1. Tropisms and Photosynthesis

2. Tropisms Tropism is the growth of a plant towards or away from a stimulus A Stimulus is something that causes change like light, gravity, water, or contact. There are positive and negative tropisms: – Positive Tropisms are towards the stimulus – Negative Tropisms are away from the stimulus

3. Phototropism/Gravitropism

4. Types of Tropisms Phototropism ‘Photo-’ means ‘light’ Phototropism is the bending of a plant towards light (remember that ‘towards’ is a positive tropism) This is caused by a plant hormone called Auxin Auxin promotes plant growth and cell elongation.

5. Types of Tropisms Gravitropism AKA Geotropism ‘Gravi-’ refers to ‘Gravity’ Gravitropism is the bending of a plant towards or away from gravity -Roots are a positive gravitropism and grow towards gravity -Shoots are a negative gravitropism and grow away from gravity

6. Thigmotropism

7. Types of Tropisms Thigmotropism ‘Thigmo-’ refers to ‘Touch’ Thigmotropism is the bending of a plant in response to touch You see this with vines that twist around trees or buildings This is what venus fly traps are able to do

8. Venus Fly Traps

9. Types of Tropisms Hydrotropism Hydro – means “water” Hydrotropism is the bending of a plant towards water. This is what happens with tree roots when they get into the pipes in your house.

10. Photosynthesis Plants utilize tropisms to increase the amount of sunlight that they can acquire to maximize photosynthesis See if you can write the chemical equation for photosynthesis in your notebook. Reactants → Products

11. Photosynthesis Now I will give you the components, see if you can get them on the correct side of the equation: C 6 H 12 O 6 Energy H2OH2O O2O2 CO 2 ? ?

12. Photosynthesis Here is the equation with everything on the correct side. Check your work, but remember that it doesn’t matter which order you have them in so long as they are on the correct side. __CO 2 + __H 2 O + Energy  __C 6 H 12 O 6 + __O 2 Now Balance the Equation

13. Photosynthesis Your final equation should look like this: Now write the equation for Respiration!

14. Name that Tropism! What type of tropism is this? Positive or Negative? Gravitropism Negative

15. Name that Tropism! What type of tropism is this? Positive or Negative? Thigmotropism Positive

16. Name that Tropism! What type of tropism is this? Positive or Negative? Gravitropism Positive

17. Name that Tropism! What type of tropism is this? Positive or Negative? Phototropism Positive

18. Name that Tropism! What type of tropism is this? Positive or Negative? Positive Hydrotropism

19. Name that Tropism! What type of tropism is this? Positive or Negative? Thigmotropism Positive

20. Name that Tropism! What type of tropism is this? Positive or Negative? Phototropism Negative