Photosynthesis and Leaf Structure Flashcards

Vocabulary practice flashcards covering plant photosynthesis, mineral requirements, rate experiments, and leaf structural adaptations.

Photosynthesis

The process by which plants manufacture carbohydrates from raw materials using energy from light.

Raw materials of photosynthesis

Carbon dioxide and water. (Light energy is required for the reaction but is not a physical substance, so it cannot be a raw material).

Chlorophyll

A green pigment found in chloroplasts within plant cells that absorbs light energy and transfers it into chemical energy for the synthesis of carbohydrates.

Balanced chemical equation for photosynthesis

$$6\,CO_2 + 6\,H_2O \xrightarrow[\text{chlorophyll}]{\text{light}} C_6H_{12}O_6 + 6\,O_2$$

Starch in plants

An insoluble carbohydrate polymer converted from glucose that acts as an effective energy store without affecting osmosis in cells.

Chlorosis

Yellowing between the veins of leaves caused by a deficiency in magnesium ions ($Mg^{2+}$), which are required to make chlorophyll.

Nitrate deficiency

A mineral deficiency in plants causing stunted growth and yellowing of leaves, as nitrates are needed to produce amino acids for protein synthesis.

Destarching

The process of placing a plant in the dark for 24 hours to ensure any stored starch is used up prior to conducting a photosynthesis experiment.

Variegated leaf

A leaf that is partially green and partially white, used in experiments to test whether chlorophyll is necessary for photosynthesis.

Limiting factor

Something present in the environment in such short supply that it restricts life processes.

Hydrogencarbonate indicator

A pH indicator used to measure carbon dioxide levels in solution; it turns yellow at highest $CO_2$, red at atmospheric levels, and purple at lowest $CO_2$ levels.

Wax cuticle

A protective, waterproof layer on the top of a leaf that reduces water loss by evaporation.

Upper epidermis

A thin and transparent tissue layer that allows light to pass through directly to the palisade mesophyll cells below.

Palisade mesophyll

A layer of column-shaped cells tightly packed with chloroplasts near the upper surface of the leaf to maximize light absorption for photosynthesis.

Spongy mesophyll

Tissue containing large air spaces between cells to increase the internal surface area for the rapid diffusion of gases like carbon dioxide and oxygen.

Stomata

Small pores located mainly on the lower epidermis that facilitate gas exchange between the leaf and the atmosphere.

Guard cells

Specialized cells that change shape when absorbing or losing water to open or close the stomata, regulating gas exchange and transpiration.

Xylem

Vascular tissue responsible for transporting water and dissolved mineral ions from roots up to the leaves.

Phloem

Vascular tissue responsible for transporting sucrose and amino acids around the plant via translocation.

Temperature effect on photosynthesis rate

The rate increases with temperature due to increased substrate-enzyme collisions up to an optimum point, after which higher temperatures denature the enzymes and the rate drops.

Micrograph of leaf cross-section

A microscopic view displaying the structural layout of a dicotyledonous leaf cross-section, showing cuticle, upper epidermis, mesophyll layers, lower epidermis, and guard cells.