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Presentation on theme: "Photosynthesis."— Presentation transcript:

1 Photosynthesis

2 Energy and Life Plants and some other types of organisms are able to use light energy from the sun to produce food. Autotrophs: organisms such as plants, which make their own food Heterotrophs: obtain energy from the foods they consume All living organisms must be able to produce energy from the environment in which they live, store energy for future use, and use energy in a controlled manner.

3 Autotrophs

4 Heterotrophs

5 Chemical Energy and ATP
A quick source of energy that is stored in the chemical bonds of a molecule that can be used quickly and easily by the cell is called adenosine triphosphate (ATP). ATP is an energy molecule The energy of ATP becomes available when the molecule is broken down. The addition and release of a phosphate group on adenosine diphosphate creates a cycle of ATP formation and breakdown. This means the cell doesn’t have to store all the ATP it needs.

6 ATP Continued Cells use this energy to make new cells, maintain homeostasis, and to power functions (like movement). The characteristics of ATP make it exceptionally useful as the basic energy source of all plant cells.

7 ATP Adenine Ribose 3 Phosphate groups

8 Comparison of ADP and ATP to a Battery
Energy Energy Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP) Partially charged battery Fully charged battery

9 Comparison of ADP and ATP to a Battery
Energy Energy Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP) Partially charged battery Fully charged battery

10 Photosynthesis Photosynthesis: Plants use energy from the sun to convert water and carbon dioxide into high energy carbohydrates (sugars and starches) and give off oxygen as a waste product. Photosynthesis happens in 2 phases: light-dependent reactions and light-independent reactions. In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll, a molecule in chloroplasts.

11 Photosynthesis Equation

12 Photosynthesis: Reactants and Products
Light Energy Chloroplast CO2 + H2O Sugars + O2

13 Light and Pigments Plants gather the sun’s energy with light absorbing molecules called pigments. The plants’ principal pigment is chlorophyll. 2 types of chlorophyll: Chlorophyll a and Chlorophyll b Chlorophyll absorbs light very well in the blue-violet and red regions of the visible spectrum. However, chlorophyll does not absorb light very well in the green region of the spectrum. Green is reflected by leaves, which is why plants look green.

14 Chlorophyll Light Absorption
Absorption of Light by Chlorophyll a and Chlorophyll b Chlorophyll b Chlorophyll a V B G Y O R

15 The Reactions of Photosynthesis
Photosynthesis takes place inside the chloroplasts The Chloroplasts contain saclike photosynthetic membranes called thylakoids, which are arranged in stacks known as grana. The space outside of the grana is called the stroma. Proteins in the thylakoids membrane organize chlorophyll and other pigments into clusters known as photosystems, which are the light collecting units of chloroplasts.

16 Chloroplasts

17 Light Dependent Reactions
Light-dependent reaction: uses light energy to produce oxygen and convert ADP and NADP+ into energy carriers ATP and NADPH The light dependent reactions take place within the thylakoid membranes (granum) of chloroplasts.

18 Light-Dependent Reactions
Hydrogen Ion Movement Photosystem II Chloroplast ATP synthase Inner Thylakoid Space Thylakoid Membrane Stroma Electron Transport Chain Photosystem I ATP Formation

19 Calvin Cycle Calvin Cycle: uses the energy carriers ATP and NADPH from the light-dependent reactions to produce high-energy sugars. (Calvin cycle is also called the light independent reaction) Calvin Cycle takes place in the stroma, outside the grana.

20 Calvin Cycle CO2 Enters the Cycle Energy Input ChloropIast 5-Carbon
Molecules Regenerated 6-Carbon Sugar Produced Sugars and other compounds

21 Factors Affecting Photosynthesis
Water, light, and temperature all affect photosynthesis

22 Photosynthesis Concept Map
includes Light- dependent reactions Calvin cycle takes place in uses use take place in Thylakoid membranes Stroma NADPH ATP Energy from sunlight to produce of to produce ATP NADPH O2 Chloroplasts High-energy sugars

23 Photosynthesis: An Overview
Light and Water O2 Sugars CO2 Chloroplast Chloroplast NADP+ ADP + P Light- Dependent Reactions Calvin Cycle ATP NADPH

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