Cell Theory and Structure All you ever wanted to know about cells but were afraid to ask.

Cell Theory: There are three parts. 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of life. 3. All cells come from existing cells.

Eukaryotic Cells - Nucleus - Membrane-covered organelles - Linear DNA inside the nucleus - All cells except bacteria Prokaryotic Cells - No nucleus - No membrane-covered organelles - Circular DNA floating in the cell - Bacteria Cell Types: Cell Theory and Structure

Cell Structure: Overview 1. The cell functions much like a factory. Do you remember the exercise we did with the PBC Factory? 2. Organelles within the cell must function together in order to meet the cell’s needs. If cells within an organism do not function properly, the organism will suffer ill effects and possibly death. 3. All cells come from existing cells. The cells that make up your body are constantly being replaced by cells that are already there.

Cell Theory and Structure Cell Structure: The Nucleus and Nucleolus (Eukaryotic cells only) 1.The nucleus is like the brain of the cell. It controls the cell type and relays instructions on what to do to the rest of the cell. 2.The nucleus contains DNA. The cell’s DNA is a set of instructions on how to make proteins. Without proteins, the cell would die. 3The dark spot inside the nucleus is the nucleolus. Basically, the nucleolus helps in making ribosomes in the cytoplasm.

Cell Theory and Structure Cell Structure: The Endoplasmic Reticulum 1.The endoplasmic reticulum (ER) delivers messages and materials to various parts of the cell. It acts like a tunnel throughout the cell. 2.The ER also breaks down harmful chemicals in the body that could destroy the cell. 3.Another important function of the ER is to make lipids (fats) that form the membranes around organelles and the cell.

Cell Theory and Structure Cell Structure: The Ribosomes 1.The ribosomes of a cell act like an assembly line at a factory. Their main job is to assemble proteins by hooking together amino acids. These proteins will be used throughout the organism for the construction of cells and organelles. Proteins also help control critical functions of the cell. Think of proteins as the building blocks of cells and cells as the building blocks of all organisms. 2.Ribosomes are the smallest of cell organelles and do not have membranes. 3.The nucleolus produces ribosomes, which are responsible for making proteins.

Cell Theory and Structure Cell Structure: The Golgi Bodies or Golgi Complex 1.Golgi bodies (Golgi complex) look a lot like the ER. However, Golgi bodies are located close to the cell membrane. 2.The function of the Golgi complex is to package and send proteins and other materials to different parts of the cell. The Golgi complex also sends proteins and other materials outside the cell.

Cell Theory and Structure Cell Structure: The Mitochondria 1.Mitochondria are the cell’s energy makers. 2.Mitochondria take food molecules and turn them into ATP. 3.Cells use ATP for energy so that they can perform all their necessary functions.

Cell Theory and Structure Cell Structure: The Lysosomes 1.Lysosomes are the cell’s custodians and SWAT team/commandos. 2.Lysosomes destroy foreign invaders inside the cell by dissolving them with enzymes. 3.Lysosomes also break down food particles and cell organelles when they become dysfunctional. 4.Lysosomes clean up and recycle wastes in the cell.

Cell Theory and Structure Cell Structure: The Vacuoles 1.Vacuoles store liquids and excess materials in a cell. 2.Vacuoles in animal cells are very small compared to vacuoles in plant cells. 3.Vacuoles in a plant contain large amounts of water and other liquids which help give the plant support. Plants wilt when their vacuoles lose water. Animal CellPlant Cell

Cell Theory and Structure Cell Structure: The Cell Membrane (All Cells) 1.The cell membrane acts a barrier and gatekeeper between the cell and the world outside of the cell. 2.The cell membrane allows certain particles out of the cell and specific particles into the cell.

Cell Theory and Structure Cell Structure: The Cell Wall (Plants, Fungi and some Protists) 1.The cell wall in plants is made of cellulose and provides support for the cell, which in turn supports the plant. Millions or perhaps trillions of these cells together give a tree its strength or celery its crunch. 2.The cell wall helps keep the cell membrane from breaking under stress. This keeps the organelles inside the cell where they belong!

Cell Theory and Structure: Reinforcement Activity 1.Choose a plant or animal cell and draw it on the front of your paper. 2.You must include the following organelles: a.Cell membrane b.Cell Wall (Plant Only) c.Nucleus d.Nucleolus e.Endoplasmic Reticulum f.Golgi Complex g.Ribosomes h.Lysosomes i.Vacuoles j.Mitochondria k.Chloroplast (Plant cell only) l.Cytoplasm 3. Draw a picture on the back or your paper to represent each of the organelles in your drawing on the front. The picture must relate to the function of the organelle not its physical characteristics. For example, you might draw a flashlight to represent mitochondria, since mitochondria provide the cell with energy.

1. All living organisms are made of cells. 2. You consist of around 100 trillion cells. 3. However, all of your cells came from existing cells…including the first cell that started your life. 4. You started off as a single cell inside your mother. From One Cell to an Organism

1. Forty hours after fertilization your one cell has divided into six to ten cells. 2. Your cells are still just stem cells at this point in time. They do not have differentiated functions…yet. 3. After six days, you are still just a mass of cells. 24 Hours40 HoursSix Days From One Cell to an Organism

1. Your cells start to differentiate around two weeks after fertilization. 2. By four weeks, 28 days you start to look like a little like a human. 3. After four months, you look very much like a human. Two WeeksFour WeeksFour Months From One Cell to an Organism

1.After your cells differentiate, and start to perform specific functions, they come together to form: TISSUES 2. A tissue is a group of cells that work together to perform a specific job in the body. Tissues include red blood cells, fat, and muscle. From One Cell to an Organism

1.Tissues of the same type come together to form ORGANS 2. An organ is two or more tissues working together to perform a specific job. Examples of organs include your stomach, heart, skin and lungs. From One Cell to an Organism

1.Organs that work together make up: ORGAN SYSTEMS 2. An organ system is organs working together to perform a particular job, such as digesting food or breathing. From One Cell to an Organism

1.Organ systems working together make up: ORGANISMS 2.An organism is anything that can live on its own. 3.Unicellular organisms are made up of one cell. 4.Multi-cellular organisms are made up of many cells. From One Cell to an Organism