Intro to Cellular Energy

Energy is the ability to do work Energy is the ability to do work. Without energy, life can’t exist and would cease.

Autotrophs harness the sun’s energy and make sugars (make their own “food” from the sun) [Autotroph = “self feeding”]

Heterotrophs must obtain food by consuming other organisms Heterotrophs must obtain food by consuming other organisms. They can’t make their own. [Heterotroph = “different feeding”] To live, ALL organisms (including plants), must unlock (release) the energy from sugar.

Energy can be transformed between/among any of these forms! Forms of Energy Solar Thermal Mechanical Electrical Chemical Nuclear Energy can be transformed between/among any of these forms!

When high energy chemical bonds are broken, they are replaced by low energy bonds. Energy is released from electrons. As electrons fall from high to low energy levels, energy can be released as heat and light. High energy bonds Low energy bonds + energy

What Is ATP? Adenosine Triphosphate Organic molecule containing high-energy Phosphate bonds Used to store and release energy Energy “currency” used by all cells

Chemical Structure of ATP Adenine Base 3 Phosphates Ribose Sugar

What Does ATP Do for You? It supplies YOU with ENERGY!

How Do We Get Energy From ATP? (How is energy RELEASED?) By breaking the high- energy bonds between the last two phosphates in ATP

What is the Process Called? HYDROLYSIS (Adding H2O) H2O

The ADP-ATP Cycle ATP Synthase ATP-ase helps break ATP into ADP + P Creates ATP from ADP and P ATP-ase helps break ATP into ADP + P

When is ATP Made in the Body? During a Process called Cellular Respiration that takes place in both Plants & Animals

Cellular Work – How does the cell use the energy it makes? Active transport Movement Synthesis of new molecules Responses to Chemical signals Other stimuli Produce light

ATP ADP = Depleted battery Glucose Great for transferring energy Like a “AA” battery or quarters $$$ ADP = Depleted battery Glucose Great for storing energy Paper money

“Cycle of Life”: Photosynthesis and Cellular Respiration

Photosynthesis: Capturing Energy from sunlight “To make” Definition: Process by which plants use the energy from sunlight to convert water (H2O) and carbon dioxide (CO2) into glucose (C6H12O6) and oxygen gas (O2)

Scientists Van Helmont Question: Do plants grow by taking material out of the soil? Method Used: Planted trees; observed and recorded data for 15 years Conclusion: Plants gain mass from water Priestly Method: mint in a jar with a burning candle Conclusion: the plant kept the flame going Ingenhousz Conclusion (from Priestly exp): plants must have light to produce CO2

Photosynthesis Equation Takes place in the chloroplasts of plant cells – must have the pigment chlorophyll Pigment = light-absorbing molecule

Chlorophyll Located in the thylakoid membranes of the chloroplasts Chlorophyll pigments harvest energy (photons) by absorbing certain wavelengths (blue and red are most important) Plants look green because the green wavelength is reflected, not absorbed. 400 500 600 700

Photosynthesis has two parts: 1. Light Reactions (light dependent reaction) Produces energy from solar power (photons) in the form of ATP and NADPH. 2. Calvin Cycle (light independent reaction) Also called Carbon Fixation or C3 Fixation Uses energy (ATP and NADPH) from light reaction to make sugar (glucose).