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Robert Hooke looked at a slice of cork under an early compound microscope. He thought it looked like a thousand tiny chambers, so he called them cells. We still use this term today.
Section 7-1 Life is Cellular
Numerous studies on cells are summarized in the cell theory which states: - All living things are composed of cells. - Cells are the basic units of structure and function in living things. - New cells are produced from existing cells. We still use microscopes to explore the cell but much more advanced microscopes.
electron microscope probe microscope - Prokaryotic cells have genetic material that is not contained in a nucleus. They are generally simpler and smaller than Eukaryotic cells - Eukaryotic cells contain a nucleus in which their genetic material is separated from the rest of the cell.
The nucleus contains nearly all the cell's DNA and with it the coded instructions for making proteins and other important molecules. Ribosomes are small particles of RNA and protein found throughout the cytoplasm. They produce proteins by following coded instructions that come from the nucleus.
Section 7-2 Eukaryotic cell Structure
(section 7-2 cont.) The endoplasmic reticulum is the site where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell. The function of the Golgi apparatus is to modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.
Lysosomes are small organelles filled with enzymes. One function of lysosomes is the digestion, or breakdown, of lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell. Vacuoles store materials such as water, salts, proteins, and carbohydrates.
Mitochondria are organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use. Chloroplasts are organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis.
The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. The cytoskeleton is also involved in movement.
A very important part of the cell is its borders which seperates the cell from the sourroundings. The cell membrane regulates what enters and leaves the cell and also provides protection and support.
Section 7-3 Cell Boundaries
The main function of the cell wall is to provide support and protection for the cell.
Diffusion: diffusion is the process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated. Molecules move across the cell membrane to creat an equal concentration on both sides, when this happens the system has reached equilibrium.
Osmosis: Osmosis is the diffusion of water through a selectively permeable membrane. Water tends to move across the membrane untill equilibrium is reached. When this happens the two solutions will be isotonic.,which means “same strength.” Before osmosis happened the more concentrated solution was hypertonic, which means “above strength,” as compared to the dilute solution. The dilute solution was hypotonic, or “below strength.”
Images from google image search and the online textbook
