Ch3 cell biology lecture pt b (webb) nov 2010[1]
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Transcript of Ch3 cell biology lecture pt b (webb) nov 2010[1]
Intercellular JunctionsTight junctions• close space between cells• located among cells that form linings
Desmosomes•form “spot welds” or “rivet” between cells
•Except it works more like “velcro”
•located among outer skin cells
Gap junctions• tubular channels
between cells• located in cardiac
muscle cells
These molecules are also known as Cellular Adhesion Molecules (CAMS)
Cytoskeleton•thin rods and tubules
•support cytoplasm•allows for movement of organelles
Cytoplasmic Organelles
Inclusions
•temporary nutrients and pigments
Nucleus: the control center of our cells!
Nuclear envelopeNuclear envelope•porous double membrane
•separates nucleoplasm from cytoplasm
NucleolusNucleolusdense collection of RNA and proteinssite of ribosome productionChromatinChromatin•fibers of DNA and proteins•stores information for synthesis of proteins
Cytoplasmic OrganellesEndoplasmic Endoplasmic ReticulumReticulum•connected, membrane-bound sacs, canals, and vesicles
•transport systemRough ERRough ER•studded with ribosomes
•protein synthesisSmooth ERSmooth ER•lipid synthesis•added to proteins arriving from rough ER
•break down of drugs
RibosomesRibosomes•free floating or connected to ER•provide structural support
Cytoplasmic OrganellesGolgi apparatus• stack of flattened,
membranous sacs• modifies, packages
and delivers proteins
Vesicles• membranous sacsmembranous sacs• store substances store substances
MitochondriaMitochondria• membranous sacs
with inner partitions• generate energy
Figure 3-4 Mitochondria are the power plants of the cells.
Golgi apparatus• stack of flattened,
membranous sacs• modifies, packages and
delivers proteins
Cytoplasmic OrganellesLysosomes•enzyme-containing sacs
•digest worn out cell parts or unwanted substances
Peroxisomes•enzyme-containing sacs
•break down organic molecules
Centrosome•two rod-like centrioles
•used to produce cilia and flagella
•distributes chromosomes during cell division
• Cell division is the reproduction of cells
• Apoptosis is the genetically controlled death of cells
• Mitosis is the nuclear division of somatic cells
• Meiosis produces sex cells
Cell Division
Cell Cycle• Interphase (G1, S, and G2 phases)
• Mitosis (M phase)• The splitting of one mother cell into two
identical daughter cells.• Four phases of mitosis: prophase,
metaphase, anaphase, and telophase.
• Most somatic cells spend the majority of their lives in this phase
• Interphase includes
•G0
•G1
•S
•G2
Interphase
Figure 3.27
Fig. 3-25a, Stage 1, p. 97
Fig. 3-25b, Stages 2 and 3, p. 97
Fig. 3-25b, Stage 4, p. 98