39 terms

7th Grade Science - Plant Unit (Tropism, Turgor Pressure, etc)

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When plants begin to wilt, it is said that they are experiencing _________ turgor pressure
Low
Once plants fill their vacuoles with water, the cells are now experiencing ___________turgor pressure
High
Plants need ____________when they are experiencing low turgor pressure
Water
When a plant is wilting, the force is greatest at what part of the plant cell?
Cell Wall
When a plant is wilting, the force is weakest at what part of the plant cell?
Vacuole
Define osmosis
The ability for water and other nutrients to pass through the cell membrane
Define a flaccid cell
A cell with a low pressure vacuole and the cell wall caves inward
Define a turgid cell
A cell with a high pressure vacuole and the cell walls are tough and rigid
Define tropism
A plant's response to a stimulus
Define stimulus
Any action that causes a response
Define response
Any reaction to a stimulus
Define geotropism
A plant's response to gravity
Define phototropism
A plant's response to light
Define thigmotropism
A plant's response to touch
Define hydrotropism
A plant's response to water
This picture reflects geotropism
gravity
This picture reflects phototropism
The plant will bend in response to the light
This picture reflects thigmotropism
because they touched, they began to wrap
This picture reflects hydrotropism
roots will grow towards water, in search of what it needs
This picture shows both positive & negative geotropism
Roots of a plant growing down (positive); stem of the plant growing up (negative)
This photo illustrates negative geotropism
even on its side, the stem will grow up (negative)
This plant relies on Thigmotropism
Venus Fly Trap; when touched, it closes and traps its prey
Water expands when it freezes. How can plant tissue be affected when temperatures approach freezing?
The water in the cell vacuole expands, causing the cell to burst. Plant tissue is damaged and thus the plant dies.
What is a vascular plant?
Plants that have a series of bundles or veins (xylem & phloem) to carry water and nutrients throughout the cell, over large distances; As a result, these plants can grow very tall
What is a nonvascular plant?
Plants that lack xylem & phloem; they are able to only pass material from cell to cell; As a result, these plants cannot grow very tall
(examples: moss & algae)
Define xylem
Vascular tubes that carry water from the roots UP to other parts of the plant
Define phloem
Vascular tubes that carry sugar from photosynthesis and other nutrients UP & DOWN the plant
This picture illustrates xylem vs. phloem (be able to differentiate them by looking at a picture!)
Define germination
A seed's readiness to become a plant; the ability to produce roots and shouts
With proper amounts of water, a seedling may __________________.
Emerge
3 factors that must be present for seed emergence
-lots of water & nutrients
-energy that has been stored inside the seed coat
-enough force to push the seedling through the soil
What do the seeds outgrow when they swell, becoming ready to grow into a plant?
The seed coat
Which part of the new seedling or plant emerges from the seed first?
The root
What is the function of the root?
To absorb water and nutrients from the soil and to anchor the seedling into the soil
Define photoperiodism
A plant's response to the number of hours of daylight and darkness it receives daily; controls when a plant may flower
Another name for geotropism
Gravitropism
Define long-day plants
Form flowers when days become longer; bloom in the spring and early summer
Define short-day plants
Form flowers when days become shorter; bloom in late summer and autumn
Define diffusion
Movement of particles from an area of high concentration to an area of lower concentration
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