Exam notes plant tissues

• Simple Ground Tissue

  Parenchyma Tissue
• Parenchyma Tissue

  • Thin cell wall
  • Large vacuole
  • Round to oval in shape
  • Intercellular air spaces
• Functions of Parenchyma Tissue

  • Acts as packing tissue
  • Stores water, sugar (in fruit) and starch
  • Intercellular air-spaces allow gases and water to pass through the tissue
• Chlorenchyma

  Parenchyma cells that have chloroplasts
• Collenchyma Tissue

  Similar to parenchyma cells, but walls are unevenly thickened
• Collenchyma Tissue

  • Walls thicker at angles when viewed in transverse section
• Functions of Collenchyma Tissue

  Act as supporting tissue, especially in young stems and leaves
• Sclerenchyma Tissue

  • Have evenly thickened cell walls impregnated with lignin, giving strength
  • Cells have no cell contents and are therefore dead cells
• Functions of Sclerenchyma Tissue

  Provide mechanical support
• Meristematic tissue

  Actively dividing cells (mitosis)
• Meristematic tissue continued

  • Usually found at root and shoot tips (apical meristems)
  • Also responsible for increase in girth (thickness) of roots and stems (secondary meristems)
  • Eventually forms permanent tissue
• Permanent tissue


  • Cells not actively dividing for growth anymore, only for repair
  • Have become structurally specialised to perform specific functions
  • Found throughout the plant body except in meristematic regions
• Permanent tissue

  • Epidermal (roots, stems, leaves)
  • Parenchyma
  • Collenchyma
  • Conducting tissue (phloem, xylem)
  • Sclerenchyma
• Collenchyma tissue

  • Similar to parenchyma
  • Difference: walls are thicker at angles in transverse section
• Collenchyma tissue functions

  Act as supporting tissue in young stems and leaves
• Sclerenchyma functions

  Provide mechanical strength and support to the plant
• Epidermal Tissue

  A thin-walled, single layer of cells covering the whole plant, serving a protective function
• Epidermal Tissue

  • No intercellular air-spaces because they are tightly packed
  • Cells surrounding a stoma are kidney shaped with chloroplasts and are known as guard cells
  • Covered by a cuticle which is waxy and transparent
• Functions of the cuticle

  1. Reduce the loss of water vapour

  2. Allow sunlight to pass through for photosynthesis

  3. Protect against infection by viruses, bacteria and fungi
• Epidermal Tissue

  • Found in leaves and stems
• No cuticle is present in some epidermal cells, which are modified
• Epidermal cell

  • Nucleus
  • Vacuole with cell sap
  • Thin outer wall
  • Thick inner wall of guard cell
  • Pore/stoma
  • Chloroplast
• Epidermal cells

  • Some are modified into root hair cells
  • Have an elongated extension
• Root hairs are found only in the water absorption area of a root
• Functions of epidermal tissue

  • Protects the inner tissues in a plant
  • Cuticle restricts water loss by evaporation
  • Stomata and lenticels allow for gases to enter and leave the plant
  • Root hair cells increase surface area to increase water absorption from the soil
• Root hair cell

  • Cell membrane
  • Cell wall
  • Cytoplasm
  • Nucleus
  • Vacuole with cell sap
• Xylem tissue

  • Consists of dead, elongated, hollow tubes
  • Walls are lignified
  • May have thickened walls for strength
• Functions of xylem

  Transport water and mineral nutrients to leaves
• Animal tissues


  • Epithelial tissue
  • Connective tissue
  • Muscle tissue
  • Nerve tissue
• Epithelial tissue


  Covers the body or lines body cavities, organs, passages and ducts
• Epithelial tissue


  • Its main function is to protect the underlying tissue
  • Some epithelial tissues have a secondary function
• Epithelial tissue


  • Forms a single layer of cells on a basement membrane, except skin epithelium which has many layers of cells
• Types of epithelial tissue


  • Squamous epithelium
  • Columnar epithelium
  • Ciliated epithelium
  • Cuboidal epithelium
• Squamous epithelium


  Flattened cells found on surface of skin and lining of mouth, oesophagus, vagina, base of lungs and blood vessels
• Squamous epithelium


  • Protects underlying tissue
  • Allows passage of O2 and CO2 through the alveoli of the lungs
  • Allows substances in solution to pass through the blood capillary
• Columnar epithelium


  Has elongated cells with an oval-shaped nucleus at the base, found lining the intestines
• Columnar epithelium


  • Supports other cells
  • In small intestine, they aid in the absorption of food, water, vitamins and salts, having micro-villi to increase surface for absorption
  • Goblet cells secrete a protective mucus in the digestive tract
• Ciliated epithelium


  Has cilia (hair-like projections) on their free surface, found in the trachea, nasal passages and urogenital passages
• Ciliated epithelium


  • In the trachea, the cilia move dust particles trapped in the mucus towards the pharynx where it is coughed out
  • In the fallopian tubes of the female reproductive system, the cilia move the ovum (egg) towards the uterus
• Cuboidal epithelium


  Appears square-shaped in section, found in the kidney tubules and glands