Science 8: Cycles in Nature - Photosynthesis

Practice flashcards covering the biological processes, structures, and chemical reactions involved in photosynthesis as presented in the Science 8 lecture.

What is the biological definition of photosynthesis?

A biological process by which green plants convert light energy into chemical energy to be stored in food molecules.

How are oxidation and reduction defined in the context of photosynthesis?

Oxidation refers to the removal of electrons from a molecule, while reduction refers to the gain of electrons by a molecule.

What is the specific wavelength range of the visible spectrum that can be seen by the human eye?

Between $400\,nm$ and $700\,nm$.

What is photorespiration?

A light-dependent process in some plants resulting in the oxidation of glycolic acid and release of carbon dioxide under certain environmental conditions.

What are guard cells and what is their function?

They are a pair of specialized crescent-shaped epidermal cells that border and control the opening and closing of a plant stoma.

What purpose do stomata serve in a plant organ like a leaf?

They are minute openings in the epidermis through which gaseous interchange takes place.

What is the function of the waxy layer known as the cuticle on the leaf epidermis?

It reduces the area of water loss through transpiration and decreases the absorption of ultraviolet or blue light to reduce heating.

How do the palisade and spongy mesophyll layers differ in structure and function?

The palisade mesophyll consists of column-shaped, tightly packed cells that aid in photosynthesis, while the spongy mesophyll consists of loosely-arranged irregular cells that allow gaseous exchange.

What are the specific roles of the xylem and phloem within the leaf's vascular bundles?

The xylem consists of tracheas and vessels that transport water and minerals, while the phloem transports photosynthetic products from the leaf to other plant parts.

In which part of the chloroplast do light-dependent reactions occur, and what do they produce?

They occur in the thylakoid membranes and produce oxygen ($O_2$), ATP, and NADPH.

Where does the Calvin Cycle take place, and what is its primary product?

It takes place in the stroma and produces glucose ($C_6H_{12}O_6$) using $CO_2$, ATP, and NADPH.

What is chlorophyll photoactivation?

The capture of light energy by chlorophyll that results in the release of energized electrons.

What enzyme is responsible for capturing $CO_2$ from the atmosphere during the dark reaction?

RUBISCO.

What is the five-carbon sugar phosphate that carbon dioxide is fixed into during the light-independent reaction?

Ribulose diphosphate (RuBP).

What chemical reactions are specifically involved in the light-dependent stage of photosynthesis?

Chlorophyll photoactivation, photolysis, and photophosphorylation.

What happens to ADP and $NADP^+$ after they are used in the Calvin Cycle?

They return to the thylakoid to be recharged during the light-dependent reactions.