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Lesson 1 Summary
Use with pp. 39–41
Lesson 1: What is inside a cell?
Vocabulary
cell membrane surrounds a cell, holding the parts of the cell together;
allows certain materials to enter the cell and waste products to exit
nucleus contains chromosomes that control how the body grows and
changes
cytoplasm all the contents of the cell outside the nucleus
vacuole store and break down materials; in plants they may store water
cell wall tough material surrounding the cell membrane in plant cells
that provides support and protection
chloroplast contains a green substance that uses the energy in sunlight
to turn water and carbon dioxide into oxygen and sugar
Cells are the most basic unit of living
things. They are the smallest living part of
an organism. A single cell is so tiny that
you need a microscope to see it. Organisms
can be made of only one cell. Organisms
made of many cells are called multicellular.
Cells have the same needs as you do. They
need food. Cells must also get rid of waste.
Cells also need energy. Cells use energy to
grow, move, and to make new cells. Cells get
energy from respiration. Respiration is the
mixing of oxygen and food to make energy.
The Parts of Cells
All cells have parts. Some parts are like
parts in your body. The cell membrane is
like your skin. It holds the cell together. The
cell membrane lets some materials, such
as water, sugar and oxygen, enter the cell.
The cell membrane also lets waste products
leave the cell. The cell’s nucleus contains
chromosomes. Chromosomes tell the body
how to grow and change. Chromosomes
are made of a chemical called DNA. Every
chromosome has small sections called genes.
Almost every cell in your body has the same
set of genes.
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Chapter 2, Lesson 1 Summary
Cytoplasm is the material between the cell
membrane and the nucleus. Mitochondria
mix oxygen and food to make energy.
Vacuoles act like a stomach. They store food
and break down waste.
Plant Cells
Plant cells have the same parts as animal
cells. They also have parts that animal cells
don’t have. Plant cells have a cell wall and
chloroplasts. A cell wall surrounds the cell
membrane. It gives the cell extra support
and protection. Chloroplasts give plants
their green color. They turn water and
carbon dioxide into oxygen and sugar. Plant
cells use oxygen and sugar for respiration.
The Size of Cells
Like most things, cells have a limit to how
big or small they can be. They cannot be
too small or too large. If they are too small,
they will not have room for all their parts. If
they are too big, oxygen and other materials
cannot reach the middle of the cell quickly.
This would cause the cell to die.
Quick Study
© Pearson Education, Inc. 5
Cells and Their Functions
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Lesson 1 Checkpoint
Use with pp. 39–41
Lesson 1 Checkpoint
1. What is the most basic unit of living things?
2.
Draw Conclusions Suppose you saw a small organism
move across your desk. Would you infer that this organism was
multicellular or a single cell?
3. Describe why cells have limits as to how big or small they can be.
© Pearson Education, Inc. 5
4. List five parts of all cells and their jobs.
Quick Study
Chapter 2, Lesson 1 Checkpoint
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