Plant Systems, Photosynthesis, and Cellular Respiration

Comprehensive vocabulary flashcards covering plant organ systems, root anatomy, photosynthetic mechanisms, limiting factors, and the stages of cellular respiration.

Plant Organs

Structures composed of distinct tissues working together to perform specific functions in a plant, primarily including roots, stems, and leaves.

Shoot System

The aerial organ system of a plant that grows or "shoots" upward toward sunlight, holds the plant upright, transports fluids, and absorbs sunlight and oxygen to facilitate photosynthesis.

Root System

The plant organ system composed of organs growing beneath and into the ground that functions in absorbing water and minerals, anchoring and supporting the plant, and storing food.

Parts of a Root

The distinct anatomical regions and branching structures of a plant root, comprising the primary, secondary, and tertiary roots, root hairs, the region of maturation, the region of elongation, the region of cell division, and the protective root cap.

Root Cap

A protective covering located at the tip of the root that shields growing root tissues as they push downward and helps the root sense gravity.

Root Meristem

A specialized plant tissue at the root tip where new root cells are continually replenished through cell division.

Photosynthesis

An endothermic chemical process in which plants convert absorbed light energy, water ($H_2O$), and carbon dioxide ($CO_2$) into carbohydrates (glucose) and release oxygen ($O_2$) as a by-product.

Chloroplast

The plant cell organelle located within mesophyll cells that contains chlorophyll and serves as the primary site of photosynthesis.

Chlorophyll

The green photosynthetic pigment housed within chloroplasts that captures sunlight energy.

Thylakoids

Flattened, pigment-containing membranous sacs inside chloroplasts that serve as the site for light-dependent reactions.

Granum

A stack of thylakoids within a chloroplast.

Stroma

The fluid-filled space within a chloroplast surrounding the thylakoid membranes where the Calvin cycle takes place.

Light-Dependent Reactions

The initial stage of photosynthesis occurring in the thylakoids, where captured sunlight and water ($H_2O$) are used to produce oxygen ($O_2$) and the energy carriers $ATP$ and $NADPH$.

Calvin Cycle

The light-independent stage of photosynthesis occurring in the stroma, where energy from $ATP$ and $NADPH$ is used to fix carbon dioxide ($CO_2$) into sugars ($G3P$), regenerating $ADP$ and $NADP^+$.

Photosynthesis Energy Cycle

The coupled biological pathway wherein light-dependent reactions convert sunlight and $H_2O$ into $O_2$, $ATP$, and $NADPH$, and the Calvin cycle consumes that energy to transform $CO_2$ into sugars while returning $ADP$ and $NADP^+$.

Limiting Factor

An environmental variable (such as light availability, temperature, or carbon dioxide concentration) that acts as a bottleneck when below its ideal level, restricting the overall rate of photosynthesis.

Optimal Temperature for Photosynthesis

The intermediate temperature range (peaking at approximately $25\,^{\circ}\text{C}$) at which photosynthetic enzymes operate at maximum activity before higher temperatures cause denaturation and a sharp drop in rate.

Light Saturation Point

The threshold of light intensity beyond which the rate of photosynthesis plateaus and ceases to increase because another factor has become limiting.

Cellular Respiration

The aerobic process occurring in both plants and animals that breaks down glucose with oxygen ($O_2$) to release energy in the form of a long-term supply of $ATP$, releasing carbon dioxide ($CO_2$) and water ($H_2O$) as by-products.

Adenosine Triphosphate (ATP)

The primary energy currency of the cell produced during respiration to power various energy-dependent cellular activities.

Glycolysis

The first, anaerobic stage of cellular respiration occurring in the cytoplasm, where one molecule of glucose is split into two molecules of pyruvate, releasing a small amount of energy without requiring oxygen.

Pyruvate

A three-carbon organic product formed from the splitting of glucose during glycolysis that is subsequently broken down during the Krebs cycle.

Krebs Cycle

The second stage of cellular respiration occurring in the mitochondrial matrix, where pyruvate is completely broken down into carbon dioxide ($CO_2$) while generating high-energy electron carriers and a small amount of extra $ATP$.

Electron Transport Chain

The final stage of cellular respiration occurring in the inner mitochondrial membrane, which uses high-energy electron carriers and oxygen ($O_2$) as the final electron acceptor to form water ($H_2O$) and produce the majority of the cell's $ATP$.

Cristae

The inner folds of the inner mitochondrial membrane that house the components of the electron transport chain to produce large amounts of $ATP$.