Explain how the genetic information in the nucleus is used to direct the production of proteins in the cytoplasm.

Transcription

1 Cells: The building blocks of life Study Guide Compare the following pairs of terms, noting the most significant differences: prokaryotic cells versus eukaryotic cells, plant cells versus animal cells. Explain how the genetic information in the nucleus is used to direct the production of proteins in the cytoplasm. Compare the structures and functions of the following : rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus. Compare the contents and functions of the following vesicles: transport vesicle, lysosomes, food vacuole, contractile vacuole and central vacuole. Compare the structure and function of chloroplasts and mitochondria. Describe the functions of the cytoskeleton. Compare the structures and functions of cilia and flagella. Describe the structure and function of a plant cell wall 1

2 Study Guide Describe the structure of the plasma membrane and other membranes of the cell. Explain why the cell membrane is called a fluid mosaic. Describe the primary functions of the membrane proteins. Explain how the structure of the plasma membrane makes it semipermeable. Describe the primary functions of the membrane proteins. Distinguish between the following pairs of terms: diffusion versus osmosis, passive transport versus active transport, hypertonic versus hypotonic, endocytosis versus exocytosis, and phagocytosis versus pinocytosis. Distinguish between surface area and volume of a cell. Describe what happens to All living things are composed of cells Each cell (in a unicellular or a multicellular organism) needs to: Make needed molecules Extract energy from molecules Obtain molecules for energy growth or replacement Transport molecules into and out Today we will learn what role does each part of the cell play in fulfilling these needs 2

3 Types of Cells Fill table of your lab handout 3

4 A certain cell has mitochondria, ribosomes, smooth and rough endoplasmic reticulum, and other parts. Based on this information, it could NOT be. 1. a cell from a pine tree 2. a grasshopper cell 3. a yeast (fungus) cell 4. a bacteria 5. actually, it could be any of the above Cytoskeleton: movement within the cell, movement of the cell Cilia: in humans and in protist Flagella: in humans and protist Cytoplasm: molecular soup inside the cell 4

5 A membrane is a fluid mosaic of phospholipids and proteins Bilayer of phospholipids with Proteins imbedded in it Fluid molecules move freely (flexible) Mosaic has a variety of proteins that perform different functions For example: The cell membrane of a RBC has 50 different kinds of proteins The Cell membrane has a mosaic of functions Main Functions of membrane 5

6 Eukaryotic cells have membrane enclosed organelles 6

7 Most of the DNA in a eukaryotic cell is in. the cytoskeleton the mitochondria the endomembrane system the cytoplasm the nucleus A plant cell was grown in a test tube containing radioactive nucleotides, the parts from which DNA is built. Later examination of the cell showed the radioactivity to be concentrated in the. lysosome rough endoplasmic reticulum central vacuole smooth endoplasmic reticulum nucleus Endomembrane system 7

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9 Your white blood cells make antibodies that are exported from the cell into the blood stream. Which of the following might be the path of an antibody from the site where its synthesized to its export? A. nucleus Golgi lysosomes cell membrane B. Golgi.vesicle.rough ER smooth ER vesicle C. rough ER vesicle Golgi. vesicle cell membrane D. smooth ER Golgi. Lysosome... cell membrane E. nucleus.golgi vesicle...rough ER cell membrane Substances in the cell are packaged or transported in membrane sacs Vesicles: transports products inside and out of the cell Central vacuole (only in plant cells): stores water (maintain cell shape) Contractile vacuole in unicellular organisms: controls the amount of water inside the cell Food vacuole: contains food particles Lysosome: contains digestive enzymes for cell s use 9

10 If a cell's lysosomes burst, the cell would. digest itself divide into two cells shrivel become denatured need to manufacture more lysosomes 10

11 Plant cells, unlike animal cells, are characterized by the presence of a. nucleus and contractile vacuole cell wall and central vacuole cell wall and contractile vacuole nucleus and cell wall cell wall and ribosomes Review questions At the end of today s lab 11

12 Microscope lab The size of Cells and their components 12

13 Light microscopes Compound light microscope: higher magnification view small or thinly sliced organism Dissecting microscope: low magnification view larger organisms but only their surface Microscope and Slides Check Out Procedure Sign in and collect key and prepared slides (under your assigned seat) Keep prepared slides in safe place Prepared slides have labels Open box and remove microscope by its arm and base Remove and store bag Wait for further instructions while you wait try to identify the parts on your microscope Using the handout provided 13

14 Rules for Microscope Use Low power objective should be in position both at the beginning and end of lab Do not leave slides on microscope when storing it Use only lens paper for cleaning lenses (ask instructor for paper) Keep the stage clean and dry to prevent rust and corrosion Do not remove parts of the microscope Keep the microscope dust free by covering it after use Report any malfunctioning or if microscope was not stored properly Parts of the light microscope and their functions Eyepieces or ocular lens note magnification Arm Nosepiece with objectives Low-Power Objective note magnification High-Power Objective note magnification Oil immersion Objective never use!!! Ocular lens Nosepiece Arm Coarse adjustment knob use ONLY when LP Objective is in use Fine adjustment knob Condenser specimens needs to be on top of light Diaphragm move lever to change amount of light less light more contrast Stage, stage clips, and stage knobs Diaphragm Base Stage Stage clips Stage knobs 14

15 Total Magnification is the number of times that the image has been magnified Microscope uses two sets of lenses to magnify specimen 1. ocular lens 2. objective lens TM = ocular lens x objective lens in use Total Magnification under the low power= X (times) Total Magnification under the high power= X Field of View is the area of your specimen that is visible through the ocular lens 40X 100X 400X What happens to the field of view when we increase the magnification? 15

16 Microscope specimens Prepared slide Make your own slide with staining without staining Part 1: Use of the Microscope Secret to success: follow instructions carefully Use prepared slide with letter e to practice focusing Low power follow steps 1 9 Your microscope is parafocal, what does this mean? High power follow steps

17 Making your own slides and types of cells Where are the supplies? Human cheek Cells stained with methylene blue Elodea Leaf Cells without stain What parts of the cell are visible? How to clean up? Making your own slides and types of cells Onion skin Cells stained with iodine solution DEMO Bacteria stained What parts of the cell are visible? Complete sketches OF ONE CELL and LABEL THEM Answer questions Based on your observations 17

18 What is Cystic Fibrosis? One of the main functions of the cell membrane is the transport of molecules into and out of the cell 18

19 Molecules tend to move to where they are less concentrated Diffusion: tendency of molecules to spread out from where they are more concentrated to where they are less concentrated or they tend move down their concentration gradient Note that both water molecules and dye molecules are diffusing Set up agar cubes experiment (groups of four) Cut cubes in following order: 3x3x3 2x2x2 1x1x1 Immerse each cube in a beaker with vinegar and start your stopwatch Take the time that it took for the entire cube to turn yellow 19

20 Cell membrane is a selectively permeable: some molecules can cross freely between phospholipids and others can NOT 20

21 Which of the following is a difference between active transport and facilitated diffusion? A) Facilitated diffusion requires energy from ATP and active transport does not. B) Facilitated diffusion involves transport proteins and active transport does not. C) Active transport involves transport proteins and facilitated diffusion does not. D) Active transport requires the expenditure of cellular energy, and facilitated diffusion does not. E) Facilitated diffusion can move solutes against a concentration gradient and active transport cannot. 21

22 How does a cell transport bulk materials into or out of the cell? Exocytosis (out of cell) Example: hormone secretion Endocytosis (into cell) engulfing Example: amoeba eating Phagocytosis cellular eating an entire cell is engulfed example: amoeba or white blood cell Pinocytosis cellular drinking external liquid is engulfed Receptor mediated endocytosis substance needs to bind to receptors, to be engulfed very specific 22

23 The extracellular fluid and cytoplasm are solutions Solution: is a mixture of two or more molecules in a liquid environment Solution= Solute + solvent (water) Concentration of a solution: % of solute Osmosis is the (diffusion) passive transport of water What happens to the volume of liquid on each side of the membrane? Why is this important? Cells can gain or loose water depending on the concentration of solutes outside vs. inside 23

24 The effect of osmosis in Animal Cells and Plant Cells Turgor pressure Difference between animal cells and plant cells is due to Pancreas: exocytosis, active transport, and osmosis 1. Pancreas cells releases digestive enzymes into duct via 2. CFTR transports ions into duct via active transport, creating a outside 3. Water diffuses out of cell by 4. Water slurry flows out of duct into intestine carrying enzymes Normal pancreas cells CF pancreas cells 24

25 Cell Transport Lab Osmosis in animal cells and plant cells Effect of cell size/shape on the speed of diffusion PART1. OSMOSIS IN ANIMAL CELLS (RED BLOOD CELLS) DEMO RBC And 0.9% Na Cl RBC And 10% NaCl RBC And Distilled water Distilled water has 0% solutes 10% NaCl solution: 10% NaCl and 90% water In which slide are the RBC in a isotonic solution? How can we find this out? 25

26 Isotonic Hypertonic Hypotonic crenated OSMOSIS IN PLANT CELLS (ELODEA LEAF CELLS) Slide 1: Elodea leaf + distilled water Slide 2: Elodea leaf + 10% NaCl solution Wait 5 min View under microscope and compare slides In which slide are the cells in a hypotonic solution? 26

27 Hypotonic Note position of chloroplasts Hypertonic Effect of cell size/shape on the speed of diffusion Cells volume = cytoplasm requirement of nutrients or wastes removed Cells surface = cell membrane area through which nutrients and wastes are transported into or out of cell Why are most cells microscopic in size? Volume increases FASTER than the surface Larger cell has problems with exchange of nutrients and wastes 27

28 Agar cubes will represent different sized cells Bromothymol Blue changes color in the presence of an acid Surface area = Volume = SA/V ratio = Acid = B blue = Time form turning completely yellow= Can cells improve their diffusion speed by having a different shape? 1x1x8 28

29 Plan of Attack Part 1. Osmosis in animal cells observe demo microscopes with blood samples Part 2. Osmosis in plant cells Work in groups of four One pair does elodea in distilled water One pair does elodea in saline water Part 3. EFFECT OF CELL SIZE OR SHAPE ON SPEED OF DIFFUSION complete table Do sketches and answer questions 29