Cells and Body Systems Notes - 1 PDF

**[Cells and body systems]** A living thing is called an **organism**. Organisms are made up of cells. All of the **organs** found in your body are made up of **tissues** and special **cells**. - **Cell** - Your body is made up of a bunch of cells. Your skin is made up of billions of individ...

**[Cells and body systems]** A living thing is called an **organism**. Organisms are made up of cells. All of the **organs** found in your body are made up of **tissues** and special **cells**. - **Cell** - Your body is made up of a bunch of cells. Your skin is made up of billions of individual cells. - **Tissue** - Is a set of cells that do a similar thing. - **Organ** - is a structure in the body that has a specific task. 1. Connective: Supports and connects different parts of the body. Example: Blood, cartilage, bones 2. Epithelial: Covers the surface of organs and body 3. Nervous: Sends signals throughout your body 4. Muscle: Allows movement. Examples: skeletal muscle, heart muscle. **[Single celled organisms and multicellular organisms]** There are 2 main types of organisms when it come to cells. Organisms that only need one cell to survive and organisms that need many cells to live. **A single celled organism** does not need more than 1 cell to live or function. Ex bacteria, viruses and algae. **A multicellular organism** needs many cells to play a role in living and functioning. **[Animal Cell]** **Most animal cells have a similar structure and design. In the following descriptions will describe a standard cell found in the body** **Cell membrane:** The outside of the cell that holds everything in and allows nutrients and water into the cell. Made of a phospholipid bilayer (two layers of oils), which makes the cell water proof. It is semipermeable, which means it lets only certain things in. **Nucleus:** A package in the center of the cell that holds the DNA. DNA holds all the information about the organism. Endoplasm reticulum (ER): Located directly by the nucleus. Takes copies of DNA (called RNA) and translates the RNA into proteins. Ribosomes: Found in the walls of the ER, converts RNA into proteins. Golgi complex: Packages up the proteins and other things to move around the cell. Mitochondria: Converts nutrients into energy for our bodies. The energy our body uses is called adenosine triphosphate (ATP). "Power house of the cell." Vacuole: Storage area for nutrients. Sometimes are used for isolating (separating) bad things from attacking the cell. Lysosome: Breaks down damaged parts of a cell so that parts can be reused for building more things. **[The Plant Cell ]** The plant cell is similar to the animal cells with a few differences. The plant cell is different in 3 ways: - **Cell wall**: In plants the cell is protected by a hard wall called the cell wall. It is made up of mostly cellulose. - **Chloroplast:** Special packages of pigment that convert light energy to sugars. - **Vacuole:** In the plant, the vacuole helps the cell maintain its shape and stores sugars. Animal cells have them too, but they are used only for storage. **[How things enter and exit the cell membrane]** Both plants and animal cells have a cell membrane that is **semi-permeable** (only lets certain things in). Some parts of the cell allow nothing in and some have little pores (open holes) that allow things like water in. Other areas have proteins that open and close when they recognize something (sugars and nutrients) that are safe to enter the cell. Things that the cell needs can enter the cell in 3 ways. Diffusion, osmosis, and active transport. **Diffusion** is when particles (atoms) move from an area of high concentration to low concentration. Image result for diffusion  **Osmosis** transports solvents. (H~2~O, other smaller particles). Liquid moves from solution of low concentration to high concentration. A good way to remember it is "Solutes suck!" (The higher the concentration the more it is going to take in water). Needs a semipermeable membrane - Hypertonic- higher concentration outside the cell. Cell will shrink - Hypotonic- lower concentration outside the cell. Cell will swell or burst - Isotonic- Same concentration. Cell will stay the same **Active transport**. Needs protiens located in the cell membrane to physically put it into the cell, requires cellular energy (ATP). The substance goes from a low concentration of solute to high.