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This image is a photograph of a plant called bryum moss. The photograph was taken with an ordinary camera. It shows what you would see if you looked at bryum moss closely.

This image also shows bryum moss. The image is a micrograph, which is a magnified picture taken with the aid of a microscope. The magnified image shows a section of the plant that is only 0.37 millimeters long!

The micrograph shows that the plant is made up of small, similarly shaped units. In this image, each unit looks like it has six sides and is surrounded by a white border. These units are called cells.

Which of the following statements are true? Select all that apply.

• Bryum Moss plants are made up of tiny units called cells

• Each bryum moss cell is so small that it can be seen only with the help of a microscope

• The organism shown in the micrograph is made up of cells, but the organism in the photograph is not

• Each bryum moss cell is over 0.37 millimeters long

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All organisms are made up of cells. Some organisms are unicellular, or made up of just one cell. Other organisms are multicellular, or made up of many cells.

These micrographs show cells from four different organisms. Look at the micrographs and read the captions.

Which of the following statements are true about the organisms shown in the micrographs above?

Select all that apply.

• The cells of the protist and the bacterium are the same shape

• The protist has one cell, and the bean plant has many cells

• The bean plant is made up of cells but the frog is not

• The bacterium has many cells and the frog has only one cell

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In all organisms, cells are the most basic units of structure and function. The structure of an organism is affected by the way its cells are shaped and organized. Many of the functions that an organism needs to carry out to stay alive happen inside its cells. A cell is the smallest unit that can get and use energy, remove waste, and carry out other processes necessary for life.

The micrographs below show cells from two different organisms: an amoeba, which is unicellular, and a hamster, which is multicellular

Amoeba is made up of ____ cell(s).

A hamster is made up of _____ cell(s).

• one;one

• many;one

• one;many

• many;many

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All cells come from other cells. New cells are created by a process called cell division.

To start cell division, a cell grows bigger and makes copies of the parts inside it. Then, the cell and its parts separate into two new cells. Each new cell contains the same types of cell parts as the original cell. Later, each of these cells may divide again to form more cells.

When a multicellular organism's cells divide, the organism can grow. Each resulting cell is part of that organism. When a unicellular organism divides, each resulting cell is a separate unicellular organism.

The micrographs below show cells from two different organisms: a rose bush, which is multicellular, and a bacterium, which is unicellular.

Which of the following statements are true? Select all that apply.

• A rose bush cell can divide to form two rose bushes

• If the bacterium divides, it will become a multicellular organism

• When a rose bush cell divides, it copies its parts then divides into two cells

• The bacterium was formed when another bacterium divided

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Over time, many scientists have carried out experiments to learn about how cells work. Together, their discoveries led to the development of cell theory. Cell theory explains what scientists have observed to be true for all cells.

Cell theory includes three main concepts.

Based on what you have learned about cells, complete the statement below:

All organisms are made up of ____ cells.

Cells are the ________ unit of structure and function in living things.

____ cells come from other cells.

• many...smallest...All

• one or more...smallest....All

• many...largest...All

• one or more...largest...All

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Cells can be represented by a type of model called a cell diagram. Scientists use cell diagrams to show the parts that make up a cell. Cell diagrams usually show one cell, even if the cell is from a multicellular organism.

The images above show a micrograph and a cell diagram of yeast, a unicellular fungus. Compare the micrograph to the cell diagram, then answer the question.

Which of the following statements are true?

Select all that apply.

• The yeast cell diagram is a representation of the type of yeast cell shown in the micrograph

• The cell wall in the yeast cell micrograph is the same color as the cell wall in the yeast cell diagram

• Both the micrograph and the diagram show that a yeast cell contains a nucleus

• Cell diagrams are used to represent only the cells of unicellular organisms

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Cells come in many different shapes and can contain different parts, but there are some traits that all cells share. Every living cell has a gel-like cytoplasm that fills the cell and contains cell parts. The cytoplasm is surrounded by a thin cell membrane.

Label the parts of the yeast cell diagram.

• 1-cell membrane 2-cytoplasm containing cell parts

• 1-cytoplasm containing cell parts 2-cell membrane

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Look again at the parts that you labeled in the yeast cell diagram. These are the parts that all cells have.

The diagram above shows a bacterial cell.

The bacterial cell does not have all of the same parts as the yeast cell. However, just like the yeast cell, the bacterial cell has a cell membrane and a gel-like cytoplasm that contains the cell parts. Label the parts of the bacterial cell

• 1-cell membrane 2-cytoplasm

• 1-cytoplasm 2-cell membrane

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All cells have parts that work together to carry out functions necessary for life.

Chloroplasts are cell parts that use photosynthesis to make sugar from carbon dioxide and water. A plant cell can use this sugar as a source of energy.

Mitochondria are cell parts that break down sugar. In both the mitochondria and the cytoplasm, chemical reactions break down sugar to form new molecules. This process releases energy for the plant cell to use.

In a plant cell _____use photosynthesis to make sugar. Then, the cytoplasm and ______ carry out chemical reactions using the sugar. These reactions release energy for the plant cells to use. This example shows that the plant cell's parts ______ to get energy for the cell.

• mitochondria...chloroplast...depend on each other

• chloroplast...mitochondria...depend on each other

• mitochondria...chloroplast...do not depend on each other

• chloroplast...mitochondria...do not depend on each other

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Like all other multicellular organisms, you are made up of many types of cells. The micrographs below show different types of human cells.

Think about cell theory and the cell models you have seen. Then, select all the true statements about these human cells.

• The cells cannot be represented by models because their structures are too complex

• Each cell contains parts that work together to carry out processes necessary to life

• Each cell has a cell membrane and a cytoplasm that contains cell parts

• The cells were formed when other human cells divided

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