Chapter 1: Cell Structure National 5 Biology Unit 1: Cell Biology 7/2/20151Mrs Smith

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Transcript of Chapter 1: Cell Structure National 5 Biology Unit 1: Cell Biology 7/2/20151Mrs Smith

  • Slide 1
  • Chapter 1: Cell Structure National 5 Biology Unit 1: Cell Biology 7/2/20151Mrs Smith
  • Slide 2
  • Learning Intentions National 5 Biology 7/2/20152Mrs Smith By the end of this chapter, you should be able to describe cell structure - Specifically be able to discuss - Cell ultrastructure and functions to include: cell wall, mitochondrion, chloroplast, cell membrane, cytoplasm, vacuole, nucleus, ribosome and plasmid. - You should also be able to describe the ultrastructure by using examples from typical plant, animal, fungi and bacterial cells. - Explain fungal structure in terms of similarity to plant and animal cells but with a different cell wall structure. (Cell wall structure in fungal and bacterial cells is different from plant cells, ie chitin not cellulose) - Bacterial structure description should include the absence of organelles (no nucleus, mitochondria vacuole or chloroplasts) and a different cell wall structure to plant and fungal cells. -Bacterial structure should also include a description of there chromosomes and plasmid.
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  • CELLS ARE THE STARTING POINT! All living organisms on Earth are divided into cells. The main concept of cell theory is that cells are the basic structural unit for all organisms. Nothing smaller than a cell can lead to independent life. Cells are small compartments that hold the biological equipment necessary to keep an organism alive and successful. Living things may be single-celled or they may be very complex such as a human being. 7/2/20153Mrs Smith
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  • Plant Cells Can be viewed under the microscope Below are examples of plant cells viewed under the microscope Some of a plant cells parts can be seen clearly when mounted in water (see below) Other cell structures that are not so obvious can often be shown up more clearly by the addition of a STAIN (dye). Iodine solution can be used on onion cells to stain the nuclei. Onion leaf cells in iodine solution Elodea leaf cells in water 7/2/20154Mrs Smith
  • Slide 5
  • Using stains with the microscope. Stains can be used to make cells more visible under the microscope, e.g. Iodine solution. Onion skin: 2 pieces were taken from the bottom layer of an onion and placed on 2 different slides. With one, some iodine was placed n the slide to see the different layers, The other slide was left unstained. 7/2/20155Mrs Smith
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  • Add 2 drops of iodine to the centre of a glass slide. Be careful! Iodine can stain your clothes. Take a small piece of onion. Use tweezers to peel off the skin from the underside (the rough, white side) of the onion. Throw the rest of the onion piece away. Carefully lay the onion skin flat in the centre of the slide on top of the iodine. Add 2 drops of iodine to the top of the onion skin. Stand a thin glass cover slip on its edge near the onion skin, next to the drop of iodine. Slowly lower the other side of the cover slip until it covers the onion skin completely. If there are air bubbles, gently tap on the glass to chase them out. Onion Cell Lab Instructions. 7/2/20156Mrs Smith
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  • Draw what you see. Why are there no chloroplasts in onion cells? Iodine Solution with air bubbles Chloroplasts are absent from onion skin cells because it grows underground in the darkness (so what would be the point?) 7/2/20157Mrs Smith
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  • This is what our Onion cell looked like! 7/2/20158Mrs Smith
  • Slide 9
  • Tear off one small leaf/stem from the plants in the fish tank. Add one drop of tap water to the slide. Stand a thin glass cover slip on its edge near the leaf, next to the drop of water. Slowly lower the other side of the cover slip until it covers the leaf completely. Make sure there are no air bubbles. Plant Cell (Pond weed). Lab Instructions 7/2/20159Mrs Smith
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  • Draw what you see. 7/2/201510Mrs Smith
  • Slide 11
  • While some cells do look different, all cells have these three basic features. nucleus cytoplasm cell membrane 7/2/201511Mrs Smith
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  • The Nucleus Controls the cells activities Controls all the chemical reactions inside the cell 7/2/201512Mrs Smith
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  • The Cell Membrane The cell membrane is selectively permeable and controls what substances may enter and leave the cell. Cell membrane 7/2/201513Mrs Smith
  • Slide 14
  • The Cytoplasm It is a jelly like material All the chemical reactions taking place in the cell occur here 7/2/201514Mrs Smith
  • Slide 15
  • Organelles are tiny structures (such as chloroplasts) that are: Present in a cells cytoplasm as discrete units normally surrounded by a membrane. Responsible for a specialised function (such as photosynthesis ORGANELLES - Continued 7/2/201515Mrs Smith
  • Slide 16
  • Ultrastructure Cell structure is actually way more complicated than we have been teaching you There are even smaller structures in a cell. These minute structures cannot be seen with a normal light microscope. They can only bee seen using a more sophisticated piece of equipment called the electron microscope. 7/2/201516Mrs Smith
  • Slide 17
  • Your group will be issued with four different cell diagrams and four different descriptions as well as your own summary sheet. 1.Read each description carefully. 2.Match up each description with the correct cell. 3.Copy each cell picture into your jotter 4.Using all of the descriptions complete your table with a general function for each of the cell parts you have identified. 5.Complete the table by stating which of the cell parts are present in each cell type. You have finished the cell race only when every member of the group has completed their own diagram and table and this has been checked by your teacher so assign group tasks wisely and remember to include everybody. Cell race Cooperative activity 20 minutes max! 7/2/201517Mrs Smith
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  • Animal Cell Animal cells are bounded by a cell membrane that controls entry and exit of substances. The cytoplasm is the factory part of the animal cell in which chemical reactions take place to manufacture various substances. The nucleus holds the DNA molecules (chromosomes) that are composed of sections called genes. Gene code for the making of proteins that control the activity of the cell. Embedded in the cytoplasm are mitochondria- sausage shaped structures with a smooth outer membrane and a folded inner membrane. It is in the mitochondria that aerobic respiration (respiration that uses oxygen) takes place. Also in the cytoplasm of animal cells free or attached to membranes are ribosomes- small spherical structures that are where protein molecules are created using instructions supplied from the DNA in the nucleus. 7/2/201518Mrs Smith
  • Slide 19
  • Plant Cell Plant cells are bounded by a cell wall made of cellulose fibres that forms a rigid box that although permeable to all but the largest molecules provides support for the cell and the plant as a whole. To the inside of the cell wall is the cell membrane that controls entry and exit of substances and is composed of proteins and phospholipids. The cytoplasm is the factory part of the plant cell in which chemical reactions take place to manufacture various substances. The nucleus holds the DNA molecules (chromosomes) that are composed of sections called genes. Genes code for the making of proteins that control the activity of the cell. Embedded in the cytoplasm are mitochondria- sausage shaped structures with a smooth outer membrane and a folded inner membrane. It is in the mitochondria that aerobic respiration (respiration that uses oxygen) takes place. Also in the cytoplasm of plant cells free or attached to membranes are ribosomes- small spherical structures that are where protein molecules are created using instructions supplied from the DNA in the nucleus. Chloroplasts are the site of photosynthesis in green plant cells. Vacuoles are fluid filled sac containing cell sap which are important in controlling water balance within the cell. 7/2/201519Mrs Smith
  • Slide 20
  • Fungal cells are bounded by a cell wall made of chitin that forms a rigid box that provides support for the cell. To the inside of the cell wall is the cell membrane that controls entry and exit of substances and is composed of proteins and phospholipids. The cytoplasm is the factory part of the fungal cell in which chemical reactions take place to manufacture various substances. The nucleus is the control centre of the cell. It holds the DNA molecules (chromosomes) that are composed of sections called genes. Gene codes for the making of proteins that control the activity of the cell. Embedded in the cytoplasm are mitochondria- sausage shaped structures with a smooth outer membrane and a folded inner membrane. It is in the mitochondria that aerobic respiration (respiration that uses oxygen) takes place. Also in the cytoplasm of fungal cells free or attached to membranes are ribosomes- small spherical structures that are where protein molecules are created using instructions supplied from the DNA in the nucleus. Vacuoles are fluid filled sac containing cell sap which are important in controlling water balance within the cell. Fungal Cell 7/2/201520Mrs Smith
  • Slide 21
  • Bacterial Cell Bacterial cells are bounded by a cell wall made of peptidoglycan that forms a rigid box that provides support for the cell. To the inside of the cell wall is the cell membrane that controls entry and exit of s