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Chapter 2- Cells


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Chapter 2- Cells

  1. 1. Chapter 2 Cells
  2. 2. Cells Section 2-1 H.W. Pg. 45 ques . 1-4 <ul><li>What are cells ? </li></ul><ul><li>- Cells are the smallest unit of living things, and are the building blocks of life. </li></ul><ul><li>All living organisms are made up of cells. </li></ul><ul><li>Some organisms are composed of many cells, like humans, animals, trees, and flowers. These multi celled organisms can be seen without the use of a microscope. </li></ul><ul><li>Other organisms are only composed of one single cell , like bacteria or some algae, and they can only be seen with the use of a microscope. </li></ul>
  3. 3. History of the Cell <ul><li>Why do they call cells, cells? </li></ul><ul><li>When the first microscope was created by Thomas Hooke, the first thing that scientists decided to look at was a piece of cork, which is made from trees. </li></ul><ul><li>What they saw was a lot of small boxes that, to them resembled prison cells. </li></ul><ul><li>Hence the name cells. </li></ul><ul><li>After other scientists looked at many animal cells they concluded that all living things are composed of cells. </li></ul>
  4. 4. Plant Cell
  5. 5. History of the Cell <ul><li>However, not all cells look like boxes. Only plant cells do. </li></ul><ul><li>- Human cells take on many different shapes. As well as bacterial, fungal and algal cells. </li></ul>
  6. 6. Cell Types <ul><li>Scientists have found that cells can be separated into two groups: </li></ul><ul><li>- Prokaryotic & Eukaryotic </li></ul><ul><li>Prokaryotic - cells that lack a nucleus and any other membrane bound organelles. (usually single celled organisms like bacteria.) </li></ul><ul><li>Eukaryotic- cells that do exhibit a nucleus and other membrane bound organelles. (could be multi- or unicellular) </li></ul>
  7. 7. Cell Composition <ul><li>Every cell of an organism, as small as they are , is made up of even small parts. </li></ul><ul><li>These smaller parts that make up a cell are called organelles . What do you think organelle means? </li></ul><ul><li>It means small organ. </li></ul>
  8. 8. Organelles <ul><li>Within a cell are many organelles that perform many specific functions. </li></ul><ul><li>We will also learn that there are different organelles in plant cells than there are in animal cells. </li></ul>
  9. 9. Organelles of an animal cell <ul><li>The organelles of an animal cell that we will explore are: </li></ul><ul><li>Cell membrane- this covers the outside of the cell and controls what material enters and leaves the cell. </li></ul><ul><li>Cytoplasm- a gel like liquid that fills the cell. All organelles move around in the cytoplasm and many cell activities occur here. </li></ul><ul><li>Nucleus- This is the brain or control center of the cell. It controls all cell activity and houses our DNA. </li></ul><ul><li>Chromosomes - Found in the nucleus and contain our DNA or genetic make up. </li></ul><ul><li>Mitochondria- This organelle is responsible for converting our food and oxygen to energy, this is called Cellular respiration . Called the Power house of the cell. </li></ul>
  10. 10. Organelles of an animal cell <ul><li>Cytoskeleton - Is a framework present inside the cytoplasm that maintains or changes the cells shape. It could also allow cells to move. An amoebas cytoskeleton contracts and stretches to allow it to move. </li></ul><ul><li>Ribosomes - The job of this organelle is to make proteins that the cell needs for chemical reactions. They receive directions from the hereditary material in the nucleus on how, when, and in what order to make specific proteins. </li></ul><ul><li>These can be found in two places in the cell. </li></ul><ul><li>1 - Freely floating in the cytoplasm. </li></ul><ul><li>2 - Or, attached to the Endoplasmic reticulum. </li></ul><ul><li>Endoplasmic Reticulum - Is a series of folded membranes that extends from the nucleus to the cell membrane and allows for the passage and processing of materials throughout the cell. </li></ul><ul><li>There are two types or ER: </li></ul><ul><li>1 - Smooth ER, has no ribosomes attached to it. </li></ul><ul><li>2 - Rough ER, does have many ribosomes attached to it. </li></ul>
  11. 11. Organelles of an animal cell <ul><li>Vacuoles - These are little storage areas in a cell that hold water, minerals, and food and waste. </li></ul><ul><li>Golgi bodies - These are stacked, flattened membranes that look like a stack of plates. Their job is to process proteins and to package them into small membrane bound vesicles. This allows the material processed by the golgi to be transported around the cell. </li></ul><ul><li>Lysosomes - These organelles are used to breakdown and recycle substances inside the cell. They contain digestive chemicals that aid in breaking down food, cell waste and old worn out organelles. </li></ul>
  12. 12. Animal Cell
  13. 13. Organelles of a plant Cell <ul><li>A plant cell contains all of the organelles that are present in an animal cell plus two more: </li></ul><ul><li>Cell Wall- This is found in plants, algae, and fungi and it is a thick covering that surrounds the cell membrane. It gives support to the cell and together all the cell walls of a plant gives structure to the whole organism. </li></ul><ul><li>Chloroplast – These organelles contain a chemical called chlorophyll, a pigment that traps sunlight and converts it into energy. It uses the sun light, water and CO2 to produce O2. This process is called photosynthesis . </li></ul>
  14. 14. Plant Cell
  15. 15. The different jobs of cells <ul><li>It is impossible for every cell in your body to be able to carry out every job that your body needs to have done. </li></ul><ul><li>That’s why there are many different cells in our bodies that all have very different, very specific jobs to do. </li></ul>
  16. 16. Different types of animal cells and how there shape is related to their function. <ul><li>Red Blood Cell- Travel though your blood vessels and carries oxygen to tissues all over the body, and removes any waste products. </li></ul><ul><li>Have a dimple in the middle of them. This dimple is where a molecule of O2 will be carried. </li></ul>
  17. 17. Different types of animal cells and how there shape is related to their function. <ul><li>Nerve Cells- They are long and shaped like wires in order to carry electrical impulses around the body. </li></ul><ul><li>Muscle Cells- Are long straight fibers that allow us to move our skeleton. They have many mitochondria. Why? </li></ul><ul><li>- They need a lot of energy. </li></ul>
  18. 18. Different types of plant cells and how there shape is related to their function. <ul><li>Cells of the stem- plant stems have many cells that are long and tube shaped. This allows water from the ground to be moved up the plant. </li></ul><ul><li>Leaf cells- These cells are brick shaped and have many chloroplasts. Why? </li></ul><ul><li>- The leaves are exposed to the sunlight and they trap it to make food by photosynthesis. </li></ul>
  19. 19. Cell organization <ul><li>All of these specific cells in your body, as well as in plants, are not just all thrown together. </li></ul><ul><li>You wouldn’t want to have liver tissue in you brain or a leg muscle cell in your stomach. </li></ul><ul><li>All common cells are grouped together to form specific tissues. </li></ul><ul><li>Ex: A lot of cells combine form to make tissues . Tissues are groups of similar cells that perform similar work. </li></ul><ul><li>- Tissues would than combine together with different tissues to form an organ . An organ is a structure made up of two or more different types of tissue that work together. </li></ul><ul><li>Ex: The stomach is an organ made up of muscle tissue, nerve tissue and blood tissue. </li></ul>
  20. 20. Cell organization <ul><li>Organs than come together to form organ systems. </li></ul><ul><li>Ex: the mouth, stomach, intestines, and liver are all organs that make up the digestive system. </li></ul><ul><li>Other systems include the respiratory, skeletal, and reproductive systems. </li></ul><ul><li>- Organs systems then give rise to organisms. </li></ul>
  21. 21. Microscopes Section 2-2 H.W. Pg. 51 ques. 1-4 <ul><li>A microscope is an instrument used by scientists to study cells and other microscopic material. </li></ul><ul><li>- Microscopes are very critical to science. They allow us to explore a world that other wise was never known. </li></ul><ul><li>Light microscopes use light and lenses in order to magnify the object that you are looking at. </li></ul><ul><li>Simple light microscope uses only one lenses, whereas a compound light microscope uses 2-4 lenses. One in the eye piece and one objective lens. </li></ul><ul><li>- Electron microscopes use a magnetic field in a vacuum to direct beams of electrons onto the object your looking at. These microscopes are a lot more powerful than light microscopes. Could magnify an object up to 1 million x </li></ul>
  22. 22. Microscope Parts <ul><li>-----------Eye piece </li></ul><ul><li>------------------- Objectives </li></ul><ul><li>-------------------Stage </li></ul>
  23. 23. Viruses Section 3-3 H.W. Pick a virus and write down its name, and 5 other facts about it. <ul><li>What is a Virus? </li></ul><ul><li>A virus is a strand of hereditary material that is surrounded by a protein coat. </li></ul><ul><li>A virus is a particle that has things in common with both living and non-living things. </li></ul><ul><li>They have the ability to reproduce so they are like living things. </li></ul><ul><li>They are like non-living things because they don’t grow or eat and they need to live inside a cell or a host to survive. </li></ul><ul><li>And for this reason viruses are not included within the six kingdoms of life. </li></ul>
  24. 24. Viruses (continued) <ul><li>All viruses cause disease. And they can infect any type of living organism. (from bacteria, to algae, to plant, to fungi, to animal) </li></ul><ul><li>Ex: H.I.V, Hepatitis </li></ul><ul><li>□ We treat viruses with vaccines, which are dead or weak viruses that are given by injection or by mouth. Ex: polio virus, mumps, measles.) </li></ul><ul><li>- These vaccines make our bodies produce substances that allow us to become resistant to the virus. </li></ul>
  25. 25. Virus life cycle <ul><li>First a virus will attach and invade a cell. </li></ul><ul><li>Next, the virus uses the cell to make copies of its DNA. </li></ul><ul><li>Once the virus makes enough copies of itself it makes the cell it is occupying explode. </li></ul><ul><li>The new viruses then escape and are free to invade the surrounding it and start the process over again. </li></ul>
  26. 26. Virus life cycle
  27. 27. Active Vs. Latent Viruses <ul><li>Active viruses enter a cell and continuously go through there life cycle numerous amounts of times without stopping. </li></ul><ul><li>Latent Viruses will enter a cell and not necessarily begin their life cycle right away. The virus makes its DNA part of the host but new virus particles are not put together yet. They wait until a certain physical or chemical change occurs within the cell, which triggers the viral particles to assembled. </li></ul>
  28. 28. Virus pictures.
  29. 29. Test on Chapter 3 in one week