Chapter 8

Plant Processes and reproduction

LESSON 1 – Energy Processing in Plants

  • Xyzlem and phloem, the vascular tissue in plants, transport materials throughout a plant
  • Plants require oxygen and carbon dioxide to make food
  • Most plants make their own food – a liquid sugar

Photosynthesis: a series of chemical reactions that convert light energy, water, and carbon dioxide into the food-energy molecule glucose and give off oxygen.

  • Most photosynthesis occurs in two types of mesophyll cells:
  • Chloroplasts
  • Palisade Mesophyll cells

Steps of Photosynthesis:

  • Light capture in Chloroplasts.
  • Chlorophyll traps and stores light energy, which can be transferred to other molecules.
  • Water molecules are split apart – releasing Oxygen (O2) into the atmosphere.
  • Chloroplasts convert Carbon Dioxide (CO2) from air into sugars – this is done by using the energy stored and trapped by chlorophyll.
  • Carbon Dioxide combines with Hydrogen atoms (H) from the splitting of water molecules, and forms sugar molecules.
  • Plants can use the sugar as an energy source, or can store it.

Cellular Respiration: a series of chemical reactions that convert the energy in food molecules into usable form of energy called ATP.

Glucose molecules break down during cellular respiration. Energy released during this process is used to make ATP, an energy storage molecule.

  • Process requires oxygen, produces water and carbon dioxide as WASTE PRODUCTS
  • Occurs in the Cytoplasm and Mitochondria of cells

RESPIRATION TABLE (Chapter page 273)

LESSON 2 – Plant Responses

Stimuli: any changes in an organism’s environment that cause a response.

Tropism: a response that results in plant growth toward or away from a stimulus.

  • Light
  • Touch
  • Gravity

Photoperiodism: a plant’s response to the number of hours of darkness in its environment.

  • Long-Day Plants
  • Short-Day Plants
  • Day-Neutral Plants

Plant Hormone: Substances that act as chemical messengers within plants.

  • Auxins – plant hormone which generally causes increased plant growth. They are responsible for phototropism, the growth of a plant toward light.
  • Ethylene – plant hormone which helps stimulate ripening of fruit.
  • Gibberellins and Cytokinins – produced in the rapid growth areas of plants, such as roots and stems. These hormones increase the rate of cell division and cell elongations.
  • Root Tips – produce most of the cytokinins.
  • Xylem carries cytokinins to other parts of a plant and slow the aging process of flowers and fruits.

LESSON 3 – Plant Reproduction

Alternation of Generations

Spore

Pollen Grain

Pollination

Ovule

Embryo

Seed

Stamen

Pistil

Ovary

Fruit