Download Plant Review Answer Key

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Plant Systems Review
Explain the concept of feedback in plants? Include the vocabulary stimulus, positive
and/or negative feedback, and response.
Plants release hormones in response to a stimulus in the environment like light, touch, or
water. In a positive feedback scenario, plants would continue to release a hormone in
response to a stimulus. A negative feedback response would result in the removal of a
hormone in response to a stimulus.
Give an example of a stimulus that would cause a positive feedback loop and a negative
feedback loop.
If a plant were to identify the location of water in the environment, it will release a
growth hormone causing the plant to grow in the direction of the water source which
would be an example of positive feedback. A negative feedback loop would be a plant
releasing a ripening hormone until the fruit was developed. The hormone production
would stop.
There are environmental conditions listed on the top and side of the table below. Match
each condition on the table and describe an adaptation a plant could have to fit each set of
conditions.
Wet
Dry
Rocky
Sandy
Freshwater
Aquatic
Sunny and Hot
No cuticle,
shallow roots
Deep roots with
lots of root
hairs, water
storage
Waxy neeedlike
like leaves need
few nutrients
and prevent
water loss
Expansive root
systems with
high hair
content
No vascular
system
Sunny and Cold
Leaves droop to
eliminate
excess snow
accumulation
Slow growing
to reduce
energy needs
Short life
cycles reduce
the need for
consistent
energy
Floating seeds
Dark and Hot
Broad leaves to
capture small
amounts of sun
Dark and Cold
Needle leaves,
dark in color to
absorb more
sunlight
Difficult for
plants to
survive
Saltwater
Aquatic
Absorption of
nutrients from
the water
What adaptations have plants developed to supply their need for energy, food and
nutrients? Photosynthesis provides energy and complex root systems draw nutrients and
water into the plant. For non-vascular plants, they have adapted to different conditions
which do not require the large scale movement of nutrients and water throughout the
plant.
Some plants use __capillary_ action to draw fluid against the force of gravity and without
muscles. Explain why plants are able to do that.
How does water enter plant roots? Osmosis and negative pressure from transpiration
draws water into the roots of plants.
Explain the function of each of the following structures below (in plants)?
a. Stomata Stomata are made of guard cells and are responsible for balancing the
appropriate amounts of gas present inside the plant cells. Stomata also allow the
movement of water into the plant and out of the plant (transpiration)
b. Xylem The xylem moves water and nutrients from the soil up the plant.
c. Phloem The phloem moves food (sugar) and water from the leaves to the roots
d. Hormones Hormones are the only communication system that plants can utilize.
They have no nerves so hormones are sent in reproduction, growth, and in times
of stress.
e. Flowers Flowers are used to attract potential pollinators and contain all the
reproductive organs.
Describe the function of a guard cell and compare its purpose to the respiratory system in
animals? Guard cells become turgid (full) and open a pore in the leaves of plants to allow
the movement of CO2, O2, and water in and out of plants. These cells are similar to the
lungs or respiratory system in animals.
What is a tropism? If a plant were to respond to light, you might call that tropism what?
If a plant were to respond to the location of water, you might call that tropism what?
Tropisms are response systems in plants. Light response is known as phototropism, water
response is known as hydrotropism, and reponse to touch is known as thigmotropism.
The following is a list of plant hormone classifications: Auxins, abscisic acids,
cytokinins, gibberellins, and ethylene. What do these types of hormones control in a
plant? Auxins, cytokinins and gibberllins all function as growth stimulators while
abscisic acid is released in response to stress and ethylene is released to ripen fruit.
How are hormones carried through a plant?
The xylem and the phloem carries hormones transported in the water.
How does water and nutrient transportation differ in vascular and non-vascular plants?
Water and nutrient transportation occurs via the xylem and phloem in vascular plants. In
non-vascular plants, there is no transportation system so the plants must live in an area
where their nutrition and water needs are met. Non-vascular plants are simpler than
vascular plants.
Why would a plant store sugar and where would it store it?
Plants store sugar in their roots as a result of over production in the leaves. Leaves are
constantly producing sugar when conditions are sunny.
Why do some plants need bright flowers to help them?
Plants utilize bright flowers to attract potential pollinators. Other adaptations to attract
pollinators would include attractive scents.