Unit 1 element 4 terms

Cell wall

part of a plant cell containing cellulose which is permeable, allowing gases and liquids through.

Lignin

an organic polymer found in plant cell walls that provides structural rigidity, water transport and decay resistance.

Cell membrane

part of a plant cell wall controlling movement of water/food/minerals in and out of the cell.

Cytoplasm

The contents of a plant cell membrane, it is a colloid containing the organelles.

Organelles

Located in the cell membrane cytoplasm, perform specific functions pessary for cell life, acting like tiny organs.

Colloid

the term which describes the make up of the cell membrane cytoplasm

Nucleus

part of a plant cell which controls the activity of the cell and contains the DNA.

Vacuole

Part of the plant cell, a large permanent fluid-filled cavity which holds the plant cell firm.

Chloroplast

an organelle in a plant cell (mainly leaves) that contains the pigment chlorophyll, which is vital for photosynthesis as it has the ability to capture light energy.

Mitochondria

an organelle in a plant cell with folded membranes where respiration takes place.

Intercellular space

The space between plant cells which allow gases to diffuse between them

Plant tissue

groups of cells within a plant which have different specialised functions in the plants metabolism

Epidermis

a protective plant tissue, the outer layer of cells around all parts of the plant.

Cuticle

a coating secreted by a plants epidermis that helps the plant retain water

Cambium

the meristematic tissue of a plant where active cell division takes place and new cells are created for growth.

Primary meristems

the cambium found at the growing tips of all plant roots and shoots

Apical meristem

the meristem at the tip of the main growing stem/root

Lateral meristem

the vascular cambium that allows for stem thickening, found in stems and branches of woody eudicot plants.

Secondary thickening

Stem thickening which occurs in the stems and branches of wood eudicot plants

Vascular tissue

plant tissue consisting of xylem and phloem, which conduct liquid and food round the plant, vital in connecting leaves, stem and roots.

Xylem tissue

groups of elongated plant cells which have no end walls, allowing water and nutrients to flow up through the plant

Tracheids

elongated, lignified dead cells within the xylem of a vascular plant, designed for water condition, mineral transport and structural support.

Lumen

the hollow, interior space of a vein/artery

Phloem tissue

plant tissue which is made up of food transport cells

Vascular bundle

the vascular system in a plant made up of the phloem, xylem and cambium (Eudicots) and phloem and xylem (monocots)

Bundle sheath

a tissue which strengthens the rigidity of a monocot stem

Endodermis

a band of tissue within a plant root which controls the passage of water as it is absorbed by the root hairs and travels towards the xylem tissue and upwards through the plant.

Cortex

a thick layer of general plant root tissue which stores food and and produces energy for root growth.

Pericycle

a ring of meristem tissue in a root from which new roots are made

Stele

the central core or cylinder of vascular tissue in a plant stem or root, functions as the primary transport system for water and nutrients.

Pith

the soft spongy tissue locate at the very centre of the stems of most vascular plants.

Cuticle

a protective waxy coating on a leaf which helps stop it drying out

Epidermis

a single layer of tissue protecting the surface of the leaf

Stomata

openings in a leaf which allow exit and entry of gases and water vapour.

Palisade cells

Mesophyll (middle layer) tissue in leaves which contain the most chloroplasts, where photosynthesis takes place.

Spongy mesophyll

loose packed cells in spongy tissue with lots of inter-cellular spaces to allow free movement of gases and water vapour, stomata open into these spaces.

Guard cells

parts of a leaf which sit either side of stoma and open in daylight and close in darkness.