Grade 11 Life Sciences: Photosynthesis Vocabulary

A complete set of vocabulary flashcards covering leaf structures, adaptations, environmental limiting factors, experimental investigations, and organic products from the Grade 11 Photosynthesis study guide.

Leaf

A plant organ specialised for capturing light and carrying out photosynthesis, as well as allowing gaseous exchange.

Cuticle

A thin, waxy, waterproof layer covering the epidermis of a leaf that reduces water loss through evaporation.

Epidermis

The outer layer of cells covering and protecting the leaf.

Palisade mesophyll

The layer of elongated cells beneath the upper epidermis that contains many chloroplasts and is a major site of photosynthesis.

Spongy mesophyll

A layer of loosely arranged cells containing air spaces that facilitate the diffusion of gases through the leaf.

Stoma (plural: stomata)

A small pore in the leaf epidermis through which gases and water vapour move between the leaf and its surroundings.

Guard cells

Specialised epidermal cells surrounding a stoma that regulate the opening and closing of the pore.

Vascular bundle

A strand of conducting tissue containing xylem and phloem.

Xylem

Vascular tissue that transports water and dissolved mineral salts from the roots to the rest of the plant.

Phloem

Vascular tissue that transports organic nutrients, particularly sugars, between sources and parts of the plant that need or store them.

Gaseous exchange

The movement of gases between an organism and its surroundings.

Diffusion

The net movement of particles from a region of higher concentration to a region of lower concentration.

Transpiration

The loss of water vapour from the aerial parts of a plant, mainly through the stomata in its leaves.

Rate of photosynthesis

The amount of photosynthesis occurring per unit of time, measured using an appropriate indicator of the process.

Limiting factor

A factor that is in shortest effective supply relative to the plant's needs and therefore restricts the rate of photosynthesis.

Optimum temperature

The temperature at which the rate of an enzyme-controlled process is highest under the given conditions.

Organic compound

A carbon-containing compound associated with living organisms, such as carbohydrates, lipids and proteins.

Destarching

Keeping a plant in darkness for a sufficient period so that stored starch is used up, mainly through respiration.

Starch test

A chemical test using iodine solution to determine whether starch is present in a sample.

Independent variable

The factor deliberately changed by the investigator.

Dependent variable

The factor measured or observed to determine the effect of changing the independent variable.

Controlled variable

A factor kept constant so that it does not unfairly affect the results.

Control experiment

An experiment or comparison group used as a reference to help determine whether the independent variable caused the observed effect.

Reliability

The extent to which results are consistent when an experiment is repeated under the same conditions.

Validity

The extent to which an investigation tests what it is intended to test, without other factors unfairly influencing the outcome.

Hypothesis

A testable prediction about the relationship between variables.

Carbohydrate

An organic compound made primarily of carbon, hydrogen and oxygen that can serve as an energy source or structural material.

Cellulose

A complex carbohydrate that forms a major structural component of plant cell walls.

Storage carbohydrate

A carbohydrate stored for later use; starch is the main storage carbohydrate in plants.