This document provides an overview of key concepts in plant form and structure. It discusses the main tissue and cell types found in plants, including primary and secondary cell walls. It also describes the main plant organs - roots, stems, and leaves - and their functions. Roots anchor the plant and absorb nutrients, stems provide structure and transport nutrients, and leaves perform photosynthesis. The document outlines the types of meristematic and vascular tissues and their roles in plant growth and transport.

1. AP Biology - Core Concept Cheat Sheet
17: Plant Form
Key Concepts
Plant Tissue and Cell Types
• Primary Cell Wall: Cell wall of parenchyma and
meristems; Contains cellulose, hemicellulose and pectin, all
polysaccharides; Function: protection, shaping cells
• Secondary Cell Wall: Cell wall of sclerenchyma,
collenchyma and xylem; Have secondary deposits of
lignified cellulose; Provide mechanical strength to the
tissue.
• Plasmodesmata: A structure connecting two neighboring
cells for cell-cell communication.
• Pits: Holes on cell wall to allow cell-cell communication. A
pit may or may not contain a plasmodesmata.
• Fibrous root: Roots branching and re-branching, most
grass species have this type of roots
• Tap root: Main root growing downward, the primary root,
grows much larger than the secondary roots. Most of the
trees have this type of root.
• Apical Meristem: A type of embryonic tissue in plants
consisting of unspecialized meristematic cells and found
in tips of roots and shoots
• Lateral meristem: Meristem tissues found in stems or
roots for growing laterally (thicker).
• Bud: A bud is an undeveloped shoot and normally occurs in
the axil of a leaf or at the tip of the stem. Once formed, a
bud may remain for some time in a dormant condition, or it
may form a shoot immediately.
Plant Body
Root
o Usually under the ground
• Function
o Anchor plants to soil
o Absorb and transduct
nutrients
• Types
o Major types: fibrous root
and tap root
o Modified roots have various
functions such as food
storage
Leave
Stem
Root
Stem
o A stem is the part of a
plant from which shoots and buds arise.
• Function
o Structural support (leave and fruit)
o Growth through increase in diameter (girth) and
elongation
o Transport of fluids between the roots and the leaves.
• Types
o Tubers – potato, food storage
o Stolons – strawberry; Generating new plants
o Bulbs – Tulips, Onions, storage of food
o Corms – Taros, Storage of Food
Epidermal Tissue
• Epidermal Cells:
o
A single layer of cells that cover plants
o
Secrets a layer of cuticular wax for protection
• Guard Cells:
o A specialized cell on the undersurface of leaves
o A hole exists between a pair of guard cells
o Controlling gas exchange and water loss
• Trichomes/Roothairs
o Hair-like outgrowth on the surface of a plant
o Protective and absorbing nutrients
Ground Tissue
• Parenchyma Cells:
o Most abundant, thin primary wall
o Food storage,
o Photosynthesis
o Aerobic respiration
• Collenchyma cells:
o Collenchyma cells
o Thick primary wall
o Providing support for young tissue
• Sclerenchyma cells
o Rigid secondary Wall
o Dead when mature
o Support the plant
Vascular Bundle Tissue
• Xylem
o The main water-conducting tissue.
o Contains vessel elements and tracheids
o Both cell types have rigid, lignin-containing secondary
cell wall
o Both dead when mature
• Phloem
o The principal food-conducting tissue in vascular plants.
o Contains sieve cells and sieve-tube members
o These cells form tubes to conduct food
Meristem: Plant embryonic tissues
• Apical Meristem
o Located on tips of stem or root
• Lateral Meristem
o For growth and thickening of stem and root
Plant Cell
Leave
• Function
o Photosynthesis
Flowers
• Function
o Reproduction
• Structure
o An anther and a filament form a stamen, the male
reproduction organ
o Carpel is the female reproduction organ
o Sepal and pedal
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