FINALS II BIOLOGY 2 - PLANTS (ORGAN SYSTEM)

• Plants


  • Green in color - caused by chlorophyll
  • Have structures (usually roots) to anchor them in place
• Plants make their own food by photosynthesis. This means they do not need to move around in search of food. They also do not need complicated organ systems found in animals.
• Functions plants need to perform


  • Exchange gases with their surroundings
  • Have an internal transportation system to move water and nutrients around their body
  • Reproduce
• Tissue


  Cells working together to form a tissue
• Organ


  Different types of tissues working together to perform a unique function
• Organ system


  Organs working together
• Plant tissues


  • Dermal tissue
  • Ground tissue
  • Vascular tissue

  
• Dermal tissue


  • Covers the outer surface of herbaceous plants
  • Composed of epidermal cells, closely packed cells that secrete a waxy cuticle that aids in the prevention of water loss
• Ground tissue cells


  • Parenchyma
  • Collenchyma
  • Sclerenchyma

  
• Parenchyma


  Cells that are alive at maturity, function in storage and photosynthesis
• Collenchyma


  Cells that support the plant, characterized by thickenings of the wall, alive at maturity

  
• Sclerenchyma


  Cells that support the plant, characterized by thickenings in their secondary walls, dead at maturity
• Vascular tissue


  • Xylem
  • Phloem

  
• Xylem


  Made up of elongated cells that are not living, transports water and dissolved minerals upward from the roots
• Phloem


  Made up of elongated cells that are living, transports food materials and hormones throughout the plant (upward or downward)
• Functions of plant organs


  • Roots - Anchorage, Absorption, Storage, Conduction
  • Stems - Support, Transport
  • Leaves - Photosynthesis
• Roots


  • Organ of a plant that typically lies below the surface of the soil
  • Can also be aerial that is growing up above the ground or especially above water
  • Non-leaf, non-nodes bearing parts of the plant's body
• Functions of roots


  • Absorption of water and inorganic nutrients
  • Anchoring of the plant body to the ground, and supporting it
  • Storage of food and nutrients
  • Vegetative reproduction and competition with other plants
• Types of root systems


  • Taproot
  • Fibrous
  • Adventitious
  • Tuberous
• Taproot


  • Large, central, and dominant root from which other roots sprout laterally, somewhat straight and very thick, tapering in shape, and grows directly downward
• Fibrous root system


  • Opposite of a taproot system, usually formed by thin, moderately branching roots growing from the stem
• Adventitious root system


  • Develops from part of the plant, a number of main roots develop at one spot and at similar thickness
• Tuberous roots


  • Swollen structure on fibrous root used to store carbohydrates (e.g. sweet potato)
• Stem


  • Central axis to which all other parts are attached, one of two main structural axes of a vascular plant
• Functions of a stem


  • Supports the leaves, flowers and fruits and connects them with the roots
  • Conducts water, nutrients and the products of photosynthesis to and from roots and leaves
  • Helps store water and the products of photosynthesis
  • Young green stem also performs a minor role in the production of food through the process of photosynthesis
  • Serves as a means of asexual reproduction in many plant species
• Parts of a stem


  • Node - point on the stem from which leaves or buds arise
  • Internode - portion between two successive nodes
  • Bud - embryonic stem which has the potential for further plant growth
  • Terminal bud - single bud found at the apex of the stem
  • Lateral/axillary buds - occur in the leaf axils, the upper angle between the stem and leaves
• Leaves


  • Powerhouse of plants, major site of food production for the plant, structures within a leaf convert the energy in sunlight into chemical energy that the plant can use as food
• Functions of leaves


  • Carry out photosynthesis in order to make glucose
  • Composed of epidermal, vascular and ground tissue
• Chlorophyll


  Molecule in leaves that uses the energy in sunlight to turn water (H2O) and carbon dioxide gas (CO2) into sugar and oxygen gas (O2)
• Leaf epidermis


  • Transparent so that sunlight can go through
  • Waxy cuticle protects against drying out
  • Lower epidermis has stomata with guard cells for gas exchange (CO2, H2O in; O2 out)
• The epidermis also secretes a waxy substance called the cuticle, which protects the leaf from insects, bacteria, and other pests
• Gases enter and exit the leaf through the stomata
• Most food production takes place in elongated cells called palisade mesophyll, and gas exchange occurs in the air spaces between the oddly-shaped cells of the spongy mesophyll
• Flower


  • Part of the plant that makes the seeds, reproductive structure found in flowering plants

  
• Parts of a flower


  • Accessory parts - Petals, Sepals
  • Female part - Pistil (Stigma, Style, Ovary, Seeds)
  • Male part - Stamen (Filament, Anther)
• Organ systems of plants


  • Shoot system - Vegetative (non-reproductive) parts like leaves and stems, Reproductive parts like flowers and fruits
  • Root system - Supports the plants and absorbs water and minerals, usually underground
• Functions of the shoot system


  • Photosynthesis
  • Reproduction
  • Storage
  • Transport
  • Hormone production
• Functions of the root system


  • Anchorage
  • Absorption
  • Storage
  • Transport
  • Production of certain hormones