Photosynthesis & Respiration

The video explains the carbon cycle, focusing on photosynthesis and respiration. It details how carbon dioxide is absorbed by plants and converted into oxygen and carbohydrates through photosynthesis. Animals obtain carbon by consuming plants or other animals, releasing carbon dioxide back into the environment via respiration. The video also discusses the role of enzymes and chlorophyll in these processes and compares respiration to combustion.

What percentage of carbon dioxide was present in the air before the use of fossil fuels?

• 0.04%

• 0.28%

• 0.38%

• 0.18%

Which process allows plants to capture carbon from carbon dioxide?

• Respiration

• Combustion

• Photosynthesis

• Fermentation

What is the main pigment involved in photosynthesis?

• Melanin

• Chlorophyll

• Hemoglobin

• Carotene

Which organisms are believed to have evolved the process of photosynthesis?

• Green plants

• Cyanobacteria

• Fungi

• Protozoa

Where does respiration primarily occur in plant and animal cells?

• Chloroplasts

• Nucleus

• Mitochondria

• Ribosomes

What is a key difference between respiration and combustion?

• Combustion releases no energy

• Respiration occurs at normal temperatures

• Combustion uses enzymes

• Respiration requires high temperatures

Why is it important for soil to be full of air for plant roots?

• To prevent waterlogging

• To reduce soil acidity

• To increase soil temperature

• To enhance mineral absorption