S: Seasons of Change
FC: Elaine Lai Esther Seo | Cells
1: Table of Contents | Cell Theory.......................... Rudolf Virchow..................... Matthias Scheliden................. Theodor Schwann.................. Robert Hooke....................... Prokaryotic vs. Eukaryotic Cells.. Plant vs. Animal Cells........... Ten Cell Structures.............. Cell Membrane................... Homeostasis.................. | 3 4 5 6 7 8 -9 10-11 12-13 14-15 16 and 17
3: Cell Theory | 1. All living organisms are composed of more cells. 2. Cells are the basic units of life. 3. All cells arise from pre-existing cells.
4: Rudolf Virchow 1855 In 1855 Rudolf Virchow proposed an important extension of cell theory that "All living cells arise from pre-existing cells". ("Omnis cellula e celula") This statement has become what is known as the "Biogenic law".
5: Matthias Schleiden 1838 | Schleiden was German Botanist the viewed plant parts under a microscope and discovered that plant parts are made of cells. He is considered to be the co-founder of cell theory together with Schwann, with whom he consulted.
6: Theodor Schwann 1839 | Schwann was a German Biologist who viewed animal parts under a microscope and discovered that animals were made up of cells. He extended Schleiden's cell theory in plants to animals, stating that all living things are composed of cells.
7: Robert Hooke 1665 | Hooke was an English scientist who looked at cork through a compound microscope and observed tiny room-like structures that reminded him of the "cells" that monks lived in. Therefore these structures became known as cells. The cork cells where not alive so he only saw the cell wall.
8: Prokaryotic Cell | Cells that lack a membrane-bound nucleus, such as bacteria and archaea. | Nucleus: No nuclear membrane or nucleoli Membrane-enclosed organelles: Absent Flagella: Consist of two protein building blocks Cell wall: usually present; chemically complex Cytoplasm: No cytoskeleton or cytoplasmic streaming Ribosomes: Small in size DNA arrangement: Singular, circular chromosome Cell Division: Binary fission Reproduction: No meiosis; transfer of DNA fragments
9: Eukaryotic Cell | Cells that contain complex structures enclosed with membranes. | Nucleus: Contains nuclear membrane and nucleoli Membrane-enclosed organelles: Present Flagella: Complex; consists of multiple microtubules Cell wall: When present, it's chemically simple Cytoplasm: Cytoskeleton; cytoplasmic streaming Ribosomes: Larger outside of organelles DNA arrangement: Multiple linear chromosomes Cell Division: Mitosis Reproduction: Involves meiosis
10: Animal Cell Nucleus: Present Cilia: Present Shape: Round shape Chloroplast: Absent Cytoplasm: Present ER(Smooth and Rough): Present Ribosome: Present Mitochondria: Present Vacuole: One or two small vacuoles Centriole: Present Golgi Apparatus: Present Cell Wall: Absent Cell membrane: Present Lysosomes: Occur in cytoplasms
11: Plant Cell Nucleus: Present Cilia: Rare Shape: Rectangular Chloroplast: Present Cytoplasm: Present ER (Smooth and Rough): Present Ribosome: Present Mitochondria: Present Vacuole: Present Centriole: Only in lower platforms Golgi Apparatus: Present Cell Wall: Present Cell membrane: Present Lysosomes: Absent
12: Cell Structures | 1. Nucleus: - Made of 2 phospholipid layers that separate the nucleus from the cytoplasm - Has several pored on the surface that allows proteins to channel in and out of the nucleolus - Contains the nucleolus inside the nucleus 2. Flagella: - Long Thread-like structures that protrude from the cell's surface - Found in some prokaryotic and eukaryotic cells 3. Cilia: - Short hair-like structures that protrude from the surface of some eukaryotic cells 4. Endoplasmic Reticulum: - A system of internal membranes - Rough ER has ribosomes attached - Smooth ER doesn't have ribosomes attached
13: 5. Lysosome: - Small, round organelles that contain the cells digestive enzymes 6. Mitochondria: - Has two membranes - The inner membrane is folded 7. Chloroplasts: - Found in plant and algae cells, and some protists - Has two membranes 8. Cell wall: - Found in prokaryotic cells and plant cells - Surrounds the cell membrane 9. Golgi Apparatus: - Flattened, membrane-bound sacs 10. Centriole: - Several centrioles (look like hollow tubes) come together in a bundle to make a spindle.
14: Cell Membrane
15: The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It consists of the lipid bilayer with embedded proteins. Cell membranes are involved in a variety of cellular processes such as cell adhesion, ion conductivity and cell signaling and serve as the attachment surface for several extracellular structures, including the cell wall, glycocalyx, and intracellular cytoskeleton. The cell membrane surrounds the cytoplasm of a cell and, in animal cells, physically separates the intracellular components from the extracellular environment. Fungi, bacteria and plants also have the cell wall which provides a mechanical support for the cell and precludes the passage of larger molecules. The cell membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell, and in attaching to the extracellular matrix and other cells to help group cells together to form tissues.
16: Homeostatis | Through the processes of diffusion and osmosis, the cell membrane works to maintain homeostasis in the cell by transporting molecules to create equilibrium between the inside of the cell and its environment. | This picture shows the cell membrane regulating what comes in or goes out of the cell.
17: The cell membrane acts as the gatekeeper to what goes into and leaves the cell. It is made up of mostly fats (lipids) and protein and is selectively permeable, meaning it only lets certain molecules pass through the membrane. It maintains homeostasis through the processes of diffusion, osmosis and filtration, which are passive forms of transport. Diffusion: The movement of solutes down the concentration gradient. It takes the excess molecules from the area in which they have the highest concentration and spread them out. Osmosis: The process of allowing water to permeate the cell membrane. It is the diffusion of water molecules.