9th Grade Plant part, Photosynthesis and Cellular Respiration

PLANTS

• Plants are a primary source of food for people and animals.

• Produce oxygen & absorb carbon dioxide.

• Also slow wind speed, provide home for wildlife, etc.

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PARTS OF A PLANT (four basic parts)

• Leaves make food through photosynthesis and carry out gas exchanges.
• The Stomata is the openings usually on bottom of leaves.
• Guard cells open and close the stomata as they fill up with and lose water
• Internal Leaf Structure:
  • The Cuticle is a waxy waterproof coating on the leafs upper surface.
  • The Epidermis is the top and bottom layer of cells. 
  • The Palisade Layer is the layer of cells where most photosynthesis occurs. Cells are arranged in columns.
  • The Spongy Mesophyll is where gas exchange occurs from stomata. Cells are spaced loosely. 
  • The Xylem carries water absorbed by the plants roots up into the leaf.
  • The Phloem carries food made during photosynthesis throughout the plant.
• Stems contain vascular bundles of xylem cells that carry water and minerals up, and phloem cells carry food down and support leaves & reproductive structures (flowers, cones, etc).  
  • Roots Anchor plant, carry water and minerals in from soil, reproduce, and store food. 

PHOTOSYNTHESIS

• Photosynthesis is the process in which chlorophyll and light energy convert CO2 and H2O into sugar/glucose (and release oxygen) ; makes food for the plant! 

  • The glucose eventually gets stored as starch.

• The two stages of photosynthesis are the light dependent reactions, then the light independent reactions.

• The Photosynthesis Equation is 6CO2 + 6H2O → C6H12O6 + 6O2

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CELLULAR RESPIRATION

• The Mitochondria is the site of respiration (powerhouse of the cell).

  • It breaks down glucose to synthesize ATP.

• Respiration is making usable energy from food (Making ATP).

• Chemical energy is converted to usable energy in this process. 

• AEROBIC RESPIRATION requires oxygen.

  • 36 total ATP from one glucose, 2 from glycolysis, 2 from krebs cycle, and 32 from electron transport for the process to take place.
  • The aerobic respiration equation is C6H12O6 + 6O2 → 6CO2 + 6H20 + energy.

• Carbon dioxide & water are the waste products/byproducts of aerobic respiration.

• The process occurs in three steps: glycolysis, krebs cycle, and electron transport. 

• ANAEROBIC RESPIRATION does not require oxygen and is less efficient; only 2 ATP produced

  • With no oxygen, respiration can only occur through glycolysis only or fermentation. 
  • Anaerobic respiration signals muscle fatigue.
  • Fermentation occurs in yeast & bacteria.