week 7 (plant structure and function)

• Plants cells contain chloroplasts (with chlorophyll) and have vacuoles not seen in animal cells
• Plant cells have rigid cells walls that contain cellulose, making that one of the most abundant plant-derived molecules on Earth
• Cuticle: Outer waxy layer on leaves that reduces water loss
• Cell wall: Multi-layered structure which protects cells
• Middle lamella: Separates primary and secondary cell wall
• Plasmodesmata: Cytoplasmic connections between cells
• Cellulose: Glucose molecules forming a long chain
• The primary cell wall contains cellulose, while the secondary cell wall has hemi-cellulose and lignin, which provides cell wall strength and thickening
• Secondary growth seen in trees is due to the thickening of secondary cell walls
• The middle lamella holds individual cells together, containing pectin and calcium
• Plasmodesmata: connections between plant cells that facilitate communication, signals, and transport of materials between cells
• Label this plant structure

  A) reproductive shoot

  B) apical bud

  C) shoot

  D) root

  E) stem

  F) leaf

  G) roots

  H) internode

  I) node

  J) apical bud

  
• Identify the leaf types

  A) simple

  B) compound

  C) doubly compound

  
• Leaves are the primary site for photosynthesis, where sugar is formed from carbon dioxide, water and oxygen is produced
• Leaves have an upper epidermis and a lower epidermis. In between are mesophyll cells – palisade mesophyll and spongy mesophyll
• Leaves have a cuticle on the surface that contain waxes (hydrophobic) that reduces water loss (transpiration)
• Stems provide physical support to the plant and are also involved in movement of water and nutrients up the plant through the vascular system (xylem and phloem)
• The apical meristem is the region of the shoot that grows vertically with actively dividing cells
• Axillary buds grow into side shoots
• Stems can be used to store food or water
• Stems allows for lateral growth to increase width
• Meristems are actively growing regions found at the tips of shoots and roots of plants that allow for continued growth
• Growth of side shoots from stems is also due to axillary bud meristems
• The expansion of width of stems (lateral growth) is also due to the activity of lateral meristems, especially cambium.
• Roots anchor the plant in the soil, absorb water, store nutrients, and allow for continued growth through its meristems
• Roots have a large surface area