Plants

1
Plants

• A study of multicellular organisms

2
Cell Specialization

• Why do cells specialize?
• Increase efficiency
• Division of labor
• What does efficiency look like?
• Special cell shapes, sizes, type and number of
  organelles, and locations in the organism

3
Cell Specialization

• The cell is the basic unit of life
• In multicellular organisms cells take on
  specialized roles to perform a specialized
  function.
• Tissues Groups of cells that perform the same
  function are called tissues
• Organ Different types of tissues can combine
  together to form an organ
• System Different organs can also work together
  to form a system

4
What are some functions done by different parts
of a plant?
Shoot System
Root System
5
Specialized cells in a leaf
6
Tissue Types in the Leaf

• Dermal Tissue
• Thin protective outer layer
• Ground Tissue
• Middle layers
• Vascular Tissue
• Cells specialized in transport

7
Dermal Tissue
8
Epidermal Cells

• Like skin cells, they form a protective layer on
  the upper and lower surface of the leaf
• one cell layer thick
• Arranged in a flat tightly knit sheet
• Transparent to allow sunlight to pass through to
  cells that specialize in photosynthesis layer

9
Cuticle

• Covers the epidermis to prevent water loss
• Waxy substance secreted by the leaf cells
• Also protects from disease causing
  micro-organisms

10
Stomata and Guard Cells

• Small openings in the epidermal layer
• Allow gasses and water to enter and leave the
  leaf
• Mostly found on the underside of the leaf
• Each stoma has 2 guard cells that regulate the
  stomas size

11
Micrographs of Stomata
12
Ground Tissue
13
Ground Tissue

• The majority of the plant
• Located under the epidermis
• In the stem
• Provides strength, support
• In the roots
• Food and water storage
• In the leaves
• Where photosynthesis occurs

14
What functions occurs inside a leaf?

• Photosynthesis!!!
• Leaves are flat and have a lot of surface area so
  that they can absorb the suns rays and use the
  energy to create glucose.
• What is the chemical formula for photosynthesis?
• CO2 H2O C6H12O6 O2

15
Where does photosynthesis occur?

• Chloroplasts
• Contain special pigments that capture light
  energy
• Therefore, leaf cells contain a lot of
  chloroplasts

16
Palisade Tissue Cells

• Cells that are structured and arranged to
  maximize efficiency for photosynthesis
• Form a distinct layer in the leaf
• Long, and narrow (look like columns)
• Tightly packed
• Contain many chloroplasts

17
Spongy Tissue Cells

• Located below palisade tissue cells
• Round and loosely packed, lots of air spaces
• Helps exchange gasses and water with the
  environment
• Contain some chloroplasts (thus, perform
  photosynthesis)