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 This PPT is very long… condense for next year… just main points…

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Presentation on theme: " This PPT is very long… condense for next year… just main points…"— Presentation transcript:

1  This PPT is very long… condense for next year… just main points…

2 Botany Unit 1 Chapter 3 Plant Cells White Ash Tree Deep Narrow Ridges/Diamond shaped pattern

3 1. The cell is the basic unit of life 2. All living things are composed of cells 3. All cells are derived from preexisting cells 3

4  Prokaryotic Cells (Prokaryotes) – Greek: Pro = “before” kary “nucleus” Cells lack nuclei Cells do not have membrane bound organelles Organisms in Domains Bacteria & Archea  Eukaryotic Cells (Eukaryotes) – Greek: Eu = “true” kary “nucleus” Cells have nuclei Cells have membrane bound organelles Organisms in Domain Eukarya

5  Nucleus  Cytoplasm (cytosol + organelles)  Cell Membrane 5

6  Plasma Membrane – a boundary that confines contents to the cell  Cytosol – fluid that suspends organelles  Ribosomes – organelles composed of protein and RNA  Genetic Information – DNA & RNA


8  A boundary that confines contents to the cell  Regulates what enters and exit the cell  This membrane is selective Some substances pass through freely Some in a controlled fashion Some are denied entrance or exit

9  Located outside the plasma membrane  A coating secreted by the cell  Support and protects the plant cell  Provides routes for water and dissolved materials to pass into and from the cell  Composed of cellulose fibers

10  Primary Cell Wall Stretches and expands as the cell increases in size  Middle Lamella A layer of pectic compounds Acts as a cement between the primary cell walls of adjacent cells  Secondary Cell Wall Forms after growth ceases Forms between primary wall and the plasma membrane Contains cellulose and lignin  Lignin (a hard substance that gives wood its distinctive texture)

11  Large, membrane-bound sacs  Filled with water that contains Salts Ions Pigments Waste products – to be recycled  Helps cell maintain Turgid shape  Provide strength for non-woody plants  Temporary storage area for excess materials

12  Structures within cells that perform photosynthesis or store starches, oils, or proteins  Provide Energy and Storage  Three Types Chloroplast Leucoplast Chromoplast

13  A type of plastid  Disc shaped  Has a photosynthetic function Convert light energy to chemical energy Water + Carbon Dioxide + Sunlight = Glucose + Oxygen + Water  Found in certain leaf & stem cells  Contain Chlorophyll A molecule with the vital role of absorbing light energy Absorbs blue and red light (reflects green) 13

14  Thylakoids – flat, disc-like sacs  Grana – stacks of thylakoids  Stroma – jellylike fluid in which grana are embedded Contains enzymes that speed up chemical reactions of photosynthesis 14

15  Leucoplasts Colorless plastids form and store starches, oils, or proteins Common in seed, root, & stem cells  Chromoplasts Contains yellow, orange, and red pigments Often form from chloroplasts when chlorophyll breaks down  Ex: Tomatoes; deciduous tree leaves 15

16  Center for processing, sorting, and packaging proteins  Consist of several flattened sacs  The edges of the sac bulge out and detach as vesicles vesicles- sacs that contain cellular products

17  Composed of RNA and Protein  Use instructions from DNA to build proteins Joins amino acids in precise sequences  Whorls of Ribosomes are called Polysomes  Are not enclosed by a membrane  Ribosomes are found: In the nucleus In Plastids In the Mitochondrion In Cytoplasm On the Rough Endoplasmic Reticulum (Rough ER)

18  An extensive network of parallel membranes that extends throughout the cells interior  Likely a continuation of the cell membrane and the nuclear envelope  Rough ER Flattened and studded with ribosomes Location of Protein synthesis (proteins are made here)  Smooth ER Tubular, no ribosomes Location of lipid synthesis (fats are made here)

19  Tiny organelles bounded by a double membrane Inner membrane called cristae  Using Cellular Respiration, converts the chemical energy (glucose) in food molecules to ATP  Distributes ATP to the rest of the cell

20  Produces ATP “Adenosine Triphosphate” “Energy Carriers” ATP is a nucleotide Has a large amount of energy stored in its phosphate bonds Energy is released when the bond is broken ATP becomes ADP (Adenosine Diphosphate)

21  A network of fiber that extends through the cytoplasm  Provides structure to a Eukaryotic cell  Composed of two types of fibers Microtubules – make up the spindle; involved in the addition to cell wall Microfilaments – thinner than microtubules, responsible for cytoplasmic streaming (movement of cytoplasm)

22  The garbage eaters  Break down cellular wastes

23  An organelle that contains DNA  Serves as the control center of the cell  Contains nucleoplasm Substance that contains DNA DNA associates with certain protein molecules to form chromatin Chromatin strands coil and thicken during cell division to form chromosomes

24 Nucleolus  Involved in making and assembling the subunits of ribosomes Nuclear Envelope  Separates the nucleus from the rest of the cell  Has a double membrane  Contains pores lined with protein molecules

25  Centrioles Made out of spindle fibers Used during cell division to retract spindle fibers; thus separating sister chromatids  Cytosol Intracellular fluid that suspends organelles  Cytoplasm Collectively all organelles and cytosol (excludes nucleus and plasma membrane & cell wall)

26 ORGANELLES FOUND IN PLANT CELLS ORGANELLES FOUND IN ANIMAL CELLS  Plasma membrane  Nucleus  Mitochondrion  Ribosomes  ER  Golgi Apparatus  Cytoskeleton  Cell Walls  Plastids  Vacuoles  Plasma membrane  Nucleus  Mitochondrion  Ribosomes  ER  Golgi Apparatus  Cytoskeleton  Centrioles  Lysosomes 26

27  Fluid Mosaic Model – see Figure 3-13 The current model for the structure of membranes Protein molecules “float” in a fluid phospholipid bilayer Characterizes the plasma membrane and other cell membranes as consisting of a double layer (bilayer) of lipid molecules Proteins are embedded in the lipid bilayer in a way the resembles a mosaic pattern The membrane structure is fluid rather than static  Lipids & proteins move sideways within the membrane 27

28  Components of Membranes Phospholipid  1 glycerol molecule + 2 fatty acids + a molecule containing a phosphate group  The phosphate end is polar (slightly charged)  Polar end is hydrophilic (hydro- “water” phil “love”)  Fatty acid chains are nonpolar  Nonpolar end is hydrophobic (hydro- “water” phobos “fear”)  Arrange hydrophilic heads toward the watery surroundings inside and outside of the cell  Hydrophobic tails form the inside of the double layer 28

29 29 Fluid Mosaic Model

30  Membrane perform many functions Membranes are selectively permeable  They regulate the passage of materials to maintain homeostasis  Homeostasis is a relatively constant set of internal conditions Membranes receive information from their surroundings  Use cell signaling, hormones, & chemicals  Help the cell to respond to its environment 30

31  Materials move passively or actively Passive transport  Diffusion – the net movement of particles (atoms, molecules, or ions) from a region of higher concentration to a region of lower concentration  Moves materials through the cytoplasm and into and out of cells  Ex. Sugar cube in a beaker of water – Fig  Osmosis – the diffusion of water across a selectively permeable membrane  Water moves from a solution with a higher concentration of water to a solution with a lower concentration of water 31

32  Osmosis Solution  A mixture in which salts, sugars, and other materials are dissolved in water  3 types of solutions  Isotonic (iso – “equal”)  Equal concentrations of solute inside and outside of membrane  Hypertonic (hyper – “over”)  Water flows out of cell – cell shrivels  Hypotonic (hypo – “under”)  Water flows into cell – cell becomes turgid/swells Solvent  The substances dissolved in water 32

33  Turgor Pressure The internal pressure of water against the cell wall As pressure increases, an equilibrium is reached The pressure forces water molecule out of the cell in equal amounts as to what is coming in by osmosis 33

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35 Facilitated Diffusion  Materials diffuse from a region of higher concentration to a region of lower concentration through special passageways  Passageways are called carrier proteins  “conveyor belts” in the direction of the concentration gradient (from high to low concentration) Active Transport – requires the cell to use energy (ATP)  The assisted movement of a substance from a lower concentration to a higher concentration  Substances move against concentration gradient 35

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