Photosynthesis Unit 2 Biochemistry Key Questions Write these

Photosynthesis Unit 2: Biochemistry

Key Questions Write these in your notebook! 1. Why is ATP useful to cells? 2. What role do pigments play in the process of photosynthesis? 3. What are the reactants and products of photosynthesis? 4. What factors affect photosynthesis?

Important Vocabulary Write these in your notebook! ● ● ● ● ATP Photosynthesis Pigment Chlorophyll Thylakoid Stroma Light-Dependent Reactions ● Light-Independent Reactions

What are the 8 characteristics of life?

Whether they get energy from food or from sunlight, all living cells store energy in the chemical bonds of certain compounds.

ATP One of the most important compounds is adenosine triphosphate or. . .

ATP can release and store energy by breaking and reforming the bonds between its phosphate groups.

ATP is such a useful source of energy but most cells have only a small amount of ATP. Why? It is not good for storing large amounts of energy over the long term. What is a more efficient way of storing energy?

The energy in food comes from the sun. Plants, algae, and some bacteria are able to use the energy from sunlight to synthesize food molecules. Nearly all life on Earth depends on this process.

Photosynthesis Photo = “light”; Synthesis = “putting together” Photosynthesis = “using light to put something together” In photosynthesis, plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates.

Let’s label our plant cell!

Energy from the sun travels in the form of light. Sunlight, which our eyes perceive as “white” light, is actually a mixture of different colors.

How do plants absorb light? Light-absorbing compounds are known as pigments. ● Chlorophyll is the primary pigment found in plant cells What color do we associate with chlorophyll?

Where does photosynthesis take place? In the chloroplast! ● They are filled with saclike chlorophyll-containing membranes called thylakoids ● The fluid portion of the chloroplast is known as the stroma

An Overview of Photosynthesis

Photosynthesis Equation (Remember this!) 6 CO 2 + 6 H 2 O + light → C 6 H 12 O 6 + 6 O 2 Reactants = the ingredients Products = the molecules that are made

Although the equation looks simple, there are many steps to get from the reactants to the final products. The first set of reactions is known as the Light-Dependent Reactions. ● They require the direct involvement of light and the light-absorbing pigments. The molecules produced in the first reaction are used during the Light-Independent Reactions.

The Light-Dependent Reaction 6 CO 2 + 6 H 2 O + light → C 6 H 12 O 6 + 6 O 2 The light energy is used to split the H 2 O molecule. ● Takes place in the Thylakoid ● O 2 is released in the process ● The light energy is converted into ATP

The Light-Independent Reaction 6 CO 2 + 6 H 2 O + light → C 6 H 12 O 6 + 6 O 2 The ATP from the Light-Dependent reaction is used to break CO 2 down into organic molecules (glucose). ● Takes place in the stroma

What factors affect photosynthesis?

Factors Affecting Photosynthesis Temperature ● The reactions of photosynthesis are made possible by enzymes ○ Temps above or below their range may slow down the rate of photosynthesis or stop it entirely

Factors Affecting Photosynthesis Light Intensity ● High light intensity increases the rate of photosynthesis ○ Plants can reach a maximum rate of photosynthesis

Factors Affecting Photosynthesis Availability of Water ● Water is one of the raw materials of photosynthesis ○ Water loss can also damage plant tissues ○ Plants that live in dry conditions typically have waxy coatings on their leaves