Photosynthesis Process and Organisms Quiz

Photosynthesis Overview

• Photosynthesis primarily occurs in the chloroplasts of plant cells, mainly within the mesophyll tissue of leaves.
• The xylem transports water and the phloem carries manufactured food (sugars) throughout the plant.

Chloroplast Structure

• The stroma is the chloroplast's fluid-filled inner space, housing the most chlorophyll and critical for the Calvin Cycle.

Chlorophyll and Light Absorption

• Chlorophyll appears green because it reflects green light and absorbs predominantly blue and red wavelengths from the spectrum of white light.

Autotrophic Requirement

• The essential requirement for autotrophic organisms to synthesize food through photosynthesis is light energy.

Leaf Protection

• The cuticle is a waxy layer that protects the leaves, reducing water loss and shielding against pathogens.

Light Reactions Purpose

• The light reactions primarily serve to convert light energy into chemical energy in the form of ATP and NADPH.

Electron Activity during Light Reactions

• During light reactions, chlorophyll absorbs light and its electrons become excited, initiating the process of converting light energy into chemical energy.

End Products of Light Reactions

• The end products of the light reactions are ATP and NADPH, which are crucial for the subsequent dark reactions (Calvin Cycle).

Calvin Cycle

• The Calvin Cycle occurs during the dark reactions of photosynthesis, utilizing ATP and NADPH to synthesize glucose from carbon dioxide.

Role of NADPH

• NADPH serves as a reducing agent providing the necessary electrons and protons in the dark reactions, facilitating the synthesis of organic compounds.

Light Intensity Factor

• The rate of photosynthesis is affected by light intensity, which provides the energy required for the reactions to occur.

Impact of Excess Light

• When light intensity exceeds a certain threshold, the rate of photosynthesis may plateau or decline, signaling potential photoinhibition or plant stress.