Plants-5th Grade Chapter 1 Lesson 3
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List plant parts
Look and wonder
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How are plants classified?
All plants need space, air, water, and sunlight
Obtain air and sunlight directly from environment
Water can be more difficult
Nonvascular- small and survive without a transport system.
Ex.: Mosses reach heights of a cm or less. Part directly touch the ground to
absorb water.
Vascular- do not have the same size limits.
Ex.: Trees can grow more than 200 ft.
Divided into seed and seedless plants
Seed plants- Ex: pine trees/flowering plants
A seed contains an undeveloped plant, stored food and a protective covering (PC)
PC prevents seed from drying out or damage
Undeveloped uses store food to grow and develop
Seedless- Ferns; produce spores
A spore is a single cell that can develop into a new plant exactly like the plant
that produced it.
Spores have tough outer covering – protects from drying out until the find the
right conditions for growth.
2 main types of seed plants:
 Gymnosperm- No flowers/hard seeds uncovered (G)
 Angiosperm- Produces flowers/covered by fruit (A)
Ex.: “G” – pines, firs, and cone-bearing trees
Ex.: “A” – fruits like apples and plums. Other are smaller and less colorful fruits;
grasses
“A” most plentiful of all plant types 250,000 kinds.
Ex.: Tulips, maple trees, rosebushes, and corn
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What are roots?
Root is the part of the plant that absorbs water and minerals, stores food, and
anchors the plant.
Roots absorb water by using fuzzy root hairs which are a thread like projection
from a plant root less than 1mm long.
A typical root is made up of three different layers and a root cap.
Root cap- covers and protects the root tip while pushing it into the ground.
Epidermis- the outer layer of the root and plant. Has hairs and absorbs water.
Cortex- located just under the epidermis and stores food and nutrients.
The vascular system is in the center of the root and transports water and minerals
from the root hairs.
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Aerial roots- never touch the ground; anchor the plant to trees/rocks/other
surfaces. Get water from the air or rain. Found in orchards and rain forests.
Fibrous roots- thin, branching roots that don’t grow deep in the ground but cover
a very wide area.
Taproots- have a single, main stalk-like root going deep in the ground with
smaller side roots branching off. Ex.: Pine trees and plants living in dry areas.
Prop roots- grow at the bottom of a plant’s stem and support it so it can’t be
knocked over. Ex.: Corn plants and mangrove trees
What are stems?
Stems are a support structure and a transport system for the plant.
Most stems must be sturdy enough to support leaves/flowers/branches.
Come in 2 basic forms:
 Soft stems: often soft, green, and can bend.
 Woody stems: often covered with bark and don’t contain chlorophyll.
Soft stems’ green color shows that its cells contain chlorophyll and produce food.
Bark- tough outer covering that serves as a protective layer.
Plant’s transport system starts in the roots and is made up of 2 kinds of cells:
 Xylem: series of tubes that move water and minerals up the stem. Transports
in 1 direction only up (rootleaves) “X”
 Phloem: moves sugars made in the plant’s leaves to other parts of the plant.
Two-way transport route up and down. “P”
“X” and “P” are separated by a layer called the cambium where “X” & “P” are
produced and then move inward.
The cells can only transport after they die and are hollow.
What are leaves?
Leaves carry out the function of photosynthesis (the process of making food).
Cells in the leaf’s epidermis make up the main food factory.
Leaves need sunlight, water and carbon dioxide for photosynthesis.
Many are flat and broad so they can collect the most sunlight possible;
chlorophyll in the leaves chloroplast traps sunlight energy.
Water enters plants via roots and the xylem tissue in the leaves veins transport it.
Cuticle- waxy waterproof layer on leaf surface preventing moisture from
evaporating.
CO2 is obtained via the air
Stoma- tiny pores in the underside of the leaves allowing air to enter in and out
and are controlled by guard cells that swell up and open the stoma when it is full
letting H2O and O leave the plant.
Transpiration- loss of H2O through a plant’s leaves.
If the plant is low on H2O the guard cells shrink and H2O can’t escape.
H20 from the roots replaces evaporated H2O
CO2 and H2O enter the chloroplasts in the plant’s cells and combine with trapped
sun energy producing O and sugar.
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Phloem tissues take the sugar to all plant cells and excess is stored as starch to be
broken down for food.
Most O leaves via stoma as a waste product.
Photosynthesis chemical equation:
6CO + 6H O + energy  C H O + 6O
2
2
6 12 6
2
How are photosynthesis and respiration related?
The Sun is the most important energy source for Earth.
Sugars made via photosynthesis are used by most organisms for energy.
Energy is released when the cells of organisms use O to break down the sugars
stored as starch during cellular respiration.
Cellular respiration- occurs in the mitochondria of your cells when O combines
with stored sugars to release energy used during work; preformed by plants and
animals.
Plant and animal cells produce CO2 and H2O as waste products which are
released back into the air and plants use the released CO2 and H2O to produce
sugars during photosynthesis