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Cells
Cells and Heredity Module
Characteristics of Cells Explore
Describe the nerve cell.
Describe the plant cell.
Describe the paramecium.
Describe the red blood cell.
Describe the animal cell.
Describe the volvox.
Describe euglena.
Characteristics of
Cells Notes
Unit 1 Lesson 1 The Characteristics of Cells
What is a cell?
• Cell --> smallest functional and structural
unit of all living organisms
• Organism --> any living thing that carries
out its own life processes.
• Robert Hooke was the first to describe cells.
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Unit 1 Lesson 1 The Characteristics of Cells
Why are most cells small?
• Cells are small because their size is limited by
their outer surface area.
• The surface area-to-volume ratio of a cell is the
ratio of the outer surface to the cell’s volume.
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Unit 1 Lesson 1 The Characteristics of Cells
Cell Hall of Fame
What is the cell theory?
• All organisms are made up of one or more cells.
• The cell is the basic unit of all organisms.
• All cells come from existing cells.
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Unit 1 Lesson 1 The Characteristics of Cells
What is the cell theory?
• Anton van Leeuwenhoek was the first to describe
living cells.
• Matthias Schleiden concluded that all plants are
made of cells.
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Unit 1 Lesson 1 The Characteristics of Cells
What is the cell theory?
• Theodor Schwann determined that all animal
tissues are made of cells.
• Rudolf Virchow proposed that cells could form only
from the division of other cells.
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Unit 1 Lesson 1 The Characteristics of Cells
What is the cell theory?
• unicellular organisms = one cell
• multicellular organisms = more than one cell are
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 1 The Characteristics of Cells
What are the two types of cells?
• Prokaryotes are single-celled organisms that do
not have a nucleus or membrane-bound
organelles.
○ DNA is in the cytoplasm.
○ They have ribosomes.
○ Some have hairlike structures called flagella
that help them move.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 1 The Characteristics of Cells
What are the two types of cells?
• Eukaryotes are organisms made up of cells that
contain DNA in a nucleus, membrane-bound
organelles, and ribosomes.
○ Animals, plants, protists, and fungi are
eukaryotes.
○ Most eukaryotes are multicellular but some
are unicellular.
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Unit 1 Lesson 1 The Characteristics of Cells
On the Cellular
What parts do all cells have in
common?
• A cell membrane --> protective layer that covers
a cell’s surface and controls materials moving into
and out of the cell.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 1 The Characteristics of Cells
What parts do all cells have in
common?
• The cytoplasm --> region inside the cell that
includes the fluid and all the organelles except for
the nucleus.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 1 Lesson 1 The Characteristics of Cells
• An organelle is a small body in the cytoplasm that
is specialized to perform a specific function.
• The nucleus is a membrane-bound organelle that
contains DNA.
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