Unit 2 Lesson 1 The Characteristics of Cells Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 2 Lesson 1 The Characteristics of Cells Florida Benchmarks Copyright © Houghton Mifflin Harcourt Publishing Company SC.6.N.2.2 Explain that scientific knowledge is durable because it is open to change as new evidence or interpretations are encountered. SC.6.L.14.2 Investigate and explain the components of the scientific theory of cells (cell theory): all organisms are composed of cells (single-celled or multi-cellular), all cells come from pre-existing cells, and cells are the basic unit of life.
Unit 2 Lesson 1 The Characteristics of Cells Florida Benchmarks Copyright © Houghton Mifflin Harcourt Publishing Company MA.6.A.3.6 Construct and analyze tables, graphs, and equations to describe linear functions and other simple relations using both common language and algebraic notation.
Cell-ebrate! Copyright © Houghton Mifflin Harcourt Publishing Company What is a cell? A cell is the smallest functional and structural unit of all living organisms. An organism is any living thing that carries out its own life processes. Robert Hooke was the first to describe cells. He looked at the bark of a cork tree under a microscope. Unit 2 Lesson 1 The Characteristics of Cells
Why are most cells small? Cells are small because their size is limited by their outer surface area. If cells get too large, they cannot take in enough materials or get rid of enough wastes. The surface area-to-volume ratio of a cell is the ratio of the outer surface to the cell’s volume. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells
Cell Hall of Fame Copyright © Houghton Mifflin Harcourt Publishing Company What is the cell theory? The cell theory lists three basic characteristics of all cells and organisms. 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. Unit 2 Lesson 1 The Characteristics of Cells
What is the cell theory? Antoni van Leeuwenhoek was the first to describe living cells. Matthias Schleiden concluded that all plants are made of cells. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells
What is the cell theory? Theodor Schwann determined that all animal tissue is made of cells. Rudolf Virchow proposed that cells could only come from the division of other cells. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells
What is the cell theory? Organisms made up of just one cell are called unicellular organisms. The single cell must carry out all of the organism’s life functions. Organisms made up of more than one cell are called multicellular organisms. The cells of multicellular organisms have specialized functions. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells
On the Cellular Copyright © Houghton Mifflin Harcourt Publishing Company What structures do cells have in common? All cells have some structures in common. A cell membrane is a protective layer that covers a cell’s surface and controls materials moving into and out of the cell. The cytoplasm is the region inside the cell that includes all the organelles except for the nucleus. Unit 2 Lesson 1 The Characteristics of Cells
What structures do cells have in common? 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. DNA, or deoxyribonucleic acid, is genetic material that provides instructions for all cell processes. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells
What structures do cells have in common? How many parts of a cell can you name? Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells
What are two types of cells? Prokaryotes are single-celled organisms that do not have a nucleus or membrane-bound organelles. Prokaryotes’ DNA is in the cytoplasm. They have organelles without cell membranes called ribosomes. Some have flagella, or hairlike structures that help them move. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells
What are 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. Copyright © Houghton Mifflin Harcourt Publishing Company Unit 2 Lesson 1 The Characteristics of Cells