Question

contrast autotrophs and heterotrophs.
question 2
describe the basic process of photosynthesis.

Explanation:

Question 1: Contrast autotrophs and heterotrophs

Autotrophs (e.g., plants, some bacteria) can produce their own food using energy from sunlight (photosynthesis) or inorganic chemicals (chemosynthesis). They use sources like \(CO_2\) and water to make organic compounds (e.g., glucose). Heterotrophs (e.g., animals, fungi) cannot make their own food and rely on consuming other organisms (autotrophs or other heterotrophs) for organic matter and energy. Autotrophs are producers in ecosystems, heterotrophs are consumers.

Photosynthesis occurs in chloroplasts of plants/algae. It has two main stages: the light - dependent reactions (in thylakoids) and the light - independent reactions (Calvin cycle, in stroma). In light - dependent reactions, light energy is absorbed by chlorophyll, splitting water (\(H_2O\)) into \(O_2\) (released), \(H^+\), and electrons. This generates ATP (energy - carrying molecule) and NADPH (electron - carrier). In the Calvin cycle, ATP and NADPH are used to convert \(CO_2\) into glucose (\(C_6H_{12}O_6\)) using the enzyme RuBisCO. The overall equation is \(6CO_2 + 6H_2O\xrightarrow[Chlorophyll]{Light}C_6H_{12}O_6+6O_2\).

Answer:

• Autotrophs: Organisms that produce their own food (e.g., via photosynthesis/chemosynthesis), use inorganic raw materials, are producers in food chains (e.g., plants, cyanobacteria).
• Heterotrophs: Organisms that obtain food by consuming other organisms, rely on organic matter from external sources, are consumers in food chains (e.g., animals, fungi).

Question 2: Describe the basic process of photosynthesis