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Xylem
The vascular tissue through which water and nutrients move in some plants.
Phloem
The vascular tissue through which food moves in some plants.
Photosynthesis
Chemical reactions that convert light energy, water, and carbon dioxide into the food-energy molecule glucose and give off oxygen.
Starting materials of photosynthesis
Carbon dioxide and water.
End products of photosynthesis
Glucose and oxygen.
Location of photosynthesis in a plant
Occurs in the leaf.
Epidermal layer
On the bottom, it contains the stomata; epidermal cells can produce a waxy covering called the cuticle which helps to protect the leaf from insects and to keep water inside.
First step of photosynthesis
Light energy is captured.
Second step of photosynthesis
Making sugars; this can occur without light and carbon dioxide combines with the hydrogen atoms created from splitting of the water molecules to form sugar molecules.
Pigments
Chemicals that absorb light.
Importance of photosynthesis
Plants help maintain the atmosphere that we breathe, and photosynthesis produces most of the oxygen in the atmosphere.
Cellular respiration
A series of chemical reactions that convert the energy in food molecules into a usable form of energy called ATP.
Starting materials of respiration
Glucose and oxygen.
End products of respiration
Carbon dioxide, water, and oxygen.
Importance of cellular respiration
If we break down food we could not get energy; plants produce sugar but they also have to undergo respiration to break down the sugars to grow, reproduce, and repair tissues.
Environmental stimuli for plants
Plants respond to different environmental stimuli including light, touch, and gravity.
Positive tropism
When a plant grows toward the stimulus.
Negative tropism
When a plant grows away from the stimulus.
Phototropism
The growth of a plant towards or away from light.
Benefit of phototropism
Helps plants grow toward light.
Thigmotropism
The response of a plant to touch.
Starting materials for thigmotropism
Auxin and ethylene.
End products of thigmotropism
Bending towards the sun.
Tendrils
Structures that respond to touch and can wrap around or cling to objects.
Gravitropism
The response of a plant to gravity.
Stem response to gravity
Stems grow away from gravity.
Root response to gravity
Roots grow towards gravity.
Gravitropism dependence on light
No.
Photoperiodism
A plant's response to the number of hours of darkness in its environment.
Long-day plants
Plants that flower when exposed to less than 10-12 hours of darkness.
Short-day plants
Plants that require 12 or more hours of darkness for flowering to begin.
Day-neutral plants
Plants that flower when they reach maturity and the environmental conditions are right.
Auxin
Generally causes increased plant growth; cells tend to grow longer, and plants grow toward light.
Ethylene
Helps stimulate the ripening of fruit and causes leaves to drop.
Gibberellins
Increase the rate of cell division, cause cell elongation, and increase growth in stems and leaves.
Cytokinins
Increase the rate of cell division in some plants and slow the aging process of flowers and fruits.
