Plant organs, xylem and phloem
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Model of a leaf (model, not to scale)
Two boxes, the air and the leaf. An arrow marked carbon dioxide runs from the air into the leaf through the stomata. An arrow marked water vapor runs from the leaf to the air through the stomata. In the model, the guard cells close the stomata, so both arrows are cut.
Ren reads a model of a leaf. In the model, the guard cells keep the stomata closed all day in bright light. What happens, and why?
- Water loss falls and sugar-making stays the same, because stomata are for water, not gases
- Water loss falls and sugar-making slows, because less carbon dioxide enters
- Water loss falls and sugar-making rises, because the leaf keeps its water
- Water loss rises and sugar-making slows, because the guard cells swell
Model of a plant (model, not to scale). Kira reads a model of a plant. In the model, the phloem is blocked just below the leaves. What happens to the roots, and why?
- They receive the same sugar, because roots make their own
- They receive less sugar, because phloem brings them sugar from the leaves
- They receive the same sugar, because the xylem brings them sugar from the leaves
- They receive less water, because the phloem brings them water
Two cards side by side as one table (model data)
hour stomata water lost in that hour (mL) 0 closed 0 6 partly open 4 12 wide open 10 18 partly open 4 Esme reads two cards for one model plant on a sunny day, shown side by side. What happened from hour 6 to hour 12, and why?
- The water lost rose by 6 mL per hour as the stomata closed
- The water lost rose by 10 mL per hour as the stomata opened wider
- The water lost rose by 6 mL per hour as the roots pumped harder
- The water lost rose by 6 mL per hour as the stomata opened wider
The textbook says up to 90 percent of the water the roots take up may be lost through the leaves. Luz reads a model data card of one plant. On which day did the leaves lose the largest share of the water the roots took up?
- No day stands out, since the share is the same each day
- Day 2, where the leaves lost the most water, 192 mL
- Day 3, where the leaves lost 90 of the 100 mL taken up
- Day 1, where the leaves lost 150 of the 200 mL taken up
Notebook (textbook facts)
line what it says 1 The shoot system includes the leaves and stems 2 Roots anchor the plant and absorb water and minerals 3 Dermal tissue covers and protects the plant 4 Ground tissue carries water and minerals up to the leaves Pia reads a notebook on plant structure. Exactly one line is wrong. Which line, and why?
- Line 4, because vascular tissue, not ground tissue, carries water and minerals
- Line 3, because dermal tissue, not vascular tissue, carries the water to the leaves
- Line 2, because roots make the sugar the plant needs
- Line 1, because the leaves belong to the root system
Use this
Notebook (textbook facts), 4 rows. Columns: line, what it says. 1, Xylem carries water and minerals up from the roots. 2, Phloem carries sugar from sources to sinks. 3, A leaf can be a source, and a root can be a sink. 4, Phloem carries sugar down from the leaves to the roots and nowhere else.
Jun reads a notebook on transport in plants. Exactly one line is wrong. Which line, and why?
- Line 1, because the phloem carries water and minerals up
- Line 2, because the xylem carries sugar from sources to sinks
- Line 4, because phloem also carries sugar up to shoot tips and seeds
- Line 3, because a root makes sugar and so is a source
Use this
Notebook (textbook facts), 4 rows. Columns: line, what it says. 1, Two guard cells surround each stoma and open and close it. 2, Open stomata let carbon dioxide in and let oxygen and water vapor out. 3, Water vapor leaving the leaf is the main driver pulling water up the xylem. 4, When the stomata close, the leaf takes in the same amount of carbon dioxide.
Tala reads a notebook on stomata. Exactly one line is wrong. Which line, and why?
- Line 3, because the roots pump the water up the xylem
- Line 1, because the guard cells sit inside the xylem
- Line 2, because stomata let water vapor out but no gas in or out
- Line 4, because closed stomata let less carbon dioxide into the leaf
Card (a model example of a textbook fact: a tuber can be a source or a sink, depending on stage and season)
season which way the phloem sugar moves at the tuber Summer from the leaves into the tuber Spring from the tuber to the new shoots Ari reads a card about an underground tuber. Why does the tuber receive sugar in summer but send sugar out in spring?
- A tuber is a sink while it fills with sugar and a source when it feeds new shoots
- The leaves stop in spring, so the tuber takes sugar from the soil
- Sugar moves down in the phloem, so the spring movement must be the xylem
- The tuber makes its own sugar underground, so it is a source in both seasons
Card (textbook facts)
time stomata water vapor leaving the leaves water in the xylem Noon open leaving pulled up Night closed stopped held in place Zee reads a card about a tall plant at night. The stomata are closed and no water vapor leaves, yet the water stays in the xylem. Why?
- The cuticle seals the xylem at night, so the water cannot move
- The phloem holds the water in place until the stomata open again
- The root cells pump the water up at night, which stops it from sinking
- Water molecules cling to each other and to the xylem walls, which holds the water in place
Use this
Card (textbook facts), 2 rows. Columns: part of a prickly pear cactus, what it does. Leaves, are spines, which have little surface for their size and so cut water loss. Stem, carries out photosynthesis and stores water.
Milo reads a card about a cactus. Its leaves are spines, so it has no flat leaves, yet it makes sugar. How, and why does this help in a dry place?
- The spines make the sugar, and the stem loses less water
- The cactus takes sugar from the soil, so it needs no leaves
- The roots make the sugar, and the spine leaves hold more water
- The stem makes the sugar, and the spine leaves lose less water