2 Cell Theory Essential Questions 1. Explain how the development of the cell theory was dependent on technological advances and previous knowledge. 2. Relate the function of a cell to its organelles 3. How do osmosis, diffusion and active transport maintain homeostasis in a cell
3 What is the fundamental structure of life that makes up every living thing? The Cell
4 The Cell The Microscope An instrument that produces magnified images. A light microscope bends rays of light. The compound light microscope most common in biology labs. Led to the discovery of microorganisms Cell Theory Germ Theory
6 In the 1600 s Anton van Leeuwenhoek discovered he could magnify things using lenses at the proper distance. Early Microscope
7 Van Leeuwenhoek used his microscope to look at pond water and other liquids. Van Leeuwenhoek was the first to identify Microscopic living things. He called these things ANIMALCULES.
8 Over the next several hundred years scientist improved the microscope. Led to other discoveries and the cell theory Important Scientist Hooke used a microscope to observe flowers insects, spider webs, and slices of cork. Woody parts of plants contained tiny rectangular chambers which he called cells.
9 Hooke and Schleiden concluded that all plants contained cells. Plants are made up of cells Schwann found that some animal tissue resembled cellular tissue of plants. Animals are made up of cells
10 Virchow Proposed that animal and plant cells are produced only by the division of cells that already exist. Cells come from cells Through cell division
11 Brown found an object near the center of cells. This object today is known as the NUCLEUS. The nucleus plays a role in cell reproduction.
12 The discoveries and observations of these scientists make up what is now called the cell theory. The cell theory forms a basis for the way biologists study living things. Cells are found in all living things The cell theory applies to all organisms unicellular or multicellular
13 THE CELL THEORY All living things are composed of cells. Cells are the smallest working units of living things. All cells come from preexisting cells by cell division.
14 Cells are not all alike. Vary in size and shape. However cells have some structures in common. Common to all cells are: Cell membrane Cytoplasm DNA Cell membrane Prokaryotic Cell Cytoplasm Cell membrane Cytoplasm Nucleus Organelles Eukaryotic Cell
15 The Nucleus Eukaryotic cells have a nucleus The nucleus is where most of the DNA is contained Prokaryotic cells do not have a nucleus The DNA material is floating in the cytoplasm
16 Prokaryote vs Eukaryote Do not have a nucleus Do not have membrane bound organelles Have a nucleus DNA is contained in nucleus Dozens of organelles Kingdom Animal Generally smaller Kingdom Perform many functions Plant Fungi Eubacteria Archeabacteria Protista
18 Cell Theory Essential Questions 1. Explain how the development of the cell theory was dependent on technological advances and previous knowledge. 2. Relate the function of a cell to its organelles 3. How do osmosis, diffusion and active transport maintain homeostasis in a cell
19 The nucleus is the control center of the cell It contains nearly all the cell s DNA. Coded instructions for making proteins and other important molecules. This storing of DNA enables the cell to better regulate and control its use
20 The DNA molecules and proteins in the nucleus form CHROMATIN It is spread through out the nucleus. During Mitosis the chromatin will form the chromosomes.
21 CHROMOSOMES: made up of condensed chromatin (DNA). The formation of chromosomes is important in dividing the genetic material evenly and accurately
22 Also contained in the nucleus is the NUCLEOLUS this is where ribosomes are assembled
23 The nucleus is surrounded by the nuclear envelope performs the same function as the cell membrane. Nuclear pores in the envelope allows movement in and out of the nucleus
24 The cytoplasm The cytoplasm is a semi-fluid mixture (Cyto = cell, Plasm = fluid). Filled with salts, sugars, and other dissolved substances. Found inside the cell between the cell membrane and the nucleus. In Eukaryotes the cytoplasm contains many small structures called ORGANELLES. Little organ like structures that perform specialized functions
25 RIBOSOME made of RNA and protein. the smallest and do not have a membrane. the site where protein production begins. The number of ribosomes is dependent upon the number of proteins a cell must make.
26 ENDOPLASMIC RETICULUM (ER). Processing and transporting proteins and other macromolecules is the function of the ER made up of tubes, sacs, and channels that provide it with a large surface area. 2 types of ER rough and smooth. Rough makes membranes and secretory proteins. Smooth makes lipids and helps to remove harmful substances.
27 GOLGI APPARATUS Made up of a system of membranous sacs. Materials that need to be modified, sorted, and packaged are handled by the golgi apparatus. Materials for cell membranes are packaged and distributed by the golgi apparatus.
28 LYSOSOMES sac-like membranes filled with chemicals and enzymes that can break down almost any thing. Lysosomes are the clean-up crew. They are also used to break down non-functioning organelles. Without lysosomes, aged and dead cells as well as other cellular debris would build up within the body.
29 VACUOLES Sac-like structures used to store materials (water, salt, proteins, and carbohydrates). VACUOLES in both plant and animal cells, Animals have many small vacuoles. Plants usually have a large central vacuole. used for support and water storage. PLASTIDS are used for storage of starch and pigment.
30 The Power house of the cell MITOCHONDRION The organelle that produces cellular energy from a chemical fuel (glucose) Cellular respiration. Converts glucose into ATP Mitochondria are found in all eukaryotic organisms Mitochondria contain DNA.
31 CYTOSKELETON The supporting framework Made of microtubules and microfilaments. holds organelles in place. aids in movement of material within the cell. helps in cell movement. Cilia and flagella are used to propel cells.
32 CHLOROPLASTS, Converts sunlight into chemical energy (glucose). Photosynthesis Found in plant and plant-like cells Contains chlorophyll (pigment).
33 Centrioles are found in animal cells Usually only visible during cell division. Aid in the assembly of microtubules. Help to divide the chromosomes
34 CELL WALL In plants, algae, and some bacteria there is a boundary on the outside of the membrane, the cell wall. It helps to protect the cell and give it support. It is made of fibers of carbohydrates and proteins. Cellulose and lignin
35 CELL MEMBRANE The outer boundary. It encloses the cell. It separates the cell from its surrounding It protects the cell It regulates what goes in or out of the cell Allows certain things to pass through. For this reason a cell membrane is described as SELECTIVELY PERMEABLE
36 Cell membranes are built around a core of PHOSPHOLIPIDS. They have a POLAR end, the HEAD, tends to attract water. They have a NON-POLAR end, the TAIL, tends to avoid water. Because of their structure, in water they are found in a double-layered pattern. A LIPID BILAYER
37 The cell membrane consists of several different types of molecules such as proteins and carbohydrates. Some proteins are used to protect the membrane Provide the cell membrane with support Some of the proteins form protein channels, help to move material across the membrane. Some proteins along with carbohydrates act as an identification card used to determine which cells are foreign objects. Mosaic
38 Mosaic is an art form which uses small pieces of materials placed together to create a unified whole. Outside of cell Cell membrane Proteins Carbohydrate chains Inside of cell (cytoplasm) Protein channel Lipid bilayer All the pieces make a whole
41 Cell Theory Essential Questions 1. Explain how the development of the cell theory was dependent on technological advances and previous knowledge. 2. Relate the function of a cell to its organelles 3. How do osmosis, diffusion and active transport maintain homeostasis in a cell
42 TRANSPORTING ACROSS THE MEMBRANE. All cells have a cell membrane The cell membrane regulates what enters and leaves the cell. There are two types of transport PASSIVE ACTIVE.
43 PASSIVE TRANSPORT involves substances crossing the membrane without the cell expending energy. DIFFUSION is caused by the energy in molecules which leads to constant movement and collisions of molecules. Substances move from regions of high concentrations to regions of low concentration.
44 EQUILIBRIUM is the state at which the concentration of the substance is equal on both sides of the membrane. The molecules will continue to move, however there will be no net change in concentration.
45 Some substances can diffuse directly across the phospholipid bilayer. Others can diffuse only through special channels. The process of diffusion through the protein channels is called FACILITATED DIFFUSION. Passive transport There are hundreds of protein channels each specific for an ion, sugar, salt, or other substance.
46 OSMOSIS is the diffusion of water molecules. Water is vital to cell survival. The CYTOPLASM of a typical cell is filled with salts, sugars, and other dissolved substances. It is not just water Controlling the movement of water is important to the survival of the cell.
47 OSMOTIC PRESSURE is the force that prevents water from moving into a solution. If a cell is surrounded by distilled water (hypo) the cell has a much lower osmotic pressure than the water. Therefore water will flood the cell. If a cell is surrounded by a concentrated salt solution (hyper) This sets up the opposite relationship the cell has a higher osmotic pressure Water will leave the cell.
48 Solution types Water moves into RBC by osmosis when surrounding solution is HYPOTONIC, or less concentrated than cells (below) Water moves out of RBC by osmosis when the surrounding solution is HYPERTONIC or more concentrated than the cells(dehydration) (above). In an ISOTONIC solution there is no movement of water across the membrane it is an equal concentration RBC = red blood cell
49 Three ways to control osmotic pressure. 1. Organisms use a cell wall, which prevents the cell from expanding. 2. Organisms pump out the water many unicellular organisms have a contractile vacuole used to pump water out. 3. Organisms bathe cells in blood prevents cells from being in direct contact with dilute water. An animal s blood and cells have nearly the same concentrations of dissolved substances.
50 ACTIVE TRANSPORT occurs when a cell expends energy to move substances. This movement can occur against a concentration difference. The process of active transport is like a pump. Most animal cells have membrane proteins that will pump sodium ions out and potassium ions in.
51 Active transport is not limited to small ions or molecules. Some transport large molecules and even whole cells. ENDOCYTOSIS occurs when a cell wraps its membrane around a particle. Then turns its membrane inside out to take in the particle. If the particle is very large the process is called Phagocytosis. (Pinocytosis liquids) EXOCYTOSIS is when a cell expends energy to expel material.
52 CELL SPECIALIZATION Many cells are specialized to perform a specific function in an organism this is the key characteristics of cells in a multicellular organism. Some cells are specialized to move or transport ciliated cells in the airways and lungs Some cells are specialized to react to their environment. Nerve cells and cells in your eye. Some cells are specialized to make certain products. Pancreas cells produce enzymes for digest.
53 Cell Diversity Cells in multicellular organisms develop in different ways to perform particular functions within the organism. This is cell specialization. LEVELS OF ORGANIZATION The levels of organization in a multicellular organism include: Cells Tissue- Groups of similar cells that perform a function. Organ- Tissues working together. Organ system- various organs working together. Specialization and interdependence is an important characteristic of living things. Multicellular organisms have cell specialization, single cell organisms do not need to.