Objectives Describe the function of the cell nucleus Describe the function of the major cell organelles Describe the function of the cell wall Describe the theory of Endosymbiosis
Cytoskeleton The cytoskeleton is a network of protein filaments that help the cell maintain its shape This also is involved in movement Principle protein filaments are: Microfilaments Microtubules
Microfilaments Microfilaments: Are made of the protein actin Help the cell maintain its shape Help cells move Pseudopods are temporary projections of eukaryotic cells
Microtubules Microtubules: Important in cell division Spindle fibers are bundles of microtubules that help move the chromosomes during cell division In Animal cells centrioles located near the nucleus help in cell division
Cilia & Flagella
7 Cytoskeleton is also used as a means of mobility. This unicellular algae have extensions of flagella that are anchored in the cell membrane.
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Cilia Connection: How does cilia help with the surface area issue? What is the cilia used for here in the trachea?
Nucleus Nuclear matrix helps it maintain its shape Control center or brain of the cell Nuclear envelope surrounds the nucleus The chromatin inside the nucleus condenses prior to cell division to form chromosomes Small openings called nuclear pores allow RNA to pass from the nucleus to the cytosol
Nucleolus Where ribosomes are made Tour of an Animal Cell.mov
Plant Cells Plant cells can have three structures that animal cells do not Cell walls Vacuoles Plastids
Cell Wall All cells are surrounded by a thin, flexible membrane All cells are surrounded by a thin, flexible membrane Plant cells also have a cell wall surrounding the membrane Plant cells also have a cell wall surrounding the membrane
Plastids Some store starch or fats, others contain pigments Some store starch or fats, others contain pigments Most common type is the chloroplast Most common type is the chloroplast Surrounded by two membranes and have their own DNA Surrounded by two membranes and have their own DNA Capture energy from the sun and convert it into chemical energy… Photosynthesis Capture energy from the sun and convert it into chemical energy… Photosynthesis Tour of a Plant Cell.mov
Endosymbiosis Endosymbiosis is a hypothesis that states mitochondria and chloroplast were originally prokaryotes and that a symbiotic relationship evolved
Comparing Animal Cells to Plant Cells
19 Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria
20 Differences between plant cells and animal cells Animal cellsPlant cells Relatively smaller in size Irregular Shape No cell wall Relatively larger in size Regular shape Cell wall present
Review Describe the function of the cell nucleus The nucleus contains most of the cells DNA and with it the codes instructions for making proteins and other important molecules Describe the function of the major cell organelles Nucleolus- where the assembly of ribosomes begins
Review… Chloroplast- capture energy from the sun and convert it into chemical energy (food) Cytoskeleton- helps the cell maintain its shape and is involved in movement Vacuoles- take up space and provide storage
Review… Describe the function of the cell wall Provide support and protection for the cell Describe the theory of Endosymbiosis Endosymbiosis is a hypothesis that states mitochondria and chloroplast were originally prokaryotes and that a symbiotic relationship evolved