BIOENERGETICS

Sun

• Major source of energy trapped by green/photosynthetic organisms

• This energy is used in Active transport, Cilia/flagella movement, mitosis, protein synthesis, and other cellular processes

ATP

• Adenosine Triphosphate

• contains adenine, ribose (5-carbon sugar molecule), and 3 phosphate groups serially bonded

• contains phosphate which are charged molecules

• energy high molecule primarily used in cellular and other biological processes

• energy that can be stored again after use

Why is ATP better than ADP and AMP

ATP contains 3 phosphate bonds that provides alot of energy, specifically located in the last bond of phosphate bond. ADP and AMP only have 2 and one phosphate groups bonded that only contains some to only a little bit of energy

ATP > ADP > AMP

Phosphorylation

• reattachment of phosphate to form ATP

• ATP —> ADP and ADP —> ATP back again

Photosynthesis

• makes use of phosphorylation

• uses sun’s energy to make simple sugars

• 6CO₂ + 6H₂O -sunlight→ C₆H₁₂O₆ + 6O₂

• carbon dioxide + water -sunlight→ sugar + oxygen

• occurs in the thylakoid membranes of the chloroplast

Cellular Respiration

• produucts of photosynthesis (C₆H₁₂O₆ + 6O₂) are utilized in cellular respiration

• done in the mitochondrion

Cellular Respiration and Photosynthesis in Plants and Animals

• Plants can both undergo cellular respiration and photosynthesis

• Humans can undergo cellular respiration because they are not photosynthetic and lacks chloroplasts.

Chlorophyll

• photosynthetic pigments embedded in the thylakoid membrane

• it is green because it absorbs every other wavelength of light except green, which is instead reflected

Thylakoid Membrane

• where chlorophyll is embedded

• has a phospholipid bilayer structure

• have light-absorbing pigments

chlorophyll a

• C₅₅H₇₇N₄O₅

• principal photosynthetic piigment

• absorbs energy from blue to violet, and orange to red

chlorophyll b

• C₅₅H₇₀MgN₄O₆

• accessory photosynthetic pigment

• collects energy and passes it to chlorophyll a, absorbs energy from green wavelength

Photosystems

• structural units of protein complexes with clusters of chlorophyll which are involved in the photosynthesis

• found in thylakoid membrane

• where chlorophylls absorb light energy and release electrons

• carries out:

  • absorption of light

  • transfer of energy and electrons

Light Dependent Reaction

1. Sun strikes in photosystem ii

2. light energy excites/energizes electrons

3. electrons are passed on from chlorophyll to an electron transport chain embedded in the thylakoid membrane

4. electrons get re-energized in photosystem II

5. At the end of ETC, electrons are carried to stroma for later use

6. NADP+ turns into NADPH+ as it transfers to the stroma

Photolysis

• used in LDR when electrons may run out

• occurs in photosystem ii

• light breaks down H₂O to produce ½ O₂, 2 H+, and 2 electrons

Uses of lost/spilled energy from Electron Transport Chain

• forming ATP from ADP

• pumping hydrogen ions in the thylakoid membrane, which produces a concentration gradient, which powers ATP synthase to produce ATP

Light Dependent Reaction

• series of reactions that us CO₂ to form sugars

• occurs in the stroma

• produces phosphoglyceraldehyde (PGA)

Phosphoglycyeraldehyde

• known as PGA

• known as G3P (glyceraldehyde-3-phosphate)

• a molecule essential for cellular respiration

Carbon Fixation

• Phase 1 of calvin-benson cycle

• 6RuBP + 6CO₂ = 12 3-PGA

Reduction

• phase 2 of the calvin-benson cycle

• 12 3-PGA + 12ATP + 12NADPH = 10G3P + 2G3P