose is broken down into smaller molecules and a small amount of energy is released. What happens in the second stage of respiration? – The smaller molecules are broken down into even smaller molecules and a large amount of energy is released.

33 Apply It! Why do you think muscle cells have many mitochondria? – The second stage of respiration, which produces lots of energy, takes place in the mitochondria. – The large numbers of mitochondria in muscle cells supply a great amount of energy for movement.

34 Fermentation Some cells are able o obtain energy from food without using oxygen. – Some single-celled organisms that live deep in the ocean or in the mud of lakes or swamps. Through fermentation, an energy-releasing process that does not require oxygen.

35 Alcoholic Fermentation Occurs when yeast (and some single-celled organisms) break down sugars. Products of this process: – Alcohol – Carbon dioxide – Small amounts of energy Important to Bakers and Brewers – Bread rises and has air pockets – Creates bubbles in in alcoholic drinks

36 Lactic Acid Fermentation Occurs when muscle use up oxygen faster than it can be replaced Fermentation occurs without oxygen to supply energy. Lactic Acid is a product of this type of fermentation You would have sore and tired muscles.

37 Obtaining Energy Without Oxygen What is the process in which energy is released without using oxygen? – Fermentation What are the products of alcoholic fermentation? – Alcohol, carbon dioxide, and energy

38 Obtaining Energy Without Oxygen What is a product of lactic-acid fermentation? – Lactic Acid When might your body release energy using fermentation? – If you are exercising so hard or long that your muscle cells cannot take up oxygen faster than it is being used.

39 Section 3

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