Science 10анаBiology Multicellular Organisms: Plants Pg

Science 10 ­ Biology
Multicellular Organisms: Plants
Pg. 296 ­ 297
Advantages of Being Multicellular
In Multicellular organisms, cells become specialized to perform specific functions within the organism. This allows multicellular organisms to grow to a size much greater than unicellular organisms.
Read the top half of pg. 297 and describe the following advantages of that multicellular organisms have:
Division of Labor ­ o Cells become specialized for one purpose and can perform that function effectively and efficiently
o Can concentrate on one task
Size ­ o Surface area to volume ratio of unicellular organisms restricts size
o Internal transport mechanisms of multicellular organisms allows it to transfer materials within and get much larger while cells stay small
Interdependence of cells ­ o Life does not depend on one cell
o If one cell dies, the whole organism does not die
Organization of Cells: (pg. 298)
1. In all multicellular organisms, cells are organized into tissues.
***Define the word tissue***
o Groups of cells performing the same function together
2. Tissues are organized into organs
***Define the word organ***
o Tissues contributing to the same function
3. Organs are organized into systems
***Define the word system***
o A set of organs that contribute the same function
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Plant Structure: (pg. 297 ­ 302)
There are many different types of cells found in any plant. These cells are grouped into specialized tissues that are found throughout the whole plant. These tissues form organs that, in turn, form the two systems common to all plants.
Different, specialized cells found in plants have very specific functions:
1. Root hair cells: absorb water and minerals. Increases surface area of root
2. Dermal Cells: produce cuticle (waxy layer) to prevent water loss
3. Guard Cells: form pores for gas exchange
4. Sieve tube Cells: form long continuous tubes that transport sugars
5. Companion Cells: attach to sieve tube cells and direct their activities
Three main types of tissues are made of the cells found in the plant:
1. Dermal Tissue: outer layer of cells that covers non­woody plants
(aka epidermis)
Responsible for exchange of matter and gases in and out of plant
a. Cuticle: waxy substance that reduces water loss and protect from micro­
organisms
2. Ground Tissue: makes up the majority of the plant and is found beneath the epidermis
found in leaf, stem and root of a plant
3. Vascular Tissue: responsible for transport of materials throughout plant
a. Xylem Tissue: moves water and minerals from root to leaves
b. Phloem Tissue: moves sugar and other dissolved solids from leaves to other parts of the plant
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Organs made of Dermal, Ground, and Vascular Tissues are:
1. Leaf: exchanges gases with the air and perform photosynthesis
2. Reproductive: responsible for producing seeds and fruits
3. Stem: provides structure and support
4. Main Root: stores sugars and absorbs water and nutrients from the soil
The Two Systems of the Plant are:
1. Shoot System: everything above ground
Includes stem, leaves, buds, flowers and fruits
Also includes tubers (swollen stems that store food) ­ potatoes, carrots
2. Root System: everything underground
Includes aerial roots even though they are above ground
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Label the 4 tissue types and 2 systems on the diagram below
Reproductive (flower), leaf, stem, main root, shoot system, root system
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