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Plant Basics- 7th Grade
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PLANTSName all the plants you can think of…What do these all have in common?
Chapter 9
• Plants are many-celled organisms
- most plants contain chlorophyll
- at least 260,000 plant species have been identified
- plants are adapted to nearly every environment on earth
- plants are important food sources for people and animals
• Photosynthesis - the process by which green
plants use sunlight to make food from carbon dioxide
and water.
- Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.
PLANT CELLS:
• Plant cells have:
- a cell membrane- a nucleus and other organelles- a cell wall- chlorophyll – the green pigment used in photosynthesis- a central vacuole which
regulates the water content of the cell
• Some plants also contain carotenoids - Carotenoids are red, yellow or orange pigments that are also used in photosynthesis
• PARTS:
- A cuticle is a waxy protective layer that covers the stems, leaves and flowers of many plants
- The cuticle helps prevent water loss in the plant
• Cellulose is a chemical compound made out of sugar
- cellulose forms tangled fibers in cell walls and provides structure and support
• Plants can be categorized as vascular or nonvascular
• Vascular plants have tubelike structures that carry water and nutrients throughout the plant
• Nonvascular plants do not have the tubelike structures
• Nonvascular plants use other ways to move water and nutrients
• Nonvascular plants have rhizoids instead of roots. • Rhizoids are structures that anchor the plants
where they grow
• Most nonvascular plants are classified as mosses
• Botany is the science of studying plants.
• In the late 1700s, Swedish botanist Carolus Linnaeus developed a system of classifying living things, using many different characteristics
PARTS OF A PLANT
Leaf – the organ of a plant where photosynthesis takes place
• Stem – support the branches, leaves, and reproductive structures
Roots – act as anchors for a growing plant, holding it in place.
- Water and substances enter a plant through its roots.
Flower – the part of certain plants that develop into fruit
- Flowering plants are called agiosperms
• Gymnosperms are vascular plants that produce seeds that are NOT protected by fruit.
• Gymnosperms have no flowers
• These plants include conifers, such as pine trees,fir trees, and spruce – all are commonevergreen trees
• In a seed plant, there are three tissues which make up the vascular system:
- xylem - conducts water and dissolved nutrients upward from the root and also helps to form the stem
- phloem - conducts sugars and other metabolic products downward from the leaves.
- cambium - a thin layer between the xylem and phloem of most vascular plants that gives rise to new cells and is responsible for secondary growth.
• In a seed plant, some spores develop into pollen
• A pollen grain is a small structure produced by the male seed plant
• The transfer of pollen grains to reproduce is called pollination
• Pollen can be transferred by gravity, wind, water, animals or insects
*FLOWERS* - Flowers have four main parts: petals, sepals,
stamen and pistils
• Petals are the colorful parts
• Sepals are the leaflike parts outside the petals. They form the outside of the flower bud
• Stamen is the male reproductive part; pollen is produced in the stamen
• Pistil is the female reproductive organ; the ovary is the base of the pistil where ovules are found–ovules produce eggs, or reproductive cells