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Chapter 1 Living Things
Lesson 1 Cells
Cells
Organisms are living things. They can be as large as a whale or as small as an amoeba.
All living things are made of cells.
A cell is the smallest unit of living things that can carry out the basic processes of life.
Cells come from other cells.
Unicellular organisms are made of one, single cell. Amoebas and Euglena are unicellular.
Multicellular organisms are made of more than one cell. Frogs, trees, and you are multicellular.
In multicellular organisms, cells work together to keep the organism alive.
Parts of an Animal Cell
Cell membrane – flexible wrapping around the outside of the cell. Gives the cell shape and controls what
can enter and leave the cell. “body guard”
Cytoplasm – a gel-like liquid that fills the space between organelles and the cell membrane.
Nucleus – the control center of the cell. It is usually in the center of the cell and is one of the larger
organelles. It contains the DNA or master plans for the cell.
Mitochondria – the energy supplier for the cell. It breaks down food and gives off energy. It’s the power
plant of the cell.
Vacuoles – stores the food, water, and waste for a cell. Some animal cells have several vacuoles and
others have none.
Parts of a Plant Cell
Plant cells have many of the same structures and organelles as animal cells but they are a boxed shape
and have a few more organelles than animal cells.
Cell Wall – the cell wall is stiff and provides strength and support. It is outside the cell membrane.
Vacuole – Plant cells usually have one large, central vacuole. It stores extra water to the plant does not
dry out.
Chloroplast – Makes food for the plant. Plants are green because the chloroplast is green. They get the
green color from the chlorophyll inside the chloroplast that absorbs sunlight.
How Cells are Organized
Our bodies contain many different types of cells with specific functions. Cells are the building blocks of
the body.
Cells work together to form tissue.
Tissues work together to form organs.
Organs work together to form organ systems.
Organ systems also work together.
(Cells – Tissues –
Organs – Organ Systems)