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Lecture 6.  Cell Structure and Function

1.  Objective

The objective is to introduce the structures and functions of different types of cells, including viruses, prokaryotic, and eukaryotic (plant and animal).

2.  The Nature of Cells

2.1.  Basic Cell Features

bulletsurface to volume relationship (6-1)
bulletunlimited microbial growth (6-2)

2.2.  Cell Size and Microscopy 

bulletmeasurements in microscopy (6-3)
bulletsize of bacteria compared to pin head (6-4)

3. Virus Structure

3.1. Figure of virus structure (6-5)

3.2. Figures of different viruses

bulletT4 bacteriophage (6-6)
bulletadenovirus (colds) (6-7)
bullettobacco mosaic virus (6-8)

 

4. Prokaryotic Cells (bacteria, bluegreen algae)

4.1.  Bacterial Cell Structure

bulletFigure of bacterial cell (6-9)
bulletEM of bacterial cell showing nucleoid (6-10)
bulletSporulating bacterium (6-11)
bulletFlagella of E. coli (6-12)

4.2.  Bluegreen Bacteria (algae)

bulletPhoto of Scytonemia (6-13)
bulletEM of Plectoneina (60-14)

4.3.  Specialized Structures

bulletflagella
bulletpilli
bulletspores

5.  Eucaryotic Cells (protozoa, fungi, plants, animals)

5.1.  Animal Cell

5.1.1.  Overview Figure of animal cell stucture (6-15)

5.1.2.  Organelle

bulletnucleus
bulletnucleolus - where ribosome subunits are made
bulletchromosomes (6-16)
bulletplasma membrane
bulletmitochondria
bulletlysosme (6-17)
bulletvacuoles
bulletendoplasma reticulum (smooth) (6-18)
bulletendoplasma reticulum (rough) (6-19) (particles are ribosomes)
bulletcentrioles - guide mitosis; point of synthesis of cilia and flagella
bulletGolgi apparatus (6-20) lipid assembly, polypeptide chain modification, packaging of polypeptides for transport to other various locations in cell 
bulletcilia protozoa (6-21)
bullettrachea (6-22)
bulletflagellum (6-23)(sea urchin spermatozoan)
bulletSizes of sub-cell components (6-24)
bullethydrolytic enzyme cycle (6-25)

5.1.3.  Plant Cell (6-26)

bulletplasmadesma
bulletchloroplasts
bulletcell wall
bulletleucoplasts (starch storage)

6.  Comparison of Prokaryotic and Eukaryotic Cells (6-27)

 

7.  Cell Membranes

7.1.  Diffusion (6-28)

7.2.  Osmosis

bulletu-tube osmosis (6-29)
bulletosmotic relationships in cells (6-30)

7.3.  Structure of Cell Membrane

7.3.1.  Fluid mosaic model (6-31)

7.3.2.  Phospholipid structure (6-32)

7.3.3.  Cholesterol in membrane (6-33)
bulletbinds to and immobilizes phospholipids (makes membranes less fluid and stronger)

7.4.  Available Routes Across Membranes

7.4.1.  Diffusion
bulletdo diffuse (hydrophobic molecules, e.g. oxygen, nitrogen, lipid soluble; small polar molecules,e.g. water, glycerol)
bulletdo not diffuse (ions; polar molecules, e.g. glucose, amino acids)

7.4.2.  Facilitated diffusion channel (6-34) (influenced by channels diam. and chem. environment)

7.4.3.  Cooperative ion channel (6-35) (two chemicals pass cooperatively)

7.4.4.  Gated channel (6-36) (allosteric effector opens channel, e.g cystic fibrosis is caused by a flaw in this mechanism)

7.4.5. Mobil carrier (6-37) (transmembrane carrier)

7.4.6.  Electrochemical gradient (6-38) (~70 mv)

7.4.7. . Ion pump (6-39) (pump ions out using ATP energy; inside becomes negatively charged)

7.4.8.  Complexation inside cell (6-40)

7.5.   Endocytosis and Exocytosis

7.5.1.  Phagocytosis (white blood cell) (6-41)

7.5.2.  Phagocytosis (amoeba) (6-42)

7.5.3.  Pinocytosis (engulfment of liquid, i.e. water from blood to lung) (6-43)

7.5.4.  Endocytosis (engulfment of particles, i.e transport of materials to lysosomes) (6-44)

7.5.5.  Endocytosis (of cholesterol) (6-45)

7.5.6. Exocytosis (tear fluid) (6-46)

 

8.  Critical Concepts or Questions

8.1.  How does surface/volume ratio influence cell metabolism and growth rates?  Compare the s/v ratios of a sphere, cube, and oblong cell with the same volume.

8.2.  What are the differences in the structures of viruses, prokaryotic, and eukaryotic cells?  What is the cell type of a bacterium, archean, bluegreen alga, green algae, protozoan, fungus, higher plant, and higher animal?

8.3.  You should be able to recognize and know the function of the organelle in plant and animal eukaryotic cells.  What are the basic differences in plant and animal cells?

8.4.  Briefly describe the mechanisms by which dissolved materials cross cell membranes.

8.5.  How do solid particles get through membranes?

8.6.  How do interconnecting cells interact with each other?

 

9.  Vocabulary

active transport cell wall central vacuole
centriole chloroplast chromosome
cilium concentration gradient cytoplasm
cytomembrane system cytoskeleton diffusion
endocytosis endoplasmic reticulum exocytosis
eukaryotic cell flagellum Golgi body
lipid bilayer lysosome microtubule
mitochondrion nuclear envelope nucleolus
nucleus organelle osmosis
passive transport plasma membrane ribosome
prokaryotic cell vesicle anaphase
cell cycle cell plate formation centromere
chromosome cleavage furrow cytokinesis
diploid haploid interphase
homologous chromosome meiosis metaphase
mitosis prophase telophase
reproduction sister chromatid spindle apparatus

10.  Webpage Links

Virtual Cell

DICTIONARY OF CELL BIOLOGY - SEARCH - J.A.T. Dow, Academic Press, London The Dictionary of Cell Biology was first published in 1989, and it is intended to provide quick access to easily-understood and cross-referenced definitions of terms frequently encountered in reading the modern biology literature. There are 5450 entries and 5772 cross-references.

WWW Cell Biology Course/Tutorial - M. Dalton, Univ. of Minnesota [Text and Images] Types of Cells - procaryotes, eucaryotes, plant, bacteria: Parts of the Cell - cell/plasma membrane, internal organelles/membranes (including membrane bound proteins), genetic material (including histones), cytoplasm, energetics (mitochondria and chloroplasts): Cell Division.

11. Illustration Documentation