Plant Cells. Chapter 3

Transcription

1 Plant Cells Chapter 3

2 Major Learning Objectives Contrast prokaryotic and eukaryotic cells Describe the functions of 10 parts of a plant cell Summarize the similarities and differences between plant cells and animal cells Explain the basic structure of the fluid mosaic model of a membrane Define the processes that are important to the cell: diffusion, osmosis, facilitated diffusion, and active transport

3 LEARNING OBJECTIVE 1 Contrast prokaryotic and eukaryotic cells

4 KEY TERMS CELL THEORY Theory that the cell is the basic unit of life, of which all living things are composed, and that all cells are derived from preexisting cells

5 Methods to Study Cells

6 Light and Electron Microscopes

7 Cells Two fundamentally different types of cells: prokaryotic and eukaryotic

8 KEY TERMS EUKARYOTIC CELL A cell that posses a nucleus and other membrane-bound organelles PROKARYOTIC CELL A cell that lacks nuclei and other membrane-bound organelles (archaea and bacteria)

9 LEARNING OBJECTIVE 2 Describe the functions of the following 10 parts of a plant cell: plasma membrane, nucleus, chloroplasts, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, vacuole, cytoskeleton, and cell wall

10 Typical Plant Cell

11 KEY TERMS PLASMA MEMBRANE Living surface membrane of a cell Acts as a selective barrier to passage of materials into and out of the cell NUCLEUS A cellular organelle that contains DNA and serves as control center of the cell

12 The Nucleus

13 KEY TERMS PLASTID A group of membrane-bound organelles occurring in photosynthetic eukaryotic cells Chloroplasts, leucoplasts, and chromoplasts Chloroplasts Sites of photosynthesis

14 The Chloroplast

15 KEY TERMS MITOCHONDRION An intracellular organelle associated with cellular respiration (in which chemical energy in fuel molecules is transferred to ATP) RIBOSOME A cellular organelle; site of protein synthesis

16 The Mitochondrion

17 ORIGINAL PROKARYOTIC HOST CELL DNA Multiple invaginations of the plasma membrane Aerobic bacteria Aerobic bacteria become mitochondria Photosynthetic bacteria... become chloroplasts Endoplasmic reticulum and nuclear envelope form from the plasma membrane invaginations (This idea is not part of the hypothesis of serial endosymbiosis) EUKARYOTIC CELLS: PLANTS, SOME PROTISTS EUKARYOTIC CELLS: ANIMALS, FUNGI, SOME PROTISTS p. 52

18 KEY TERMS ENDOPLASMIC RETICULUM (ER) An organelle composed of an interconnected network of internal membranes within eukaryotic cells Site of enzymatic activity Synthesizes membranes such as nuclear envelope Rough ER is associated with ribosomes; smooth ER lacks ribosomes

19 The ER

20 KEY TERMS GOLGI BODY An organelle composed of a stack of flattened membranous sacs Modifies, packages, and sorts proteins that will be secreted or sent to the plasma membrane or other organelles

21 The Golgi Body

22 KEY TERMS VACUOLE A large, fluid-filled, membrane-bound sac within the cytoplasm that contains a solution of salts, ions, pigments, and waste materials

23 The Vacuole

24 KEY TERMS CYTOSKELETON Composed of microtubules and microfilaments Maintains the cell s shape Involved in cellular movement

25 KEY TERMS CELL WALL Comparatively rigid supporting wall exterior to the plasma membrane in plants, fungi, prokaryotes, certain protists

26 Cellulose Fibers in a Cell Wall

27 Layers of the Plant Cell Wall

28 Plasmodesmata

29 LEARNING OBJECTIVE 3 Summarize the similarities and differences between plant cells and animal cells

30 Comparing Plant and Animal Cells 1 Structures in common Plasma membrane Nucleus mitochondria Ribosomes ER Golgi apparatus Cytoskeleton

31 Comparing Plant and Animal Cells 2 Found in plant cells only Plastids Cell walls Large vacuoles Found in animal cells only Centrioles Lysosomes

32 LEARNING OBJECTIVE 4 Explain the basic structure of the fluid mosaic model of a membrane

33 KEY TERMS FLUID MOSAIC MODEL Current model for the structure of the plasma membrane and other cell membranes in which protein molecules float in a fluid phospholipid bilayer

34 Fluid Mosaic Model Explains membrane structure Each membrane is composed of a phospholipid bilayer in which varying proteins are embedded

35 Phospholipid Bilayer Nonpolar, hydrophobic fatty acid chains of phospholipids project into interior of the double-layered membrane Polar, hydrophobic heads located on two surfaces of the double-layered membrane

36 Membrane Structure

37 LEARNING OBJECTIVE 5 Define the following processes that are important to the cell: diffusion, osmosis, facilitated diffusion, and active transport

38 KEY TERMS DIFFUSION Net movement of particles (atoms, molecules, or ions) along a concentration gradient from an area of higher concentration to an area of lower concentration

39 Diffusion

40 KEY TERMS OSMOSIS Net movement of water (principle solvent in biological systems) by diffusion through a selectively permeable membrane

41 Osmotic Terminology

42 Turgor Pressure

43 Facilitated Diffusion A carrier protein helps move a material across a membrane in the direction of the concentration gradient, from high to low concentration

44 Active Transport Energy is expended to move a material against the concentration gradient, from low to high concentration

45 Diffusion, Facilitated Diffusion, and Active Transport