Biology 110, Ch.5, Midtrm

Carbon Reactions

Use Carbon from CO2 to create sugars

Output of Photosynthesis

The main outputs are oxygen, which is released into the air, and glucose sugar (chemical energy), which is used to keep the plant alive.

How do plants convert CO2 into Oxygen?

- By using the energy of sunlight, plants can convert carbon dioxide and water into carbohydrates and oxygen in a process called photosynthesis. - As photosynthesis requires sunlight, this process only happens during the day.

Why are leaves green?

- Chlorophyll is a pigment found in the thylakoid membranes of the chloroplasts in the leaves; plants are green because they have green Chloroplasts (organelles that carry out photosynthesis)

Photosynthesis

- Conversion of light energy from the sun into chemical energy. - sun's energy to convert water and carbon dioxide into sugars

Light reaction steps:

- Light absorption & splitting of water molecules. - Production of ATP. - Movement of electrons through electron acceptors to power a hydrogen pump. - Re-energizing electrons so they can produce NADPH.

Light Cycle

- The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesis: the energy storage molecule ATP and the reduced electron carrier NADPH. In plants, the light reactions take place in the thylakoid membranes of organelles called chloroplasts.

Calvin Cycle

- a biochemical pathway of photosynthesis in which carbon dioxide is converted into glucose using ATP - process by which a photosynthetic organism uses energy to synthesize simple sugars from CO2

ATP and NADPH Role in Light Reactions

ATP and NADPH, which are used in the second stage of photosynthesis. ATP and NADPH are generated by two electron transport chains. During the light reactions, water is used and oxygen is produced

Calvin Cycle Steps:

1. Fixation - CO2 Binds to RuBp sugar 2. Reduction - Carbon Molecules coverted to G3P (It is a 3-carbon suga ) (process uses ADP+ and NADPH as energy) 3. Carbohydraes are formed from G3P 4. Regeneration- ATP binds with G3P Carbohydrates to form RuBP sugars again

Pigments (Function)

Because they interact with light to absorb only certain wavelengths, pigments are useful to plants and other autotrophs --organisms which make their own food using photosynthesis.

Photosystem 1

Creates ATP and splits water

Photosystem 2

Creates NADPH

H20 In Photosynthesis

During photosynthesis, the plants take carbon dioxide (which is present throughout the air) and water (which is also in the air and dirt) and turn it into sugar and oxygen

What is the energy used by the calvin cycle?

Energy to fuel chemical reactions in this sugar-generating process is provided by ATP and NADPH, chemical compounds which contain the energy plants have captured from sunlight.