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Section 7-1: Life Is Cellular
The cell theory states that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells.
Biologists divide cells into two categories: eukaryotes and prokaryotes. The cells of eukaryotes have a nucleus; the cells of prokaryotes do not.
Section 7-2: Cell Structures
The main function of the cell wall is to provide support and protection for the cell.
The nucleus controls most cell processes and contains the hereditary information of DNA.
The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. The cytoskeleton is also involved in many forms of cell movement.
The endoplasmic reticulum is the organelle in which components of the cell membrane are assembled and some proteins are modified.
Enzymes in the Golgi apparatus attach carbohydrates and lipids to proteins.
Chloroplasts use the energy from sunlight to make energy-rich food molecules, a process known as photosynthesis.
Mitochondria use the energy from food to make high-energy compounds that the cell can use to power growth, development, and movement.
Section 7-3: Movement Through the Membrane
The cell membrane regulates what enters and leaves the cell and also provides protection and support.
Diffusion causes many substances to move across a cell membrane but does not require the cell to use energy.
Osmosis is the diffusion of water through a selectively permeable membrane.
Section 7-4: The Diversity of Cellular Life
Cells in multicellular organisms are specialized to perform particular functions within the organism.
The levels of organization in a multicellular organism are individual cells, tissues, organs, and organ systems.