Energy and Photosynthesis

These flashcards cover key concepts regarding energy, photosynthesis, the importance of algae, the types of energy, and the role of biofuels, as presented in the lecture notes.

Why are photosynthetic organisms like algae important?

They are crucial because they convert sunlight into energy-rich food molecules such as glucose, which is the ultimate energy source for all living organisms.

What is the ultimate source of energy on Earth?

The ultimate source of energy on Earth is the sun.

What are the two main types of energy?

Kinetic energy (energy of motion) and potential energy (stored energy).

What is photosynthesis?

Photosynthesis is the process by which plants and other autotrophs capture the energy of sunlight to make energy-rich molecules.

Where does photosynthesis occur in plants?

Photosynthesis occurs in chloroplasts, the organelles present in cells of plants and algae.

What is the photosynthesis chemical equation?

The overall equation is: 6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ + 6O₂.

What role does chlorophyll play in photosynthesis?

Chlorophyll absorbs light energy from sunlight, mostly from the blue and red wavelengths, and reflects green.

What are biofuels?

Biofuels are renewable fuels made from living organisms, including those produced from algae.

What is carbon fixation in photosynthesis?

Carbon fixation is the process of capturing carbon dioxide gas from the air and incorporating carbon atoms into sugar.

How do plants and algae transform solar energy into chemical energy?

They capture light energy in the 'photo' step, split water, then use that energy to convert carbon dioxide into glucose in the 'synthesis' step.

How does energy transformation efficiency relate to energy supplies?

Energy transformation is not efficient; with each transformation, some energy is lost as heat, requiring continuous energy supply.

What are algal biofuels compared to fossil fuels?

Algal biofuels can serve as an alternative to fossil fuels, potentially offering sustainability and lower emissions.

What are some practical hurdles for alga-based biofuels?

Algal biofuels are currently at the prototype stage, and broader applications like sustainable materials are still being developed.

What is the energy transformation when a cyclist ingests food?

Potential chemical energy from the food is released during digestion, transforming into kinetic energy and heat as the cyclist moves.

What percentage of U.S. petroleum is imported?

Approximately 42% of the U.S. petroleum usage is imported, with about 8 million barrels per day from other sources.

What happens to carbon dioxide produced from burning biofuels?

It is the same carbon dioxide that was taken up by photosynthesis, leading to a closed carbon cycle.