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Cells and Systems 6-8 / Week 04 / Nature Day
6/6
Week 04 · Plant Cells Have More

Nature Day

Nature Day: Leaf vein hunt
// Cell walls, chloroplasts and the color green
⏱ about 20 min

Nature Day: Leaf Vein Hunt

Saturday morning, the crew heads out with the hand lens and the Windowsill Log.

Raven picks up a fallen leaf from the path and holds it to the sky. "What do you notice about the veins?"

"A net," Rocket says. "A midrib down the middle, branches off it, then smaller branches." He finds a blade of grass. "This one is all straight lines."

Nova hovers over both. "Two patterns," she says. "Net-like, and parallel. Both carry water and both reflect green."

Rocket holds the grass beside the leaf. "Different shapes, same xylem inside." Raven nods. "And cell walls holding every one up."

"Look from where you stand," Nova reminds them. "Fallen leaves only. Then hands washed."

  1. Plant cells have everything animal cells have, plus a cell wall, chloroplasts and a large central vacuole.
  2. The cell wall is rigid. It protects the cell, supports it and gives it shape. That is why a stalk stands upright.
  3. Chloroplasts hold chlorophyll, which captures light to make food. Chlorophyll reflects green, so leaves look green.
  4. Xylem conducts water up from the roots. Transpiration, water evaporating from leaves, pulls it upward.
  5. A full vacuole presses on the cell wall and keeps the plant firm. A plant wilts when its vacuoles lose water.
◇ FAMILY LEAF VEIN HUNT
Walk a garden, park or block together. Collect only fallen leaves from the ground, three or four different kinds.
Hold each leaf up to the sky. Sort them: veins in a branching net, or veins in parallel lines. Grasses are usually parallel.
Pick the greenest leaf and the least green. Talk about which has more working chlorophyll.
Back home, check the seed jar together. Add water if needed and measure the longest root and stem.
For a grown-up
Outdoors, the crew picks up only fallen leaves. Nothing growing is picked, and nests, insects and berries are only looked at.
Everyone washes hands after handling leaves or soil.
The facts in this week's recap come from the OpenStax textbooks Concepts of Biology and Biology, free at openstax.org.
Safety first
Collect only leaves already on the ground. Never pick from an unknown plant, and never touch berries.
Nothing found outside goes in your mouth.
Wash your hands when you come back inside.
THINK IT THROUGH
  • Read the question.
  • Tap your answer.
A leaf shows a midrib with branches forming a net. The biology text calls that pattern what?
Why does the greenest leaf look green?
Nature Day checkTrue or false?
Grass leaves usually have parallel veins.?
Leaf veins carry water.?
A leaf stands flat because its cells have no walls.?
WHY THIS EXERCISEVein patterns are the vascular tissue you colored in the celery, seen in a leaf.
Draw two leaves from your hunt: one with net-like veins and one with parallel veins. Label each pattern.
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