1 Unit Five Cellular Matter and Energy

Photosynthesis transforms light energy into stored chemical energy. Photosynthesis

“Photo”  Light “Synthesis”  To Make What do plants make with light? 3

What is Cellular Energy? Energy = The ability to do work. Photosynthesis = Plants convert light energy into stored chemical energy (carbohydrates) that they can use for life functions.

Light and Chemical Energy The ultimate source of all new energy for the Earth is sunlight. Chemical energy is stored energy in a food molecule, such as a carbohydrate.  Light energy is transformed into chemical energy.  Chemical energy is often measured in calories. 5

Photosynthetic vs. Non-Photosynthetic Almost all organisms on Earth require sunlight – either directly or indirectly. AutotrophsHeterotrophs Producers that can use the sun’s energy directly. Consumers that can’t use the sun’s energy directly. Use sunlight to produce food from simple inorganic molecules in the environment. Obtain energy from the food they eat (may eat autotrophs, heterotrophs or both). Plants, Some Protists (Algae), Some Bacteria Animals, Fungi, Some Protists, Most Bacteria

Chloroplast & Mitochondrion ChloroplastMitochondrion Both of these cellular organelles change energy from one form to another. Found in plant & algae cells only. Found in ALL eukaryotic cells. Traps energy from the sun and converts it to food energy for plant. Converts energy in food to ATP energy that can be used by the cell.

Photosynthesis Requires Chloroplasts Chloroplasts are the green organelles found in plant and algae cells. 8

Chloroplast Eukaryotic cell organelle. Found only in plant cells and algae. Location where photosynthesis takes place. Absorbs and transforms light energy into stored chemical energy (carbohydrates).

Sunlight The colorless “white” light from the sun is actually a mixture of many different wavelengths (colors) of light. These wavelengths (colors) of light contain energy that plants can use to power photosynthesis. Some wavelengths (colors) provide more energy for photosynthesis than others.

Pigments Absorb Light Photosynthesis begins when light is absorbed by a pigment in plant cells. Pigment = Colored substance that can absorb light. Chlorophyll (a green pigment) is the main pigment in plant cells, but there are others as well.

Absorption of Light by Pigments Chlorophyll a and Chlorophyll b are common pigments. The graph shows how well different colors of light are absorbed by these pigments. Only light absorbed by pigments can be used to make carbohydrates for the plant.

Basics of Photosynthesis Plants require:  Carbon Dioxide (CO 2 )  Water (H 2 O)  Light Energy Plants produce:  Carbohydrates (C 6 H 12 O 6 )  Oxygen (O 2 ) Reactants Products

Photosynthesis Equation 6 CO H 2 O  C 6 H 12 O H 2 O + 6 O 2 Carbon Water Carbohydrate Water Oxygen Dioxide *Photosynthesis takes place in chloroplasts!* light Will only yield the products in the presence of light!

Carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules. Macromolecules

Element: Made of only one type of atom (simple unit of matter) Molecule: Two or more atoms combined Macromolecule: A large, carbon-based molecule produced by living things.  May contain hundreds to thousands of linked atoms.  Essential for cell functions. Building Macromolecules

17 Elements in Humans 96% of the total weight of the human body is made up of just four elements.  Oxygen – 65%  Carbon – 18%  Hydrogen – 10%  Nitrogen – 3%

18 Types of Macromolecules There are four groups of macromolecules essential for living organisms:  Carbohydrates  Lipids  Proteins  Nucleic Acids

Photosynthesis and Macromolecules Photosynthesis produces carbohydrates (sugars). Sugars produced can be:  Stored by the plant.  Used to produce energy for the plant through a process called respiration.  Converted to other macromolecules (proteins, lipids, etc.) through a process called biosynthesis. 19

20 Carbohydrates We often refer to these as sugars and starches. Carbohydrates contain Carbon (C), Hydrogen (H), and Oxygen (O). The major function of carbohydrates is short-term energy storage. Some carbohydrates can help build structures, such as cell walls or exoskeletons.

Carbohydrate Diagrams Glucose (C 6 H 12 O 6 ) is a common carbohydrate that provides energy for cells. Glucose has circular or straight chain forms, but both forms only contain C, H, and O. 21

22 Lipids We often refer to these as fats or oils and they do not dissolve in water. Lipids contain Carbon (C), Hydrogen (H), and Oxygen (O). The major function of lipids is long-term energy storage. Lipids can form layers for protection or warmth in organisms. Waxes are lipids that can form waterproof layers to prevent organisms from drying out.

Lipid Diagram The triglyceride shown below is a common lipid in living organisms. Lipids store more energy than carbohydrates due to their large number of carbon-hydrogen bonds. 23

24 Proteins Proteins contain Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N). Proteins are built from smaller units called amino acids. Proteins are “workers” in the cell that carry out many important functions.

Protein Diagram Amino acids like those shown below connect together to form proteins. These molecules contain nitrogen, an element that is not found in carbohydrates or lipids. 25

26 Nucleic Acids Examples include DNA and RNA. Nucleic Acids contain Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N). The major function of nucleic acids is to store and transmit genetic information needed for life.

Nucleic Acid Diagram Nucleic acids typically have helix shapes.  RNA – Single Helix  DNA – Double Helix The sequence of bases (C, G, A, T/U) contain the genetic information. 27

Cellular respiration is a chemical process whereby the bonds of food molecules and oxygen molecules are broken and the bonds in new compounds are formed resulting in a net transfer of energy. Cellular Respiration

Cellular Respiration = Process by which carbohydrates are broken down to produce ATP energy for a cell. Autotrophs produce carbohydrates required for cellular respiration. Heterotrophs consume (eat) carbohydrates required for cellular respiration. Cellular Energy

Mitochondrion Organelle found in ALL eukaryotic cells (plants, animals, fungi, and protists). Location where cellular respiration takes place. Transforms food molecules into ATP energy the cell can use for life functions.

31 Adenosine Triphosphate (ATP) ATP is the main energy molecule used by all living cells. Cells cannot use stored energy in food like carbohydrates directly. Cells must first convert the food energy into usable energy in the form of ATP. ATP functions like a battery that can store and transport energy from one part of the cell to another.

Point of Clarification Plant cells contain BOTH the chloroplast AND the mitochondrion. The chloroplast produces carbohydrates which must be converted to ATP by the mitochondrion before the plant cell can use the energy. 32

Basics of Cellular Respiration Required:  Carbohydrate (C 6 H 12 O 6 )  Oxygen (O 2 ) Produced:  Carbon Dioxide (CO 2 )  Water (H 2 O)  ATP (Cell Energy) Reactants Products

Cellular Respiration Equation C 6 H 12 O O 2  6 CO H 2 O + ATP Carbohydrate Oxygen Carbon Dioxide Water Energy *Cellular respiration takes place in the mitochondrion!*

Carbohydrates (Food) Cellular respiration releases CO 2 to the atmosphere. Photosynthesis absorbs CO 2 from the atmosphere. Photosynthesis & Cellular Respiration Are Linked

Autotrophs and Heterotrophs Are Linked

Construct and revise an explanation based on evidence for the cycling of matter and flow of energy in aerobic and anaerobic conditions. Aerobic vs. Anaerobic

Aerobic = With Oxygen Anaerobic = Without Oxygen 38

Cellular Respiration = Aerobic Respiration C 6 H 12 O O 2  6 CO H 2 O + ATP Carbohydrate Oxygen Carbon Dioxide Water Energy *Cellular respiration is aerobic respiration because it requires oxygen!*

Aerobic Respiration Requires oxygen from environment Efficient process that can produce large amounts of ATP. 40 InputsOutputs Carbohydrate Oxygen Carbon Dioxide Water Large Amounts of ATP

Anaerobic Respiration Does NOT require oxygen from environment Less efficient process that produces small amounts of ATP. Also known as fermentation. 41 InputsOutputs CarbohydrateLactic Acid or Alcohol Carbon Dioxide Small Amounts of ATP

Aerobic Organisms Some organisms are only capable of aerobic respiration. These organisms must live in an environment containing oxygen. Examples include most animals as well as some types of fungi and bacteria. 42

Anaerobic Organisms Some organisms are only capable of anaerobic respiration and might even be poisoned by oxygen. These organisms must live in an environment that contains no oxygen. Examples include some types of bacteria. 43

Aerobic/Anaerobic Organisms Some organisms are capable of both aerobic and anaerobic respiration. While they can live in either type of environment, these organisms will often prefer aerobic conditions since they can produce more ATP. Examples include some types of fungi and bacteria. 44

Bacteria can be aerobic, anaerobic, or both aerobic/anaerobic. 45 Aerobic Bacteria Require Oxygen Anaerobic Bacteria Avoid Oxygen Bacteria capable of both aerobic & anaerobic respiration can grow anywhere but prefer areas with oxygen. Bacteria Capable of Both Processes

Human Muscle Cells Even in aerobic organisms like a human, individual cells can often switch to anaerobic respiration if the oxygen supply is low. Example: Human muscle cells during strenuous exercise. 46